| Abstract
| - Four luminescent cyclometalated iridium(III) diimine complexes [Ir(N−C)2(N−N)](PF6) (HN−C = 2-(4-(N-((2-biotinamido)ethyl)aminomethyl)phenyl)pyridine, Hppy-4-CH2NHC2NH-biotin, N−N = 3,4,7,8-tetramethyl-1,10-phenanthroline, Me4-phen (1a); N−N = 4,7-diphenyl-1,10-phenanthroline, Ph2-phen (2a); HN−C = 2-(4-(N-((6-biotinamido)hexyl)aminomethyl)phenyl)pyridine, Hppy-4-CH2NHC6NH-biotin, N−N = Me4-phen (1b); N−N = Ph2-phen (2b)), each containing two biotin units, have been synthesized and characterized. The photophysical andelectrochemical properties of these complexes have been investigated. Photoexcitation of these iridium(III) diiminebis(biotin) complexes in fluid solutions at 298 K and in alcohol glass at 77 K resulted in intense and long-livedluminescence. The emission is assigned to a triplet metal-to-ligand charge-transfer (3MLCT) (dπ(Ir) → π*(N−N))excited state. The emissive states of complexes 1a,b are probably mixed with some 3IL (π → π*) (Me4-phen)character. The interactions of these iridium(III) diimine bis(biotin) complexes with avidin have been studied by4‘-hydroxyazobenzene-2-carboxylic acid (HABA) assays and emission titrations. The potential for these complexesto act as cross-linkers for avidin has been examined by resonance-energy transfer- (RET-) based emission quenchingexperiments, microscopy studies using avidin-conjugated microspheres, and HPLC analysis.
- Four luminescent cyclometalated iridium(III) diimine complexes [Ir(N−C)2(N−N)](PF6), each containing two biotin units, have been synthesized and characterized. The photophysical and electrochemical properties of these complexes have been investigated. The interactions of these iridium(III) complexes with avidin have been studied by 4‘-hydroxyazobenzene-2-carboxylic acid (HABA) assays and emission titrations. The potential for these complexes to act as cross-linkers for avidin has been examined by resonance-energy transfer- (RET-) based emission quenching experiments, microscopy studies using avidin-conjugated microspheres, and HPLC analysis.
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