Spectroscopic and Computational Study on New Blue Emitting ReL(CO) 3 Cl Complexes Containing Pyridylimidazo[1,5‐ a ]pyridine Ligands

The structural and photophysical properties of three new ReL(CO) 3 Cl complexes (Re L1 –Re L3 ) and their 1‐(2‐pyridyl)imidazo[1,5‐ a ]pyridine ligands, namely 3‐methyl‐1‐(2‐pyridyl)imidazo[1,5‐ a ]pyridine ( L1 ), 1‐(2‐pyridyl)‐3‐[4‐(trifluoromethyl)phenyl]imidazo[1,5‐ a ]pyridine ( L2 ), and 3‐(4‐nitrophenyl)‐1‐(2‐pyridyl)imidazo[1,5‐ a ]pyridine ( L3 ), were studied by spectroscopy, X‐ray diffraction, and computational methods. Re L1 –Re L3 have high‐energy singlet emissions arising from a π → π* ligand‐centered state. In oxygen‐free acetonitrile solutions, the complexes display dual fluorescence due to intense ligand‐centered triplet emission.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)