Ab initio calculations on tetramethoxymethane

Abstract

This paper is dedicated to Professor Charles A . McDobvell on the occasion of his 70th birthdayR. J. MCEACHERN, J. A. WEIL, and P. G. MEZEY. Can. J. Chem. 66, 2041Chem. 66, (1988. Minimal basis set ab initio SCF-MO calculations were performed on the 21-atom system of tetramethoxymethane (tetramethyl orthocarbonate). The geometric configuration of this model was optimized in two conformations, one having quasi-S4 symmetry and the other DZd symmetry. The S4 conformation was found to be 8 kJ mol-' lower in energy than the D,, conformation, at the STO-3G level. The calculated energy difference is consistent with the recently measured geometric configuration of crystalline tetrabenzyl orthocarbonate. The calculated values of the bond lengths and angles were compared to the results of an electron diffraction study of the methyl species, and agree well with experiment. The theoretical electric dipole moment was calculated to be 0.01 D. [Traduit par la revue]