The ring-puckering potential energy function and theoretical calculations for silacyclopent-2-ene-d(0) and 1,1-d(2) and the difluoro and dichloro derivatives
Academic Article
Overview
Research
Identity
Additional Document Info
Other
View All
Overview
abstract
High level ab initio and DFT calculations have been carried out for silacyclopent-2-ene and its 1,1-d2, 1,1-difluoro, and 1,1-dichloro derivatives. The previously published far-infrared spectra of the ring-puckering vibration, which had been interpreted to be characteristic of a rigid planar molecule, have been reanalyzed for the hydride and 1,1-d2 derivative. Both the spectra and the theoretical calculations show the molecule to have a small barrier to planarity. The experimental data analyzed with a Gaussian barrier produce a barrier of 49 cm-1 as compared to a value of 47 cm-1 computed using the CCSD/6-311++G(d,p) basis set. The experimental value for the deuteride was determined to be 41 cm-1 from the one-dimensional approximation. All MP2 and DFT computations for the 1,1-difluoro derivative predict a planar structure whereas the MP2 computation when used with triple- basis set predicts a barrier of 13 cm-1 for the chloride. Vibrational frequencies were also computed for these molecules and compared to experimental results for the characteristic frequencies for these types of molecules. 2007 Elsevier Inc. All rights reserved.
