Luminescent Dirhenium(I)-Double-Heterostranded Helicate and Mesocate

The semirigid ligands 1,4-bis­(2-(2-hydroxyphenyl)­benzimidazol-1-ylmethyl)­benzene (H2-pBC) and 1,3-bis­(2-(2-hydroxyphenyl)­benzimidazol-1-ylmethyl)-2,4,6-trimethylbenzene (H2-mBC), containing two hydroxyphenylbenzimidazolyl units as bis-chelating (or bis­(bidentate)) N∩OH donor, were synthesized and were used to assemble neutral, luminescent heteroleptic, unsaturated double-hetero-stranded, rhenium­(I)-based helicate (1) and mesocate (2) with the flexible bis­(monodentate) nitrogen donor (1,4-bis­(benzimidazol-1-ylmethyl)­benzene/1,3-bis­(benzimidazol-1-ylmethyl)­benzene), and Re2(CO)10. The photophysical properties of the complexes were studied. Both complexes 1 and 2 exhibit dual emissions in both solution and solid state. In solution, these complexes show both fluorescence and phosphorescence. Complex 1 undergoes a predominantly ligand-centered oxidation, resulting in the generation of phenoxyl radicals.