Utilization of the Highly Environment-Sensitive Emission Properties of Rhenium(I) Amidodipyridoquinoxaline Biotin Complexes in the Development of Biological Probes

Citations Over TimeTop 10% of 2006 papers

Abstract

We report the synthesis and characterization of luminescent rhenium(I) amidodipyridoquinoxaline biotin complexes [Re(CO)3(dpqa)(L)](PF6) (dpqa = 2-(n-butylamido)dipyrido[3,2-f:2',3'-h]quinoxaline; L = 4-(biotinamidomethyl)pyridine (py-4-CH2-NH-biotin) (1), 3-(N-((2-biotinamido)ethyl)amido)pyridine (py-3-CO-NH-en-NH-biotin) (2), 4-(N-((6-biotinamido)hexanoyl)aminomethyl)pyridine (py-4-CH2-NH-cap-NH-biotin) (3)), and their biotin-free counterpart [Re(CO)3(dpqa)(py)](PF6) (py = pyridine (4)). Upon irradiation, these complexes exhibited intense triplet metal-to-ligand charge-transfer (3MLCT) (dpi(Re) --> pi(dpqa)) emission in fluid solutions at 298 K and in alcohol glass at 77 K. However, the emission became much weaker in aqueous buffer, probably due to the interactions of water molecules with the amide substituent of the dpqa ligand. These properties render the complexes good candidates as luminescent probes for hydrophobic media, such as the substrate-binding sites of proteins. The avidin-binding properties of the new biotin complexes have been studied by 4'-hydroxyazobenzene-2-carboxylic acid (HABA) assays, emission titrations, and competitive association and dissociation assays. Most importantly, the complexes showed a profound increase in emission intensities upon binding to avidin. Additionally, we found that the fluorescence of anthracene was quenched by these rhenium(I) complexes, and the 3MLCT emission of the complexes was also quenched by anthracene. On the basis of these findings, new homogeneous assays for biotin using these complexes, avidin, and anthracene-labeled avidin have been designed.

Related Papers

• → Oxochloride Complexes of Rhenium(1971)22 cited
• → Design and Synthesis of Tunable Ligands with 4,4′-Bipyridyl as an Electron-Accepting Unit and Their Rhenium Complexes(2017)12 cited
• → Half-sandwich rhenium(III) acyl complexes: synthesis, structure and conversion to rhenium(I) and rhenium(III) isonitrile complexes(1996)14 cited
• → Rhenium-Oxo and Rhenium-Peroxo Complexes in Catalytic Oxidations(2007)33 cited
• → ИСПОЛЬЗОВAНИЕ ПОТЕНЦИAЛA СОЦИAЛЬНЫХ ПAРТНЕРОВ В ПОДГОТОВКЕ БУДУЩИХ ПЕДAГОГОВ(2024)