Use of lithium containing compounds in vapor deposition and precursors for vapor deposition

Abstract

The invention relates to the use of a specific group of lithium containing precursors of the following formula (I) in the formation of lithium containing films in vapor deposition methods, R1, R2, R3 and R4 being organic residues and Z being O or NR. The invention further relates to a sub-group of compounds of said lithium containing precursors and a method of producing such lithium containing precursors. Further the invention relates to a method of coating a substrate with one or more lithium containing layers and a coated substrate obtainable by such method.

Description

[0001] USE OF LITHIUM CONTAINING COMPOUNDS IN VAPOR DEPOSITION AND PRECURSORS FOR VAPOR DEPOSITION

[0002] The present invention relates to the use of a specific group of lithium containing precursors in the formation of lithium containing films in vapor deposition methods, such as chemical vapor deposition, particularly atomic layer deposition as well as a particularly preferred sub-group of compounds of the afore-mentioned specific group of lithium containing precursors and a method of producing such lithium containing precursors. Further the invention relates to a method of coating a substrate with one or more lithium containing layers and a coated substrate obtainable by such method.

[0003] BACKGROUND

[0004] Various types of vapor deposition methods are used to deposit thin films on substrates.

[0005] In the field of thin film deposition, Physical Vapor Deposition (PVD) is a popular technique that involves vaporizing a solid material in a vacuum chamber. The process begins with heating a solid material, which causes it to vaporize and form a plasma of ions and neutral particles, which is directed towards a substrate, where the ions and particles in the plasma condense and form a thin film. The thickness of the film can be controlled by adjusting the deposition time and the rate of material vaporization. This method can also be used to create multilayered thin films by sequentially depositing different materials to form a complex structure. This technique is widely used in industries such as semiconductor, optical, and automotive, where high-quality thin films are crucial for product performance and reliability.

[0006] Another technique to provide thin films is the Chemical Vapor Deposition (CVD), involving the introduction of a gas or vapor comprising one or more volatile reactive and / or decomposable precursors into a vacuum chamber containing a substrate. Through a thermal or plasma-assisted process, the gas or vapor reacts with the substrate to form a solid thin film. The thickness of the film can be regulated by varying the deposition time and the concentration of the gas or vapor. This technique is widely used in industries such as semiconductor, aerospace, biomedical and the manufacture or lithium-ion batteries (LIBs).

[0007] A subset of CVD is the atomic layer deposition (ALD). In ALD, the growth of the films progresses layer by layer by alternatively pulsing the gaseous precursors. This enables ultra-fine thickness control. On the other hand, in most other CVD techniques, all source gases flow simultaneously in the reaction chamber.

[0008] CVD / ALD techniques are well suited to produce thin films containing lithium. Thin films of lithium carbonate were reported to be obtained via ALD by Putkonen, M.; Aaltonen, T.; Aines, M.; Sajavaara, T.; Nilsen, 0.; Fjellvaag, H. in the scientific article "Atomic layer deposition of lithium containing thin films” in J. Mater. Chem. 2009, 19 (46), 8767-8771 , using lithium t-butoxide, lithium 2,2,6,6-tetramethyl-3,5-heptandionate, lithium cyclopentadienyl, n-butyl lithium and lithium dicyclohexylamide. Films of AI2O3-LI2O were made via ALD using lithium t-butoxide and (CHaJaAl as disclosed by Aaltonen, T.; Nilsen, 0.; Magraso, A.; Fjellvag, H. in the scientific article "Atomic Layer Deposition of LI2O-AI2O3 Thin Films” in Chem. Mater. 2011, 23 (21), 4669-4675. Films of lithium nitride and lithium carbonate were made using lithium bis-trimethylsilylamide as reported by Ostreng, E.; Vajeeston, P.; Nilsen, 0.; Fjellvag, H. in the scientific article "Atomic layer deposition of lithium nitride and carbonate using lithium sily lamide” in RSC Adv. 2012, 2 (15), 6315-6322. Films of Lithium carbonate, LixSiyOzand LixAlyOzwere obtained using lithium trimethylsilanolate by Ruud, A.; Miikkulainen, V.; Mizohata, K.; Fjellvaag, H.; Nilsen, 0. as described in the scientif acrticle "Enhanced process and composition control for atomic layer deposition with lithium trimethylsilanolate” in J. Vac. Sci. Technol., A 2017, 35 (1), 01 B133 / 1-01 B133 / 8.

[0009] However, lithium containing precursors for CVD / ALD must satisfy several requirements. Ideally, the precursor compounds must in the first instance be sufficiently volatile. Precursors should also vaporize rapidly and at a reproducible rate, conditions that are most typically met by liquid precursors. Thus, the afore-mentioned precursors worked more or less satisfactory.

[0010] Simple lithium carboxylates, such as lithium acetate, lithium trifluoroacetate and lithium benzoate were found to be not volatile enough (see Ruud, A. et al., above).

[0011] Examples of recent developments of CVD / ALD lithium precursors are (N,N-Di-iso-propylacetamidinato) lithium ("New ALD Li Precursor for UPON” Cambridge Network 2020, https: / / www.cambridgenetwork.co.uk / news / new- lithium-precursor-available-ald-source-li-films-applications-battery-technology, accessed on 16. July 2024) and Li- diaminosilylamide (Griffiths, M. B. E.; Zanders, D.; Land, M. A.; Masuda, J. D.; Devi, A.; Barry, S. T. "(t- BuN)SIMe2NMe2 - A new N,N'-K2-monoanionic ligand for atomic layer deposition precursors” in Journal of Vacuum Science & Technology A 2021, 39 (3), 032409 / 1-032409 / 12).

[0012] Lithium containing materials made by CVD / ALD are highly promising for manufacturing of advanced lithium-ion batteries.

[0013] Lithium-ion batteries are being widely used in today's electronics, such as mobile phones, computers, medical implants, self-powered integrated circuits, and electric vehicles. Recent attention has been focused on all solid- state lithium-ion batteries due to their flexibility in design, miniaturization for microelectronic devices and improved safety due to the absence of liquid electrolytes. Significant efforts have been dedicated recently to the development of CVD / ALD processes of lithium compounds for solid-state electrolyte (SSE) materials. Among the very promising potential candidates, glassy lithium phosphorus oxynitride (LIPON) has become one of the most popular SSE materials for thin film batteries. Despite of some progress in the development of good performing precursors, the most common lithium precursor for CVD / ALD thin films used in battery technology remains lithium t-butoxide. However, the drawback of lithium t- butoxide is its rather low vapor pressure and very high melting point, which may lead to an undesired particle formation on the substrate.

[0014] Therefore, a need for improved and readily available lithium precursors for vapor deposition methods remains. Thus, the object of the present invention was to find a group of lithium containing compounds showing distinct advantages for use as precursors for formation of materials containing lithium using vapor deposition methods, such as the chemical vapor deposition method, particularly the atomic layer deposition method.

[0015] SUMMARY

[0016] The objects of the present invention were achieved by providing a use of a lithium containing compound of formula (A) and / or its tautomers wherein

[0017] R1being selected from the group consisting of linear or branched alkyl groups containing 1 to 8 carbon atoms, cycloalkyl groups containing 4 to 6 carbon atoms, aralkyl groups, aryl groups,

[0018] - CF3;

[0019] R2being selected from the group consisting of linear or branched alkyl groups containing 1 to 8 carbon atoms,

[0020] - CF3, linear or branched alkoxy groups containing 1 to 8 carbon atoms, cycloalkyl groups containing 4 to 6 carbon atoms, O-cycloalkyl groups containing 4 to 6 carbon atoms, aralkyl groups, aryl groups,

[0021] O-aralkyl groups, and if Z = 0, NRaRbgroups wherein Raand Rbare independently selected from alkyl groups containing 1 to 8 carbon atoms; or

[0022] R1and R2together are a linking group CH2-CRr2-CH2, wherein both residues Rrare independently of each other H or CH3, thus forming a 6-membered ring with the adjacent C-C(R3)=C motive;

[0023] R3being selected from the group consisting of

[0024] - H, linear or branched alkyl groups containing 1 to 8 carbon atoms, cycloalkyl groups containing 4 to 6 carbon atoms, allyl groups, aralkyl groups and aryl groups;

[0025] R4being selected from the group consisting of

[0026] - H,

[0027] NRaRbas defined for residue R2,

[0028] ORC, wherein Rcis an alkyl group containing 1 to 6 carbon atoms,

[0029] - L-N=CR1’-CR3’=CR2’-Z’-Li, wherein

[0030] L is a divalent hydrocarbon group containing 2 to 6 carbon atoms,

[0031] R1' is defined as R1,

[0032] R2' is defined as R2,

[0033] R3' is defined as R3, and

[0034] Z' is defined as Z below,

[0035] R5-X, wherein

[0036] R5is a divalent aliphatic, araliphatic or aromatic hydrocarbon residue containing 1 to 16 carbon atoms, and

[0037] X being selected from the group consisting of H, NRaRbas defined for residue R2and ORCwherein Rcis an alkyl group containing 1 to 6 carbon atoms;

[0038] Z being 0 or NR6, wherein R6is selected from the group consisting of

[0039] - H,

[0040] ORcwherein Rcis an alkyl group containing 1 to 6 carbon atoms,

[0041] NRaRb, wherein Raand Rbare as defined for residue R2; and

[0042] R5-X, wherein R5and X are as defined for residue R4; as precursor in the formation of lithium containing films in a vapor deposition method, preferably chemical vapor deposition method, particularly preferred in an atomic layer deposition method.

[0043] The above use and its preferred embodiments as described herein below are also denoted as "use according to the invention” or "use of the invention.”

[0044] Further subject matter of the present invention is a lithium containing compound of formula (A) and / or its tautomers as defined in the use according to the invention, wherein R3, R6, Ra, Rband Rcare defined in the use of the present invention, and being further defined in that

[0045] (I) R1and R2are as defined in the use according to the invention, and

[0046] R4is selected from the group consisting of benzyl, cycloalkyl groups containing 4 to 6 carbon atoms

[0047] NRaRb,

[0048] ORC,

[0049] L-N=CR1’-CR3’=CR2’-Z’-Li, wherein

[0050] L is a divalent hydrocarbon group containing 2 to 6 carbon atoms,

[0051] R1' is defined as R1in the use according to the invention,

[0052] R2' is defined as R2in the use according to the invention,

[0053] R3' is defined as R3in the use according to the invention, and

[0054] Z' is defined as Z in the use according to the invention; and

[0055] R5-X, wherein R5-X is selected from the group consisting of

[0056] CR2-CR2-CR2-X, wherein the R residues are independently selected from the group consisting of

[0057] H, and linear or branched alkyl group containing 1 to 3 carbon atoms, and the X is selected from the group consisting of

[0058] H, linear or branched alkyl containing 1 to 6 carbon atoms,

[0059] NRaRb, and

[0060] ORC, wherein Ra, Rband Rcare independently from each other alkyl groups containing 1 to 6 carbon atoms; in case of Z is NR6, R6is a linear or branched C1-C3 alkyl group; and in case of Z is 0, and X is NRaRbor ORCa. the sum of carbon atoms in R1, R2plus R3> 3; and / or b. the sum of carbon atoms in Raplus Rb> 3; and / or c. R2is selected from the group consisting of linear or branched alkoxy groups containing 1 to 8 carbon atoms and O-cycloalkyl groups containing 4 to 6 carbon atoms;

[0061] (ii) in case only R1is CF3, residues R2, R3, R4and Z are as defined in the use according to the invention; and in case only R2is CF3, residues R1, R3, R4are as defined in the use according to the invention and Z=0; and in case R1= R2= CF3, residues R3, R4and Z are as defined in the use according to the invention, with the proviso that R4is neither an aromatic group nor CH2-CH2-N(Et)2.

[0062] The above lithium containing compound and / or its tautomers and the preferred embodiments thereof as described herein below are also denoted as "lithium containing compound according to the invention” or "lithium containing compounds of the invention.”

[0063] Yet another subject matter of the invention is a method of producing a lithium containing compound of the invention, wherein a. a compound of formula (I) is reacted with a compound of formula R4-NH2or a compound of formula H2N-L-NH2, and, if Z is NR6, is further reacted with a compound of formula R6-NH2, followed by b. lithiation; all residues are as being defined for the lithium containing compounds of the invention. This method and its preferred embodiments are denoted as "method of producing a lithium containing compound of the invention or according to the invention.”

[0064] A further subject matter of the invention is method of coating a substrate with one or more lithium containing layers, wherein the lithium containing compound or compounds and / or its tautomers, as defined in the use of the present invention, are vaporized, and deposited on a substrate.

[0065] This method and its preferred embodiments are denoted as "method of coating a substrate according to the invention.”

[0066] Yet another subject matter of the invention is a coated substrate as obtainable by the method of coating a substrate according to the invention.

[0067] The coated substrate and its preferred embodiments are also denoted as "coated substrate of the invention or according to the invention.”

[0068] DETAILED DESCRIPTION

[0069] The term "tautomers", as used herein in accordance with IUPAC terminology, denotes for interconvertable compounds resulting from at least one formal migration of an atom, herein a lithium atom, and at least one change in valency, e.g., a single bond to a double bond, or vice versa. Tautomers belong to structural isomers.

[0070] Tautomers of the compound of structure (A) are, e.g., compounds of structures (A') and (A”):

[0071] (A) (A1) (A")

[0072] Depending of the definition of residues R1, R2, R3and R4further tautomeric structures are possible.

[0073] Use According to the Invention

[0074] The invention provides a use of a lithium containing compound of formula (A) and / or its tautomers as precursor in the formation of lithium containing films in a vapor deposition method. Several different gas phase deposition methods as, e.g., chemical vapor deposition (CVD), physical vapor deposition (PVD), and / or their respective subclasses atomic layer deposition (ALD) and sputtering. Techniques like PVD and CVD to prepare inorganic layers, e.g., metal oxide layers, are known to one of skill in the art and, e.g., described in US 2013 / 0034689 A1 and EP 2 692 520 A1. Furthermore, a CVD method to produce such layers is e.g., described in DE 40 35 951 C1 or in CA 2 562 914 A1 and references therein; a PVD method to produce such layers is e.g., described in US 5,900,271 A and references therein; and a sputtering method to produce such layers is e.g., described in US 2004 / 0005482 A1.

[0075] ALD is particularly preferred, since it is possible by using ALD to step-wise deposit chemically-bound, self-limiting layers with excellent thickness control that are highly conformal, well ordered, and dense each with a defined thickness. Suitable ALD methods are, e.g., disclosed in WO 2011 / 099858 A1 , WO 2015 / 188990 A2 and WO 2015 / 188992 A1.

[0076] The lithium containing compound of formula (A) and / or its tautomers as employed in the use of the present invention can be depicted as follows wherein

[0077] R1being selected from the group consisting of linear or branched alkyl groups containing 1 to 8 carbon atoms, cycloalkyl groups containing 4 to 6 carbon atoms, aralkyl groups, such as benzyl groups, aryl groups, such as phenyl groups,

[0078] - CF3;

[0079] R2being selected from the group consisting of linear or branched alkyl groups containing 1 to 8 carbon atoms,

[0080] - CF3, linear or branched alkoxy groups containing 1 to 8 carbon atoms, cycloalkyl groups containing 4 to 6 carbon atoms, O-cycloalkyl groups containing 4 to 6 carbon atoms, aralkyl groups, such as benzyl groups, aryl groups, such as phenyl groups, 0-aralkyl groups, and if Z = 0, NRaRbgroups wherein Raand Rbare independently selected from alkyl groups containing 1 to 8 carbon atoms; or

[0081] R1and R2together are a linking group CH2-CRr2-CH2, wherein both residues Rrare independently of each other H or CH3, thus forming a 6-membered ring with the adjacent C-C(R3)=C motive;

[0082] R3being selected from the group consisting of

[0083] - H, linear or branched alkyl groups containing 1 to 8 carbon atoms, cycloalkyl groups containing 4 to 6 carbon atoms, allyl groups, aralkyl groups and aryl groups;

[0084] R4being selected from the group consisting of

[0085] - H,

[0086] NRaRbas defined for residue R2,

[0087] ORC, wherein Rcis an alkyl group containing 1 to 6 carbon atoms,

[0088] - L-N=CR1’-CR3’=CR2’-Z’-Li, wherein

[0089] L is a divalent hydrocarbon group containing 2 to 6 carbon atoms,

[0090] R1' is defined as R1,

[0091] R2' is defined as R2,

[0092] R3' is defined as R3, and

[0093] Z' is defined as Z below,

[0094] R5-X, wherein

[0095] R5is a divalent aliphatic, araliphatic or aromatic hydrocarbon residue containing 1 to 16 carbon atoms, and

[0096] X being selected from the group consisting of H, NRaRbas defined for residue R2and ORCwherein Rcis an alkyl group containing 1 to 6 carbon atoms;

[0097] Z being 0 or NR6, wherein R6is selected from the group consisting of

[0098] - H,

[0099] ORcwherein Rcis an alkyl group containing 1 to 6 carbon atoms,

[0100] NRaRb, wherein Raand Rbare as defined for residue R2; and R5-X, wherein R5and X are as defined for residue R4. The term "aralkyl group” denominates any univalent radical derived from an alkyl radical by replacing one or more hydrogen atoms by aryl groups. Likewise, the term "araliphatic group” denominates an aliphatic group to which an aryl group is bound. An example for both terms is a benzyl group, which is an alkyl group, namely a methyl group wherein one hydrogen is replaced by a phenyl group. Since a methyl group is aliphatic and a phenyl group is aromatic group, a benzyl group is an araliphatic group.

[0101] It is further noted that aralkyl groups and aryl groups may optionally possess linear or branched alkyl groups, preferably 1 , 2 or 3 alkyl groups, each having preferably 1 to 4, more preferred 1 to 3 carbon atoms, if alkyl groups are present at all, on their aromatic moiety. For example, if an aryl group is a phenyl group, the phenyl groups might, e.g., be a 2,6-di- / -propyl phenyl group (thus comprising 12 carbon atoms in total) or a 2,4,6-trimethyl phenyl group (thus comprising 9 carbon atoms in total) etc. The same applies, e.g., for the phenyl group (Ph) in a benzyl group being CFh-Ph.

[0102] In some cases, it is not desired that the precursors contain fluorine, particularly in residues R1and R2such as in CF3 residues, since it is possible that HF, which is harmful to health, is formed as a by-product in vapor deposition. Further, in those cases where the incorporation of fluorine into the deposited layers is to be avoided, the respective CF3 residues should be avoided.

[0103] Furthermore, it was observed that residues R4comprising a phenyl group, such as a phenyl group itself or a benzyl group, may be less preferred due to the possibility of intramolecular interaction caused by TT-TT stacking, which may lead to a lower vapor pressure and a higher melting point, thus needing higher temperatures in vapor deposition.

[0104] Yet another aspect of the invention lies in the fact that the compounds of formula (A) contain at least one nitrogen atom. Typically, lithium-ion conductivity can be tuned by the presence of nitrogen in the deposited layer, which increases the performance of, e.g., a lithium-ion battery. Compounds of formula (A), wherein Z = NR6, contain even at least two nitrogen atoms, increasing the effect. On the other hand, compared with compounds of formula (A), wherein

[0105] Z = 0, those compounds with Z = NR6often have a higher melting point. Thus, the advantages and disadvantages of the presence of nitrogen in Z must be weighed up.

[0106] Preferably, the residues of the compounds of formula (A) are defined as follows:

[0107] R1being selected from the group consisting of linear or branched alkyl groups containing 1 to 6 carbon atoms, aryl groups, such as phenyl groups, and

[0108] - CF3; R2being selected from the group consisting of linear or branched alkyl groups containing 1 to 6 carbon atoms, aryl groups, such as phenyl groups,

[0109] - CF3, linear or branched alkoxy groups containing 1 to 6 carbon atoms if Z = 0, NRaRbgroups wherein Raand Rbare independently selected from alkyl groups containing 1 to 8 carbon atoms; or

[0110] R1and R2together are a linking group CH2-CH2-CH2, thus, forming a 6-membered ring with the adjacent C(0)-C(R3)-C(0) motive;

[0111] R3being selected from the group consisting of

[0112] - H, linear or branched alkyl groups containing 1 to 6 carbon atoms, cyclohexyl, and aralkyl groups, such as benzyl groups;

[0113] R4being selected from the group consisting of

[0114] - H,

[0115] NRaRbas defined for residue R2,

[0116] ORC, wherein Rcis an alkyl group containing 1 to 6 carbon atoms,

[0117] - L-N=CR1’-CR3’=CR2’-Z’-Li, wherein

[0118] L is a divalent hydrocarbon group containing 2 to 6 carbon atoms,

[0119] R1' is defined as R1,

[0120] R2' is defined as R2,

[0121] R3' is defined as R3, and

[0122] Z' is defined as Z below,

[0123] R5-X, wherein

[0124] R5is a divalent aliphatic, araliphatic or aromatic hydrocarbon residue containing 1 to 16 carbon atoms, and

[0125] X being selected from the group consisting of H, NRaRbas defined for residue R2and ORCwherein Rcis an alkyl group containing 1 to 6 carbon atoms;

[0126] Z being 0 or NR6, wherein R6is selected from the group consisting of

[0127] H,

[0128] ORcwherein Rcis an alkyl group containing 1 to 6 carbon atoms, NRaRb, wherein Raand Rbare as defined for residue R2; and R5-X, wherein R5and X are as defined for residue R4.

[0129] Lithium Containing Compounds of the Invention

[0130] Particularly preferred in the use of the invention are the following novel compounds of formula (A) and / or their tautomers, wherein

[0131] (I) R1and R2are as defined in in the use according to the invention, and

[0132] R4is selected from the group consisting of aralkyl groups, such as benzyl, cycloalkyl groups containing 4 to 6 carbon atoms

[0133] NRaRb,

[0134] ORC,

[0135] L-N=CR1'-CR3'=CR2'-Z'-Li, wherein

[0136] L is a divalent hydrocarbon group containing 2 to 6 carbon atoms,

[0137] R1' is defined as R1in the use according to the invention,

[0138] R2' is defined as R2in the use according to the invention,

[0139] R3' is defined as R3in the use according to the invention, and

[0140] Z' is defined as Z in the use according to the invention; and R5-X, wherein R5-X is selected from the group consisting of CR2-CR2-CR2-X, wherein the R residues are independently selected from the group consisting of

[0141] H, and linear or branched alkyl group containing 1 to 3 carbon atoms, and the X is selected from the group consisting of

[0142] H, linear or branched alkyl containing 1 to 6 carbon atoms,

[0143] NRaRb, and

[0144] ORC, wherein Ra, Rband Rcare independently from each other alkyl groups containing 1 to 6 carbon atoms; in case of Z is NR6, R6is a linear or branched C1-C3 alkyl group; and in case of Z is 0, and X is NRaRbor ORCd. the sum of carbon atoms in R1, R2plus R3> 3; and / or e. the sum of carbon atoms in Raplus Rb> 3; and / or f. R2is selected from the group consisting of linear or branched alkoxy groups containing 1 to 8 carbon atoms and O-cycloalkyl groups containing 4 to 6 carbon atoms; or

[0145] (ii) in case only R1is CF3, residues R2, R3, R4and Z are as defined in the use according to the invention; and in case only R2is CF3, residues R1, R3, R4are as defined in in the use according to the invention and Z=O; and in case R1= R2= CF3 residues R3, R4and Z are as defined in the use according to the invention, with the proviso that R4is neither an aromatic group nor CH2-CH2-N(Et)2.

[0146] Particularly preferred are such lithium containing compounds of formula (A) and / or the tautomers thereof and the lithium containing compounds of the invention and / or their tautomers, which have a melting point of < 200 °C, more preferred < 180 °C, and / or which have an onset of mass loss at a temperature < 180 °C, more preferred < 150 °C.

[0147] Method of Producing Lithium Containing Compounds

[0148] The invention further provides a method of producing a lithium containing compound of the invention, which is also suitable for the known lithium containing compounds (A) and / or their tautomers as defined above. The method being characterized in that a. a compound of formula (I) is reacted with a compound of formula R4-NH2 or a compound of formula H2N-L-NH2, and, if Z is NR6, is further reacted with a compound of formula R6-NH2, followed by b. lithiation. More detailed, the following scheme 1 shows the reaction routes leading to compounds (A) and / or their tautomers as defined in the use according to the invention, with Z = 0 (compounds of formula (A1)) and Z = NR6(compounds of formula (A2)):

[0149] Scheme 1

[0150] In step 1 a of the method of producing lithium containing compounds, compounds of formula (I) are reacted with compounds of R4-NH2 to obtain compounds of formula (Ila), i.e., P-iminoketones, p-iminoesters and p-iminoamides. The synthesis of such compounds is, e.g., described by Zhang, Y.; Raines, A. J.; Flowers, R. A. in the scientific article "Solvent-Dependent Chemoselectivities in Additions of p- Carbonyl Imines to Allyltrimethylsilane with CTAN” published in The Journal of Organic Chemistry 2004, 69 (19), 6267-6272.

[0151] In the following suitable compounds of formula (I) and R4-NH2 are described.

[0152] Compounds of Formula (I)

[0153] The compounds of formula (I) are preferably selected from p-diketones (I'), p-ketoesters (I”) and p-ketoamides (I'”).

[0154] Th p-diketones (I') can be depicted as follows: wherein

[0155] R1being selected from the group consisting of linear or branched alkyl groups containing 1 to 8 carbon atoms, cycloalkyl groups containing 4 to 6 carbon atoms, benzyl groups and phenyl groups,

[0156] - CF3;

[0157] R2being selected from the group consisting of linear or branched alkyl groups containing 1 to 8 carbon atoms,

[0158] - CF3, cycloalkyl groups containing 4 to 6 carbon atoms, benzyl groups, phenyl groups; and

[0159] R3being selected from the group consisting of

[0160] - H, linear or branched alkyl groups containing 1 to 8 carbon atoms, cycloalkyl groups containing 4 to 6 carbon atoms, allyl groups, benzyl groups and phenyl groups;

[0161] Alternatively, to the presence of single groups R1and R2, respectively,

[0162] R1and R2together are a linking group CH2-CRr2-CH2, wherein both residues Rrare independently of each other H or CH3, thus forming a 6-membered ring with the adjacent C-C(R3)=C motive.

[0163] The latter cyclic compound can be depicted by the following formula (l’c):

[0164] The p-ketoesters (I ) can be depicted as follows: wherein

[0165] R1being selected from the group consisting of linear or branched alkyl groups containing 1 to 8 carbon atoms, cycloalkyl groups containing 4 to 6 carbon atoms, benzyl groups and phenyl groups,

[0166] - CF3;

[0167] R2being selected from the group consisting of linear or branched alkoxy groups containing 1 to 8 carbon atoms, O-cycloalkyl groups containing 4 to 6 carbon atoms,

[0168] O-benzyl groups; and

[0169] R3being selected from the group consisting of

[0170] - H, linear or branched alkyl groups containing 1 to 8 carbon atoms, cycloalkyl groups containing 4 to 6 carbon atoms, allyl groups, benzyl groups and phenyl groups.

[0171] The p-ketoamides (I'”) can be depicted as follows: wherein

[0172] R1being selected from the group consisting of linear or branched alkyl groups containing 1 to 8 carbon atoms, cycloalkyl groups containing 4 to 6 carbon atoms, benzyl groups and phenyl groups,

[0173] - CF3;

[0174] R2being selected from the group consisting of NRaRbgroups wherein Raand Rbare independently selected from alkyl groups containing 1 to 8 carbon atoms; and

[0175] R3being selected from the group consisting of

[0176] - H, linear or branched alkyl groups containing 1 to 8 carbon atoms, cycloalkyl groups containing 4 to 6 carbon atoms, allyl groups, benzyl groups and phenyl groups.

[0177] Compounds of formula R4-NH and H2N-L-NH2

[0178] Compounds of formula R4-NH2 are preferably selected from the group consisting of ammonia,

[0179] H2N-(Ci-Ci6-hydrocarbyl), including e.g., benzyl amine and aniline

[0180] H2N-(di valent Ci-Ci6-hydrocarbon group)-NRaRb, wherein Raand Rbare independently selected from Ci-Cs-alkyl groups

[0181] H2N-(di valent Ci-Ci6-hydrocarbon group)-O-(Ci-Ce-alkyl) dialkylhydrazine of formula H2N-NRaRb, wherein Raand Rbare independently selected from Ci-Cs- alkyl groups,

[0182] O-alky Ihydroxy lami ne of formula H2N-O-(Ci-C6-alkyl), and

[0183] H2N-(divalent C2-C6-hydrocarbon group)-N=CR1'-CR3'=CR2'-Z'-Li, wherein R1' is defined as R1, R2' is defined as R2, R3' is defined as R3, and Z' is defined as Z

[0184] Instead of first synthesizing and isolating the latter compound, a dimer can also, and preferably be obtained in situ, if a compound H2N-L-NH2 is used, L being a divalent C2-Ce-hydrocarbon group. In such case H2N-L-NH2 is reacted with two molecules of compound (I) as shown in scheme 2 below:

[0185] Scheme 2

[0186] Step 1b In case at least one Z = NR6, step 1 b is carried out, i.e., compounds of formula (lib) are to be produced in that at least one of the one or two C=0 moieties in compounds of formula (Ila) are reacted with compounds of formula R6- NH2. Two moieties are present in case the compound of formula (Ila) is a dimer.

[0187] In some cases, compounds of formula (lib) can be obtained in a one-step reaction wherein steps 1 a and 1 b are carried out in one step. This is particularly the case if R4and R6are the same. An example of such synthesis is described by El-Zoghbi, I.; Ased, A.; Oguadinma, P. 0.; Tchirioua, E.; Schaper, F. in the scientificic article "One- pot synthesis of [3-diketimine ligands” in Can. J. Chem. 2010, 88 (10), 1040-1045.

[0188] Another example, where R4and R6are bis(Ci-C4-alkyl)amino, i.e., R4-NH2 = R6-NH2 = H2N-N(Ci-C4-alkyl)2, is e.g., described by Sedai, B.; Heeg, M. J.; Winter, C. H. in the scientific article "Volatility Enhancement in Calcium, Strontium, and Barium Complexes Containing [3-Diketiminate Ligands with Dimethylamino Groups on the Ligand Core Nitrogen Atoms” in Organometallics 2009, 28 (4), 1032-1038.

[0189] Generally applicable procedures to obtain compounds of formula (lib), bearing also different substituents R4and R6, are, e.g., described by McGeachin, S. G. in the scientifc article "Synthesis and properties of some [3-diketimines derived from acetylacetone, and their metal complexes” in Can. J. Chem. 1968, 46 (11), 1903; by Park, K.-H. and Marshall, W. J. in the scientifc article "Routes to N,N‘-Unsymmetrically Substituted 1 ,3-Diketimines” in The Journal of Organic Chemistry 2005, 70 (6), 2075-2081 ; or by Bradley, A. Z.; Thorn, D. L; Glover, G. V. in the scientific article "Efficient Synthesis of Alkyl P-Diketimines” in. J. Org. Chem. 2008, 73 (21), 8673-8674.

[0190] Compounds of formula R6-NH2

[0191] Compounds of formula R6-NH2 are preferably selected from the group consisting of ammonia

[0192] N, N-dialkylhydrazine of formula H2N-NRaRb, wherein Raand Rbare independently selected from C1- Cs-alkyl groups,

[0193] O-alky Ihydroxy lami ne of formula H2N-O-(Ci-C6-alkyl), and

[0194] H2N-(Ci-Ci6-hydrocarbyl)

[0195] H2N-(di valent Ci-Ci6-hydrocarbon group)-NRaRb, wherein Raand Rbare independently selected from Ci-Cs-alkyl groups

[0196] H2N-(di valent Ci-Ci6-hydrocarbon group)-O-(Ci-C6-alkyl).

[0197] Step 2

[0198] In this step the lithiation of compounds of formula (Ila), i.e., p-iminoketones, p-iminoesters and p-iminoamides or the lithiation of compounds of formula (lib) is carried out. As lithiation reagent Li-R° is preferably used, wherein R° is preferably selected from the group consisting of H; alkyl groups having 1 to 8, preferably 4 to 6 carbon atoms, such as n-butyl and n-hexyl; aryl groups such as phenyl; NH2; O-alkyl groups having 1 to 8, preferably 1 to 4, more preferred 1 or 2 carbon atoms, such as O-methyl; and OH. Alternatively, lithium metal can be used as lithiation reagent.

[0199] The lithiation can be performed without additional solvent, but also in a suitable inert solvent. Examples of suitable solvents are aliphatic or aromatic hydrocarbons, for instance hexane, heptane, cyclohexane, benzene, or toluene. Suitable are also ethers, e.g., tetrahydrofurane, ferf-butyl-methyl ether, dibutyl ether or ethylene glycol dimethylether. The reaction can be carried out at room temperature, or under cooling, for example with acetonedry ice mixture at -78 °C.

[0200] Method of Coating a Substrate with Lithium-containing Lavers

[0201] The present invention further provides a method of coating a substrate with one or more lithium containing layers, wherein the lithium containing compound or compounds as defined in the use of the invention are vaporized and deposited on a substrate.

[0202] This method preferably comprises the steps of a. providing an uncoated or precoated substrate, b. depositing at least one inorganic layer (L') on the uncoated or precoated substrate by gas phase deposition, preferably chemical gas phase deposition, more preferred atomic layer deposition, comprising steps b.1 and b.2, namely b.1 vaporizing and depositing one or more lithium containing compounds of formula (A) and / or its tautomers on the uncoated or precoated substrate to form layer b1 , and b.2 subsequently to step b.1 applying one or more reactants on layer b1 , which react with layer b1 to form layer U, and wherein step b. is carried out one or more times to deposit one or more inorganic layers (U).

[0203] Step a - Substrate

[0204] The substrate can be any substrate typically used in a vapor deposition method, such as a metallic substrate or a polymeric substrate. The substrates may be uncoated substrates or precoated substrates. Preferably, the substrate is an uncoated or precoated metallic substrate. The substrate preferably exhibits a high planarity, wherein preferably a difference between the highest point of the substrate surface to the lowest point of the substrate surface is less than 100 nm, more preferably less than 50 nm.

[0205] If the substrate is a metallic substrate, the term "metallic” includes pure metals, but also alloys. Typical metallic substrates are, e.g., copper, aluminum, titanium, stainless steel, brass, bronze nickel, iron, zinc, or silver. In the field of manufacturing lithium-ion batteries, the substrate is preferably lithium or even more preferred a lithium alloy, such as, e.g., an alloy of lithium with aluminum, preferably serving as an electrode, particularly an anode.

[0206] If the metallic substrate is an alloy, such alloy can, e.g., even be formed in situ by a vapor deposition method, e.g., in that a lithium substrate, preferably a high purity lithium substrate, is exposed to a metal containing compound, such as trimethyl aluminum for some period under vapor deposition conditions. A thus formed alloy typically possesses a monolayer of chemisorbed trimethyl aluminum on top of the alloy, which is preferably further reacted to form an inorganic layer. Consequently, in such case the metallic substrate is a precoated alloy substrate.

[0207] It is further possible that on a precoated metallic substrate further inorganic layers (!_'') are present, which are obtainable as in step b, but with the difference, that instead also other metal containing compounds, such as e.g. non-lithium containing compounds (precursors) may be used to form one or more inorganic layer(s) (U).

[0208] It is further possible that on a precoated metallic substrate further layers are present before step b is carried out. E.g. an inorganic / organic hybrid layer (L'°) can be deposited on the substrate by gas phase deposition, preferably molecular layer deposition, comprising steps c.1 and c.2, namely c.1 vaporizing and depositing one or more precursors selected from inorganic precursors, metal organic precursors and organometallic precursors on the precoated substrate to form layer d, and c.2 subsequently to step c.1 applying one or more organic precursors on layer d , which are reactive with d to form an inorganic / organic hybrid layer (L'°), and wherein step c is carried out one or more times to deposit one or more inorganic / organic hybrid layers (L'°).

[0209] Step b

[0210] Preferably, any inorganic layer (L') is deposited on the metal substrate by gas phase deposition selected from chemical vapor deposition (CVD) and particularly a sub-class thereof, namely atomic layer deposition (ALD), wherein the one or more reactants in step b.2 comprise an oxygen source, a reducing agent, a sulfur source and / or a nitrogen source. Preferably, any inorganic layer (L') is deposited by ALD, since it is possible by using ALD to step-wise deposit chemically-bound, self-limiting layers with excellent thickness control that are highly conformal, well ordered, and dense each with a defined thickness. An ALD method, particularly to produce metal oxide layers is, e.g., disclosed in WO 2011 / 099858 A1 , WO 2015 / 188990 A2 and WO 2015 / 188992 A1.

[0211] The gas phase deposition in step b. may be applied batchwise or a continuous (e.g. roll-to-roll) system in vacuum or at atmospheric conditions, whereby preferably a continuous system is used, more preferably a continuous roll- to-roll system is used. Preferably, a spatial sequence is used for the gas phase deposition.

[0212] Preferably, reactants suitable in step b.2 are selected from oxygen, water, ozone, hydrogen peroxide, oxygen plasma, hydrogen, hydrogen plasma, alcohols, hydrogen sulfide, sulfur, diethyl disulfide, nitrogen, ammonia and nitrogen plasma, more preferably are selected from oxygen, water, ozone, hydrogen peroxide, oxygen plasma, and alcohols, even more preferably are selected from oxygen, water and ozone.

[0213] Preferably, one or more a lithium containing compound of formula (A) and / or its tautomers as used in step b.1 have a melting point of below 180 °C, more preferably a melting point of below 150 °C. The same applies to reactants which are suitable in step b.2.

[0214] Preferably, any combination of the above-mentioned precursors and reactants suitable for step b.1 and b.2 may be applied, more preferably exactly one of the one or more a lithium containing compound of formula (A) and / or its tautomers and exactly one of the above-mentioned reactants are applied in the respective step to deposit an inorganic layer (U).

[0215] Preferably, step c.1 and c.2 each are carried out at a temperature in a range from room temperature to 180 °C, more preferably in a range from 60 °C to 150 °C.

[0216] Preferably, steps b.1 and b.2 each are carried out at a pressure in a range from 106mbar to 5000 mbar, more preferably in a range from 102mbar to 2500 mbar, even more preferably in a range from 1 .0 mbar to 1500 mbar.

[0217] Preferably, steps b.1 and b.2 each are carried out for 0.5 ms to 120 min, more preferably for 1 .0 ms to 60 min, even more preferably for 10.0 ms to 20 min, most preferably for 100 ms to 5 min.

[0218] Preferably, after step b.1 and / or step b.2 have been carried out, excess precursors and by-products are removed, more preferably by either purging with argon or by applying vacuum.

[0219] Step b is optionally followed by steps c.1 and c.2 for one or more times, which might again be followed by one or more steps b. The sequence of one or more steps b using lithium containing compounds of formula (A) and / or its tautomers or other metal containing compounds as precursors, and optionally one or more steps c.1 and c.2 can be repeated until the desired number of layers is deposited on one and another.

[0220] Coated substrate

[0221] The present invention further relates to a coated substrate as obtainable according to the method of coating a substrate with one or more lithium containing layers as described above.

[0222] Particularly, the substrate is defined as in the afore-mentioned method and the lithium compounds are those as defined for the compound of formula (A) as used in the method according to the invention.

[0223] In the following the present invention is further described by use of examples.

[0224] EXPERIMENTAL PART

[0225] Thermogravimetric measurements were conducted on a Mettler-Toledo DSC / TGA 1 STAR® System. 8 to 10 mg of Li-compound was introduced in an Al crucible (100 l, type ME-51119872) under inert atmosphere in an N2 filled glovebox. The crucible was then transferred from the glovebox to the setup. The sample was heated in N2 from 25 °C to 400 °C with a heating rate of 10 K / min. Data processing was conducted with the manufacturers software to identify the onset of evaporation.

[0226] Differential scanning calorimetry measurements were conducted on a Mettler-Toledo DSC1 type system. 8 to 10 mg of Li-compound was introduced in an Al crucible (40 pl, type ME-27331) under inert atmosphere in an N2 filled glovebox. The crucible was then transferred from the glovebox to the setup. The sample was heated from 25 °C to 400 °C with a heating rate of 10 K / min. Data processing was conducted with the manufacturers software to identify the melting point and decomposition temperature. If melting points and / or decomposition points are herein referred to as a range, the melting point and / or decomposition point is the lowest temperature reported at which melting starts.

[0227] The melting point, decomposition temperature and onset of mass loss was determined with the software (STAR ® SW 14.00) according to Lukas Muller et al., Materials, 2020, 13(20), 4486. The melting point is the onset of the first endothermic peak in DSC, determined as intersection between baseline and tangential at the left point of inflection. The decomposition temperature is the onset of the first exothermic peak in DSC, determined as intersection between baseline and tangential at the left point of inflection. The onset of mass loss is the temperature determined by the intersection between the baseline and the first point of inflection in thermogravimetric analysis (TGA).

[0228] 1-Methyl-3-propylimino-but-1-enoxy-lithium

[0229] (R1= R2= CH3, R3= H, R4= n-propyl, Z = O) A 500 ml three neck flask equipped with magnetic stirrer, thermometer, dropping funnel and Schlenk sintered glass frit was attached to the Schlenk line and filled with argon. Then, 50 ml of anhydrous n-hexane and 32.48 g (0.23 mol) of 4-(propylimino)-2-pentanone (prepared as described in: Zhang, Y.; Raines, A. J.; Flowers, R. A. Solvent- Dependent Chemoselectivities in Additions of P-Carbonyl Imines to Allyltrimethylsilane with CTAN. The Journal of Organic Chemistry 2004, 69 (19), 6267-6272) were charged into the flask. The colorless solution was then deoxygenated via five consecutive steps of evacuation (to 100 mbar) I backfilling with argon. The flask was then immersed into water-ice bath and 100 ml of a 2.3 M-solution of n-hexyllithium (0.23 mol) was added during 10 minutes under intense stirring. The flask with the light-yellow solution was slowly immersed into acetone-dry ice bath (-78 °C), and the mixture was stirred 1 h at this temperature. The white precipitate was filtered off on the Schlenk frit. The filter cake was washed with 50 ml of cold (-78 °C) deoxygenated hexane and then dried under 0.4 mbar vacuum for 8 h to afford 12.4 g of the title compound as white powder, having a melting point at 124 °C.

[0230] Example 2

[0231] 3-lsopropylimino-1-methyl-but-1-enoxy-lithium

[0232] (R1= R2= CH3, R3= H, R4= i-propyl, Z = O)

[0233] This compound was prepared as described in: Brehon, M.; Cope, E. K.; Mair, F. S.; Nolan, P.; O'Brien, J. E.; Pritchard, R. G.; Wilcock, D. J. Structural studies of lithiated enaminones: the 1-oxa-5-azapentadienyllithium fluxional heterocubane [(PriNCMeCHCMeOLi)4] and its dimeric hexamethylphosphoric triamide complex [{PriNCMeCHCMeOLi.OP(NMe2)3}2], J. Chem. Soc., Dalton Trans. 1997, (19), 3421-3425. A white solid was obtained having a melting point at -176 °C.

[0234] Example 3

[0235] 3-lsobutylimino-1-methyl-but-1-enoxy-lithium

[0236] (R1= R2= CH3, R3= H, R4= CH2-CH(CH3)2, Z = O)

[0237] In a 250 ml round bottomed flask with magnetic stirrer and Dean-Stark water trap were charged 100 ml benzene, 60.1 g (0.6 mol) acetyl acetone and 48.3 g (0.66 mol) iso-butylamine. The mixture was then refluxed until the water separation stops. The benzene was then evaporated on a rotary evaporator and the yellow liquid residue was distilled under reduced pressure to afford 82.7 g of pure 4-[(2-methylpropyl)imino]-2-pentanone as a colorless liquid, boiling point: 59-60 °C at 0.07 mbar (1H-NMR data (CDCI3, 300 MHz, ppm): 11-10.8 (bs, 1 H), 4.81 (s, 1 H), 2.91 (t, 2H), 1.88 (s, 3H), 1.73 (s, 3H), 1.68 (heptet, 1 H), 0.83 (d, 6 H).

[0238] The title compound was prepared in analogy to Example 1 using 35,7 g (0,23 mol) of the 4-[(2-methylpropyl)imino]- 2-pentanone as obtained above, 10 ml n-hexane solvent and 100 ml of a 2.3 M-solution of n-hexyllithium in hexane. Yield: 26.7 g of a white solid melting at 105 °C. Example 4

[0239] 3-(2-Ethylhexylimino)-1-methyl-but-1-enoxy-lithium

[0240] (R1= R2= CH3, R3= H, R4= CH2-CH(C2H5)-CH2CH2CH2CH3, Z = 0)

[0241] First, 4-[(2-ethylhexyl)imino]-2-pentanone was prepared in analogy to Example 3, but using 60.1 g (0.6 mol) acetyl acetone, 77.5 g (0.6 mol) of 2-ethylhexylamine and 100 ml of benzene. Yield: 115,2 g of a colorless liquid, boiling point 105-7 °C at 0,07 mbar. The lithiation of the

[0242] 4-[(2-ethylhexyl)imino]-2-pentanone was carried out in analogy to Example 1, but using 48.6 g (0.23 mol) of 4-[(2- ethylhexyl)imino]-2-pentanone, 10 ml n-hexane solvent and 100 ml of a 2.3 M-solution of n-hexyllithium in hexane. After evaporation of hexane, 49.9 g of the title compound as a slightly yellow viscous oil was obtained.

[0243] Example 5

[0244] 3-(3-Methoxypropylimino)-1-methyl-but-1-enoxy-lithium

[0245] (R1= R2= CH3, R3= H, R4= CH2CH2CH2-O-CH3, Z = O)

[0246] This compound was prepared as described in: Junge Puring, K.; Zywitzki, D.; Taffa, D. H.; Rogalla, D.; Winter, M.; Wark, M.; Devi, A. Rational Development of Cobalt P-Ketoiminate Complexes: Alternative Precursors for Vapor- Phase Deposition of Spinel Cobalt Oxide Photoelectrodes. Inorg. Chem. 2018, 57 (9), 5133-5144. A white solid having a melting point ranging from 110-115 °C was obtained.

[0247] Example 6

[0248] 3-[3-(Dimethylamino)propylimino]-1-methyl-but-1-enoxy-lithium

[0249] (R1= R2= CH3, R3= H, R4= CH2CH2CH2-N(CH3)2, Z = O)

[0250] This compound was prepared as described in: Scheiper, C.; Dittrich, D.; Woelper, C.; Blaeser, D.; Roll, J.; Schulz, S. Synthesis, Structure, and Catalytic Activity of Tridentate, Base-Functionalized [3-Ketiminate Zinc Complexes in Ring-Opening Polymerization of Lactide. Eur. J. Inorg. Chem. 2014, 2014 (13), 2230-2240. A white solid having a melding point ranging from 102-107 °C was obtained.

[0251] Example 7

[0252] 1-Methyl-3-phenylimino-but-1-enoxy-lithium

[0253] (R1= R2= CH3, R3= H, R4= phenyl, Z = O)

[0254] This compound was prepared as described in: Patil, S. A.; Medina, P. A.; Antic, A.; Ziller, J. W.; Vohs, J. K.; Fahlman, B. D. Hafnium (IV) chloride complexes with chelating p-ketiminate ligands: Synthesis, spectroscopic characterization and volatility study. Spectrochim. Acta, Part A 2015, 148, 223-231. A yellow solid having a melting point at 253 °C was obtained.

[0255] Example 8 lsopropyl-(3-isopropylimino-1-methyl-but-1-enyl)-amino-lithium

[0256] (R1= R2= CH3, R3= H, R4= CH(CH3)2, Z = NCH(CH3)2)

[0257] This compound was prepared as described in: Kuhn, N.; Fuchs, S.; Steimann, M. Synthesis and structure of vinamidinatodiiodoalanes. Z. Anorg. Allg. Chem. 2002, 628 (2), 458-462. A white solid, with a decomposition temperature at 160 °C was obtained.

[0258] Example 9

[0259] 3-[3-(Diethylamino)propylimino]-1-methyl-but-1-enoxy]-lithium

[0260] (R1= R2= CH3, R3= H, R4= CH2CH2CH2N(C2H5)2, Z = O)

[0261] First, 4-[3-(diethylamino)propylimino]pentan-2-one was prepared as described in: Fan, W.; Gao, J.; Jia, J.; Han, L; Sheng, W.; Li, Y. Solvent-free synthesis of p-enamino ketones (esters) under high-speed vibration milling (HSVM) condition. Youji Huaxue 2010, 30 (11), 1732-1736.

[0262] The title compound was prepared in analogy to Example 1 using 48,84 g (0,23 mol) of 4-[3- (diethylamino)propylimino]pentan-2-one and 100 ml of a 2.3 M-solution of n-hexyllithium in hexane. Yield: 33 g of a white solid having a melting point ranging from 80-85 °C.

[0263] Example 10

[0264] 3-(2-methoxyethylimino)-1-methyl-but-1-enoxy]-lithium

[0265] (R1= R2= CH3, R3= H, R4= CH2CH2-O-CH3, Z = O)

[0266] This compound was prepared as described in: O'Donoghue, R.; Rahman, S.; Mallick, B.; Winter, M.; Rogalla, D.; Becker, H.-W.; Devi, A. Molecular engineering of Ga-ketoiminates: synthesis, structure and evaluation as precursors for the additive-free spin-coated deposition of gallium oxide thin films. New J. Chem. 2018, 42 (5), 3196- 3210. A white solid having a melting point ranging from 80-85 °C was obtained.

[0267] Example 11

[0268] 3-Cyclohexylimino-1-methyl-but-1-enoxy]lithium

[0269] (R1= R2= CH3, R3= H, R4= cyclohexyl, Z = O)

[0270] First, 4-cyclohexyliminopentan-2-one was prepared as described in: Stalzer, M. M.; Lohr, T. L; Marks, T. J. Synthesis, Characterization, and Thermal Properties of N-alkyl P-Diketiminate Manganese Complexes. Inorganic Chemistry 2018, 57 (6), 3017-3024. The title compound is prepared in analogy to Example 1 using 41 ,69 g (0,23 mol) of 4-cyclohexyliminopentan-2-one, and 100 ml of a 2.3 M-solution of n-hexyllithium in hexane. Yield: 40 g of a white solid having a melting point ranging from 180-185 °C.

[0271] Example 12

[0272] 3-Benzylimino-1-methyl-but-1-enoxy]-lithium

[0273] (R1= R2= CH3, R3= H, R4= benzyl, Z = O)

[0274] First, 4-benzyliminopentan-2-one was prepared as described in: Chuang, W.-J.; Huang, Y.-T.; Chen, Y.-H.; Lin, Y.- S.; Lu, W.-Y.; Lai, Y.-C.; Chiang, M. Y.; Hsu, S. C. N.; Chen, H.-Y. Synthesis, characterization, and catalytic activity of sodium ketminiate complexes toward the ring-opening polymerization of l-lactide. RSC Advances 2016, 6 (39), 33014-33021. The title compound was prepared in analogy to Example 1 using 43,53 g (0,23 mol) of 4- benzyliminopentan-2-one, and 100 ml of a 2.3 M-solution of n-hexyllithium in hexane. Yield: 35 g of a white solid having a melting point ranging from 120-125 °C.

[0275] Example 13

[0276] 1-Ethoxy-3-isopropylimino-but-1-enoxy]-lithium

[0277] (R1= CH3, R2= O-CH2CH3, R3= H, R4= i-propyl, Z = O)

[0278] This compound was prepared as described in: Mears, K. L; Bhide, M. A.; Knapp, C. E.; Carmalt, C. J. Investigations into the structure, reactivity, and AACVD of aluminium and gallium amidoenoate complexes. Dalton Trans. 2022, 51 (1), 156-167. A white solid having a melding point ranging from 130-135 °C was obtained.

[0279] Example 14

[0280] 1-Ethoxy-3-(3-methoxypropylimino)but-1-enoxy]-lithium

[0281] (R1= CH3, R2= O-CH2CH3, R3= H, R4= CH2-CH2-CH2-O-CH3, Z = O)

[0282] First, ethyl (3E)-3-(3-methoxypropylimino)butanoate was prepared as described in: Fan, W.; Gao, J.; Jia, J.; Han, L; Sheng, W.; Li, Y. Solvent-free synthesis of p-enamino ketones (esters) under high-speed vibration miling (HSVM) condition. Youji Huaxue 2010, 30 (11), 1732-1736. The title compound is prepared in analogy to Example 1 using 46.29 g (0.23 mol) of ethyl (3E)-3-(3-methoxypropylimino)butanoate, and 100 ml of a 2.3 M-solution of n- hexyllithium in hexane. The compound, about 40 g, separated as a thick, light-yellow oil after cooling of the reaction mixture to -60 °C. It formed at room temperature a clear, light yellow viscous oil.

[0283] Example 15

[0284] [(E,3E)-3-[3-(diethylamino)propylimino]-1-ethoxy-but-1-enoxy]lithium

[0285] (R1= CH3, R2= O-CH2CH3, R3= H, R4= CH2-CH2-CH2-N(CH2CH3)2, Z = O) First, ethyl (3E)-3-[3-(dimethylamino)propylimino]butanoate was prepared as described in: Steck, E. A.; Brundage, R. P.; Fletcher, L. T. Some applications of the Nenitzescu reaction. J. Org. Chem. 1959, 24, 175O._The title compound is prepared in analogy to Example 1 using 49.29 g (0.23 mol) of ethyl (3E)-3-[3- (dimethylamino)propylimino]butanoate, and 100 ml of a 2.3 M-solution of n-hexyllithium in hexane. Yield: 37,2 g of a white solid having a melding point ranging from 102-108 °C.

[0286] [(Z,3E)-3-butylimino-1-methyl-but-1-enoxy]lithium

[0287] (R1= R2= CH3, R3= H, R4= n-butyl, Z = O)

[0288] First, (4E)-4-butyliminopentan-2-one was prepared as described in: Matthews, J. S.; Onakoya, 0. 0.; Ouattara, T. S.; Butcher, R. J. Synthesis and characterization of zinc AP-MOCVD precursors and their utility in the growth of ZnO. Dalton Trans. 2006, (31), 3806-3811. The title compound was prepared in analogy to Example 1 using 35.7 g (0.23 mol) of (4E)-4-butyliminopentan-2-one, and 100 ml of a 2.3 M-solution of n-hexyllithium in hexane. Yield: 27 g of a white solid having a melding point ranging from105-108 °C.

[0289] Example 17

[0290] [(Z,3E)-1-(dimethylamino)-3-(3-methoxypropylimino)but-1-enoxy]lithium

[0291] (R1= CH3, R2= N(CH3)2, R3= H, R4= CH2-CH2-CH2-O-CH3, Z = O)

[0292] First, (3E)-3-(3-methoxypropylimino)-N,N-dimethyl-butanamide was prepared as follows. In a 250 ml round bottomed flask with magnetic stirrer and Dean-Stark water trap were charged 80 ml benzene, 77.5 g (0.6 mol) dimethylamino-aceto-acetamide and 64.2 g (0.72 mol)

[0293] 3-methoxy-propylamine. The mixture was then refluxed until the water separation stops. The benzene was then evaporated on a rotary evaporator, and the yellow liquid residue was distilled under reduced pressure to afford 90.3 g of the pure title compound as a colorless liquid, having a boiling point ranging from 125-126 °C at 0,06 mbar H- NMR data: (CDCI3, 300 MHz, ppm): 9,4 (bs, 1 H), 4,45 (s, 1 H), 3,35 (t, 2H), 3,25 (s, 3H), 3,18 (m, 2H), 2,8 (s, 6H), 1,85 (s, 3H), 1 ,65 (m, 2H)). The title compound was prepared in analogy to Example 1 using 46.1 g (0.23 mol) of (3E)-3-(3-methoxypropylimino)-N,N-dimethyl-butanamide, and 100 ml of a 2.3 M-solution of n-hexyllithium in hexane. Yield: 41 .3 g of a light-yellow solid melting at 90-95 °C.

[0294] [(Z,3E)-1-(dimethylamino)-3-[3-(dimethylamino)propylimino]but-1-enoxy]lithium

[0295] (R1= CH3, R2= N(CH3)2, R3= H, R4= CH2-CH2-CH2-N(CH3)2, Z = O) First, (3E)-3-[3-(dimethylamino)propylimino]-N,N-dimethyl-butanamide was prepared in analogy to the first step of Example 17 using 3-dimethylamino-propylamine instead of 3-methoxy-propylamine. A colorless liquid resulted, (yield: 90.4 g), boiling point range from 129-130 at 0,05 mbar (1H-NMR data: (CDCI3, 300 MHz, ppm): 9,4 (bs, 1 H), 4,40 (s, 1 H), 3, 1 (m, 2H), 2,75 (s, 6H), 2,15 (t, 2H), 2,05(s, 6H), 1 ,75 (s, 3H), 1 ,55 (m, 2H)). The title compound was prepared in analogy to Example 1 using 49.1 g (0.23 mol) of (3E)-3-[3-(dimethylamino)propylimino]-N, N-dimethyl- butanamide, and 100 ml of a 2.3 M-solution of n-hexyllithium in hexane. Yield: 47.5g of a white solid having a melting point ranging from 140-143 °C.

[0296] Example 19

[0297] [(Z,3E)-3-(dimethylhydrazono)-1-methyl-but-1-enoxy]lithium

[0298] (R1= CH3, R2= CH3, R3= H, R4=-N(CH3)2, Z = O)

[0299] First, 2,4-pentanedione, 2-(2,2-dimethylhydrazone) was prepared as described in: N. V. Kuratieva, E. S. Vikulova, A. D. Shushanyan, N. S. Nikolaeva, S. I. Dorovskikh, N. S. Mikhaleva, N. B. Morozova. Structure of Cu(ll) and Pd(ll) complexes with 2-(2,2-dimethylhydrazone)pentanone-4. Journal of Structural Chemistry. Vol. 58, No. 5, pp. 1004-1008, 2017.

[0300] The title compound was prepared in analogy to Example 1 using 32.7 g (0.23 mol) of 2,4-pentanedione, 2-(2,2- dimethylhydrazone), and 100 ml of a 2.3 M-solution of n-hexyllithium in hexane. Yield: 27 g of a white solid having a melding point ranging from 165-170 °C.

[0301] Example 20

[0302] [(E,3Z)-1-ethoxy-4,4,4-trifluoro-3-isopropylimino-but-1-enoxy]lithium

[0303] (R1= CF3, R2= OCH2CH3, R3= H, R4= CH(CH3)2, Z = O)

[0304] First, ethyl 4,4,4-trifluoro-3-[(1-methylethyl)imino]butanoate was prepared as described in: A. W. Lutz, S. H.

[0305] Trotto. Novel 6-(trifiuoromethyl)cytosines and 6-(trifluoromethyl)uracils. Journal of Heterocyclic Chemistry 1972 Vol. 9 Issue 3 Pages 513-522.

[0306] The title compound was prepared in analogy to Example 1 using 51 ,7 g (0.23 mol) of ethyl 4,4,4-trifluoro-3-[(1- methylethyl)imino]butanoate, and 100 ml of a 2.3 M-solution of n-hexyllithium in hexane. Yield: 42 g of a white solid having a melding point ranging from 140-145 °C.

[0307] Example 21

[0308] [(3Z)-3-(3-methoxypropylimino)cyclohexen-1-yl]oxylithium

[0309] (R1and R2form together a linking group CH2-CH2-CH2, R3= H, R4= CH2CH2CH2OCH3, Z = 0) First, 3-[(3-methoxypropyl)amino]-2-cyclohexen-1-one was prepared as described in: "Process for producing 3- aminocyclohex-2-en-1-ylidene compounds” IP.com J. 2013 Vol. 13 Issue 2A P. 25.

[0310] The title compound was prepared in analogy to Example 1 using 42,2 g (0.23 mol) of 3-[(3-methoxypropyl)amino]- 2-cyclohexen-1-one, and 100 ml of a 2.3 M-solution of n-hexyllithium in hexane. Yield: 37,5 g of a white solid not melting before 200 °C.

Claims

CLAIMS1. Use of a lithium containing compound of formula (A) and / or its tautomerswhereinR1being selected from the group consisting of linear or branched alkyl groups containing 1 to 8 carbon atoms, cycloalkyl groups containing 4 to 6 carbon atoms, aralkyl groups, aryl groups, and CF3;R2being selected from the group consisting of linear or branched alkyl groups containing 1 to 8 carbon atoms,CF3, linear or branched alkoxy groups containing 1 to 8 carbon atoms, cycloalkyl groups containing 4 to 6 carbon atoms, O-cycloalkyl groups containing 4 to 6 carbon atoms, aralkyl groups, aryl groups,O-aralkyl groups, and if Z = 0, NRaRbgroups wherein Raand Rbare independently selected from alkyl groups containing 1 to 8 carbon atoms; orR1and R2together are a linking group CH2-CRr2-CH2, wherein both residues Rrare independently of each other H or CH3, thus forming a 6-membered ring with the adjacent C-C(R3)=C motive;R3being selected from the group consisting of H,linear or branched alkyl groups containing 1 to 8 carbon atoms, cycloalkyl groups containing 4 to 6 carbon atoms, allyl groups, aralkyl groups and aryl groups;R4being selected from the group consisting ofH,NRaRbas defined for residue R2,ORC, wherein Rcis an alkyl group containing 1 to 6 carbon atoms, L-N=CR1'-CR3'=CR2'-Z'-Li, whereinL is a divalent hydrocarbon group containing 2 to 6 carbon atoms, R1' is defined as R1,R2' is defined as R2,R3' is defined as R3, andZ' is defined as Z below,R5-X, whereinR5is a divalent aliphatic, araliphatic or aromatic hydrocarbon residue containing 1 to 16 carbon atoms, andX being selected from the group consisting of H, NRaRbas defined for residue R2, and 0Rcwherein Rcis an alkyl group containing 1 to 6 carbon atoms;Z being 0 or NR6, wherein R6is selected from the group consisting ofH,ORCwherein Rcis an alkyl group containing 1 to 6 carbon atoms, NRaRb, wherein Raand Rbare as defined for residue R2; and R5-X, wherein R5and X are as defined for residue R4; as precursor in the formation of lithium containing films in a vapor deposition method, preferably chemical vapor deposition method, particularly preferred in an atomic layer deposition method.

2. Use of a lithium containing compound of formula (A) and / or its tautomers according to claim 1 , characterized in thatR1is selected from the group consisting of linear or branched alkyl groups containing 1 to 6 carbon atoms, and phenyl groups;R2is selected from the group consisting of linear or branched alkyl groups containing 1 to 6 carbon atoms, linear or branched alkoxy groups containing 1 to 6 carbon atoms, and phenyl groups;R3is selected from the group consisting of H, linear or branched alkyl groups containing 1 to 4 carbon atoms, cycloalkyl groups containing 5 to 6 carbon atoms, allyl, and benzyl groups.

3. Use of a lithium containing compound of formula (A) as defined in claim 1 , wherein R3,R6, Ra, Rband Rcare defined in claim 1 or 2, being further characterized in that the(I) R1and R2are as defined in claims 1 or 2, andR4is selected from the group consisting of benzyl, cycloalkyl groups containing 4 to 6 carbon atomsNRaRb,ORC,L-N=CR1’-CR3’=CR2’-Z’-Li, whereinL is a divalent hydrocarbon group containing 2 to 6 carbon atoms,R1' is defined as R1in claim 1 or 2,R2' is defined as R2in claim 1 or 2,R3' is defined as R3in claim 1 or 2, andZ' is defined as Z in claim 1 or 2; andR5-X, wherein R5-X is selected from the group consisting ofCR2-CR2-CR2-X, wherein the R residues are independently selected from the group consisting ofH, and linear or branched alkyl group containing 1 to 3 carbon atoms, and the X is selected from the group consisting ofH, linear or branched alkyl containing 1 to 6 carbon atoms,NRaRb, andORC, wherein Ra, Rband Rcare independently from each other alkyl groups containing 1 to 6 carbon atoms; in case of Z is NR6, R6is a linear or branched C1-C3 alkyl group; and in case of Z is 0, and X is NRaRbor OR'g. the sum of carbon atoms in R1, R2plus R3> 3; and / or h. the sum of carbon atoms in Raplus Rb> 3; and / or i. R2is selected from the group consisting of linear or branched alkoxy groups containing 1 to 8 carbon atoms and O-cycloalkyl groups containing 4 to 6 carbon atoms; or(ii) in case only R1is CF3, residues R2, R3, R4and Z are as defined in claims 1 or 2; and in case only R2is CF3, residues R1, R3, R4are as defined in claims 1 or 2 and Z=O; and in case R1= R2= CF3 residues R3, R4and Z are as defined in claims 1 or 2, with the proviso that R4is neither an aromatic group nor CH2-CH2-N(Et)2.

4. Use of a lithium containing compound of formula (A) and / or its tautomers according to any one or more of the preceding claims, characterized in that the lithium containing compound of formula (A) has a melting point of < 200 °C, more preferred < 180 °C.

5. Use of a lithium containing compound of formula (A) and / or its tautomers according to any one of more of the preceding claims, characterized in that the lithium containing compound of formula (A) has an onset of mass loss at a temperature < 180 °C, more preferred < 150 °C.

6. Lithium containing compound of formula (A) and / or its tautomers as defined in claim 3.

7. Lithium containing compound of formula (A) and / or its tautomers according to claim 6, characterized in that the lithium containing compound of formula (A) has a melting point of < 200 °C, more preferred < 180 °C.

8. Lithium containing compound of formula (A) and / or its tautomers according to any one of more of the preceding claims, characterized in that the lithium containing compound of formula (A) has an onset of mass loss at a temperature < 180 °C, more preferred < 150 °C.

9. Method of producing a lithium containing compound of formula (A) and / or its tautomers as defined in claim 3, characterized in thata. a compound of formula (I)is reacted with a compound of formula R4-NH2 or a compound of formula H2N-L-NH2, and, if Z is NR6, is further reacted with a compound of formula R6-NH2, followed by b. lithiation.

10. Method of coating a substrate with one or more lithium containing layers, characterized in that the lithium containing compound or compounds and / or their tautomers, as defined in any one or more or claims 1 to 5, are vaporized and deposited on a substrate and subsequently reacted.

11. Method according to claim 10, wherein the lithium containing compound is vaporized and deposited by chemical vapor deposition, preferably atomic layer deposition.

12. Method according to claim 11, comprising a. providing an uncoated or precoated substrate, b. depositing at least one inorganic layer (L') on the uncoated or precoated substrate by gas phase deposition, preferably chemical gas phase deposition, more preferred atomic layer deposition, comprising steps b.1 and b.2, namely b.1 vaporizing and depositing one or more lithium containing compounds of formula (A) and / or its tautomers on the uncoated or precoated substrate to form layer b1, and b.2 subsequently to step b.1 applying one or more reactants on layer b1, which react with layer b1 to form layer L', and wherein step b. is carried out one or more times to deposit one or more inorganic layers (U).

13. Method according to claim 12, wherein the one or more reactants applied in step b.2 are selected from the group consisting of oxygen, water, ozone, hydrogen peroxide, oxygen plasma, hydrogen, hydrogen plasma, alcohols, hydrogen sulfide, sulfur, diethyl disulfide, nitrogen, ammonia, and nitrogen plasma.

14. Coated substrate obtained according to the method of claim 10 to 13.

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