Rare earth metal coordination complexes for binding phosphate ions

Abstract

A coordination complex (120) for detecting phosphate ions (140) can have the following general structure: In this structure, A can be a linear or branched alkyl group, L can include a linkage group that includes at least one non-carbon atom, R can be an organic group that includes at least two carbon atoms, and M can be a rare earth metal. In one example, the coordination complex can be included in a phosphate sensor (100). The coordination complex can bind to phosphate ions in a sample material.

Description

[0001] RARE EARTH METAL COORDINATION COMPLEXES FOR BINDING PHOSPHATE IONS

[0002] CROSS REFERENCE TO RELATED APPLICATIONS

[0003] This application claims priority to U.S. Provisional Application No. 63 / 764,110, filed February 27, 2025, which is hereby incorporated herein by reference.

[0004] STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[0005] This invention was made with government support under 2317823 awarded by the National Science Foundation. The government has certain rights in the invention.

[0006] BACKGROUND

[0007] Phosphorus is involved in a wide variety of biological processes and industrial applications. In biological processes, phosphorus is a nutrient that contributes to plant growth, genetic material, energy transfer, health of bones and teeth in animals, among other uses. Because phosphorus promotes plant growth, phosphorus is used industrially to make fertilizers for agricultural use. Although phosphorus is often beneficial in these applications, high levels of phosphorus pollution released into the environment can cause negative effects. For example, since phosphorus is a nutrient promoting plant growth, phosphorus pollution in bodies of water can cause rapid growth of algae, which may cover the surface of the bodies of water and block sunlight from reaching aquatic plants. This can also cause low dissolved oxygen levels in the water, which can harm fish. Some algae can also produce toxins, making such algal blooms dangerous for humans and animals. Phosphorus pollution is often in the form of phosphate ions that can be introduced into bodies of water or groundwater by runoff from lawns, gardens, storm drains, fertilizers used in agriculture, animal waste, wastewater from industrial processes such as paper making, and other sources.

[0008] Waste water treatment plants are required by law to monitor the concentration of phosphate in treated water. Many industrial processes and agricultural companies are also required to monitor phosphate levels in their waste. However, the methods for measuring phosphate concentration currently in use can be cumbersome. Typically, measuring phosphate concentration involves collecting a sample, storing the sample, processing thesample by extraction and / or enrichment of the sample, analyzing the sample using colorimetric analysis or laboratory-based spectrophotometric, fluorescent, or chromatographic methods. These methods involve significant labor by skilled analysts, and these methods do not allow for continuous monitoring of phosphate levels.

[0009] SUMMARY

[0010] This invention relates to coordination complexes made up of a metal atom coordinated to a ligand, where the coordination complex can selectively bind to phosphate ions. In one example, a coordination complex can have the following general chemical structure:

[0011]

[0012] where A is a linear or branched alkyl group, where L comprises a linkage group comprising at least one non-carbon atom, where R is an organic group comprising at least two carbon atoms, and where M is a rare earth metal. In some examples, the rare earth metal atom M can be Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Y, La, Ce, Pr, Nd, Sm, or a combination thereof. In a particular example, M can be Eu. The A group can include -CH2-, -(CH2)2-, -(CH2)s-, -(CH2)4-, -(CH2)S-, or a combination thereof. The L group can include -O-, -S-, -C(=O)O-, -C(=O)S-, -C(=O)NH-, -NH-, or a combination thereof. In certain examples, the R group can include a polycyclic group. The polycyclic group can be at least partially aromatic in some examples. In other examples, the R group can include a linear or branched alkyl group. The R group can include from 2 to 17 carbon atoms in some cases. Generally, suitable R groups can be electrically conductive. In some examples, the R group can include an electrically conductive group in some cases. Some example chemical structures that can be used as the R group include:

[0013]

[0014] 5 and combinations thereof.

[0015] In some particular examples, the coordination complex can have a chemical structure selected from the group consisting of:

[0016]

[0017]

[0018] and combinations thereof.

[0019] The present technology also includes sensors that can include the coordination complex described above. In one example, a phosphate sensor can include a phosphate-binding coordination complex configured to contact a sample material, wherein the coordination complex has a general chemical structure:

[0020]

[0021] where A is a linear or branched alkyl group, where L comprises a linkage group comprising at least one non-carbon atom, where R is an organic group comprising at least two carbon atoms, and where M is a rare earth metal. In some examples, the sensor can include a sensing surface and the coordination complex can be on the sensing surface. The coordinationcomplex can be coated on the sensing surface, or covalently linked to the sensing surface, or at least partially embedded in the sensing surface, or a combination thereof.

[0022] In certain examples, the coordination complex can be deposited on the sensing surface by physical vapor deposition, spin-coating, drop-casting, dip-coating, slot-die coating, doctor blading, bar coating, ink-jet printing, roll-to-roll coating, or a combination thereof.

[0023] In further examples, the sensing surface can include an electrically conductive or semi-conductive polymer. The coordination complex can be blended with the polymer, or copolymerized in the polymer, or coated on the polymer, or a combination thereof. In certain examples, the sensor can include a field effect transistor and the sensing surface can be in a channel of the field effect transistor. The sample material can include water, blood, soil, or a combination thereof in some cases. In certain examples, the sample material can include groundwater, seawater, wastewater, agricultural wastewater, radioactive wastewater, or a combination thereof.

[0024] The present technology also includes methods of measuring phosphate levels. One example method of measuring phosphate levels in a sample material can include contacting the sample material with a phosphate-binding coordination complex to bind phosphate ions from the sample material to the coordination complex; and measuring an amount of the phosphate ions bound to the coordination complex. The coordination complex can have a general chemical structure:

[0025]

[0026] where A is a linear or branched alkyl group, where L comprises a linkage group comprising at least one non-carbon atom, where R is an organic group comprising at least two carbonatoms, and where M is a rare earth metal. In some examples, measuring the amount of the phosphate ions bound to the coordination complex can be accomplished by measuring luminescence of the coordination complex. In other examples, the coordination complex can be in a channel of a field effect transistor, and measuring the amount of the phosphate ions bound to the coordination complex is accomplished by measuring a change in conductivity of the channel. In certain examples, the sample material can include water, blood, soil, or a combination thereof. In further examples, the sample material can include groundwater, seawater, wastewater, agricultural wastewater, radioactive wastewater, or a combination thereof.

[0027] The present technology also includes methods of separating phosphate from a sample. In one example, a method of separating phosphate from a liquid can include contacting the liquid with a phosphate-binding coordination complex to bind phosphate ions from the liquid to the coordination complex, wherein the coordination complex has a general chemical structure:

[0028]

[0029] where A is a linear or branched alkyl group, where L comprises a linkage group comprising at least one non-carbon atom, where R is an organic group comprising at least two carbon atoms, and where M is a rare earth metal. In some examples, the liquid can include blood, water, groundwater, seawater, wastewater, agricultural wastewater, radioactive wastewater, or a combination thereof. The method can also include debinding the phosphate from the coordination complex and collecting the phosphate for disposal or use as a product.

[0030] There has thus been outlined, rather broadly, the more important features of the invention so that the detailed description thereof that follows may be better understood, andso that the present contribution to the art may be better appreciated. Other features of the present invention will become clearer from the following detailed description of the invention, taken with the accompanying drawings and claims, or may be learned by the practice of the invention.

[0031] BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic cross-sectional view of an example phosphate sensor in accordance with an example of the present technology.

[0032] FIG. 2 is a schematic cross-sectional view of another example phosphate sensor in accordance with an example of the present technology.

[0033] FIG. 3 is a schematic view of an example fluorescence sensor for detecting phosphate in accordance with an example of the present technology.

[0034] FIG. 4 is a schematic view of an example membrane for separating phosphate from a liquid in accordance with an example of the present technology.

[0035] FIG. 5 is a reaction scheme for production of Eu-Lys-HOPO-Oleyl complex in accordance with another example. In this case reaction conditions in each stage were as follows: (a) HATU, NEt3, CH2CI2, rt, 6 h; (b) TFA, CH2CI2, 0 °C, 1 h; [CH3(CH2)7]4N+BR-, K2CO3, H2O / CH2CI2, rt, 6 h; (c) HCl / AcOH; (d) Oleic acid, HATU, DIPEA, N,N’ DMF; (e) LnCh 6H2O, Pyridine, H2O / CH3OH, 50 °C, 6 h.

[0036] FIG. 6 is a schematic showing amphiphilic coordination complexes as phosphate receptors to transport phosphate across a lipid bilayer membrane in accordance with an example.

[0037] These drawings are provided to illustrate various aspects of the invention and are not intended to be limiting of the scope in terms of dimensions, materials, configurations, arrangements or proportions unless otherwise limited by the claims.

[0038] DETAILED DESCRIPTION

[0039] While these exemplary embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, it should be understood that other embodiments may be realized and that various changes to the invention may be made without departing from the spirit and scope of the present invention. Thus, the following more detaileddescription of the embodiments of the present invention is not intended to limit the scope of the invention, as claimed, but is presented for purposes of illustration only and not limitation to describe the features and characteristics of the present invention, to set forth the best mode of operation of the invention, and to sufficiently enable one skilled in the art to practice the invention. Accordingly, the scope of the present invention is to be defined solely by the appended claims.

[0040] Definitions

[0041] In describing and claiming the present invention, the following terminology will be used.

[0042] The singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a metal” includes reference to one or more of such materials and reference to “the sensor” refers to one or more of such devices.

[0043] As used herein with respect to an identified property or circumstance, “substantially” refers to a degree of deviation that is sufficiently small so as to not measurably detract from the identified property or circumstance. The exact degree of deviation allowable may in some cases depend on the specific context.

[0044] As used herein, the term “about” is used to provide flexibility and imprecision associated with a given term, metric or value. The degree of flexibility for a particular variable can be readily determined by one skilled in the art. However, unless otherwise enunciated, the term “about” generally connotes flexibility of less than 2%, and most often less than 1%, and in some cases less than 0.01%.

[0045] As used herein, a plurality of items, structural elements, compositional elements, and / or materials may be presented in a common list for convenience. However, these lists should be construed as though each member of the list is individually identified as a separate and unique member. Thus, no individual member of such list should be construed as a de facto equivalent of any other member of the same list solely based on their presentation in a common group without indications to the contrary.

[0046] As used herein, the term “at least one of’ is intended to be synonymous with “one or more of.” For example, “at least one of A, B and C” explicitly includes only A, only B, only C, or combinations of each.Numerical data may be presented herein in a range format. Tt is to be understood that such range format is used merely for convenience and brevity and should be interpreted flexibly to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited. For example, a numerical range of about 1 to about 4.5 should be interpreted to include not only the explicitly recited limits of 1 to about 4.5, but also to include individual numerals such as 2, 3, 4, and subranges such as 1 to 3, 2 to 4, etc. The same principle applies to ranges reciting only one numerical value, such as “less than about 4.5,” which should be interpreted to include all of the above-recited values and ranges. Further, such an interpretation should apply regardless of the breadth of the range or the characteristic being described.

[0047] Any steps recited in any method or process claims may be executed in any order and are not limited to the order presented in the claims. Means-plus-function or step-plus-function limitations will only be employed where for a specific claim limitation all of the following conditions are present in that limitation: a) “means for” or “step for” is expressly recited; and b) a corresponding function is expressly recited. The structure, material or acts that support the means-plus function are expressly recited in the description herein. Accordingly, the scope of the invention should be determined solely by the appended claims and their legal equivalents, rather than by the descriptions and examples given herein. Example Embodiments

[0048] The technology described herein includes coordination complexes made up of a central metal atom coordinated to a multidentate ligand. These coordination complexes can selectively bind to phosphate ions. The coordination complexes can have a general chemical structure as shown below:

[0049]

[0050] where A is a linear or branched alkyl group, L comprises a linkage group comprising at least one non-carbon atom, R is an organic group comprising at least two carbon atoms, and M is a rare earth metal. In this chemical structure, the dashed lines represent coordinate bonds between the rare earth metal atom and oxygen atoms of the ligand.

[0051] The coordination complexes can be capable of binding anions. In particular, one or more anions can bind to the rare earth metal atom in the coordination complex. In certain examples, the coordination complex can selectively bind phosphate anions. This can make the coordination complex useful in sensors for detecting phosphate, and also in processes for capturing, retaining, transporting, releasing, regenerating, or otherwise separating phosphate from other substances.

[0052] In certain examples, europium (Eu) can be used as the central metal atom in the coordination complex. The high charge density of Eu3+can contribute to a strong binding affinity toward PCh3' ions. According to the hard and soft acids and bases (HSAB) theory, the hard Lewis acidic nature of Eu3+can make it preferentially bind with hard Lewis bases such as phosphate (PO43) ions due to the high negative charge density on the oxygen atoms, making phosphate a good match for Eu3+in terms of binding affinity. The multiple oxygen atoms of phosphate act as donors to form coordination bonds with Eu3+. This allows for strong chelation and stable coordination complexes to form between europium and phosphate, increasing the overall binding affinity.

[0053] The coordination complex can be used as a receptor to bind phosphate ions, and incorporated into a sensorthat allows detecting of the bound phosphate ions. Various sensor designs can utilize these receptors. In some examples, the receptor can be included in a field effect transistor sensor, such as an organic field effect transistor (OFET). The receptors canbe deposited in a conductive channel of the OFET, and the conductivity of the channel can change in response to the present of phosphate ions bound to the receptors. The conductive channel can also include a conductive or semi-conductive polymer film in some examples. The polymer film can be formed using various solution-processing methods and the receptors can be blended with the polymer or deposited on the polymer film to form a bilayer. The conductive channel can be formed between two or more colinear electrodes and in proximity to one or more gate electrodes. These sensors can detect phosphate present in low concentrations, in some cases as low as millimolar concentrations or less.

[0054] Other sensor designs can utilize fluorescent effects of phosphate binding to the coordination complex. The fluorescent response of the coordination complex can change when one or more phosphate ions bind to the central rare earth metal atom, and the change in fluorescent response can be measured to detect the present of the phosphate ions.

[0055] The sensors described herein can be used for detection of anions in real-world samples including medical, environmental, agricultural, industrial, etc. Some particular types of samples can include blood, soil, water, groundwater, seawater, wastewater, agricultural wastewater, radioactive wastewater, and others. In addition to sensing phosphate ions in these sample materials, the coordination complexes can be used to separate the phosphate ions from these materials. For example, the coordination complex can be used to bind to phosphate ions to remove the phosphate ions from the sample material. The phosphate can then be debinded from the coordination complex and collected. The collected phosphate can be disposed of or used as a valuable product.

[0056] The coordination complexes can have a variety of chemical structures, which can generally be described by the following general chemical structure:

[0057]

[0058] In this structure, a central rare earth metal atom (M) is bonded by coordinate bonds to a multidentate ligand. In particular, the ligand includes three l-hydroxy-pyridin-2-one (1,2-HOPO) moi eties. Each of these moieties includes two oxygen atoms that can bond coordinately with the central rare earth metal atom. In some examples, the central rare earth metal atom can be capable of forming additional coordinate bonds. In certain examples, the central rare earth metal atom can be capable of forming one, two, or three additional coordinate bonds. When the coordination complex is exposed to water, in some cases the rare earth metal atom can form additional coordinate bonds with oxygen atoms in water molecules surrounding the coordination complex. When phosphate ions are present in the water, in some examples the phosphate ions can replace one, two, or three water molecules bonded to the rare earth metal atom.

[0059] Examples of rare earth metal atoms that can be used in the coordination complex include europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), yttrium (Y), lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), or a combination thereof. Each individual molecule of the coordination complex can include a single rare earth metal atom. Therefore, a “combination thereof’ can refer to a collection of multiple molecules where some of the molecules can have different rare earth metal atoms, and not to a single molecule that includes a combination of multiple rare earth metal atoms. The rare earth metal atom can be europium in certain examples. Additionally, in some examples the rare earth metal atom can be in an oxidation state of +3. In certain examples, the rare earth metal atom can be Eu(III). In other specific examples, the rare earth metal atom can be Gd(III), Tb(III), Dy(III), Ho(III), Er(III), Tm(III), Yb(III), Lu(III), Y(III), La(III), Ce(III), Pr(III), Nd(III), Sm(III), or a combination thereof.

[0060] As shown in the chemical structure above, the multi-dentate ligand used in the coordination complex can include a group labelled R-L-A-.This group can have several useful effects on the performance of the coordination complex. In some examples, the R-L-A- group can help to increase selectivity of the coordination complex to bind with phosphate or other anions. In further examples, the R-L-A- group can modulate solubility of the coordination complex. This group can also make the coordination complex more compatible with polymers that can be used in sensors. In certain examples, an OFET sensor can includea conductive or semi conductive polymer in a channel. The coordination complex can be blended into the polymer or coated on the polymer. The R-L-A- group can help reduce or prevent leaching of the coordination complex out of such sensors in some examples. The R-L-A- group may include a functional group that maintains the coordination complex in a blend with or in a coating on the polymer surface. In certain examples, the R-L-A group can include a polymerizable moiety that can be copolymerized with the polymer or linked to the polymer. In further examples, the R-L-A- group can include a covalent attachment group that covalently bonds to the sensor surface. The R-L-A- group can also include electrically conductive groups that can provide a desired electric conductivity in the sensor channel.

[0061] In more detail, the R-L-A- group can be divided into smaller subgroups, including the R- group, the -L- group, and the -A- group. The A group can be a linear or branched alkyl chain. In some examples, the -A- group can include from 1 to 20 carbon atoms, or from 1 to 10 carbon atoms, or from 1 to 5 carbon atoms. In certain examples, the -A- group can be a linear alkyl group with 1 to 5 carbon atoms. In particular examples, the -A- group can include -CH2-, -(CH2)2-, -(CH2)3-, -(CH2)4-, -(CH2)5-, -(CH2)6-, -(CH2)7-, -(CH2)8-, -(CH2)9-, -(CH2)IO-, or a combination thereof. In further examples, the -A- group can include one of the following:

[0062]

[0063] or combinations thereof. In these structures, the represents locations where the -A- group can be bonded to the -L- group or to the remainder of the coordinating ligand.The -L- group can include a linkage that includes at least one non-carbon atom. Some example linkages can include amine linkages, amide linkages, ether linkages, ester linkages, thioether linkages, thioester linkages, and others. In certain examples, the -L- group can include -O-, -S-, -S(=O)-, -C=(O)-, -C(=O)O-, -C(=O)S-, -C(=O)NH-, -NH-, NR- (R=alkyl or cycloalkyl), -C6H5-O- , -C6H5-S-, or a combination thereof.

[0064] A variety of organic groups can be used as the R- group. In some examples, the R-group can be selected to provide the effects described above, such as modulating solubility, blending with polymers, reducing leaching, modulating electrical conductivity, providing covalent attachment to a surface, providing copolymerization with a polymer, and others. In certain examples, the R- group can modulate the solubility of the coordination complex in water. The R- group can include one or more ionic functional groups, alcohol groups, or combinations thereof in order to make the coordination complex more soluble in water. Alternatively, the R- group can include large organic functional groups such as linear or branched alkyl groups or cyclic or polycyclic organic groups in order to make the coordination complex less soluble in water. In certain examples, the R- group can include an electrically conductive group. Some example electrically conductive groups can include nitroxide, pyrrole, thiophene, carbazole, indazole, polyacetylene, sulfonic acid, and combinations thereof. In other examples, the R- group can include a cyclic or polycyclic group. The cyclic or polycyclic group can be partially or fully aromatic in some examples. In other examples, the R- group can include an aliphatic group. In some examples, the R-group can include a cyclohexyl group, a cyclopentyl group, or a combination thereof. For example, the R- group can include a linear or branched alkyl group. In certain examples, the R- group can include from 2 to 20 carbon atoms, or from 2 to 18 carbon atoms, or from 2 to 17 carbon atoms, or from 6 to 20 carbon atoms, or from 12 to 20 carbon atoms. Some specific example R- groups can include the following:

[0065]

[0066]

[0067]

[0068]

[0069] and combinations thereof. In these structures, the represents an attachment location where the R- group is attached to the -L- group.

[0070] As mentioned above, in some examples, the coordination complex can be coupled to a polymer by co-polymerizing, cross-linking, blending, or coating. A variety of polymers can be used. In some examples, the polymer can be an electrically conductive or semiconductive polymer such as polyaniline (PANI), polyacetylene (PA), polypyrrole (PPy), polythiophene (PTh), poly(3,4-ethylenedioxythiophene) (PEDOT), poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS), poly(3 -alkylthiophene), poly(phenylene vinylene) (PPV), or combinations thereof. In some examples, the polymer can be physically blended with the coordination complex, such that the coordination complex is not covalently bonded to the polymer. In other examples, the coordination complex can include a polymerizable or cross-linkable functional group that can covalently bond to the polymer. The bonding of the coordination complex to the polymer can occur during polymerization of the polymer and / or during cross-linking of the polymer. Thus, any of the polymers described above can be modified by including covalent bonds to the coordination complex either as a part of a main polymer chain or cross-linked to a polymer chain. In various examples, a polymerizable or cross-linkable function group can be present in the R-, -L-, or -A- groups described above. Some example polymerizable or cross-linkable functional groups can include amine, aminophenyl, aminobenzyl, vinyl, alkynyl, nitrile, epoxide, carboxylic acid, alcohol, isocyanate, aldehyde, thiol, and combinations thereof. In some examples, the coordination complex can include at least two polymerizable functional groups, which can allow the coordination complex to polymerize with other monomers to form the polymer, wherein thecoordination complex is covalently bonded as a part of the polymer chain. In other examples, the coordination complex can include a single polymerizable functional group, and the coordination complex can covalently bond to a polymer chain and terminate the chain. In further examples, the coordination complex can include at least one cross-linkable functional group that can covalently bond to a polymer chain after the polymer chain has already been formed.

[0071] The coordination complex described above can be used in sensors for detecting and measuring phosphate. FIG. 1 shows one example phosphate sensor 100 that is configured as an OFET. This sensor includes a sensing surface 110 and molecules of a coordination complex 120 as described herein coated on the sensing surface. In this figure, the coordination complex is represented as a central europium atom 122 (as one example of the rare earth metal atoms that can be used) surrounded by a ligand 124, which is simplified in this figure instead of showing the entire chemical structure of the ligand. The sensing surface is made of a semi-conductive polymer layer 112. This polymer layer is deposited over a dielectric layer 114 and a gate electrode 116. A source electrode 130 and a drain electrode 132 are formed on the sensor surface, and the coordination complex is in the channel between the source electrode and the drain electrode. The sensor surface can be exposed to a sample material such as waste water. When phosphate 140 is present in the sample material, the phosphate ions can bind to the europium atoms. This can change the conductivity of the channel, which can be detected using the OFET.

[0072] In various examples, the coordination complex can be coated on the sensing surface, or covalently linked to the sensing surface, or at least partially embedded in the sensing surface. FIG. 2 shows another example phosphate sensor 200 that includes a sensing surface 210 made up of a polymer 212 having the coordination complex 220 embedded in the polymer. At least a portion of the coordination complex molecules can be exposed at the polymer surface, allowing these coordination complexes to bind to phosphate ions. As in the previous example, this sensor also includes a dielectric layer 214 beneath the polymer layer and a gate electrode 216 beneath the dielectric layer. A source electrode 230 and a drain electrode 232 are formed on the sensor surface.

[0073] In various examples, the coordination complex can include a polymerizable group or cross-linkable group that allows the coordination complex to be copolymerized with a semi-conductive or conductive polymer on the sensing surface. In other examples, the coordination complex can be blended into the polymer without being copolymerized with the polymer. In still other examples, the sensing surface can be formed from the polymer first, and then the coordination complex can be coated onto the polymer surface. Some example methods of coating the coordination complex on the sensing surface can include physical vapor deposition, spin-coating, drop-casting, dip-coating, slot-die coating, doctor blading, bar coating, ink-jet printing, roll-to-roll coating, or a combination thereof.

[0074] The sensor can be designed for measuring phosphate levels in a variety of different sample materials. In some examples, the sensor can be configured to measure phosphate levels in water. The sensor can be submerged in water, such as a body of water (i.e., a lake, pond, river, wetland, ocean, etc.) or water in a wastewater treatment plant, a wastewater stream from an industrial process, a wastewater stream from an agricultural process, groundwater, well water, or other water. In other examples, the sensor can be configured to measure phosphate levels in samples of water extracted from a body of water, such as water pumped to the sensor from a body of water or well or other water source. The sensor can also be configured as a soil sensor. The soil sensor can be inserted into soil so that the soil contacts the sensing surface.

[0075] In certain examples, the sensor can be configured to measure phosphate levels in biological fluid, such as blood. In one example, the sensor can be an implantable sensor that can measure phosphate in blood within a blood vessel. In some examples, the implantable sensor can include a filament that is inserted under the skin, similar to the filaments used in continuous glucose monitors. In further examples, the implantable sensor can be inserted into a vein or artery using a needle, catheter, or combination thereof. Such sensors can include an OFET that incorporate the coordination complex as in the examples described above. The sensing surface of the OFET can be positioned to contact the blood or other biological fluid.

[0076] The sensors can be configured to provide continuous measurement of phosphate levels. This can be useful to have continuous data of phosphate concentrations in a body of water, or a waste water stream, or blood in a blood vessel, etc. Other potential applications can include, but are not limited to, quantifying phosphate levels in water sources such as wastewater, surface water, municipal water, irrigation water, etc.The coordination complex described herein can also be used to detect phosphate through fluorescent response. When phosphate ions bind to the coordination complex, the fluorescence response of the coordination complex can change. In one example, the coordination complex can be mixed with a sample liquid, such as water, in which the phosphate is to be detected. An illumination source can then be used to excite the coordination complex molecules, and a light detector can be used to measure light emitted by the coordination complex molecules. The spectrum of light measured with the light detector can be compared to a spectrum measured when the coordination complex is excited in the absence of phosphate. Differences between the spectra can indicate the presence of phosphate in the sample liquid.

[0077] FIG. 3 shows a schematic view of an example fluorescence sensor 300. A sample fluid 310 can be brought into contact with a coordination complex 320. In various examples, the coordination complex can be coated on a sensing surface, embedded in a polymer, or mixed with the sample fluid. Phosphate ions 340 in the sample fluid can bind to the coordination complex. As explained above, the fluorescence spectrum of the coordination complex can be different when a phosphate ion is bound to the coordination complex compared to when the coordination complex is free of phosphate ions. This sensor also includes a light source 350 that emits light to excite the coordination complex. In some examples, the light source can include an ultraviolet light, a visible light, a predetermined combination of wavelengths, or another type of light source. The coordination complex then re-emits light by its fluorescent response. The light re-emitted by the coordination complex is received by a light sensor 360. In some examples, the light sensor can be configured to measure the intensity of the re-emitted light, or the wavelength of the re-emitted light, or a combination thereof. In some examples, the light sensor can include a spectrometer configured to measure a spectrum of the re-emitted light.

[0078] In additional to detecting and measuring phosphate levels, the coordination complex can also be used to separate phosphate from water or other liquids. Phosphate ions in the liquid can bind to the coordination complex and thus be removed from the liquid. The phosphate ions can subsequently be debinded from the coordination complex and discarded or used as a product. The coordination complex can then be reused to separate more phosphate ions. In some examples, the coordination complex can be immobilized on asurface and then contacted with the liquid to separate phosphate ions from the liquid. For example, the coordination complex can be immobilized on a membrane, a fdter, or another solid with high surface area for contacting the liquid. In various examples, such systems can be used to separate phosphate from blood, water, groundwater, seawater, wastewater, agricultural wastewater, radioactive wastewater, or a combination thereof.

[0079] FIG. 4 shows one example membrane 400 that can be used for separation of phosphate ions from a liquid. The membrane is made up of polymer fibers 410 that include coordination complexes 420 as described herein. The coordination complex can be coated on the surfaces of the polymer fibers or embedded in the polymer fibers using any of the methods described above. In some examples, the coordination complex can be copolymerized or crosslinked in the polymer used to form the fibers, or the coordination complex can be blended with the polymer, or the coordination complex can be coated on the surface of the polymer fibers with or without covalent bonding between the coordination complex and the polymer fibers. In some examples, a liquid can pass through the membrane and phosphate ions in the liquid can be bound to the coordination complexes, thus separating the phosphate from the liquid. If the coordination complexes in the membrane become saturated with phosphate ions, then the membrane can be replaced with another fresh membrane, or the membrane can be regenerated by removing the phosphate ions from the coordination complexes.

[0080] In various examples, a separator for separating phosphate ions from a liquid can include the coordination complex coated on or embedded in a woven membrane, an electrospun membrane, a sintered membrane, any other type of porous membrane. In further examples, the coordination complex can be coated on or embedded in a high-surface-area particulate material such as activated carbon, charcoal, ceramic particles, zeolites, silica gel, random packing material for a packed bed, structured packing material for a packed bed, or other high-surface-area particulate materials. The separator can have a variety of designs or form factors, such as a membrane, a dialysis membrane, a tubular membrane, a fdter, a packed bed, a fluidized bed, or others. In some examples, the separator can be used to remove phosphate from water, groundwater, seawater, wastewater, agricultural wastewater, radioactive wastewater, blood, other biological fluids, or other liquids. In certain examples,the phosphate can be debinded from the coordination complexes in the separator and then collected for disposal or for use as a product.

[0081] Generally, these coordination complexes can be used to capture, retain, transport, release, or otherwise separate phosphates from other materials. As an example, the coordination complexes can be exposed to phosphates so as to capture the phosphates. The phosphate bound complexes can then be used to retain or transport the phosphate. For example, coordination complexes (e.g. Euni-Lys-HOPO-Oleyl or other amphiphilic complexes as described herein) can be used for selectively transporting phosphate over other relevant anions across lipid bilayers by leveraging transverse diffusion mechanisms.

[0082] In some cases, the coordination complexes can be attached or immobilized onto solid surfaces as a support substrate. Immobilization can occur through covalent bonding, ionic bonding, van der Waals attraction, mechanical adherence, or any other suitable securing technique. Non-limiting examples of suitable support substrates can include carbonaceous substrates (e.g. graphene, carbon black, etc), metal or metal-oxide substrates (e.g. Au, Pt, Pd, Ti, Al, ITO, FTO, alumina, silica, titania, zirconia, ceria, etc, including anodized versions of these such as anodized aluminum), polymeric substrates (polystyrene, polyacrylate, polyamide, PTFE, PVDF, nylon, polypropylene, polyethylene, cellulose, polysulfone, polyimide, PDMS, polyurethane, etc), porous membranes, particulate sorbents, or combinations thereof. These substrates can be in the form of nanotubes (e.g. SWCNT, MWCNT, etc), nanoparticles, films, porous membranes (e.g. selectively permeable membranes), fabrics, foams, aerogels, hydrogels, packed bed media, zeolites, MOFs, clay, biochar, and the like.

[0083] In the case of sensors, the support substrate can be a conductive material such that sensor current and / or capacitance can be monitored over time and changes in current can be correlated to binding with phosphate. Generally, these coordination complexes immobilized on a support substrate can also be used for simultaneous separation and / or transportation, as well as sensors (i.e. detection and separation). In some cases, the support substrate can include nanopores into which the coordination complex can be immobilized. Such materials can be particularly suitable for both separation and sensing.

[0084] Examples

[0085] Example 1A Eu-Lys-HOPO-Oleyl complex was formed according to the reaction scheme outlined in FIG. 5 and below. Cbz deprotection (i.e. hydrogenolysis) was performed by providing a solution of the Cbz-protected, Boc-protected polyamine scaffold (1.0 equiv) in MeOH. This solution was treated with Pd / C (10 wt %). The reaction vessel was purged with H2 and stirred under H2, 4 atm pressure at room temperature until complete consumption of the starting material. The mixture was filtered through a Celite pad, rinsing with MeOH, and the filtrate was concentrated under reduced pressure to afford the corresponding amine, which was used directly in the next step.

[0086] Amide coupling was used to install the Oleyl chain (HATU / DIPEA). The crude amine, Lys (Boc)3 (1.0 equiv) and Oleic acid (1.1 equiv) were dissolved in anhydrous DMF and cooled to 0 °C. HATU (1.2 equiv) was added, followed by DIPEA (3 equiv). The mixture was warmed to room temperature and stirred until completion. The reaction was diluted with water and extracted with CH2CI2 (or EtOAc). The combined organic layers were washed (brine), and dried over Na2SO4, filtered, and concentrated. The residue was purified by flash chromatography to afford the Lys-(Boc)3 -Oleyl.

[0087] Installation of HOPO(Bn) groups was then accomplished by dissolving the Lys(BOC)s-Oleyl in trifluoroacetic acid (TFA, 10 mL) and CH2CI2 (10 mL). The reaction mixture was stirred for 2 h at 0 °C. The dried TFA salt was then dissolved in milli-Q water (10 mL). Separately, HOPO(Bn)-OSu (3 eq) was dissolved in acetonitrile (10 mL) and added to the reaction mixture, followed by excess K2CO3. The reaction mixture was stirred for 12 h at room temperature. The organic layer was collected, washed with 10% citric acid (1 X 10 mL), 10% NaHCCL (aq; 3 X 10 mL), dried over anhydrous MgSCL (s), and concentrated under reduced pressure. The crude product was purified by over silica column chromatography, eluting with 5% methanol / 95% CH2CI2 to yield Lys-HOPO-(OBn)-Oleyl as a white solid.

[0088] Debenzylation (HCl / AcOH) was performed by treating the Lys-HOPO-(OBn)-Oleyl with HC1 in AcOH (HCI / CH3COOH) and stirred until complete removal of benzyl protecting groups. Solvents were removed under reduced pressure, and the crude Lys-HOPO-Oleyl ligand was purified by reverse-phase column chromatography to yield the deprotected ligand.

[0089] The Eu(III) complexation by dissolving the deprotected HOPO ligand in 1:1 Me0H:H20. EuCh 6H2O (1.0 equiv) was added to it in the presence of pyridine, which wasstirred at 80 °C overnight. The reaction mixture was cooled down to room temperature. The suspension was filtered, rinsed with methanol, and collected. The solid was further dried in a vacuum oven, yielding the final Eu(III) complex as a beige powder. The resulting complex was then conjugated to a solid-support.

[0090] Example 2

[0091] Both Eu-Lys-HOPO-Oleyl and Lnni-Lys-HOPO-Oleyl complexes were formed as in Example 1. Since these complexes are amphiphilic receptors which include both hydrophilic and hydrophobic properties, they can be used to enable transport of phosphate across a lipid bilayer membrane as shown in FIG. 6. Phosphate participates in physiological functions where cellular homeostasis is maintained by sodium-dependent phosphate cotransporters (SLC20A1 and SLC20A2) and XPR1 which regulates phosphate export. Disruptions in these transport systems result in conditions like rickets, tumoral calcinosis, vascular calcification, advanced chronic kidney disease, and bone abnormalities. Therefore, coordination complexes such as those described throughout this specification, can be used with targeted phosphate transport to treat such malfunctions.

[0092] The affinity of compound Eu-Lys-HOPO-Oleyl for inorganic phosphate (Pi) was confirmed by monitoring changes in the emission intensity of the europium center using time-gated luminescence spectroscopy. The selectivity of compound Eu-Lys-HOPO-Oleyl for Pi over various environmentally relevant anions CT, Br, F', SOL", NOs', NO2-, HCOa’, ClOF, B(OH)s, CH2CO2-, and P2O?4"at pH 7.4 was determined. With the exception of P2O?4' , the luminescence intensity of Eu-Lys-HOPO-Oleyl remains unchanged in the presence of these competing anions (white bars). Additionally, these anions do not affect Pi coordination. While Eu-Lys-HOPO-Oleyl was not selective against pyrophosphate, it can effectively bind polyphosphates for resource recovery applications. Notably, this selectivity for Pi remains intact despite the receptor's hydrophobic tail functionalization.

[0093] Pi transport was also evaluated by monitoring the luminescence response of a hydrophilic Pi-binding europium probe EuChBn encapsulated in l,2-dioleyl-sn-glycero-3-phosphocholine (DOPC) lipids self-assembled into large unilamellar vesicles (LUV, 0.3mM DOPC, ~ 200 nm diameter) at pH 7.4. This probe has demonstrated high affinity and selectivity for Pi in water. Moreover, EuChBn sensitizes Pi at an excitation wavelength of 317 nm, which too closely overlaps with that of Eu-Lys-HOPO-Oleyl at 330 nm. Thus, anadjusted transporter conjugated with a Yb111center that sensitizes at longer near-infrared wavelengths eliminates any possible luminescence interference.

[0094] A normalized Pi transport profile of Ybni-Lys-HOPO-OA (1-Yb) was produced with and without a supporting V ionophore. 25 mM Pi pulses to LUV solutions without added transporter showed relatively negligible transport over one hour before vesicle lysis, indicating effective EuChBn encapsulation. The slight observable increase was likely attributed to the bulky hydrophobic benzyl groups perturbing some interactions between lipid chains in the vesicle bilayer. With the addition of 2 mol% of 1-Yb, intravesicular Pi increased by nearly 3-fold after 1 hour, confirming Pi transport mediated by 1-Yb. When equimolar 1-Yb and V together enable Pi / K+symport into the vesicle, enhanced Pi transport was observed. Ratiometric comparison of the transporter concentrations against normalized emission intensity before lysis also confirmed the synergy 1-Yb and V.

[0095] Accordingly, this shows that selective Pi transport via a supramolecular lanthanide-based amphiphile can be accomplished using these coordination complexes. By harnessing the dual functionality of a hydrophobic oleyl chain conjugated onto a Pi coordinating Eu111-Lys-HOPO complex, facile anion separation was achieved. Transport profiles and selectivity analysis illustrate that Euin-Lys-HOPO was capable of effective Pi sequestration from environmentally relevant anions across an ion impermeable membrane.

[0096] Additional Examples

[0097] The technology described herein can include any of the following additional enumerated examples:

[0098] 1. A coordination complex having a general chemical structure:

[0099]

[0100] wherein A is a linear or branched alkyl group, wherein L comprises a linkage group comprising at least one non-carbon atom, wherein R is an organic group comprising at least two carbon atoms, and wherein M is a rare earth metal.

[0101] 2. The coordination complex of any of examples 1-12 or the phosphate sensor of any of examples 13-21 or the method of any of examples 22-29, wherein M comprises Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Y, La, Ce, Pr, Nd, Sm, or a combination thereof.

[0102] 3. The coordination complex of any of examples 1-12 or the phosphate sensor of any of examples 13-21 or the method of any of examples 22-29, wherein M comprises Eu.

[0103] 4. The coordination complex of any of examples 1-12 or the phosphate sensor of any of examples 13-21 or the method of any of examples 22-29, wherein A comprises -CH2-, -(CH2)2-, -(CH2)3-, -(CH2)4-, -(CH2)S-, or a combination thereof.

[0104] 5. The coordination complex of any of examples 1-12 or the phosphate sensor of any of examples 13-21 or the method of any of examples 22-29, wherein L comprises include -O-, -S-, -S(=O)-, -C=(O)-, -C(=O)O-, -C(=O)S-, -C(=O)NH-, -NH-, NR- (R=alkyl or cycloalkyl), -C6H5-O- , -C6H5-S-, or a combination thereof.

[0105] 6. The coordination complex of any of examples 1-12 or the phosphate sensor of any of examples 13-21 or the method of any of examples 22-29, wherein R comprises a polycyclic group.

[0106] 7. The coordination complex of any of examples 1-12 or the phosphate sensor of any of examples 13-21 or the method of any of examples 22-29, wherein the polycyclic group is at least partially aromatic.

[0107] 8. The coordination complex of any of examples 1-12 or the phosphate sensor of any of examples 13-21 or the method of any of examples 22-29, wherein R comprises a linear or branched alkyl group.9. The coordination complex of any of examples 1-12 or the phosphate sensor of any of examples 13-21 or the method of any of examples 22-29, wherein R comprises from 2 to 17 carbon atoms.

[0108] 10. The coordination complex of any of examples 1-12 or the phosphate sensor of any of examples 13-21 or the method of any of examples 22-29, wherein R comprises an electrically conductive group.

[0109] 11. The coordination complex of any of examples 1-12 or the phosphate sensor of any of examples 13-21 or the method of any of examples 22-29, wherein R has a chemical structure selected from the group consisting of

[0110]

[0111] and combinations thereof.

[0112] 12. The coordination complex of any of examples 1-12 or the phosphate sensor of any of examples 13-21 or the method of any of examples 22-29, wherein the coordination complex has a chemical structure selected from the group consisting of:

[0113]

[0114] and combinations thereof.

[0115] 13. A phosphate sensor, comprising a phosphate-binding coordination complex configured to contact a sample material, wherein the coordination complex has a general chemical structure:

[0116]

[0117] wherein A is a linear or branched alkyl group, wherein L comprises a linkage group comprising at least one non-carbon atom, wherein R is an organic group comprising at least two carbon atoms, and wherein M is a rare earth metal.

[0118] 14. The coordination complex of any of examples 1-12 or the phosphate sensor of any of examples 13-21 or the method of any of examples 22-29, wherein the sensor comprises a sensing surface and wherein the coordination complex is on the sensing surface.

[0119] 15. The coordination complex of any of examples 1-12 or the phosphate sensor of any of examples 13-21 or the method of any of examples 22-29, wherein the coordination complex is coated on the sensing surface, or covalently linked to the sensing surface, or at least partially embedded in the sensing surface, or a combination thereof.

[0120] 16. The coordination complex of any of examples 1-12 or the phosphate sensor of any of examples 13-21 or the method of any of examples 22-29, wherein the coordination complex is deposited on the sensing surface by physical vapor deposition, spin-coating, drop-casting, dip-coating, slot-die coating, doctor blading, bar coating, ink-jet printing, roll-to-roll coating, or a combination thereof.

[0121] 17. The coordination complex of any of examples 1-12 or the phosphate sensor of any of examples 13-21 or the method of any of examples 22-29, wherein the sensing surface comprises an electrically conductive or semi-conductive polymer.18. The coordination complex of any of examples 1-12 or the phosphate sensor of any of examples 13-21 or the method of any of examples 22-29, wherein the coordination complex is blended with the polymer, or copolymerized in the polymer, or coated on the polymer, or a combination thereof.

[0122] 19. The coordination complex of any of examples 1-12 or the phosphate sensor of any of examples 13-21 or the method of any of examples 22-29, wherein the sensor comprises a field effect transistor and wherein the sensing surface is in a channel of the field effect transistor.

[0123] 20. The coordination complex of any of examples 1-12 or the phosphate sensor of any of examples 13-21 or the method of any of examples 22-29, wherein the sample material comprises water, blood, soil, or a combination thereof.

[0124] 21. The coordination complex of any of examples 1-12 or the phosphate sensor of any of examples 13-21 or the method of any of examples 22-29, wherein the sample material comprises groundwater, seawater, wastewater, agricultural wastewater, radioactive wastewater, or a combination thereof.

[0125] 22. A method of measuring phosphate levels in a sample material, comprising:

[0126] contacting the sample material with a phosphate-binding coordination complex to bind phosphate ions from the sample material to the coordination complex; and measuring an amount of the phosphate ions bound to the coordination complex; wherein the coordination complex has a general chemical structure:

[0127]

[0128] wherein A is a linear or branched alkyl group, wherein L comprises a linkage group comprising at least one non-carbon atom, wherein R is an organic group comprising at least two carbon atoms, and wherein M is a rare earth metal.

[0129] 23. The coordination complex of any of examples 1-12 or the phosphate sensor of any of examples 13-21 or the method of any of examples 22-29, wherein measuring the amount of the phosphate ions bound to the coordination complex is accomplished by measuring luminescence of the coordination complex.

[0130] 24. The coordination complex of any of examples 1-12 or the phosphate sensor of any of examples 13-21 or the method of any of examples 22-29, wherein the coordination complex is in a channel of a field effect transistor, and wherein measuring the amount of the phosphate ions bound to the coordination complex is accomplished by measuring a change in conductivity of the channel.

[0131] 25. The coordination complex of any of examples 1-12 or the phosphate sensor of any of examples 13-21 or the method of any of examples 22-29, wherein the sample material comprises water, blood, soil, or a combination thereof.

[0132] 26. The coordination complex of any of examples 1-12 or the phosphate sensor of any of examples 13-21 or the method of any of examples 22-29, wherein the sample material comprises groundwater, seawater, wastewater, agricultural wastewater, radioactive wastewater, or a combination thereof.27. A method of separating phosphate from a liquid, comprising contacting the liquid with a phosphate-binding coordination complex to bind phosphate ions from the liquid to the coordination complex, wherein the coordination complex has a general chemical structure:

[0133]

[0134] wherein A is a linear or branched alkyl group, wherein L comprises a linkage group comprising at least one non-carbon atom, wherein R is an organic group comprising at least two carbon atoms, and wherein M is a rare earth metal.

[0135] 28. The coordination complex of any of examples 1-12 or the phosphate sensor of any of examples 13-21 or the method of any of examples 22-29, wherein the liquid comprises blood, water, groundwater, seawater, wastewater, agricultural wastewater, radioactive wastewater, or a combination thereof.

[0136] 29. The coordination complex of any of examples 1-12 or the phosphate sensor of any of examples 13-21 or the method of any of examples 22-29, further comprising debinding the phosphate from the coordination complex and collecting the phosphate for disposal or use as a product.

[0137] 30. The coordination complex of any of examples 1-12 or the phosphate sensor of any of examples 13-21 or the method of any of examples 22-29, wherein the coordination complex is amphiphilic and adapted to allow phosphate transport across a lipid bilayer.Reference was made to the examples illustrated in the drawings and specific language was used herein to describe the same. It will nevertheless be understood that no limitation of the scope of the technology is thereby intended. Alterations and further modifications of the features illustrated herein and additional applications of the examples as illustrated herein are to be considered within the scope of the description.

[0138] Furthermore, the described features, structures, or characteristics may be combined in any suitable manner in one or more examples. In the preceding description, numerous specific details were provided, such as examples of various configurations to provide a thorough understanding of examples of the described technology. It will be recognized, however, that the technology may be practiced without one or more of the specific details, or with other methods, components, devices, etc. In other instances, well-known structures or operations are not shown or described in detail to avoid obscuring aspects of the technology.

[0139] Although the subject matter has been described in language specific to structural features and / or operations, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features and operations described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims. Numerous modifications and alternative arrangements may be devised without departing from the spirit and scope of the described technology.

Claims

CLAIMSWhat is claimed is:

1. A coordination complex having a general chemical structure:wherein A is a linear or branched alkyl group, wherein L comprises a linkage group comprising at least one non-carbon atom, wherein R is an organic group comprising at least two carbon atoms, and wherein M is a rare earth metal.

2. The coordination complex of claim 1, wherein M comprises Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Y, La, Ce, Pr, Nd, Sm, or a combination thereof.

3. The coordination complex of claim 1, wherein M comprises Eu.

4. The coordination complex of claim 1, wherein A comprises -CH2-, -(CH2)2-, -(CH2)3-, -(CH2)4-, -(CH2)S-, or a combination thereof.

5. The coordination complex of claim 1, wherein L comprises -O-, -S-, -S(=O)-, -C=(O)-, -C(=O)O-, -C(=O)S-, -C(=O)NH-, -NH-, NR- (R=alkyl or cycloalkyl), -C6H5-O- , -C6H5-S-, or a combination thereof.

6. The coordination complex of claim 1, wherein R comprises a polycyclic group.

7. The coordination complex of claim 6, wherein the polycyclic group is at least partially aromatic.

8. The coordination complex of claim 1, wherein R comprises a linear or branched alkyl group.

9. The coordination complex of claim 1, wherein R comprises from 2 to 17 carbon atoms.

10. The coordination complex of claim 1, wherein R comprises an electrically conductive group.

11. The coordination complex of claim 1, wherein R has a chemical structure selected from the group consisting of:and combinations thereof.

12. The coordination complex of claim 1, wherein the coordination complex has a chemical structure selected from the group consisting ofand combinations thereof.

13. A phosphate sensor, comprising a phosphate-binding coordination complex configured to contact a sample material, wherein the coordination complex has a general chemical structure:wherein A is a linear or branched alkyl group, wherein L comprises a linkage group comprising at least one non-carbon atom, wherein R is an organic group comprising at least two carbon atoms, and wherein M is a rare earth metal.

14. The phosphate sensor of claim 13, wherein the sensor comprises a sensing surface and wherein the coordination complex is on the sensing surface.

15. The phosphate sensor of claim 14, wherein the coordination complex is coated on the sensing surface, or covalently linked to the sensing surface, or at least partially embedded in the sensing surface, or a combination thereof.

16. The phosphate sensor of claim 14, wherein the coordination complex is deposited on the sensing surface by physical vapor deposition, spin-coating, drop-casting, dip-coating, slotdie coating, doctor blading, bar coating, ink-jet printing, roll-to-roll coating, or a combination thereof.

17. The phosphate sensor of claim 14, wherein the sensing surface comprises an electrically conductive or semi-conductive polymer.

18. The phosphate sensor of claim 17, wherein the coordination complex is blended with the polymer, or copolymerized in the polymer, or coated on the polymer, or a combination thereof.

19. The phosphate sensor of claim 14, wherein the sensor comprises a field effect transistor and wherein the sensing surface is in a channel of the field effect transistor.

20. The phosphate sensor of claim 13, wherein the sample material comprises water, blood, soil, or a combination thereof.

21. The phosphate sensor of claim 13, wherein the sample material comprises groundwater, seawater, wastewater, agricultural wastewater, radioactive wastewater, or a combination thereof.

22. A method of measuring phosphate levels in a sample material, comprising:contacting the sample material with a phosphate-binding coordination complex to bind phosphate ions from the sample material to the coordination complex; and measuring an amount of the phosphate ions bound to the coordination complex; wherein the coordination complex has a general chemical structure:wherein A is a linear or branched alkyl group, wherein L comprises a linkage group comprising at least one non-carbon atom, wherein R is an organic group comprising at least two carbon atoms, and wherein M is a rare earth metal.

23. The method of claim 22, wherein measuring the amount of the phosphate ions bound to the coordination complex is accomplished by measuring luminescence of the coordination complex.

24. The method of claim 22, wherein the coordination complex is in a channel of a field effect transistor, and wherein measuring the amount of the phosphate ions bound to the coordination complex is accomplished by measuring a change in conductivity of the channel.

25. The method of claim 22, wherein the sample material comprises water, blood, soil, or a combination thereof.

26. The method of claim 22, wherein the sample material comprises groundwater, seawater, wastewater, agricultural wastewater, radioactive wastewater, or a combination thereof.

27. A method of separating phosphate from a liquid, comprising contacting the liquid with a phosphate-binding coordination complex to bind phosphate ions from the liquid to the coordination complex, wherein the coordination complex has a general chemical structure:wherein A is a linear or branched alkyl group, wherein L comprises a linkage group comprising at least one non-carbon atom, wherein R is an organic group comprising at least two carbon atoms, and wherein M is a rare earth metal.

28. The method of claim 27, wherein the liquid comprises blood, water, groundwater, seawater, wastewater, agricultural wastewater, radioactive wastewater, or a combination thereof.

29. The method of claim 27, further comprising debinding the phosphate from the coordination complex and collecting the phosphate for disposal or use as a product.

30. The method of claim 27, wherein the coordination complex is amphiphilic and the contacting occurs in the presence of a lipid bilayer such that phosphate transport via the coordination complex occurs across the lipid bilayer.

Images