QUANTUM-CHEMICAL INVESTIGATION OF THE ELECTRONIC AND SPATIAL STRUCTURE OF 1-VINYLTETRAZOLES

Abstract

Calculations have been carried out of the total Mulliken charges on carbon and nitrogen atoms, the relative stability, and equilibrium populations of the s-cis(R) and s-trans(R) conformers of a series of 1-vinyl-5R-tetrazoles (R = H, Me, n-Bu, tert-Bu, Ph, NH2, I, CF3, NO2) by the ab initio MP2/6-31G** method. Out-of-plane structures correspond to the stable s-cis(R) conformer, and the deviation from planarity grows regularly with an increase in the bulk of the substituent. The proportion of s-trans(R) conformation increases in the same  series and reaches 100% for R = tert-C4H9. The data of quantum-chemical calculations are in agreement with the results of investigations of the spatial structure of 1-vinyl-5R-tetrazoles by  1H and  13C NMR methods. Values of the total energies of the corresponding homodesmotic reactions were calculated to assess the effect of the nature of the substituent in position 5 of the tetrazole ring on the size of the conjugation  energy in planar s-trans(R) conformations of the compounds investigated. The quantum-chemical calculations carried out show that the conjugation energy decreases regularly according to the increase in electron-withdrawing properties of the substituent in position 5 of the ring.

How to Cite
Ivashkevich, O. A.; Matulis, Vadim E.; Matulis, Vitalii E.; Gaponik, P. N.  Chem. Heterocycl. Compd. 2005, 41, 456. [Khim. Geterotsikl. Soedin. 2005, 537.]

For this article in the English edition, see DOI 10.1007/s10593-005-0171-y