Aluminum and Indium Complexes derived from Guanidines, Triazenes, and Amidines

Abstract

Abstract The reaction of guanidines, triazenes, amidines, and lithium amidinates with trimethylamine alane ([AlH3(NMe3)]), lithium tetrahydridoaluminate, trimethylaluminum, aluminum trichloride, and indium trichloride is reported. Equimolar reactions utilising hindered N,N′‐bis(2, 6‐diisopropylphenyl)guanidines afford [{AlX2L}n] species through hydrogen elimination (X = H) from [AlH3(NMe3)] (n = 2) with HCGiso (1), HDGiso (2), or HDPiso (3) [CGiso = N,N′‐bis(2, 6‐disopropylphenyl)‐N′′‐dicyclohexylguanidinate, DGiso = N,N′,N′′‐tris(2, 6‐diisopropylphenyl)guanidinate, DPiso = N,N′‐bis(2, 6‐diisopropylphenyl)‐P‐2, 6‐diisopropylphenylphosphguanidinate], or through methane elimination (X = Me) from AlMe3 [n = 1, L = CGiso (5)]. The analogous reactions of the triazene HTiso with LiAlH4 and AlMe3 selectively afford [AlH(Tiso)2] (4) and [AlMe2(Tiso)] (6), respectively [Tiso = 1, 3‐bis(2, 6‐diisopropylphenyl)triazenide]. Reactions of N,N′‐bis(aryl)formamidines/ates with half an equivalent of AlMe3/AlCl3 result in [AlXL2] complexes [X = Me; L = Fxy (7) or Fet (8); X = Cl; L = Fet (9) or L = Fiso (10)] [Fxy = N,N′‐bis(2, 6‐dimethylphenyl)formamidinate, Fet = N,N′‐bis(2, 6‐diethylphenyl)formamidinate, Fiso = N,N′‐bis(2, 6‐diisopropylphenyl)formamidinate]. Treatment of 1 with one equivalent of I2 yields [AlI2(CGiso)] (11). Attempts to prepare [InCl2L] congeners of 11 with L = Fxy and Fet led to the isolation of prodigious quantities of [InCl3(HFxy)2] (12) and [InCl2(Fet)(HFet)] (13) due to adventitious water. The X‐ray crystal structures of 1–13 are reported.