Spectroscopic and Computational Investigations of Stable Radical Anions of Triosmium Benzoheterocycle Clusters

0181838 - UFCH-W 20030282 RIV DE eng J - Journal Article
Nervi, C. - Gobetto, R. - Milone, L. - Viale, A. - Rosenberg, E. - Rokhsana, D. - Fiedler, Jan
Spectroscopic and Computational Investigations of Stable Radical Anions of Triosmium Benzoheterocycle Clusters.
Chemistry - A European Journal. Roč. 9, - (2003), s. 5749-5756. ISSN 0947-6539. E-ISSN 1521-3765
R&D Projects: GA MŠMT OC D15.10; GA ČR GA203/03/0821
Institutional research plan: CEZ:AV0Z4040901
Keywords : cluster compounds * electron transfer * osmium
Subject RIV: CF - Physical ; Theoretical Chemistry
Impact factor: 4.353, year: 2003

The radical anions 1ů, 2ů and 3ů can be prepared by both exhaustive electrolysis and partially by chemical reduction with cobaltocene and with sodium dispersion (only with sodium dispersion in the case of 3ů). DFT calculations on 1 ů 3 reveal that the LUMO for the electron deficient 1 and 2 involves significant contributions from both the heterocyclic ligand and the two metal atoms bridged by the ligand and the -hydride. The character of this orbital rationalizes the previously observed regioselective reactions of these complexes with nucleophiles. In contrast, the LUMO for the electron precise 3 involves only ligand based orbitals. Partial chemical reduction of 1 and 2 requires an excess of either cobaltocene or sodium and their 1H and 13C NMR spectra reveal selective line broadening of those proton resonances that are predicted by DFT calculations to bear the greatest amount of free spin density. The.
Permanent Link: http://hdl.handle.net/11104/0078353