Structural Investigation of New Lithium Amidinates and Guanidinates

Abstract

A series of potentially useful lithium amidinates and guanidinates were prepared and fully characterized. Treatment of N,N′‐diisopropylcarbodiimide with phenyllithium in diethyl ether afforded the lithium amidinate [PhC(NiPr)2Li(OEt2)]2 (1). Similar treatment of N,N′‐diorganocarbodiimides R′–N=C=N–R′ [R′ = iPr, cyclohexyl (Cy)] with secondary lithium amides LiNR2 [R2 = Et2, iPr2, (CH2)4] followed by crystallization from THF or 1,4‐dioxane gave the lithium guanidinates [R2NC(NR′)2Li(S)]2 [2: R = Et, R′ = iPr, S = THF; 3: R2 = (CH2)4, R′ = iPr, S = THF; 4: R = R′ = iPr, S = ½ 1,4‐dioxane; 5: R2 = (CH2)4, R′ = Cy, S = 1,4‐dioxane] as crystalline solids. Reaction of N‐lithioaziridine with the corresponding carbodiimides afforded solvent‐deficient [{C2H4NC(NiPr2)2}2Li2(THF)]2 (6), and [C2H4NC(NEt)(NtBu)Li(THF)]2 (7). Crystal structure determination revealed the presence of common ladder‐type dimeric structures for 1–5. Compound 6 exists as a dimer of two ladder‐type dimers in the crystal, and 7 exhibits an unusual dimeric structure comprising an eight‐membered C2N4Li2 ring.

Synthesis and Complexation Study of New Aminoalkynyl−amidinate Ligands

“…The range of N−Li−N bite angles in the lithium salt 2 a are fully consistent with this rule [N(1)−Li(1)−N(2) 65.3(1) and N(1 A)−Li(1 A)−N(2 A) 65.4(1)°]. All other bond lengths and angles in 2 a are in good agreement with similar structures of previously reported lithium amidinates [35–41] . The crystal structure of 1 a has also been determined, but due to poor diffraction only the connectivity could be clearly established.…”

High-Performance Iridium Thin Films for Water Splitting by CVD Using New Ir(I) Precursors

“…1:1 (Li-R: THF). At least for [Li­(THF)­(DPAMD)] 2 , a dimeric nature in the solid state of the complex could be proven by single-crystal X-ray diffraction (SC-XRD) analysis (Supporting Information, SI, Figure S9, Table S1) and is moreover in line with the results described by Liebing et al for similar lithium amidinate- and guanidinate-type complexes . Due to the extremely high reactivity of the lithiated complexes toward the ambient, further analysis and purification was not undertaken.…”

“…At least for [Li(THF)(DPAMD)] 2 , a dimeric nature in the solid state of the complex could be proven by single-crystal X-ray diffraction (SC-XRD) analysis (Supporting Information, SI, Figure S9, Table S1) and is moreover in line with the results described by Liebing et al for similar lithium amidinateand guanidinate-type complexes. 32 Due to the extremely high reactivity of the lithiated complexes toward the ambient, further analysis and purification was not undertaken. Hence, the lithiated complexes were directly used after isolation for the formation of the targeted iridium complexes through a salt metathesis reaction with [Ir(COD)Cl] 2 dimer species at mild reaction conditions.…”

High-performance iridium thin films for water splitting by CVD using new Ir(I) precursors

“…At least for [Li(THF)(DPAMD)]2, a dimeric nature in the solid state of the complex could be proven by single-crystal x-ray diffraction (SC-XRD) analysis (Supporting Information, SI, Figure S9, Table S1) and is moreover in line with the results described by Liebing et al for similar lithium amidinateand guanidinate-type complexes. [29] Due to the extremely high reactivity of the lithiated complexes towards the ambient, further analysis and purification was not undertaken. Hence, the lithiated complexes were directly used after isolation for the formation of the targeted iridium complexes through a salt metathesis reaction with [Ir(COD)Cl]2 dimer species at mild reaction conditions.…”