Structure, configuration, conformation and quantification of the push pull-effect of 2-alkylidene-4-thiazolidinones and 2-alkylidene-4,5-fused bicyclic thiazolidine derivatives
Abstract
Structures of a series of push-pull 2-alkylidene-4-thiazolidinones and 2-alkylidene-4,5-fused bicyclic thiazolidine derivatives were optimized at the B3LYP/6-31G(d) level of theory in the gas phase and discussed with respect to configurational and conformational stability. Employing the GIAO method, C-13 NMR chemical shifts of the C-2, C-2', C-4 and C-5 atoms were calculated at the same level of theory in the gas phase and with inclusion of solvent, and compared with experimental data. Push-pull effect of all compounds was quantified by means of the quotient pi*/pi, length of the partial double bond, C-13 NMR chemical shift difference (Delta delta(C=C)) and H-1 NMR chemical shifts of olefinic protons. The effect of bromine on donating and accepting ability of other substituents of the push-pull C=C double bond is discussed, too. (C) 2010 Elsevier Ltd. All rights reserved.
Keywords:
Push-pull effect / 2-Alkylidene-4-thiazolidinones / Ab initio MO calculation / NBO analysis / NMR spectroscopySource:
Tetrahedron, 2010, 66, 46, 8958-8967Publisher:
- Pergamon-Elsevier Science Ltd, Oxford
Projects:
- Deutscher Akademischer Austauschdienst (DAAD) [504 252 70]
- Ministry of Science of the Republic of Serbia
DOI: 10.1016/j.tet.2010.09.040
ISSN: 0040-4020