Ab initio determination of the geometric structure of oligo-2-thienyl ketones

Conformations, structural parameters and charge distributions of 2-acetylthiofene (THCO), di-2-thienyl ketone (2THCO) and higher oligomers (3THCO and 4THCO) have been determined by ab initio calculations at the HF/6-31** level of theory. Electron correlation effects have been investigated at the MP2/6-31G** level for THCO and at the MP2/6-311G**//HF/6-31G** level for 2THCO. The most probable conformation of oligo-2-thienylene ketones is rod-like, with a ring deviation from the main molecular plane of about 20 degrees and with prevailing S,O-cis orientation. (C) 1998 Elsevier Science B.V. All rights reserved.