Syntheses and crystal structures of 2-methyl-1,1,2,3,3-penta-phenyl-2-sila-propane and 2-methyl-1,1,3,3-tetra-phenyl-2-silapropan-2-ol.

ABSTRACT: The sterically hindered silicon compound 2-methyl-1,1,2,3,3-penta-phenyl-2-sila-propane, C₃₃H₃₀Si (I), was prepared via the reaction of two equivalents of di-phenyl-methyl-lithium (benzhydryllithium) and di-chloro-methyl-phenyl-silane. This bis-benzhydryl-substituted silicon compound was then reacted with tri-fluoro-methane-sulfonic acid, followed by hydrolysis with water to give the silanol 2-methyl-1,1,3,3-tetra-phenyl-2-silapropan-2-ol, C₂₇H₂₆OSi (II). Key geometric features for I are the Si-C bond lengths that range from 1.867?(2) to 1.914?(2)?Å and a ?₄ descriptor for fourfold coordination around the Si atom of 0.97 (indicating a nearly perfect tetra-hedron). Key geometric features for compound II include Si-C bond lengths that range from 1.835?(4) to 1.905?(3)?Å, a Si-O bond length of 1.665?(3)?Å, and a ?₄ descriptor for fourfold coordination around the Si atom of 0.96. In compound II, there is an intra-molecular C-H?O hydrogen bond present. In the crystal of I, mol-ecules are linked by two pairs of C-H?? inter-actions, forming dimers that are linked into ribbons propagating along the b-axis direction. In the crystal of II, mol-ecules are linked by C-H?? and O-H?? inter-actions that result in the formation of ribbons that run along the a-axis direction.

SUBMITTER: Williams A 

PROVIDER: S-EPMC6727049 | biostudies-literature | 2019 Sep

REPOSITORIES: biostudies-literature