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Bioinorganic Chemistry and Applications
Volume 2009, Article ID 381925, 9 pages
Research Article

Analysis of One-Bond Se-Se Nuclear Couplings in Diselenides and 1,2-Diselenoles on the Basis of Molecular Orbital Theory: Torsional Angular Dependence, Electron Density Influence, and Origin in

Department of Material Science and Chemistry, Faculty of Systems Engineering, Wakayama University, 930 Sakaedani, Wakayama 640-8510, Japan

Received 19 January 2009; Revised 15 April 2009; Accepted 8 May 2009

Academic Editor: Vito Lippolis

Copyright © 2009 Akito Tanioku et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Nuclear couplings for the Se-Se bonds, , are analyzed on the basis of the molecular orbital (MO) theory. The values are calculated by employing the triple basis sets of the Slater type at the DFT level. are calculated modeled by MeSeSeMe (1a), which shows the typical torsional angular dependence on . The dependence explains well the observed of small values ( Hz) for (1) (simple derivatives of 1a) and large values (330–380 Hz) observed for 4-substituted naphto[1,8-]-1,2-diselenoles (2) which correspond to symperiplanar diselenides. (Se, Se : 2) becomes larger as the electron density on Se increases. The paramagnetic spin-orbit terms contribute predominantly. The contributions are evaluated separately from each MO and each transition, where and are occupied and unoccupied MO's, respectively. The separate evaluation enables us to recognize and visualize the origin and the mechanism of the couplings.