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 (ReL1-ReL3) and their 1-(2-pyridyl)-imidazol[1,5-a]pyridine(L1), 1-(2-pyridyl)imidazo[1,5-a]pyridine (L2), and 3-(4-nitro-phenyl)-1-(2-pyridyl)imidazol[1,5-a]pyridine (L3), were studied by spectroscopy, X-ray diffraction, and computational methods. ReL1-ReL3 have high-energy singlet emissions arising from a pi -> pi ligand-centered state. In oxygen-free acetonitrile solutions, the complexes display dual fluorescence due to intense ligand-centered triplet emission. ((C) Wiley-VCH Verlag Gmbh & Co. KGaA, 69451 Weinheim, Germany, 2008).