The influence of structural isomerism on luminescence properties of [Re(CO)2(dppv)(pbi)] complexes containing cis-1,2-bis(diphenylphosphino)-ethene and 2-(2-pyridyl)benzimidazole ligands

Abstract Simple reaction procedure, boiling of an equimolar mixture [Re(Cl)(CO) 3 (dppv)] (dppv— cis -1,2-bis(diphenylphosphino)-ethene), 2-(2-pyridyl)benzimidazole (pbi), and TlClO 4 in o -dichlorobenzene solution, leads to two, chromatographically separable, isomers [Re(CO) 2 (dppv)(pbi)] complex. The obtained species, the yellow-emissive [ OC -6–54] orange-emissive -6–53] isomers, have been identified using FT-IR, 1 H NMR, 31 P NMR spectroscopy their structures confirmed by means X-ray investigations. According crystallography results, investigated differ mainly arrangement anion structures. Diverse dppv pbi ligand around central -[Re(CO) ] + core results well-pronounced changes luminescence properties studied luminophores. from performed DFT TDA-DFT computations, isomer emission occurs intra-ligand excitation localized within ligand. In contrary that, indicates some metal-to-ligand charge-transfer character associated with charge transfer Re(CO) (dppv) fragment Moreover, both exhibit different decays, mono-exponential bi-exponential for ones, respectively. view DFT/TDA-DFT this has explained presence additional excited dark state, operative only case (pbi)