Chiral Dimethylindium Aminoalkoxides

Abstract

Chiral dimethylindiumaminoalkoxides of general formula Me₂InOR^* [OR^* = (+);(–)-2-piperidyl-methoxy (1), (+);(–)-dimethylamino-2-propoxy (2), (S)-(+)-amino-2-propoxy (3), (s)-α, α-diphenyl-2-pyrrolidinyl-methoxy (4)] have been prepared by reaction of Me₃In with the corresponding aminoalcohols HOR^* and characterized by ¹H and ¹³C nmr spectroscopy and X-ray crystallography. Dimeric molecules of 1 – 4 are composed of two μ²-O-bridged chelating rings, the latter formed due to N — In donor-acceptor interaction. This geometry is comparable with that of aluminium and gallium analogues previously investigated. In the case of 1 and 4, the formation of the N — In bond proceeds stereospecifically. The absolute structure of 3 and 4 was confirmed by refinement of the Flack parameter. 1: C2/m; a = 15.999(3) Å, b = 9.803(2) Å, c = 7.410(1) Å, β = 111.04(3)°; Z = 2; density (calc.) = 1.586 Mg/m³; R1 = 0.026 for 944 independent reflections with F² > 2σ(F²). 2: C2/c; a = 13.184(3) Å, b = 9.987(2) Å, c = 15.851(3) Å, β = 90.66(3)° Z = 4; density (calc.) = 1.573 Mg/m³; R1 = 0.021 for 1890 independent reflections with F² > 2σ(F²). 3: P2₁; a = 8.701(2) Å, b = 11.944(2) Å, c = 8.831(1) Å, β = 113.26(3)° Z = 2; density (calc.) = 1.725 Mg/m³; R1 = 0.018 for 2873 independent reflections with F² > 2σ(F²). 4: R3; a = 29.708(4) Å, c = 11.017(2) Å; Z = 9; density (calc.) = 1.265 Mg/m³; R1 = 0.034 for 5890 independent reflections with F² > 2σ(F²).