Silicon version of enamines: Amino-substituted disilenes by the reactions of the disilyne RSi SiR (R = Si Pr[CH(SiMe3)2]2) with amines
摘要:
The reaction of 1,1,4,4-tetrakis[bis(trimethylsilyl) methyl]-1,4-diisopropyltetrasila-2-yne 1 with secondary or primary amines produced amino-substituted disilenes R(R-2'N)Si]Si=HR 2a-d (R = (SiPr)-Pr-i[CH (SiMe3)(2)](2), R-2'N=Et2N (2a), (CH2CH2)(2)N (2b), Bu-t(H)N (2c), and Ph2N (2d)). Spectroscopic and X-ray crystallographic analyses of 2 showed that 2a-c have a nearly coplanar arrangement of the Si=Si double bond and the amino group, giving pi-conjugation between the Si=Si double bond and the lone pair on the nitrogen atom, whereas 2d has a nearly perpendicular arrangement precluding such conjugation. Theoretical calculations indicate that pi-conjugation between the pi-orbital of the Si=Si double bond and the lone pair on the nitrogen atom is markedly influenced by the torsional angle between the Si=Si double-bond plane and the amino-group plane. (C) 2010 Elsevier B.V. All rights reserved.
Addition of Amines and Hydroborane to the Disilyne RSi≡SiR (R = Si<sup><i>i</i></sup>Pr[CH(SiMe<sub>3</sub>)<sub>2</sub>]<sub>2</sub>) Giving Amino- and Boryl-Substituted Disilenes
The reaction of 1,1,4,4-tetrakis[bis(trimethylsilyl)methyl]-1,4-diisopropyltetrasila-2-yne 1 with diethylamine or diphenylamine produced the corresponding amino-substituted disilenes R(R'N-2)Si=SiHR 2a, b (R = (SiPr)-Pr-i[CH(SiMe3)(2)](2), R' = Et (2a), Ph (2b)). The reaction of 1 with 9-borabicyclo[3.3.1]nonane afforded the boryl-substituted disilene R(R '' B-2)Si=SiHR 3 (R '' B-2 = 9-borabicyclo[3.3.1]nonan-9-yl). Spectroscopic and X-ray crystallographic analyses of 2a, b, and 3 showed that 2a and 3 have a coplanar arrangement of the Si=Si double bond and amino or boryl groups, giving pi-conjugation between the Si=Si double bond and the lone pair on the nitrogen atom or vacant orbital on the boron atom, whereas 2b exhibits no such conjugation.