Carborane compound, or a salt thereof

Abstract

Disclosed is a carborane of formula I, or a salt thereof, wherein ●, ο, E, J and Q are as disclosed herein Also disclosed is a process for synthesis of the carborane of formula I, or a salt thereof, an apparatus for capturing a metal ion, a method for manufacturing the apparatus for capturing a metal ion, and a method of capturing a metal ion. The carborane of formula I, or salt thereof, can be used for capturing a metal ion.

Description

CARBORANE COMPOUND, OR A SALT THEREOFCROSS REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of and priority to U.S. Provisional Patent Application No. 63 / 551,367, filed February 8th, 2024. The contents of the U.S. Provisional Patent Application are hereby expressly incorporated herein by reference.FIELD

[0002] The specification relates to a carborane compound, or a salt thereof.BACKGROUND

[0003] Lithium is a critical element which is experiencing a skyrocketing demand due to the rapid deployment of Li-ion batteries for energy storage applications. Current lithium (Li+) ion extraction relies on Li-rich ore mining or on the lime-soda solar evaporation technique from Li-rich brines, especially from the “Lithium Triangle” centered around Chile, Bolivia, and Argentina; however, this latter process is very slow (1-2 years). Moreover, with surging demand for Li, it is expected that current production (120 kt / year) will very soon not meet projected market demands (up to 900 kt / yr by 2025). It is estimated that seawater contains about 10,000 more dissolved Li than all terrestrial and freshwater reserves. While many sorbent-based membrane technologies are being explored for the selective capture of Li from seawater or from salty brine well waters, such as in Direct Lithium Extraction (DLE), these methods typically rely on further treatment of the membranes with strong acids to remove the extracted Li. They usually require a large amount and many cost-increasing active materials, such as specific molecules and life-limited absorbents, cannot work well for seawater Li ion concentration which is very low among many concentrated salts. What is needed are improved methods of extracting lithium from lithium containing solutions.

[0004] Similar to lithium, there is also a need for extraction and separation of other metals, including rare earth elements.

[0005] PCT publication number WO 2023 / 205411 (incorporated herein by reference) discloses a selective electrochemical capture and release of lithium from seawater. The PCT publication describes compositions of matter useful in extracting Li from a lithium containing fluid, such as seawater. Further, described is a system and method capturing and releasing the lithium using the composition of matter and an electrochemical approach requiring only the application of an electrical current to control the capture and release of Li.

[0006] There is a need in the art for a compound that can be used for capture of a metal ion. In addition, there is a need in the art for a compound that can selectively bind to a metal ion. Further, there is a need in the art for a compound that can be used for capture and release of a metal ion. Moreover, there is a need in the art for an apparatus, a method of manufacturing the apparatus and a method for capturing a metal ion using the apparatus. Furthermore, there is a need in the art for a process for preparation of such a compound.

[0007] The background herein is included solely to explain the context of the disclosure. This is not to be taken as an admission that any of the material referred to was published, known, or part of the common general knowledge as of the priority date.SUMMARY

[0008] In a first aspect, the specification relates to a carborane of formula I, or salt thereof:

[0009] wherein •, o, E, J and Q are as disclosed herein.

[0010] In a second aspect, the specification relates to an apparatus for capturing a metal ion, comprising:

[0011] a circuit comprising a solid electrical conducting substrate; and

[0012] a carborane of formula I, or salt thereof:

[0013] wherein • , o, E, J and Q are as disclosed herein.

[0014] In a third aspect, the specification relates to a process for preparation of a carborane, or a salt thereof, of formula I, the process comprising:

[0015] reacting a carborane of formula II with a compound of formula III, to form the carborane, or a salt thereof, of formula I,II III I

[0016] wherein M is a metal ion, LG is a leaving group, and •, o, E, J and Q are as disclosed herein.

[0017] In a fourth aspect, the specification relates to a process for preparation of a carborane, or a salt thereof, of formula I, the process comprising:

[0018] reacting a carborane of formula IV with a compound of formula V, to form the carborane, or a salt thereof, of formula I,

[0019] wherein M is a metal ion, LG is a leaving group, and •, o, E, J and Q are as disclosed herein.

[0020] In a fifth aspect, the specification relates to a process for preparation of a carborane, or a salt thereof, of formula I, the process comprising:

[0021] reacting a carborane of formula VI with a compound of formula VII, to form the carborane, or a salt thereof, of formula I,VI VII I

[0022] wherein LG is a leaving group, and •, o, E, J and Q are as disclosed herein.

[0023] In a sixth aspect, the specification relates to a method for manufacturing of an apparatus for capturing a metal ion, the method comprising:

[0024] electrografting a linker to a solid electrical conducting substrate, and

[0025] coupling a carborane of formula I, or a salt thereof, to the linker,

[0026] wherein •, o, E, J and Q are as disclosed herein.

[0027] In a seventh aspect, the specification relates to a method of capturing a metal ion, the method comprising:

[0028] providing a carborane of formula I, or a salt thereof, wherein the carborane of formula I, or a salt thereof is in electrical communication with a solid electrically conducting substrate;

[0029] wherein •, o, E, J and Q are as disclosed herein;

[0030] applying a current to the solid electrically conducting substrate in contact with a liquid containing the metal ion, so as to change a shape and / or configuration of the carborane of formula I, or salt thereof, between a first state and a second state,

[0031] wherein at a first potential, the carborane of formula I, or a salt thereof, has a shape and / or configuration to bind to the metal ion in the liquid, and at a second potential, the carborane of formula I, or a salt thereof, has a shape and / or configuration to release the metal ion in the liquid.BRIEF DESCRIPTION OF DRAWINGS

[0032] Reference will now be made, by way of example, to the accompanying drawings which show example embodiments of the present application, and by whichthe present application can be further understood from the following description with reference to the Figures. The present application includes drawings, wherein:

[0033] Figure 1 shows a1H NMR (600 MHz) of 11 in deuterated chloroform (CDCb);

[0034] Figure 2 shows anB NMR (193 MHz) of 11 in chloroform-d (CDC );

[0035] Figure 3 shows a13C NMR (151 MHz, CD3CN of 11 in chloroform-d(CDCb);

[0036] Figure 4 shows a electrospray ionization (ESI-MS) (high resolution mass spectrometry (HRMS)) for 11;

[0037] Figure 5 shows a1H NMR (400 MHz) of 12 in chloroform-d (CDCb);

[0038] Figure 6 shows a13C NMR (151 MHz) of 12 in acetonitrile-ds (CD3CN);

[0039] Figure 7 shows a Distortionless Enhancement by Polarization Transfer(DEPT-135)13C NMR (151 MHz) of 12 in (CD3CN);

[0040] Figure 8 shows anB NMR (128 MHz) of 12 in acetonitrile-ds (CD3CN);

[0041] Figure 9 shows a ^^H COSY spectrum of 12 in acetonitrile-ds(CD3CN);

[0042] Figure 10 shows a electrospray ionization (ESI-MS) (high resolution mass spectrometry (HRMS)) for 12;

[0043] Figure 11 shows a1H NMR (400 MHz) of 11 formed from oxidation of 12 in chloroform-d (CDCb);

[0044] Figure 12 shows anB NMR (128 MHz) of 11 formed from oxidation of 12 in acetonitrile-ds (CD3CN);

[0045] Figure 13 shows a crudeXH NMR (400 MHz) of 13 in acetonitrile-ds (CD3CN);

[0046] Figure 14 shows a crudenB NMR (128 MHz) of 13 in acetonitrile-ds (CD3CN);

[0047] Figure 15 shows a crude7Li NMR (156 MHz) of 13 in acetonitrile-d3(CD3CN);

[0048] Figure 16 shows ESI-MS (high resolution mass spectrometry (HRMS)) for 13;

[0049] Figure 17 shows a crudeXH NMR (400 MHz) of 14 in acetonitrile- d3(CD3CN);

[0050] Figure 18 shows a13C NMR (151 MHz, CD3CN of 14 in chloroform-d (CDCI3);

[0051] Figure 19 shows a Distortionless Enhancement by Polarization Transfer (DEPT-135)13C NMR (151 MHz) of 14 in (CD3CN);

[0052] Figure 20 shows anB NMR (128 MHz) of 14 in crude acetonitrile-d3(CD3CN);

[0053] Figure 21 shows a electrospray ionization (ESI-MS) (high resolution mass spectrometry (HRMS)) for 14;

[0054] Figure 22 shows a crudeXH NMR (400 MHz) of 15 in acetonitrile-d3(CD3CN);

[0055] Figure 23 shows a13C NMR (151 MHz, CD3CN of 14 in chloroform-d (CDCI3);

[0056] Figure 24 shows a Distortionless Enhancement by Polarization Transfer (DEPT-135)13C NMR (151 MHz) of 14 in (CD3CN);

[0057] Figure 25 shows a crudenB NMR (128 MHz) of 15 in acetonitrile-d3(CD3CN);

[0058] Figure 26 shows a (a) crudeXH NMR (400 MHz) for reaction of 12 with a mixture of 2 equivalent each of LiPF6, NaPF6and KPF6in CD3CN; and (b)XH NMR (400 MHz) for the reaction of 12 with LiPF6, representing the selectivity towards Li- ion;

[0059] Figure 27 shows a (a) crudenB NMR (128 MHz) for reaction of 12 with a mixture of 2 equivalent each of LiPF6, NaPF6and KPF6in CD3CN, and (b)nB NMR(128 MHz) for the reaction of 12 with LiPF6, representing the selectivity towards Li- ion;

[0060] Figure 28 shows a crudeXH NMR (600 MHz) of Example 13 in CD3CN, confirming the conversion of 13 into 11;

[0061] Figure 29 shows a crudenB NMR (193 MHz) of Example 13 in CD3CN, confirming the conversion of 13 into 11;

[0062] Figure 30 shows a crude7Li NMR (233 MHz) of Example 13 in CD3CN, confirming the conversion of 13 into 11;

[0063] Figure 31 showsXH NMR for (a) the precipitate obtained from charging or capture of lithium in CD3CN, and (b) the crude from the reaction of isolated 12 with 2 eq. LiPF6. (c) the isolated crystal of 13 complex in CD3CN, showing selective lithium compound precipitation from a mixture of LiTFSI, NaTFSI and KTFSI;

[0064] Figure 32 shows thenB NMR for (a) the precipitate obtained from charging or capture of lithium in CD3CN, and (b) the isolated crystal of 13 complex in CD3CN (c) the crude from the reaction of isolated 13 with LiPF6;

[0065] Figure 33 shows the7Li NMR for the precipitate obtained from charging or capture of lithium in CD3CN;

[0066] Figure 34 shows (a) theX1B NMR for the oxidation of precipitate obtained from charging or capture of lithium in CD3CN, proving the release of lithium and regeneration of compound 11, and (b)X1B NMR of isolated compound 11 in CD3CN; and

[0067] Figure 35 shows the7Li NMR for the oxidation of precipitate obtained from charging or capture of lithium in CD3CN, proving the release of lithium and regeneration of compound 11.DESCRIPTION OF EXAMPLE EMBODIMENTS

[0068] Unless otherwise explained, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art towhich this disclosure belongs. It is also to be understood that the terminology used herein is for the purpose of describing particular aspects only, and is not intended to be limiting. In addition, although any methods and materials similar or equivalent to those described herein can be used in the practice for testing of the present invention, the typical materials and methods are described herein. Further, many patent applications, patents, and publications are referred to herein to assist in understanding the aspects described. Each of these references are incorporated herein by reference in their entirety.

[0069] When introducing elements disclosed herein, the articles “a”, “an”, “the”, and “said” are intended to mean that there may be one or more of the elements.

[0070] The term "comprising" and its derivatives, as used herein, are intended to be open ended terms that specify the presence of the stated features, elements, components, groups, integers, and / or steps, but do not exclude the presence of other unstated features, elements, components, groups, integers and / or steps. The foregoing also applies to words having similar meanings such as the terms, "including", "having" and their derivatives. It will be understood that any embodiments described as “comprising” certain components may also “consist of’ or “consist essentially of,” these components, wherein “consisting of” has a closed-ended or restrictive meaning and “consisting essentially of” means including the components specified but excluding other components except for materials present as impurities, unavoidable materials present as a result of processes used to provide the components, and components added for a purpose other than achieving the technical effects described herein.

[0071] It will be understood that any component defined herein as being included may be explicitly excluded from the claimed invention by way of proviso or negative limitation, such as any specific compounds or method steps, whether implicitly or explicitly defined herein.

[0072] In addition, all ranges given herein include the end of the ranges and also any intermediate range points, whether explicitly stated or not.

[0073] Finally, terms of degree such as "substantially", "about" and "approximately" as used herein mean a reasonable amount of deviation of the modifiedterm such that the end result is not significantly changed. These terms of degree should be construed as including a deviation of at least ±5% of the modified term if this deviation would not negate the meaning of the word it modifies.

[0074] The abbreviation, “e.g.” is derived from the Latin exempli gratia, and is used herein to indicate a non-limiting example. Thus, the abbreviation “e.g.” is synonymous with the term “for example.” The word “or” is intended to include “and” unless the context clearly indicates otherwise.

[0075] The phrase “at least one of’ is understood to be one or more. The phrase “at least one of... and...” is understood to mean at least one of the elements listed or a combination thereof, if not explicitly listed. For example, “at least one of A, B, and C” is understood to mean A alone or B alone or C alone or a combination of A and B or a combination of A and C or a combination of B and C or a combination of A, B, and C.

[0076] Redox-active carborane (Cb) crown molecules, as disclosed herein, contain a crown binding sphere that can be modulated electrochemically by switching from the close to the nido Cb states (Scheme 1). Reduction of the c / oso-Cb to the nido- Cb results in rupture of the C-C bond resulting in cage opening and an increased crown bite angle (Keener, M.; Mattejat, M.; Zheng, S.-L.; Wu, G.; Hayton, T. W.; Menard, G. Selective electrochemical capture and release of uranyl from aqueous alkali, lanthanide, and actinide mixtures using redox-switchable carboranes. Chem. Sci. 2022, 13, 3369- 3374, incorporated herein by reference). This redox-switchable binding motif allows for two possible binding pathways: (1) strong binding in the nido form, but poor binding in the closo form, or (2) the opposite, with strong binding in the closo form, but weak binding in the nido form. Further information on carborane crowns and their use in capture and release of a lithium ion is disclosed in PCT publication number WO 2023 / 205411 (incorporated herein by reference).closo form nido formScheme 1 showing the closo and nido forms of a carborane (Cb) crown molecule.

[0077] In a first aspect, the specification relates to a carborane of formula I, or salt thereof:

[0078] wherein

[0079] each • in the carborane independently is B-R1,

[0080] R1is H, a halogen, a -Ci-20-substituent optionally having one or more heteroatoms, -PR11PR12, -PR11R12R13, -SR11, -+SR11R12, -NR11R12or -+NR11R12R13;

[0081] each R11, R12or R13independently is H or -C1-10 substituent optionally having one or more heteroatoms;

[0082] each o in the carborane is C;

[0083] E is -C(=O), -C(=O)N(R2), -N(R2), -+N(R2)2, -P(R3), -+P(R3)2, -P(=O)(R3), - S-, -+S(R4)-, -S(=O), Se, -+Se(R5)- or -Se(=O);

[0084] each R2independently is H or a -C1-8 substituent optionally having one or more heteroatoms;

[0085] each R3independently is H or a -C1-8 substituent optionally having one or more heteroatoms;

[0086] R4is a -C1-8 substituent optionally having one or more heteroatoms;

[0087] R5is a -C1-8 substituent optionally having one or more heteroatoms;

[0088] J is present or absent, and when present, J is a -C1-14 substituent optionally having one or more heteroatoms; and

[0089]

[0090] each G independently is O, NR6, S or S=O, where R6is a H or a -C1-8 substituent optionally having one or more heteroatoms, and

[0091] n is an integer from 1 to 6.

[0092] The term, halogen or the like, as used herein is not particularly limited and should be known to a person of skill in the art. In one embodiment, for example and without limitation, a halogen can include, F, Cl, Br or I . Therefore, in one embodiment, for example and without limitation, the carborane of formula I, or salt thereof, the halogen is directly bonded to the boron (B) of the carborane (Cb) ring.

[0093] The term, -Ci-20-substituent or the like, as used herein is not particularly limited and should be known or understood by a person of skill in the art. The term, as used herein, refers to a group that contains carbon and hydrogen, linked generally via a carbon backbone, however, can contain heteroatoms in the backbone where the -C1-20- substituent contains a one or more heteroatoms, as disclosed herein. A -C1-20- substituent can include, for example and without limitation, alkyl, alkenyl, alkynyl, aryl, carbocyle and combinations thereof having from 1 to 20 carbon atoms, where the backbone or chain can be linear or branched. In an embodiment, for example and without limitation, R1is a substituent having from 1 to 20, 1 to 15, 1 to 12, 1 to 10, 1 to 8, 1 to 5 or 1 to 3 carbon atoms, with one or more heteroatoms.

[0094] Terms, such as, alkyl, alkenyl, alkynyl, aryl, carbocyle and the like, are not particularly limited and should be known or understood by a person of skill in the art.Alkyl can include, for example and without limitation, methyl, ethyl, n-propyl, i-propyl, n- butyl, i-butyl, sec-butyl, t-butyl, n- pentyl, i-pentyl, sec-pentyl, t-pentyl, n-hexyl, i-hexyl, 1 ,2-dimethylpropyl, 2- methylbutyl, 1 ,2-dimethylbutyl, 1-ethyl-2-methylpropyl, 1,1,2- trimethylpropyl, 1 ,1 -dimethylbutyl, 2,2-dimethylbutyl, 2-ethylbutyl, 1 ,3-dimethylbutyl, 2- methylpentyl or 3-methylpentyl, and the like.

[0095] An alkenyl substituent has a double bond present between two carbon atoms. Alkenyl can include, for example and without limitation, ethenyl, n-propenyl, isopropenyl, 1-butene, 2-butene, 2-methylprop-1-ene, 1-pentene, 2-pentene, 2-methyl- 1 -butane, 2-methyl-2-butene, 3-methyl-1 -butene, and the like.

[0096] An alkynyl substituent has a triple bond present between two carbon atoms. Alkynyl can include, for example and without limitation, ethynyl, n-propynyl, 1- butyne, 2-butyne, 1-pentyne, 2-pentyne, 3-methylbut-1-yne, and the like.

[0097] The term, carbocycle, as used herein, is not particularly limited and should be known or understood by a person of skill in the art. A carbocycle refers to a cyclic organic moiety having all carbon atoms in the ring formation. The carbocycle can be saturated or unsaturated, having one or more double or triple bonds. Carbocycle contains at least three carbon atoms that form the ring, and can include, for example and without limitation, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cyclohexenyl, and the like.

[0098] The term, aryl, as used herein, is not particularly limited and should be known or understood by a person of skill in the art. The term, aryl, generally refers to a substituent derived from an aromatic ring. Non-limiting examples of any aryl include phenyl, naphthyl, biphenylenyl, fluorenyl, phenalenyl, phenanthrenyl and the like.

[0099] As noted herein, the -Ci-20-substituent can contain one or more heteroatoms. The term, heteroatoms or the like, as used herein is not particularly limited and should be known or understood by a person of skill in the art. In general, heteroatoms refer to any atom other than carbon and hydrogen. In one embodiment, for example and without limitation, the term, heteroatom, as used herein refers to nitrogen, oxygen, halogen, P, S and Se. Hence, a -Ci-20-substituent having one or more heteroatoms, as used herein, can include, for example and without limitation, aheteroatom substituted alkyl, a heteroatom substituted alkenyl, a heteroatom substituted alkynyl, a heteroatom substituted aryl, a heteroatom substituted carbocyle and combinations thereof having from 1 to 20 carbon atoms, where the backbone or chain can be linear or branched and the heteroatom is present in the non-limiting examples noted herein. Further, non-limiting examples of a -Ci-20-substituent having one or more heteroatoms include methoxy, ethoxyethyl, pyridyl, trifluoromethyl and the like. Hence, a -Ci-20-substituent having one or more heteroatoms as used herein encompasses organic substituents having different functional groups, and where the substituent would be considered, for example and without limitation, an alcohol, an ether, a ketone, an aldehyde, an ester, an amine, an amide, a thiol and the like.

[0100] The term, -C1-10 substituent optionally having one or more heteroatoms, as used herein is not particularly limited and should be known or understood by a person of skill in the art. The term -C1-10 substituent optionally having one or more heteroatoms is similar to a -C1-20 substituent optionally having one or more heteroatoms, as used herein, but with the difference that the substituent contains from 1 to 10 carbon atoms.

[0101] The term, -C1-8 substituent optionally having one or more heteroatoms, as used herein is not particularly limited and should be known or understood by a person of skill in the art. The term -C1-8 substituent optionally having one or more heteroatoms is similar to a -C1-20 substituent optionally having one or more heteroatoms, as used herein, but with the difference that the substituent contains from 1 to 8 carbon atoms.

[0102] The term, -C1-14 substituent optionally having one or more heteroatoms, as used herein is not particularly limited and should be known or understood by a person of skill in the art. The term -C1-14 substituent optionally having one or more heteroatoms is similar to a -C1-20 substituent optionally having one or more heteroatoms, as used herein, but with the difference that the substituent contains from 1 to 14 carbon atoms.

[0103] In one embodiment, for example and without limitation, when E is

[0104] In a second embodiment, for example and without limitation, when E is - S(=O)-, J is a C2 or C3 substituent, G is O.

[0105] In a third embodiment, for example and without limitation, when E is S, N or P, J is a Ci substituent, G is other than O and NR6.

[0106] In a second aspect, the specification relates to an apparatus for capturing a metal ion, comprising:

[0107] a circuit comprising a solid electrical conducting substrate; and

[0108] a carborane of formula I, or salt thereof, coupled to and in electrical communication with the solid electrical conducting substrate,

[0109] wherein •, o, E, J and Q are as disclosed herein.

[0110] The apparatus for capturing a metal ion is not particularly limited, and can include any device having a circuit that contains a solid electrical conducting substrate to which the carborane of formula I, or salt thereof, can be coupled to and be in electrical communication with.

[0111] The term, metal, and the like, as used herein is not particularly limited and should be known to a person of skill in the art. Metals can include elements that are considered as metals, and present in the main group metals in Group 1 , 2, 13, 14, 15, transition metals, lanthanides and actinides. Non-limiting examples of metals include lithium (Li), sodium (Na), potassium (K), magnesium (Mg), scandium (Sc), titanium (Ti), Vanadium (V), aluminum (Al), cobalt (Co), nickel (Ni) and gallium (Ga), and the like. In one embodiment, for example and without limitation, the metal can be a rare-earth element. In another embodiment, for example and without limitation, the metal is lithium (Li).

[0112] The term, circuit, and the like, as used herein is not particularly limited and should be known or understood by a person of skill in the art. The circuit used herein is an electrical circuit providing a closed loop, allowing a voltage potential to be created and giving a return path for the current. The circuit contains a solid electrical conducting substrate that provides the means for the electrical circuit and flow of current.

[0113] The carborane of formula I, or salt thereof, is coupled to the solid electrical conducting substrate. The method of coupling is not particularly limited, so long as it allows for the reduction and oxidation of the carborane of formula I, or salt thereof, whereby the carborane switches between the closo and nido forms, and vice versa (Scheme 1).

[0114] In one embodiment, a linker group is used to tether the carborane of formula I, or salt thereof, to the solid electrical conducting substrate. As disclosed herein, in one embodiment (as shown in Scheme 2), the circuit can be used to achieve a reduction potential that leads to reduction of the carborane of formula I, or salt thereof. In such an embodiment, the size of the cage on the carborane of formula I, or salt thereof, and the negative charge helps in selectively capturing the metal ion (for example, lithium), while other ions are generally not captured from a solution containing a mixture of ions. Once the solution containing a mixture of ions has passed, the reduction potential can be changed to allow for oxidation of the carborane of formula I, or salt thereof, using the solid electrical conducting substrate, which can lead to a change in the size of the cage bonded to the carborane and also a change in the overall charge of the carborane of formula I, or salt thereof, leading to release of the metal ion. However, it should be noted that the opposite methodology is also possible where upon oxidation, the metal ion is captured and upon reduction, the metal ion is released.+ LiScheme 2 showing capture and release of a metal ion upon reduction and oxidation of a carborane, where L is a ligand for coordinating with the metal ion.

[0115] In a third aspect, the specification relates to a process for preparation of a carborane, or a salt thereof, of formula I, the process comprising:

[0116] reacting a carborane of formula II with a compound of formula III, to form the carborane, or a salt thereof, of formula I,

[0117] wherein M is a metal ion, LG is a leaving group, and •, o, E, J and Q are as disclosed herein.

[0118] In such an embodiment, carborane can be deprotonated to form the carborane of formula II, which can be reacted with a compound of formula III, having the leaving LG to form he compound of formula I. The compound of formula III leads to the crown moiety of the carborane of formula I.

[0119] In one embodiment, for example and without limitation, in the process disclosed as the third aspect, E is -C(=O), -C(=O)N(R2), -N(R2), -P(R3), -+P(R3)2, - P(=O)(R3), -S-, -S(=O), Se, or -Se(=O), while the other substituents are as disclosed herein. In another embodiment, for example and without limitation, reaction of the compound of formula II with the compound of formula III leads to a compound of formula I, where E is -N(R2), -P(R3), -S(=O), or -Se(=O). This is followed by a second step, for example and without limitation, reaction with another agent to alkylate or oxidize the compound to another embodiment of the compound of formula I. A first nonlimiting example of such an embodiment can include reaction of a compound of formula I where E is -N(R2), or -P(R3) with a compound of formula R2- X or R3- X (where R2and R3is an alkyl substituent and X is a leaving group), respectively, using conditions known for carrying out alkylation reactions, to form a compound of formula I where E is-+N(R2)2, or -+P(R3)2, respectively. A second non-limiting example of such an embodiment can include oxidizing a compound of formula I where E is -P(R3), -S-, or - Se-, under oxidizing conditions, to form a compound of formula I where E is - P(=O)(R3), - S(=O)- , or -Se(=O)-. Such oxidizing agents are not particularly limited, and should be known or can be determined by a person of skill in the art. In one embodiment, for example and without limitation, the oxidizing agent is meta- chloroperoxybenzoic acid (mCPBA).

[0120] A leaving group as disclosed herein is a molecular fragment or stable species that can be detached from a molecule in a bond-breaking step. The leaving group, in accordance with the specification, is not particularly limited and should be known to a person of skill in the art or can be determined. The ability of a leaving group to depart is correlated with the pKa of the conjugate acid, with lower pKa being associated with better leaving group ability. Non-limiting examples of leaving group include, halide or a sulfonate. Halides can include, for example, Cl, Br or I. Examples of sulfonates can include, without limitation, nonaflate, triflate, fluorosulfonate, tosylate, mesylate or besylate. In one embodiment, for example and without limitation, the leaving group is chloride, mesylate or tosylate. The functional groups that can be converted into leaving groups, in accordance with the specification, are not particularly limited. In one embodiment, for example the functional group can be a hydroxyl group that can be converted into a leaving group.

[0121] In a fourth aspect, the specification relates to a process for preparation of a carborane, or a salt thereof, of formula I, the process comprising:

[0122] reacting a carborane of formula IV with a compound of formula V, to form the carborane, or a salt thereof, of formula I,

[0123] wherein M is a metal ion, LG is a leaving group, and •, o, E, J and Q are as disclosed herein.

[0124] In the process disclosed above as the fourth aspect of the specification, the nucleophilic moiety is formed by the compound of formula V, while the leaving group LG is present on the carborane of formula IV.

[0125] In one embodiment, for example and without limitation, in the process disclosed as the fourth aspect, E is -C(=O), -P(R3), -P(=O)(R3), -S-, -S(=O), Se, or - Se(=O), while the other substituents are as disclosed herein. The compounds formed, where E is for example, -P(R3), can be further reacted to form another embodiment of the compound of formula I, as disclosed herein. Non-limiting examples of such an embodiment include, reaction of -P(R3) in the compound of formula I with a compound of formula R3- X, using methods known in the art, to form an embodiment of the compound of formula I, where E is -P(R3). Another non-limiting example of such an embodiment includes, oxidation of -P(R3) in the compound of formula I, using methods known in the art, to form an embodiment of the compound of formula I, where E is -P(=O)(R3).

[0126] In a fifth aspect, the specification relates to a process for preparation of a carborane, or a salt thereof, of formula I, the process comprising:

[0127] reacting a carborane of formula VI with a compound of formula VII, to form the carborane, or a salt thereof, of formula I,VI VII I

[0128] wherein LG is a leaving group, and •, o, E, J and Q are as disclosed herein.

[0129] In the process disclosed above as the fifth aspect of the specification, the nucleophilic moiety is formed by the compound of formula VI, while the leaving group LG is present on the carborane of formula VII. The exact process used to prepare the carborane of formula I will depend on the particular substituents selected as E, J and Q, and the inventors have provided different routes for synthesis depending on the particular carborane of formula I being synthesized.

[0130] In one embodiment, for example and without limitation, in the process disclosed as the fifth aspect, E is -N(R2), -P(R3), -S-, or Se, while the other substituents are as disclosed herein.

[0131] In a second embodiment, for example and without limitation, reaction of the compound of formula VI with the compound of formula VII leads to a compound of formula I, where E is -N(R2), -P(R3), -S, or -Se. This is followed by a second step, for example and without limitation, reaction with another agent to alkylate or oxidize the compound to another embodiment of the compound of formula I. A first non-limiting example of such an embodiment can include reaction of a compound of formula I where E is -N(R2), -P(R3), - S- or -Se- with a compound of formula R2- X, R3- X, R4- X, or R5- X (where, for example and without limitation, R2, R3, R4or R5is an alkyl group), respectively, using conditions known for carrying out alkylation reactions, to form a compound of formula I where E is -+N(R2)2,-+P(R3)2, -+S(R4)-, or -+Se(R5), respectively. A second non-limiting example of such an embodiment can include oxidizing a compound of formula I where E is -P(R3), -S-, or -Se-, under oxidizing conditions, to form a compound of formula I where E is -P(=O)(R3), -S(=O)-, or- Se(=O)-.

[0132] In a sixth aspect, the specification relates to a method for manufacturing of an apparatus for capturing a metal ion, the method comprising:

[0133] electrografting a linker to a solid electrical conducting substrate, and

[0134] coupling a carborane of formula I, or a salt thereof, to the linker,

[0135] wherein •, o, E, J and Q are as disclosed herein.

[0136] The term, electrografting and the like, is not particularly limited and should be known to a person of skill in the art. Electrografting refers to the electrochemical reaction that permits organic layers to be attached to solid conducting substrates, providing a real bond between the substrate and the organic compound. Electrografting applies to a variety of substrates including carbon, metals and their oxides, but also dielectrics such as polymers (Daniel Belangera and Jean Pinsonb, Chem. Soc. Rev., 2011, 40, 3995-4048, incorporated herein by reference).

[0137] The term, linker and the like, as used herein is not particularly limited and should be known or understood by a person of skill in the art. Linker refers to a moiety that can be electrografted onto the solid electrical conducting surface, and also be used for coupling to the carborane, as disclosed herein. Non-limiting examples of a linker include thiophenyl or sytenyl moiety.

[0138] The process of coupling the carborane of formula I, or a salt thereof, to the linker, is not particularly limited. In one embodiment, for example and without limitation, the boron (B) on the carborane moiety has a substituent that can react with the linker to form a bond, and be in electrical communication with the solid electrical conducting substrate. Non-limiting examples of substituents include a thiol or an allyl substituent.

[0139] In a seventh aspect, the specification relates to a method of capturing a metal ion, the method comprising:

[0140] providing a carborane of formula I, or a salt thereof, wherein the carborane of formula I, or a salt thereof is in electrical communication with a solid electrically conducting substrate;

[0141] wherein •, o, E, J and Q are as disclosed herein;

[0142] applying a current to the solid electrically conducting substrate in contact with a liquid containing the metal ion, so as to change a shape and / or configuration of the carborane of formula I, or salt thereof, between a first state and a second state,

[0143] wherein at a first potential, the carborane of formula I, or a salt thereof, has a shape and / or configuration to bind to the metal ion in the liquid, and at a second potential, the carborane of formula I, or a salt thereof, has a shape and / or configuration to release the metal ion in the liquid.

[0144] The specification also provides examples (as disclosed herein) that provide a methodology for the synthesis of the carboranes of formula I, or salt thereof, and which can be taken into consideration in combination with the disclosure of PCT publication number WO 2023 / 205411 (incorporated herein by reference). For instance, Examples 1 discloses the synthesis of 1 ,2-bis(2-bromophenoxy)ethane (1), which can be used for synthesis of a carborane of formula I, or salt thereof, as shown in Example 2, where a compound of formula (4) is synthesized.

[0145] Examples 3-5 disclose synthesis of another embodiment of the carborane of formula I, or salt thereof, which can be used for grafting of the carborane on an solid electrical conducting surface (Example 16). Such tethering methodology can be utilized with any of the compounds disclosed herein. An embodiment of a synthesis of a compound of formula I is shown in Example 6, where compound 11 is obtained by the oxidation of compound 10. Compound of formula 12 can be converted from the closo- form (compound of formula 12) to the n / cfo-form (compound of formula 13) upon reduction, as shown in Example 7, and back to the c / oso-form, as shown in Example 8. Examples 9-11 disclose the use of the compound of formula 13 for capturing lithium (Li),sodium (Na) and potassium (K), and Example 12 shows that compound of formula 13 are selective towards Li over Na and K, forming compound 13-Li (where Li is captured by the compound of formula 13). Upon oxidation of compound 13-Li, compound of formula 13 is formed, along with release of lithium ions. A general procedure for the capture and release of lithium is disclosed in Examples 14 and 15.EXAMPLES

[0146] The above disclosure generally describes the present invention. A more complete understanding can be obtained by reference to the following specific Examples. These Examples are described solely for purposes of illustration and are not intended to limit the scope of the invention. Changes in form and substitution of equivalents are contemplated as circumstances may suggest or render expedient. Without further description, it is believed that one of ordinary skill in the art can, using the preceding description and the following illustrative examples, make and utilize the constructs of the present invention and practice the claimed methods. The following working examples therefore, specifically point out the typical aspects of the present invention and are not to be construed as limiting in any way in the remainder of the disclosure. Although specific terms have been employed herein, such terms are intended in a descriptive sense and not for purposes of limitation.

[0147] EXAMPLE 1 : Synthesis of 1,2-bis(2-bromophenoxy)ethane (1)

[0148] The synthesis of this compound was completed in one step following literature procedure (Cuthbert, E. N. T.; Busico, V.; Herbert, D. E.; Budzelaar, P. H. M. Formation and Activation of Zr / Hf Bis(phenolate-ether) Precatylsts. Eur. J. Inorg. Chem. 2019, 29, 3396-3410, incorporated herein by reference). 2-Bromophenol (2.1 equivalents, 3.15 mmol, 545.0 mg) and potassium carbonate (4 equivalents, 6.0 mmol,829.3 mg) were combined in dimethylformamide (DMF) (5 mL) and stirred for 30 minutes. Ethylene di(p-toluenesulfonate) (1.0 equivalent, 1.5 mmol, 555.7 mg) was dissolved in DMF (5 mL) and this solution was added dropwise over 15 minutes. The reaction solution was stirred for 16 hours at room temperature. The reaction was subsequently quenched with distilled water (10 mL). Diethyl ether (20 mL) was added to perform a liquid-liquid extraction. The organic phase is washed two times with 10% NaOH, three times with distilled water, and once with a saturated brine solution. The diethyl ether was removed under reduced pressure with a rotary evaporator, leaving a brown-white powder (0.2892 g, 52% yield).

[0149] EXAMPLE 2: Synthesis of compound of formula (4)

[0150] The synthesis of the compound of formula (4) was completed in three steps under inert atmosphere conditions in a VAC glovebox, equipped with a cold well.

[0151] Step 1 : 1,2-bis(2-bromophenoxy)ethane (1, 1.0 equivalents, 0.081 mmol, 30.0 mg) was dissolved in toluene (2 mL) in a 5-dram vial with stirring. n-BuLi (2.1 equivalents, 2.5 M in hexanes, 0.17 mmol, 0.0681 mL) was dissolved in toluene (1 mL). Both vials were cooled to -89°C. The n-BuLi solution was added to 1 dropwise over 5 minutes. The reaction mixture was left at -89°C for one hour before being brought to room temperature to react for another two hours, becoming a pale orange solution.

[0152] Step 2: The reaction mixture from the previous step was cooled back down to -89°C. Closo-(1 ,2-PhPCI)2-1 ,2-dicarbadodecaborane (2, 1.0 equivalents, 0.081 mmol, 34.8 mg) (prepared as per Alexander, R. P.; Schroeder, H. Inorg. Chem. 1963, 2, 1107-1110, and incorporated herein by reference) was dissolved in toluene (2 mL) in a 5-dram vial and cooled to -89°C. Another 5-dram vial with toluene (1 mL) was cooled to -89°C. Each reactant solution was simultaneously added to the toluene vial dropwise over twenty minutes. The reaction mixture was stirred for 30 minutes at -89°C, then brought to room temperature to react overnight. The reaction mixture was filtered over a glass frit and washed twice with toluene. The toluene was removed under reduced pressure, leaving pale yellow crystals. The crystals were redissolved in the minimal amount of hexanes / dichloromethane (DCM) for recrystallization yielding 3 (10.1* mg, 21.6% yield).

[0153] Step 3: The product 3 (1.0 equivalent, 0.0175 mmol, 10.1 g) is redissolved in toluene (5 mL) in a 5-dram vial with stirring. meta-Chloroperoxybenzoicacid (mCPBA) (2.1 equivalents, 0.162 mmol, 28.0 mg) is dissolved in toluene (2 mL) and added to the carborane vial dropwise. The reaction mixture is left to stir overnight. The toluene is removed under reduced pressure and the resulting solid is redissolved in the minimal amount of hexanes / DCM for recrystallization (9.09 mg, 90% yield).

[0154] Example 3: Preparation of 9-I-C2B10H11

[0155] Halogenation step using modified literature procedure (Andrews, J. S.; Zayas, J.; Jones, M., 9-lodo-o-carborane. Inorganic Chemistry 1985, 24 (22), 3715- 3716, incorporated herein by reference). Under an inert atmosphere, AICI3 (1 equiv.), I2 (1 equiv.) , and o-carborane (1 equiv.) is stirred in dichloromethane, producing a dark purple color. The heterogenous solution is refluxed for 3 hours, producing a light brown solution. Cold deionized (DI) water is added dropwise and additionally washed with NaHCOs aqueous solution, dried with MgSC , and filtered. The product is a white solid. Purification: Sublimation at 90 °C.1H NMR (400 MHz, CDCI3) 5 3.88 (s, 1 H), 3.68 (s, 1 H), 3.45 - 1.37 (broad, 9H).11B{1H} NMR (128 MHz, CDCI3) 5-0.94, -7.50, -12.84, - 13.47, -14.75, -16.65.

[0156] Example 4: Preparation of 9-allyl-C2BioHn1 ) XPhos (5%), XPhos Pd G3 (5%),

[0157] Cross coupling step using modified literature procedure (Anderson, K. P.;Mills, H. A.; Mao, C.; Kirlikovali, K. O.; Axtell, J. C.; Rheingold, A. L.; Spokoyny, A. M., Improved synthesis of icosahedral carboranes containing exopolyhedral BC and CCbonds. Tetrahedron 2019, 75 (2), 187-191 , incorporated herein by reference). Under an inert atmosphere, 9-I-C2B10H9 (1 equiv.), XPhos ligand (5%), and XPhos-Pd-G3 catalyst (5%) is stirred in 1 ,4 dioxane at 0 °C for 15 minutes. Allyl magnesium chloride (3.2 equiv.) is added dropwise to the cold solution and subsequently heated to 75 °C for 4 hours. At completion, diethyl ether is added to solution and quenched with water. Organic solution is washed with water and brine, dried with MgSO4, and filtered. The product is a clear liquid after purification. Purification: Silica gel column, 100% hexanes as eluent.1H NMR (400 MHz, CDCI3) 6 5.87 - 5.64 (m, 1 H), 4.87 - 4.66 (m, 2H), 3.50 (s,1 H), 3.43 (s,1 H), 1.63 (s, 2H), 0.5-3.05 (broad, 9H).11B{1H} NMR (128 MHz, CDCI3) 6 7.75, -2.03, -8.86, - 13.72, -14.30, -15.38.

[0158] Example 5: Preparation of 9-allyl-1,2-(PPh20)2-C2BioH9

[0159] The synthesis of modified phosphine oxide carboranes was accomplished in two steps by modified literature procedures (Popescu, A.-R.; Laromaine, A.; Teixidor, F.; Sillanpaa, R.; Kivekas, R.; Llambias, J. I.; Vihas, C., Uncommon Coordination Behaviour of P(S) and P(Se) Units when Bonded to Carboranyl Clusters: Experimental and Computational Studies on the Oxidation of Carboranyl Phosphine Ligands. Chem. Eur J. 2011, 17 (16), 4429-4443; and Maaliki, C.; Canac, Y.; Lepetit, C.; Duhayon, C.; Chauvin, R., P-oxidation of gem-dicationic phosphines. RSC Advances 2013, 3 (43), 20391-20398, both incorporated herein by reference).

[0160] Step 1. Under an inert atmosphere, 2.1 equiv. of n-BuLi (2.5 M in hexanes) was added dropwise to a solution of 9-allyl-C2B H9 (1 equiv.) in dry diethyl ether at -78 °C resulting in a white precipitate. After 10 minutes, the solution was warmed to room temperature and stirred for an additional hour. After stirring, themixture was cooled back to -78 °C. Diphenylphoshine chloride (2 equiv., 6.92 mmol) was added dropwise producing a pale orange solution with a white precipitate. The mixture was warmed to room temperature and stirred for 1.5 hours. The solvent was removed in vacuo and filtered through a fritted flask with celite with dichloromethane. The residue was purified by recrystallization or column chromatography. Product is a white solid. Purification: Recrystallization from DCM / hexanes or purified using silica gel column, ~3-5% Ethtyl acetate / Hexanes.1H NMR (500 MHz, CDCI3) 5 7.87 (m, 8H), 7.53 - 7.39 (m, 12H), 5.66 (m, 1 H), 4.75 - 4.67 (m, 2H), 2.86 - 1.19 (broad, 11 H).11B{1H} NMR (160 MHz, CDCI3) 5 9.73, -0.21 , -7.00, -10.41.31P NMR (162 MHz, CDCI3) 5 7.72 - 4.49 (m).

[0161] Step 2. In air, the product from Step 1 (1 equiv.) was dissolved in DCM and stirred for 20 minutes at 0 °C. / Wefa-chloroperoxybenzoic acid (2 equiv.) was dissolved in minimal DCM and added dropwise. The reaction stirred for an additional 30 minutes at room temperature. The reaction was stopped by the addition of an aqueous solution of NaHCOs. The organic phase was washed with water and brine, dried with MgSC>4 and filtered. The solvent was removed, and the solid was purified by recrystallization or column chromatography. Product is a white solid. Purification: Silica gel column 100% hexanes to 20% EtOAc / Hexanes.1H NMR (500 MHz, CDCI3) 5 8.05- 7.99 (m, 8H), 7.57 - 7.46 (m, 12H), 5.55-5.50 (m, 1 H), 4.67 - 4.62 (m, 2H), 2.86 - 1.19 (broad, 11 H).31P NMR (162 MHz, CDCI3) 5 23.87 (d, J = 71.6 Hz).11B NMR (128 MHz, CDCI3) 5 11.57, 1.49, -7.42, -10.36.

[0162] Example 6: Synthesis of 1 ,2-(1 ,10-Disulfinyl-4,7-dioxadecane-1 ,10-diyl)- 1 ,2-dicarba-closo-dodecaborane) (11)

[0163] A solution of mCPBA in 10 mL chloroform (427 mg, 2.47 mmol) was added dropwise through a dropping funnel to a solution of 1 ,2-(1 , 10-Dithia-4,7- dioxadecane-1 ,10-diyl)-1 ,2-dicarba-closo-dodecaborane 10 (obtained as per Teixidor, F.; Vinas, C.; Rius, J.; Miravitlles, C.; Casabo, J. Inorg. Chem. 1990, 29, 149-152, incorporated herein by reference) (200 mg, 0.619 mmol) in chloroform (10 mL) at -40°C. The reaction was slowly warmed to room temperature. After stirring for 12 hours at room temperature, the mixture was washed with saturated sodium thiosulfate followed by saturated sodium bicarbonate, till the pH turned neutral. The phases were separated, and the aqueous phase was extracted by 3 x 15 mL of chloroform. The combined organic phase was dried on MgSCM, filtered and dried over rotavap to yield a colourless compound. Yield (167 mg, 76.25%). Figures 1 to 4 show the1H,11B,13C NMR spectra and ESI mass spectra of compound of formula 11 , respectively.1H NMR (600 MHz, CD3CN) 54.04 (td, J = 12.5, 2.2 Hz, 2H), 3.89 (ddd, J = 12.1 , 4.2, 2.3 Hz, 2H), 3.76 (ddd, J = 14.1, 12.8, 4.2 Hz, 2H), 3.72 - 3.67 (m, 2H), 3.51 - 3.45 (m, 2H), 2.95 (dt, J = 14.2, 2.2 Hz, 2H), 2.90 - 1.95 (m, 10H, B-H).11B NMR (193 MHz, CD3CN) 5 -3.81, -7.68 (d, J = 338.9 Hz), -13.28 (t, J = 223.8 Hz).13C NMR (151 MHz, CD3CN) 5 70.14, 64.78, 59.88. ESI-MS (HRMS): - 355.2044 (m / z)

[0164] Example 7: Synthesis of 1,2-(1,10-Disulfinyl-4,7-dioxadecane-1 ,10-diyl)- 1 ,2-dicarba-nido-dodecaborane) bis-cobaltocenium (12).

[0165] Inside an N2-filled glovebox, Coldwell maintained at liq. N2 temperature, a 20 mL scintillation vial, 11 (25 mg, 0.0704 mmol) dissolved into 5 mL toluene was allowed to freeze, on the frozen solution another 2 mL of toluene was added and allowed to freeze. In another 20 mL scintillation vial, dodecamethylcobaltocene (46.5 mg, 0.141 mmol) was weighed and dissolved into 5mL of dry toluene, the solution was added dropwise into the frozen solution of 11 and allowed the solution to freeze for 30min. followed which solution was allowed to thaw into the glovebox freezer at -35°C for overnight, Brown coloured solid lump appeared, the solution was decanted and the solid was washed multiple times with dry pentane and dried over a high vacuum. Yield ( 57mg, 80.28%). Figures 5 to 10 show the1H,11B,13C NMR spectra and ESI mass spectra of compound of formula 12.1H NMR (400 MHz, CD3CN) 5 3.99 - 3.80 (m, 4H), 3.75 - 3.62 (m, 4H), 3.33 (m, 2H), 2.77 (m, 2H), 1.72 (s, 60H), B-H protons were too broad to be observed.13C NMR (151 MHz, CD3CN) 5 94.14, 70.28, 65.65, 57.51 , 7.29.11B NMR (128 MHz, CD3CN) 5 -4.34, -18.5, -20.06, -22.94, -23.97.

[0166] Example 8: Conversion of compound of formula (12) - oxidation from nido to closo form

[0167] Inside an N2-filled glovebox, in a 20 mL scintillation vial, compound 12 (10 mg, 0.0098 mmol) was dissolved into 0.5 mL acetonitrile-ds. On the solution, solid Ferrocenium hexafluorophosphate (6.5 mg, 0.0197mmol) was added, resulting in yellow solution turning into green and the solution was allowed to be stirred for 1 hour at the room temperature. The solution was transferred into the NMR tube for further NMR probe. 100 % conversion of compound 12 (nido) to 11 (c / oso) on a1H and11B NMR scale was found, as shown in Figures 11 and 12.

[0168] Example 9: Reaction of compound of formula (12) with LiPFe for the formation of compound of formula (13)

[0169] Inside an N2-filled glovebox, Coldwell maintained at liq. N2 temperature, a20 mL scintillation vial, 12 (10 mg, 0.0098 mmol) was dissolved into 0.5 mL acetonitrile- ds, which was allowed to freeze. On the frozen solution, solid LiPFe (3 mg,0.0197mmol) was added, and the solution was allowed to thaw to room temperature and stirred for another 2 hours at the same temperature. The solution was transferred into the NMR tube for further NMR probe. 100 % conversion on a1H NMR scale was found. Figures 13 to 16 show the1H,11B,7Li NMR spectra and ESI mass spectra of compound of formula 13.1H NMR (400 MHz, CD3CN) 5 4.15 - 4.04 (m, 4H), 3.79 (m, 2H), 3.69 (m, 2H), 3.34 - 3.25 (m, 2H), 3.13 - 3.05 (m, 2H).7Li NMR (156 MHz, CD3CN) 5 -1.72.11B NMR (128 MHz, CD3CN) 5 -7.49, -9.17, -13.69, -19.84, -25.01 , - 29.4.19F NMR (376 MHz, CD3CN) 5 - 72.9 (d, J= 705.2Hz).31P NMR (162 MHz, CD3CN) 5 146.5 (sept, J = 705.2Hz).

[0170] Procedure for single crystal isolation 13:- The single crystal of compound 13 was isolated by performing a single pot reaction in CD3CN(1mL) of 12 ( 15mg, 0.0422mmol) and 2 eq. of LiPFe (13mg, 0.0845mmol) at liq. N2 temperature. Further 2eq. of (28mg, 0.0845mmol) decamethylcobaltocene was added, and the solution was thawed to room temperature. The resulting yellow solution was filtered through celite, and filtrate was kept at room temperature for slow evaporation. After 24H a white precipitate appeared. The solution was once again filtered through celite and kept at room temperature for slow evaporation, resulting in white needle-shaped crystals over 48 hours.

[0171] Example 10: Reaction of compound of formula (12) with NaPFe for the formation of compound of formula (14)

[0172] Inside an N2-filled glovebox, Coldwell maintained at liq. N2 temperature, a20 mL scintillation vial, 12 (10 mg, 0.0098 mmol) dissolved into 0.5 mL acetonitrile-d3and was allowed to freeze. On the frozen solution solid, NaPFe (3.3 mg, 0.0197mmol) was added, and the solution was allowed to thaw to room temperature and stirred for another 2 hours at the same temperature. The solution was transferred into the NMR tube for further NMR probe. 100 % conversion on a1H NMR scale was found. Figures 17 to 21 show the1H,13C,11B NMR spectra and ESI mass spectra of compound of formula 14.1H NMR (400 MHz, CD3CN) 5 4.13 (m, 2H), 4.06 (m, 2H), 3.79 (m, 2H), 3.67 (m, 2H), 3.33 (m 2H), 3.02 (m, 2H).11B NMR (128 MHz, CD3CN) 5 -7.12, -9.81 , - 11.02, -13.7, -19.87, -22.7, -26.08.19F NMR (376 MHz, CD3CN) 5 - 72.9 (d, J= 705.2Hz, 6F).31P NMR (162 MHz, CD3CN) 5 146.5 (sept, J = 705.2Hz).

[0173] Example 11 : Reaction of compound of formula (12) with KPFe for the formation of compound of formula (15)

[0174] Inside an N2-filled glovebox, Coldwell maintained at liq. N2 temperature, a 20 mL scintillation vial, 12 (10 mg, 0.0098. mmol) dissolved into 0.5 mL acetonitrile-d3and was allowed to freeze. On the frozen solution, solid KPFe (3.7 mg, 0.0197 mmol) was added, and the solution was allowed to thaw to room temperature and stirred for another 2 hours at the same temperature. The solution was transferred into the NMR tube for further NMR probe. 100 % conversion on a1H NMR scale was found. Figures 22 to 25 show the1H,13C, and11B NMR spectra of compound of formula 15 (proposed structure disclosed).1H NMR (400 MHz, CD3CN) 5 4.02 - 3.85 (m, 4H), 3.67 (S, 4H), 3.28 (m, 2H), 2.92 (dt, J = 13.5, , 2H).11B NMR (128 MHz, CD3CN) 5 -4.06, -9.73, - 13.71 , -18.18, 19.96, -22.92, -24.22.19F NMR (376 MHz, CD3CN) 5 - 72.9 (d, J= 705.2Hz, 6F).31P NMR (162 MHz, CD3CN) 5 146.5 (sept, J = 705.2Hz,).

[0175] Example 12: Reaction of 12 with a mixture of 2 equivalent each of LiPFe,NaPFe and KPFe

[0176] Inside an N2-filled glovebox, Coldwell maintained at liq. N2 temperature, a20 mL scintillation vial, 12 (10 mg, 0.0098 mmol) dissolved into 0.5 mL acetonitrile-ds and was allowed to freeze. On the frozen solution solid, mixture of LiPFe (3 mg, 0.0197 mmol), NaPFe (3.3 mg, 0.0197 mmol) and KPFe (3.7 mg, 0.0197 mmol) was added, and the solution was allowed to thaw to room temperature and stirred for another 2 hours at the same temperature. The solution was transferred into the NMR tube for further NMR probe. 100 % conversion on a1H NMR scale was found; the resultant1H and11B NMR matches well for the1H and11B NMR obtained for the independent reaction between 12 and LiPFe, confirming the selectivity of 12 towards Li-ion (see Figures 26 and 27).1H NMR (400 MHz, CD3CN) 5 4.15 - 4.04 (m, 4H), 3.79 (m, 2H), 3.69 (m, 2H), 3.34 - 3.25 (m, 2H), 3.13 - 3.05 (m, 2H).7Li NMR (156 MHz, CD3CN) 5 -1.72.11B NMR (128 MHz,CD3CN) 5 -7.49, -9.17, -13.69, -19.84, -25.01 , -29.4.19F NMR (376 MHz, CD3CN) 5 - 72.9 (d, J= 705.2Hz).31P NMR (162 MHz, CD3CN) 5 146.5 (sept, J = 705.2Hz,).

[0177] Example 13: Reaction of 13 with ferrocenium hexafluorophosphate (nido to closo oxidation)

[0178] Inside an N2-filled glovebox, in a 20 mL scintillation vial, in-situ generated 13 (from 10 mg, 0.0098 mmol of 12 and 3mg, 0.0197mmol of LiPFe) dissolved into 0.5 mL Acetonitrile-ds, on the solution solid Ferrocenium hexafluorophosphate (6.5 mg, 0.0197 mmol) was added, resulting in yellow solution turning into green and the solution was allowed to be stirred for 1 hour at the room temperature. The solution was transferred into the NMR tube for further NMR probe. 100 % conversion of 13 to 11 (c / oso) on a1H NMR scale was found (Figures 28 - 30).

[0179] Example 14: General procedure for lithium separation(Capture)

[0180] In the working compartment of the H-cell equipped with medium pore glass-frit, 22.5mg (0.0633mmol) of 11 and 178mg (0.62mmol, 10eq.) of LiTFSI (TFSI= bis(trifluoromethanesulfonyl)imide)), 188mg (0.62mmol, 10eq.) of NaTFSI and 198mg (0.62mmol, 10eq.) of KTFSI was dissolved in 7mL of dry acetonitrile. In the counter compartment, 300 mg of ketjenblack, 178mg of LiTFSI, 188mg of NaTFSI, and 198mg of KTFSI was dissolved in 7mL of dry acetonitrile. 2.5mA current was applied for 1H 15min to achieve 90% SOC. The solution from the working compartment from two parallel such reactions was transferred into a 20 mL scintillation vial and the solvent volume was reduced to approximately 2mL (white precipitate started appearing) another 5 mL of Diethyl ether was added into it and the solution was filtered through filtration frit, and the collected solid was dried and collected (35mg),1H,11B and ICP-MS wasperformed on collected solid. The1H,11B and7Li NMR shows selective lithium compound precipitation (Figures 31 - 33).

[0181] Example 15: General Procedure for lithium release

[0182] In the working compartment of the H-cell equipped with medium pore glass-frit, 32 mg (0.04345mmol) of 13 precipitate obtained from lithium capture and 62 mg (0.217 mmol, 5 eq.) of LiTFSI dissolved in 7mL of dry acetonitrile. In the counter compartment, 300 mg of ketjenblack, and 62mg of LiTFSI, were dissolved in 7mL of dry acetonitrile to obtain a white turbid solution. 1.164 mA current was applied for 1H 45min to achieve approximately 15% SOC. The white turbid solution became clear, and an aliquot of the solution was transferred into an NMR tube equipped with CDCh filled capillary.11B,7Li NMR (Figures 34 and 35, respectively) and ICP-MS were performed on a collected solution.

[0183] Example 16: Synthesis for grafting carboranes onto carbon surfaces

[0184] Step 1 : Diazonium Electrografting of 4-thiolbenzene (Zhang, Y.;Tamijani, A. A.; Taylor, M. E.; Zhi, B.; Haynes, C. L.; Mason, S. E.; Hamers, R. J., Molecular Surface Functionalization of Carbon Materials via Radical-Induced Grafting of Terminal Alkenes. J. Am. Chem. Soc. 2019, 141 (20), 8277-8288, and Debela, A. M.;Ortiz, M.; Beni, V.; O'Sullivan, C. K., Facile Electrochemical Hydrogenation and Chlorination of Glassy Carbon to Produce Highly Reactive and Uniform Surfaces for Stable Anchoring of Thiolated Molecules. Chem. Eur. J. 2014, 20 (25), 7646-7654, both incorporated herein by reference).

[0185] Thiol diazonium cation is made in situ, by stirring 4-thiolbenzene (1 equiv., 0.05mmol) and NaNC (1 equiv., 0.05mmol) in 10mL of sparged 0.5M HCI. The solution is stirred for 15 minutes at 0 °C and the color changes from light orange to yellow. The electrografting on 4cm2carbon fiber is carried out by applying a constant potential of - 0.7 V for 10 minutes. After electrografting, the carbon fiber electrode is rinsed with deionized (DI) water, sonicated for 15 seconds, and rinsed again with isopropyl alcohol.

[0186] Step 2: Functionalization of Electrodes with redox-switchable carboranes (Zhang, L.; Vila, N.; Klein, T.; Kohring, G.-W.; Mazurenko, I.; Walcarius, A.; Etienne, M., Immobilization of Cysteine-Tagged Proteins on Electrode Surfaces by Thiol-Ene Click Chemistry. ACS Appl. Mater. Interfaces 2016, 8 (27), 17591-17598, and Gautier, C.; Lopez, I.; Breton, T., A post-functionalization toolbox for diazonium (electro)-grafted surfaces: review of the coupling methods. Materials Advances 2021, 2 (9), 2773-2810, both incorporated herein by reference).

[0187] The diazonium grafted electrode is immersed in a methanol solution with 9-allyl-(Ph2PO)2-o-carborane (5mM) and tris(2-carboxyethyl)phosphine (TCEP) (5mM) as a catalyst. Electrode is immersed in the stirred solution for 3 days. It is subsequently sonicated and rinsed with DI water, methanol, and tetrahydrofuran (THF).

[0188] All publications, patents and patent applications cited herein incorporated by reference in their entirety to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated by reference in its entirety.

[0189] Although preferred embodiments of the invention have been described herein in detail, it will be understood by those skilled in the art that variations may be made thereto without departing from the spirit of the invention or the scope of the appended claims.

[0190] References:

[0191] Heinrich, S.; Benhaim, H.; Mattejat, M.; Pan, D.; DiMarco, S.; Wu, G.; Menard, G. Inorg. Chem. 2023, 62, 15076-15083.

[0192] Andrews, J. S.; Zayas, J.; Jones, M., Jr. Inorg. Chem. 1985, 24, 3715- 3716.

[0193] Li, J.; Logan, C. F.; Jones, M., Jr. Inorg. Chem. 1991 , 30, 4866-4868.

[0194] Anufriev, S. A.; Sivaev, I. B.; Bregadze, V. I. Russ. Chem. Bull. 2015, 64, 712-717.

[0195] Stibr, B.; Tok, O. L.; Holub, J. Inorg. Chem. 2017, 56, 8334-8340.

[0196] Rudakov, D. A.; Kurman, P. V.; Potkin, V. I. Russ. J. Gen. Chem. 2011 ,81, 1137-1142.

[0197] Herzog, A.; Maderna, A.; Harakas, G. N.; Knobler, C. B.; Hawthorne, M. F. Chem. Eur. J. 1999, 5, 1212-1217.

[0198] Anufriev, S. A.; Sivaev, I. B.; Bregadze, V. I. Russ. Chem. Bull. 2015, 64, 712-717.

[0199] Anderson, K. P.; Mills, H. A.; Mao, C.; Kirlikovali, K. O.; Axtell, J. C.; Rheingold, A. L.; Spokoyny, A. M. Tetrahedron 2019, 75, 187-191.

[0200] Puga, A. V.; Teixidor, F.; Sillanpaa, R.; Kivekas, R.; Area, M.; Barbera, G.; Vinas, C. Chem. Eur. J. 2009, 15, 9755-9763.

[0201] Mills, H. A.; Jones, C. G.; Anderson, K. P.; Ready, A. D.; Djurovich, P. I.; Khan, S. I.; Hohman, J. N.; Nelson, H. M.; Spokoyny, A. M. Chem. Mater. 2022, 34, 6933-6943.

[0202] Zhang, X.; Tang, X.; Yang, J.; Li, Y.; Yan, H.; Bregadze, V. I. Organometallics 2013, 32, 2014-2018.

[0203] Kataki-Anastasakou, A.; Axtell, J. C.; Hernandez, S.; Dziedzic, R. M.; Balaich, G. J.; Rheingold, A. L.; Spokoyny, A. M.; Sletten, E. M. J. Am. Chem. Soc. 2020, 142, 20513-20518.

[0204] Li, J.; Pang, R.; Li, Z.; Lai, G.; Xiao, X.-Q.; Muller, T. Angew. Chem. Int. Ed. 2019, 58, 1397-1401.

[0205] Schulz, J.; Kreienbrink, A.; Coburger, P.; Schwarze, B.; Grell, T.; Lbnnecke, P.; Hey-Hawkins, E. Chem. Eur. J. 2018, 24, 6208-6216.

[0206] Balema, V. P.; Pink, M.; Sieler, J.; Hey-Hawkins, E.; Hennig, L. Polyhedron 1998, 17, 2087-2093.

[0207] Heinrich, S.; Benhaim, H.; Mattejat, M.; Pan, D.; DiMarco, S.; Wu, G.;Menard, G. Inorg. Chem. 2023, 62, 15076-15083.

[0208] Smith, H. D., Jr.; Obenland, C. O.; Papetti, S. Inorg. Chem. 1966, 5, 1013- 1015.

[0209] Stogniy, M. Y.; Timofeev, S. V.; Sivaev, I. B.; Bregadze, V. I. Carborane- based Thioethers and Complexes Thereof in Handbook of Boron Science, p 21-96.Teixidor, F.; Vinas, C.; Rius, J.; Miravitlles, C.; Casabo, J. Inorg. Chem. 1990, 29, 149- 152.

Claims

WE CLAIM:1 . A carborane of formula I, or salt thereof:wherein each • in the carborane independently is B-R1,R1is H, a halogen, a -Ci-20-substituent optionally having one or more heteroatoms, -PR11PR12, -PR11R12R13, -SR11, -+SR11R12, -NR11R12or -+NR11R12R13; each R11, R12or R13independently is H or -C1-10 substituent optionally having one or more heteroatoms; each o in the carborane is C;E is -C(=O), -C(=O)N(R2), -N(R2), -+N(R2)2, -P(R3), -+P(R3)2, -P(=O)(R3), -S-, -+S(R4)-, -S(=O), Se, -+Se(R5)- or -Se(=O); each R2independently is H or a -C1-8 substituent optionally having one or more heteroatoms; each R3independently is H or a -C1-8 substituent optionally having one or more heteroatoms;R4is a -C1-8 substituent optionally having one or more heteroatoms;R5is a -C1-8 substituent optionally having one or more heteroatoms;J is present or absent, and when present, J is a -C1-14 substituent optionally having one or more heteroatoms; andeach G independently is O, NR6, S or S=O, where R6is a H or a -C1-8 substituent optionally having one or more heteroatoms, and n is from 1 to 6.

2. The carborane of formula I, or a salt thereof, as claimed in claim 1 , whereinE is -N(R2), -P(=O)(R3) or -S(=O).

3. The carborane of formula I, or a salt thereof, as claimed in claim 1 or 2, whereinR3is phenyl.

4. The carborane of formula I, or a salt thereof, as claimed in any one of claims 1 to 3, wherein J is -C(=O).

5. The carborane of formula I, or a salt thereof, as claimed in any one of claims 1 to3, wherein R1is -SR11.

6. An apparatus for capturing a metal ion, comprising: a circuit comprising a solid electrical conducting substrate; a carborane, or salt thereof, of Formula I coupled to the solid electrical conducting substrate,wherein each • in the carborane independently is B-R1,R1is H, a halogen, a -Ci-20-substituent optionally having one or more heteroatoms, -PR11PR12, -PR11R12R13, -SR11, -+SR11R12, -NR11R12or -+NR11R12R13; each R11or R12independently is H or -C1-10 substituent optionally having one or more heteroatoms; each o in the carborane is C;E is -C(=O), -C(=O)N(R2), -N(R2), -+N(R2)2, -P(R3), -+P(R3)2, -P(=O)(R3), -S-, -+S(R4)-, -S(=O), Se, -+Se(R5)- or -Se(=O); each R2independently is H or a -C1-8 substituent optionally having one or more heteroatoms; each R3independently is H or a -C1-8 substituent optionally having one or more heteroatoms;R4is a -C1-8 substituent optionally having one or more heteroatoms;R5is a -Ci-8 substituent optionally having one or more heteroatoms;J is present or absent, and when present, J is a -C1-14 substituent optionally having one or more heteroatoms; andeach G independently is O, NR6, S or S=O, where R6is a H or a -C1-8 substituent optionally having one or more heteroatoms, and n is from 1 to 6.

7. The apparatus of claim 6, wherein the carborane, or salt thereof, of formula I is electrically coupled to the solid electrical conducting substrate permitting reduction or oxidation of the carborane of formula I, or salt thereof.

8. The apparatus of claim 6 or 7, wherein9. The apparatus of any one of claims 6 to 8, whereinE is -N(R2), -P(=O)(R3) or -S(=O).

10. The apparatus of any one of claims 6 to 9, whereinR3is phenyl.

11. The apparatus of any one of claims 6 to 10, wherein J is -C(=O).

12. The apparatus of any one of claims 6 to 11 , wherein R1is -SR11.

13. The apparatus of any one of claims 6 to 12, wherein the metal ion is lithium.

14. A process for preparation of a carborane, or a salt thereof, of formula I, the process comprising: reacting a carborane of formula II with a compound of formula III, to form the carborane, or a salt thereof, of formula I,LG is a leaving group; each • in the carborane independently is B-R1,R1is H, a halogen, a -Ci-20-substituent optionally having one or more heteroatoms, -PR11, -+PR11R12, -SR11, -+SR11R12, -NR11or -+NR11R12; each R11or R12independently is H or -C1-10 substituent optionally having one or more heteroatoms; each o in the carborane is C;E is -C(=O), -C(=O)N(R2), -N(R2), -P(R3), -+P(R3)2, -P(=O)(R3), -S-, -S(=O), Se, or -Se(=O); each R2independently is H or a -C1-8 substituent optionally having one or more heteroatoms; each R3independently is H or a -C1-8 substituent optionally having one or more heteroatoms;R4is a -Ci-8 substituent optionally having one or more heteroatoms;R5is a -Ci-8 substituent optionally having one or more heteroatoms;J is present or absent, and when present, J is a -C1-14 substituent optionally having one or more heteroatoms; andeach G independently is O, NR6, S or S=O, where R6is a H or a -C1-8 substituent optionally having one or more heteroatoms, andn is from 1 to 6.

15. A process for synthesis a carborane, or a salt thereof, of formula I, the process comprising: reacting a carborane of formula IV with a compound of formula V, to form the carborane, or a salt thereof, of formula I,IV V I whereinM is a metal ion; LG is a leaving group; each • in the carborane independently is B-R1,R1is H, a halogen, a -Ci-20-substituent optionally having one or more heteroatoms, -PR11, -+PR11R12, -SR11, -+SR11R12, -NR11or -+NR11R12; each R11or R12independently is H or -C1-10 substituent optionally having one or more heteroatoms; each o in the carborane is C;E is -C(=O), -P(R3), -P(=O)(R3), -S-, -S(=O), Se, or -Se(=O); each R2independently is H or a -C1-8 substituent optionally having one or more heteroatoms;each R3independently is H or a -C1-8 substituent optionally having one or more heteroatoms;R4is a -C1-8 substituent optionally having one or more heteroatoms;R5is a -C1-8 substituent optionally having one or more heteroatoms; J is present or absent, and when present, J is a -C1-14 substituent optionally having one or more heteroatoms; andeach G independently is O, NR6, S or S=O, where R6is a H or a -C1-8 substituent optionally having one or more heteroatoms, and n is from 1 to 6.

16. A process for synthesis a carborane, or a salt thereof, of formula I, the process comprising: reacting a carborane of formula VI with a compound of formula VII, to form the carborane, or a salt thereof, of formula I,LG is a leaving group; each • in the carborane independently is B-R1,R1is H, a halogen, a -Ci-20-substituent optionally having one or more heteroatoms, -PR11, -+PR11R12, -SR11, -+SR11R12, -NR11or -+NR11R12; each R11or R12independently is H or -C1-10 substituent optionally having one or more heteroatoms; each o in the carborane is C;E is -N(R2), -P(R3), -S-, or Se; each R2independently is H or a -C1-8 substituent optionally having one or more heteroatoms; each R3independently is H or a -C1-8 substituent optionally having one or more heteroatoms;R4is a -C1-8 substituent optionally having one or more heteroatoms;R5is a -C1-8 substituent optionally having one or more heteroatoms;J is present or absent, and when present, J is a -C1-14 substituent optionally having one or more heteroatoms; andeach G independently is O, NR6, S or S=O, where R6is a H or a -C1-8 substituent optionally having one or more heteroatoms, and n is from 1 to 6.

17. The process of claim 14 or 15, wherein M is lithium.

18. The process of any one of claims 14 to 17, wherein LG is Cl, Br, I, tosylate (OTs) or mesylate (OMs).

19. A method for manufacturing of an apparatus for capturing a metal ion, the method comprising: electrografting a linker to a solid electrical conducting substrate, and coupling a carborane of formula I, or a salt thereof, to the linker,wherein each • in the carborane independently is B-R1,R1is H, a halogen, a -Ci-20-substituent optionally having one or more heteroatoms, -PR11, -+PR11R12, -SR11, -+SR11R12, -NR11or -+NR11R12, wherein at least one of R1is other than H or halogen; each R11or R12independently is H or -C1-10 substituent optionally having one or more heteroatoms; each o in the carborane is C;E is -N(R2), -+N(R2)2, -P(R3), -+P(R3)2, -P(=O)(R3), -S-, -+S(R4)-, -S(=0), Se, -+Se(R5)- or -Se(=O); each R2independently is H or a -C1-8 substituent optionally having one or more heteroatoms; each R3independently is H or a -C1-8 substituent optionally having one or more heteroatoms;R4is a -C1-8 substituent optionally having one or more heteroatoms;R5is a -C1-8 substituent optionally having one or more heteroatoms;J is present or absent, and when present, J is a -C1-14 substituent optionally having one or more heteroatoms; andeach G independently is O, NR6, S or S=O, where R6is a H or a -C1-8 substituent optionally having one or more heteroatoms, and n is from 1 to 6.

20. The method of claim 19, wherein R1and the linker have formula21. The method of claim 19 or 20, whereinE is -N(R2), -P(=O)(R3) or -S(=O).

22. The method of any one of claims 19 to 21, wherein R3is phenyl.

23. The method of any one of claims 19 to 22, wherein J is -C(=O).

24. The method of any one of claims 19 to 23, wherein the metal ion is lithium.

25. A method of capturing a metal ion, the method comprising: providing a carborane of formula I, or a salt thereof, wherein the carborane of formula I, or a salt thereof is in electrical communication with a solid electrically conducting substrate;wherein each • in the carborane independently is B-R1,R1is H, a halogen, a -Ci-20-substituent optionally having one or more heteroatoms, -PR11, -+PR11R12, -SR11, -+SR11R12, -NR11or -+NR11R12, wherein at least one of R1is other than H or halogen; each R11or R12independently is H or -C1-10 substituent optionally having one or more heteroatoms; each o in the carborane is C;E is -N(R2), -+N(R2)2, -P(R3), -+P(R3)2, -P(=O)(R3), -S-, -+S(R4)-, -S(=O), Se, -+Se(R5)- or -Se(=O); each R2independently is H or a -C1-8 substituent optionally having one or more heteroatoms; each R3independently is H or a -C1-8 substituent optionally having one or more heteroatoms;R4is a -C1-8 substituent optionally having one or more heteroatoms;R5is a -C1-8 substituent optionally having one or more heteroatoms;J is present or absent, and when present, J is a -C1-14 substituent optionally having one or more heteroatoms; andeach G independently is O, NR6, S or S=O, where R6is a H or a -C1-8 substituent optionally having one or more heteroatoms, and n is from 1 to 6;applying a current to the solid electrically conducting substrate in contact with a liquid containing the metal ion, so as to change a shape and / or configuration of the carborane of formula I, or salt thereof, between a first state and a second state, wherein at a first potential, the carborane of formula I, or a salt thereof, has a shape and / or configuration to bind to the metal ion in the liquid, and at a second potential, the carborane of formula I, or a salt thereof, has a shape and / or configuration to release the metal ion in the liquid.

26. The method of claim 25, wherein E is -N(R2), -P(=O)(R3) or -S(=O).

27. The method of claim 25 or 26, whereinR3is phenyl.

28. The method of any one of claims 25 to 27, wherein J is -C(=O).

29. The method of any one of claims 25 to 28, wherein the metal ion is lithium.