Ab initio study of medium effects on the geometries of the compounds of trigonal-bipyramidal silicon with coordination center ClSiC3O

For a number of (O-Si)chelate and zwitterionic intramolecular complexes wit h coordination center ClSiC3O, appreciable discrepancies between the experi mental solid state geometry and those calculated at the HF/6-31G* level for the gas phase and solution were found. The established regularity of chang ing the molecular structure of complexes in going from the gas phase to the solution, and the solid state corresponds to that expected from an analysi s of the Si-29 NMR data and a physical model of the influence of medium on the geometry of hypervalent silicon compounds, developed earlier by the pre sent authors. (C) 2001 Elsevier Science B.V. All rights reserved.