title: 1-Cyclohepta-2,4,6-trienyl-selanes--a 77Se NMR study: indirect nuclear 77Se--13C spin-spin coupling constants and application of density functional theory (DFT) calculations.
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.
authors.affiliation: Anorganische Chemie II, Universität Bayreuth, D-95440 Bayreuth, Germany. b.wrack@uni-bayreuth.de
authors.forename: Bernd
authors.initials: B
authors.lastname: Wrackmeyer
authors.forename: Zureima García
authors.initials: ZG
authors.lastname: Hernández
authors.forename: Max
authors.initials: M
authors.lastname: Herberhold
mesh_terms: D002247:Carbon Isotopes; D006573:Heterocyclic Compounds, 1-Ring / Q000138:chemical synthesis / Q000737:chemistry*; D007554:Isotopes; D009682:Magnetic Resonance Spectroscopy / Q000379:methods* / Q000592:standards; D008956:Models, Chemical; D015394:Molecular Structure; D016566:Organoselenium Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D011789:Quantum Theory; D012015:Reference Standards; D012643:Selenium / Q000737:chemistry*; D012680:Sensitivity and Specificity; D013237:Stereoisomerism
chemical_list: D002247:Carbon Isotopes; D006573:Heterocyclic Compounds, 1-Ring; D007554:Isotopes; D016566:Organoselenium Compounds; D012643:Selenium