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Photophysics and Acid‐Base Chemistry of Re(CH 3 bpyCOOH)(CO) 3 X (X=Cl − , and Imidazole) Complexes
Author(s) -
Lin RenJay,
Chang IJy
Publication year - 2002
Publication title -
journal of the chinese chemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.329
H-Index - 45
eISSN - 2192-6549
pISSN - 0009-4536
DOI - 10.1002/jccs.200200025
Subject(s) - chemistry , protonation , imidazole , titration , quenching (fluorescence) , solvent , photochemistry , absorption (acoustics) , absorption spectroscopy , electron transfer , ligand (biochemistry) , metal , luminescence , inorganic chemistry , crystallography , fluorescence , stereochemistry , ion , organic chemistry , physics , quantum mechanics , acoustics , biochemistry , receptor , optoelectronics
Rheniumtricarbonyl(4′‐methyl‐2,2′‐bipyridine‐4‐carboxylic acid)X (where X is Cl − and imidazole) complexes have been prepared. These two complexes exhibit similar spectroscopic properties. The metal‐ to‐ligand charge‐transfer (MLCT) absorption and the corresponding emission are observed. This charge transfer band is highly solvent dependent. Due to the stronger electron‐withdrawing ability of the ‐COOH (in comparison to the ‐COO − group), the MLCT band has red‐shifted during protonation. Emission quantum yields are dramatically reduced while life time remains similar upon protonation. These behaviors are typical in static quenching mechanism by protons. The ground state pK a of Re(CO) 3 (CH 3 bpyCOOH)Cl obtained from the pH titration curve of the complex absorption at 409 nm was 2.5.