Luminescent rhenium(I) phenanthroline complexes with a benzoxazol-2-ylidene ligand: Synthesis, characterization, and photophysical study

Article abstract of DOI:10.1021/om300526e

A series of luminescent rhenium(I) phenanthroline complexes containing benzoxazol-2-ylidene ligands with the general formula {Re(CO) ₃(phen)[CN(X)C₆H₄-2-O]}⁺ and cis,trans-{Re(CO)₂(phen)(L)[CN(H)C₆H₄-2-O]} ⁺ (X = H, methyl; phen = 1,10-phenanthroline; L = PPh₃, PPh₂Me, P(OEt)₃) have been synthesized and characterized. The X-ray crystal structures of most of the carbene complexes and some of their synthetic precursors have also been determined. A new synthetic methodology for the preparation of dicarbonyl rhenium diimine synthetic precursors with a labile acetonitrile ligand, [Re(CO)₂(phen)(PR₃)(MeCN)] ⁺, was developed. Photophysical study shows that these carbene complexes display a green to red ³MLLCT [dπ(Re) → π*(N-N)] phosphorescence at room temperature. The N-deprotonations of the benzoxazol-2-ylidene ligand in these complexes were investigated.