Structure of cyclohexylsilanetriol: The first x-ray crystal structure of a silanetriol

Abstract

The structure of cyclohexylsilanetriol C6H11Si(OH)3 has been determined by single-crystal x-ray diffraction methods. The molecule crystallizes in the monoclinic system, space group C2/m, with a=7.876(3), b=6.637(6), c=15.802(11) Å, β=95.51(3)° at −60 °C, and Z=4. The intensities of 1031 independent reflections were measured using the ω-scan technique on a Syntex P3 diffractometer (monochromatic MoKα). The final R factor is 0.057, based on anisotropic thermal parameters for all atoms except hydrogens. The molecules pack in a head-to-head, tail-to-tail arrangement with the cyclohexyl groups forming a hydrophobic double sheet and the silanetriol groups forming a second, hydrophilic, double sheet. The structure has a distorted hydrogen bond network with the hydrogen on each oxygen having equal probability of hydrogen bonding to oxygens in two different molecules. Two types of hydrogen bonds exist in the hydrophilic double sheet; O(1)⋅⋅⋅O(2) intrasheet hydrogen bonds, 2.724(2)Å, and O(2)⋅⋅⋅O(2) intrasheet hydrogen bond, 2.722(3) Å.