Luminescent ruthenium(II) polypyridine biotin complexes : Synthesis, characterization, photophysical and electrochemical properties, and avidin-binding studies

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review

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Original languageEnglish
Pages (from-to)5275-5282
Journal / PublicationInorganic Chemistry
Issue number17
Publication statusPublished - 23 Aug 2004


Two luminescent ruthenium(II) polypyridine complexes containing a biotin moiety [Ru(bpy)2(L1)](PF6)2 (1) and [Ru-(bpy)2(L2)](PF6)2 (2) (bpy = 2,2′-bipyridine; L1 = 4-(N-((2-biotinamido)ethyl)amido)-4′-methyl-2, 2′-bipyridine; L2 = 4-(N-((6-biotinamido)hexyl)amido)-4′-methyl-2, 2′-bipyridine) have been synthesized and characterized, and their photophysical and electrochemical properties have been studied. Upon photoexcitation, complexes 1 and 2 display intense and long-lived triplet metal-to-ligand charge-transfer (3MLCT) (dπ(Ru) → π*(L1 or L2)) emission in fluid solutions at 298 K and in low-temperature glass. We have studied the binding of these ruthenium(II) biotin complexes to avidin by 4′-hydroxyazobenzene-2-carboxylic acid (HABA) assays, luminescence titrations, competitive assays using native biotin, and quenching experiments using methyl viologen. On the basis of the results of these experiments, a homogeneous competitive assay for biotin has been investigated.

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