LINEAR SI-O-SI FRAGMENTS - STRUCTURE OF 1,1,3,3-TETRAMETHYL-1,3-BIS[(2-OXO-1-PYRROLIDINYL)METHYL]DISILOXANE DIHYDROCHLORIDE AND ANALYSIS OF DISPLACEMENT PARAMETERS

An X-ray diffraction study of 1,1,3,3-tetramethyl-1,3-bis[2-oxo-1-pyrrolidinyl)methyl]disiloxane dihydrochloride, C14H30N2O3Si2(2+).2Cl-, M(r) = 357.1, has been carried out at 120 K. The crystal is monoclinic, space group P2(1)/n, Z = 2; the cell dimensions at 120 K are a = 11.116 (3), b = 8.176 (3), c = 12.138 (6) angstrom, beta = 114.34 (3)-degrees, V = 1005.1 angstrom 3. Weighted least-squares refinement based on 1885 reflections converged at R = 0.031. The crystal is built of linear centrosymmetric disiloxane dications and Cl- anions bonded to the dications by strong O-H...Cl hydrogen bonds. Some aspects of the atomic motion and small deviations from standard geometry in the dication may be interpreted as indicating a weak Si...O interaction. Analysis of the displacement parameters of eight linear disiloxane moieties suggests that disordered arrangements of bent Si-O-Si fragments lead to apparent linearity of the molecules.