Ring slippage vs charge transfer in the reductive chemistry of [IndMo(CO)(2)(alpha-diimine)](+) cations

• Type: Article in International Scientific Journal
• Date: 2006

Authors

Claudia C L Pereira (Author) Other; Paulo J Costa (Author) Other; Maria Jose Calhorda (Author) Other; Cristina Freire (Author) FCUP; Sandra S Rodrigues (Author) Other; Eberhardt Herdtweck (Author) Other; Carlos C Romao (Author) Other

Journal

Title: Organometallics

Vol. 25

Pages: 5223-5234

ISSN: 0276-7333

Publisher: American Chemical Society

Indexing

ISI Web of Knowledge - 8 Citations

Scopus - 8 Citations

Scientific classification

FOS: Natural sciences > Chemical sciences

Other information

Authenticus ID: P-004-GHS

DOI: 10.1021/om050986r

Abstract (EN): Thirteen complexes of the type [IndMo(CO)(2)L-2](+) were prepared from IndMo(eta(3)-C3H5)(CO)(2) by protonation with HBF4 center dot Et2O followed by addition of alpha-diimine ligands L, in the presence of 1,2-dimethoxyethane. The complexes are numbered as follows: L = 1,4-bis(p-tolyl)diazabutadiene (p-tolDAB, 1), 1,4-bis(cyclohexyl)diazabutadiene (cyDAB, 2), biquinoline (biq, 3), 5,6-Ph-2-3-(2-py)-1,2,4-Tz (tz, 4), dipyrido[3,2-a:2',3'-c]phenazine (dppz, 5), 2,2'-bipyridine (bipy, 6), 4,4'-diphenyl-2,2'-bipyridine (4,4'-Ph-2-bpy, 7), 1,10-phenanthroline (1,10-phen, 8), 4,7-diphenyl-1,10-phenanthroline (4,7-Ph-2-1,10-phen, 9), 4,7-dimethyl-1,10-phenanthroline (4,7-Me-2-1,10-phen, 10), 2-(2-pyridyl)benzimidazole (2-(2-py)- benz, 11), 2,2'-biimidazole (2,2'-Biim, 12), 1,2-phenylenediamine (phendiam, 13). The bonding mode of the ligand in 4 was ascertained by single-crystal X-ray diffraction. None of the complexes undergo NCMe addition to form ring-slipped [(eta(3)-Ind)Mo(CO)(2)L-2(NCMe)](+) species. The reductive electrochemistry was studied in order to search for possible reductively induced ring-slippage rearrangements. In the cases of 1-5 reversible reduction processes were observed. UV-vis spectroscopy combined with DFT calculations provided an interpretation for the structures of the reduced species. The data suggest that the unpaired electron in the formally 19e reduced products [IndMo(CO)(2)L-2](center dot) is localized on the alpha-diimine ligand with minimal structural changes and no indenyl slippage taking place. However, such slippage is predicted to take place with the second reduction step, but in most cases MoL2 bond breaking leads to irreversible electrochemistry.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 12