Ruthenium(II) complexes with phenanthroline-, benzimidazole-, benzothiazole-, and pyridine-derived bidentate and tridentate ligands: reactivity and spectroscopic and electrochemical characterization
✍ Scribed by Michael R. McDevitt; Yu Ru; Anthony W. Addison
- Publisher
- Springer
- Year
- 1993
- Tongue
- English
- Weight
- 816 KB
- Volume
- 18
- Category
- Article
- ISSN
- 0340-4285
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✦ Synopsis
Ruthenium complexes of some tridentate and bidentate benzimidazole-, benzothiazole-and pyridine-derived ligands have been prepared as their PF 6 salts, and their constitutions have been confirmed by elemental analysis, ~H-n.m.r. spectroscopy and electrochemistry. The complexes are redox-active, displaying a metal-centred Ruin/ Ru m oxidation process and sequential ligand-localized reduction processes. Both the 2-(2'-pyridyl)benzimidazole complex [Ru(PybimH)3] 2 § and the 2,2'-dipyridylamine one, [Ru(DpyaH)3] 2+ behave as weak BrCnsted-Lowry acids. The secondary amino nitrogen of each DpyaH in the [Ru(DpyaH)3] 2+ complex can be deprotonated with hydride anion, and then acts as a strong nucleophile, allowing selective N-alkylation by alkyl halides. Most of the complexes exhibit ligand-localized luminescence emission at ambient temperature. The strong intrinsic fluorescences of 2-(2'-quinolyl)-N-methylbenzimidazole and 2-(2'-pyridyl)benzimidazole are quenched when they are coordinated to Ru ~, and emission from the chelates entailing 5-nitrol:10-phenanthroline occurs only from the non-nitrated ligands.