Transition Metal Chemistry

, Volume 18, Issue 2, pp 197–204

Ruthenium(II) complexes with phenanthroline-, benzimidazole-, benzothiazole-, and pyridine-derived bidentate and tridentate ligands: reactivity and spectroscopic and electrochemical characterization


  • Michael R. McDevitt
    • Chemistry DepartmentDrexel University
  • Yu Ru
    • Chemistry DepartmentDrexel University
  • Anthony W. Addison
    • Chemistry DepartmentDrexel University
Full Papers

DOI: 10.1007/BF00139956

Cite this article as:
McDevitt, M.R., Ru, Y. & Addison, A.W. Transition Met Chem (1993) 18: 197. doi:10.1007/BF00139956


Ruthenium complexes of some tridentate and bidentate benzimidazole-, benzothiazole- and pyridine-derived ligands have been prepared as their PFf6p− salts, and their constitutions have been confirmed by elemental analysis, 1H-n.m.r. spectroscopy and electrochemistry. The complexes are redox-active, displaying a metal-centred RuII/ RuIII 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 Brønsted-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 RuII, and emission from the chelates entailing 5-nitro-1:10-phenanthroline occurs only from the non-nitrated ligands.

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© Chapman & Hall 1993