Luminescent ruthenium(II) amidodipyridoquinoxaline biotin complexes that display higher avidin-induced emission enhancement

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review

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Detail(s)

Original languageEnglish
Pages (from-to)293-302
Journal / PublicationInorganica Chimica Acta
Volume360
Issue number1
Publication statusPublished - 1 Jan 2007

Abstract

A series of luminescent ruthenium(II) amidodipyridoquinoxaline biotin (dpq-B) complexes [Ru(N-N)2(N-N′)](PF6)2 (N-N = 2,2′-bipyridine (bpy), 1,10-phenanthroline (phen), 4,7-diphenyl-1,10-phenanthroline (Ph2-phen); N-N′ = 2-((2-biotinamido)ethyl)amidodipyrido[3,2-f:2′,3′-h]quinoxaline (dpq-C2-B), 2-((6-biotinamido)hexyl)amidodipyrido[3,2-f:2′,3′-h]quinoxaline (dpq-C6-B)) has been designed as new luminescent probes for avidin. The electrochemical and photophysical properties of these complexes have been investigated. Upon irradiation, all the complexes exhibited metal-to-ligand charge-transfer (3MLCT) (dπ(Ru) → π*(diimine)) emission in fluid solutions at 298 K and in low-temperature glass. In aqueous buffer, the emission was extremely weak, probably a consequence of hydrogen-bonding interactions between the amide moiety of the dpq-B ligands and the water molecules. The avidin-binding properties of all the complexes have been studied by 4′-hydroxyazobenzene-2-carboxylic acid (HABA) assays, luminescence titrations, kinetics experiments and confocal microscopy using avidin-conjugated microspheres. © 2006 Elsevier B.V. All rights reserved.

Research Area(s)

  • Avidin, Biotin, Luminescence, Probes, Ruthenium complexes