MRC: Magnetic Resonance in Chemistry, updated to April 2007

1-Cyclohepta-2,4,6-trienyl-selanes - a 77Se NMR study: Indirect nuclear 77Se13C spin-spin coupling constants and application of density functional theory (DFT) calculations
Bernd Wrackmeyer *, Zureima García Hernández, Max Herberhold
Anorganische Chemie II, Universität Bayreuth, D-95440 Bayreuth, Germany

*Correspondence to Bernd Wrackmeyer, Anorganische Chemie II, Universität Bayreuth, D-95440 Bayreuth, Germany.

Keywords
cylohepta-2,4,6-trienes • selenium • NMR • coupling constants • DFT calculations

Abstract
1-Cyclohepta-2,4,6-trienyl-selanes Se(C7H7)2 (2c), RSeC7H7 with R = Bu, tBu, Ph, 4-FC6H4 (12a,b,c,d) were prepared by the reaction of the corresponding silanes, Si(SeMe3)2 and RSeSiMe3, respectively, with tropylium bromide C7H7Br. In spite of the low stability of the selanes even in dilute solutions and at low temperature, they could be characterised by their 1H, 13C and 77Se NMR parameters. Coupling constants 1J(77Se,13C) were measured and calculated by DFT methods at the B3LYP/6-311+G(d,p) level of theory. The comparison of experimental and calculated coupling constants 1J(77Se,13C) included numerous selenium carbon compounds with largely different SeC bonds, revealing a satisfactory agreement. Both the spin-dipole (SD) and the paramagnetic spin-orbital (PSO) terms contributed significantly to the spin-spin coupling interaction, in addition to the Fermi contact (FC) term. Copyright © 2006 John Wiley & Sons, Ltd.
Received: 23 October 2006; Revised: 3 November 2006; Accepted: 7 November 2006

Digital Object Identifier (DOI)

10.1002/mrc.1946