New emissive fac-tricarbonylchlorobis(ligand)rhenium(I) complexes prepared from pyridine/thiophene hybrid ligands

Stille coupling between tributyl-(2,3-dihydro-thieno3,4-b]1,4]dioxin-5-yl)-stannane and 4-bromopyridine resulted in the preparation of the new pyridine/thiophene hybrid ligand 4-(2,3-dihydro-thieno3,4-b]1,4]dioxin-5-yl)-pyridine 4-py-EDOT] (1). Reaction of 1, 4-thiophen-2-yl-pyridine (2), or 4-2,2^′]bithiophenyl-5-yl-pyridine (3) with ClRe(CO)₅ resulted in the isolation of complexes 4-6, ClRe(L)₂(CO)₃, where L=1, 2, or 3 respectively. The solid-state structure of 4 was determined by X-ray crystallography, which clearly shows the fac arrangement of the three CO ligands and the two 4-py-EDOT ligands arranged cis to one another. The metal complexes 4-6 have been characterized by ¹H and ¹³C NMR, ESI or FAB MS, FTIR, UV-Vis, fluorescence, and elemental analysis.