@article { , title = {Probing the use of long lived intra-ligand Ï€-Ï€ * excited states for photocatalytic systems: a study of the photophysics and photochemistry of [ReCl(CO)3(dppz-(CH3)2)]}, abstract = {We report the excited state photophysics and photochemistry of [ReCl(CO)3(dppz-(CH3)2)] (dppz-(CH3)2 = 11,12-dimethyl-dipyrido[3,2-a:2’,3’-c]phenazine) in CH3CN using timeresolved infrared (TRIR) and Fourier transform infrared (FTIR) spectroscopy. Excitation of the 1MLCT (metal-to-ligand charge transfer) band of [ReCl(CO)3(dppz-(CH3)2)] populates a 3MLCT excited state which rapidly interconverts on a timescale < 1 ns to a long lived IL (intra-ligand) Ï€-Ï€* excited state with a lifetime of 190 (± 5) ns. In the presence of an electron donor (NEt3), the IL excited state of [ReCl(CO)3(dppz-(CH3)2)] can be reductively quenched to [ReCl(CO)3(dppz-(CH3)2)]− with the radical in the latter localised on the distal phenazine (phz) portion of the dppz ligand. The phz based electron in [ReCl(CO)3(dppz-(CH3)2)]− has minimal interaction with the rhenium metal centre which increases the stability of the photosensitiser in its reduced form. In non-dried, non-degassed CH3CN (1 M NEt3), [ReCl(CO)3(dppz-(CH3)2)]− shows no significant change in the carbonyl region of the IR spectrum for at least 2 hours during continuous photolysis. In addition, we investigate the use of [ReCl(CO)3(dppz-(CH3)2)]− to reduce the previously studied catalyst [NiFe2], with facile electron transfer from [ReCl(CO)3(dppz-(CH3)2)]− to form [NiFe2]–.}, doi = {10.1016/j.poly.2016.11.005}, eissn = {0277-5387}, issn = {0277-5387}, journal = {Polyhedron}, note = {12 months embargo. OL 13.09.2017}, pages = {259-264}, publicationstatus = {Published}, publisher = {Elsevier}, url = {https://nottingham-repository.worktribe.com/output/845392}, volume = {123}, keyword = {Rhenium , Time-resolved IR , Photophysics , Intra-ligand excited state , Reductive quenching}, year = {2017}, author = {Summers, Peter A. and Calladine, James A. and Ibrahim, Nasiru and Kusumo, Kennedy P. and Clark, Charlotte A. and Sun, Xue-Z. and Hamilton, Michelle L. and Towrie, Michael and McMaster, Jonathan and Schröder, Martin and George, Michael W.} }