Coordination of 2,6-bis(8'-quinolinyl)pyridine on rhenium(I) and photochemistry of cyclopentadienyl tricarbonyl molybdenum dimer with arene disulfides

An ideal photosensitizer should have an excited state with high energy and sufficiently long lifetime to promote electron and/or energy transfer processes. Many facial-tricarbonyl Re(I)-diimine complexes have demonstrated sufficiently long lifetimes to photosensitize many reactions. However, these complexes only utilize small portions of the visible spectrum, thereby diminishing their overall effectiveness. Recent work has resulted in opening a synthetic route to the meridionally tris-chelated mer,cis-Re(tpy-kappa 3N)(CO)2Cl (tpy = 2,2':6,2-terpyridine) complex which absorbs light throughout the entire visible spectrum. However, as with many other metal-terpyridine complexes, the mer,cis-[Re(tpy-kappa 3N)(CO)2L]n+ (L = NCCH 3, PPh3, NC5H5, PEt3, and Cl; n = 0 or 1) failed to produce emission at room temperature.;The 2,6-bis(8'-quinolinyl)pyridine (bqp) ligand has been shown to form meridionally tris-chelated complexes with Ru(II) with observed room temperature emissions on the order of 3 mus. Results from our laboratory suggest that the mer,cis-Re(bqp-kappa3N)(CO) 2Cl complex is expected to absorb light throughout the entire visible spectrum at molar absorptivities greater than the mer,cis-Re(tpy-kappa 3N)(CO)2Cl. This study details initial coordination studies of the 2,6-bis(8'-quinolinyl)pyridine to Re(I).;The photochemistry of the molybdenum dimer [CpMo(CO)3] 2 with organic disulfides were investigated. Broad-band light sources were used for synthesis of the Mo-S containing products. Products were characterized by infrared and 1H-NMR techniques. Isolation of pure product allowed determination of UV-visible absorption parameters. These parameters were used to determine quantum yields under monochromatic irradiation.