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

✍ Scribed by Bernd Wrackmeyer; Zureima García Hernández; Max Herberhold

• Publisher: John Wiley and Sons
• Year: 2007
• Tongue: English
• Weight: 229 KB
• Volume: 45
• Category: Article
• ISSN: 0749-1581
• DOI: 10.1002/mrc.1946

✦ Synopsis

Abstract

1‐Cyclohepta‐2,4,6‐trienyl‐selanes Se(C~7~H~7~)~2~ (2c), RSeC~7~H~7~ with R = Bu, ^t^Bu, Ph, 4‐FC~6~H~4~ (12a,b,c,d) were prepared by the reaction of the corresponding silanes, Si(SeMe~3~)~2~ and RSeSiMe~3~, respectively, with tropylium bromide C~7~H~7~Br. In spite of the low stability of the selanes even in dilute solutions and at low temperature, they could be characterised by their ^1^H, ^13^C and ^77^Se NMR parameters. Coupling constants ^1^J(^77^Se,^13^C) 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 ^1^J(^77^Se,^13^C) included numerous selenium carbon compounds with largely different SeC 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.