Benzthiazole and Thiophene Capped Polyenes for Nonlinear Optical Applications: Single Crystal, Semi-empirical and A b Initio Results
Materials Research Society Symposium Proceedings
The molecule 2-(2-benzthiazolyl)-1-(2-thienyl)ethene has been studied by x-ray crystallography and has been found to be in the planar conformation with the double bonds in the trans configuration (from the N=C of the benzthiazole to the first double bond in the thiophene). Semi-empirical calculations show this configuration to be the least stable one by 1.5 Kcal/mole. To determine whether this discrepancy is due to crystal packing forces or a deficiency in the semi-empirical methodologies employed, ab initio Hartree-Fock calculations at the RHF/6–31G* level were performed on the four possible planar conformations. A comparison of the AM1 and the Hartree-Fock calculations indicates that while AM1 reproduces the trend in the energy components well, the trend in the total energy is not reproduced well. Comparisons with the experimental structure are also made. Analysis of the second hyperpolarizability indicates an enhancement of the NLO properties of this molecule over that of the uncapped polyenes.
Cambridge University Press
Yeates, Alan T.; Dudis, Douglas; Resch, T.; and Fratini, Albert, "Benzthiazole and Thiophene Capped Polyenes for Nonlinear Optical Applications: Single Crystal, Semi-empirical and A b Initio Results" (1992). Chemistry Faculty Publications. 20.