Beiträge zur Chemie des Bors, 124 [1] Tris(trimethylsilyl)silyl-borane und Tris(trimethylsilyl)silyl-borate / Contributions to the Chemistry of Boron, 124 [1] Tris(trimethylsilyl)silyl Boranes and Tris(trimethylsilyl)silyl Borates

Abstract

Abstract The reactions of several boron halides, methoxides, alkyls and hydrides with tris(tri-methylsilyl)silyllithium, which was isolated as the solvate [(CH3)3Si]3SiLi · 3C4H8O, 1(TMSSLi) have been studied. (CH3)2B−Si[Si(CH3)3]3 and 9−[(CH3)3Si]3Si-9-BBN, were isolated, while [(CH3)3Si]3Si-B(tC4H9)2 could only be detected by 11B NMR. In addition TMSS-B[N(CH3)2]2, (TMSS)2BNMe2 and (TMSS)2BOCH3 were prepared. The methoxy-boranes (CH3)3-nB(OCH3)n add to 1 forming silylborates; however, no OCH3/Si[Si(CH3)3]3 substitution occurs. The hydrogen bridge in 9-BBN is cleaved symmetrically. The results can be explained by the basicity and the steric requirements of the TMSS group. The TMSS group exhibits a deshielding effect at the boron nucleus relative to the (CH3)3Si group for silylboranes as well as for silylborates.