TY - JOUR
T1 - Electron-Transfer Reactions of Electronically Excited Zinc Tetraphenylporphyrin with Multinuclear Ruthenium Complexes
AU - Henderson, Jane
AU - Glover, Starla D.
AU - Lear, Benjamin J.
AU - Walker, Don
AU - Winkler, Jay R.
AU - Gray, Harry B.
AU - Kubiak, Clifford P.
N1 - Publisher Copyright:
© 2014 American Chemical Society.
PY - 2015/6/18
Y1 - 2015/6/18
N2 - Transient absorption decay rate constants (kobs) for reactions of electronically excited zinc tetraphenylporphyrin (3ZnTPP) with triruthenium oxo-centered acetate-bridged clusters [Ru3(μ3-O)(μ-CH3CO2)6(CO)(L)]2(μ-pz), where pz = pyrazine and L = 4-cyanopyridine (cpy) (1), pyridine (py) (2), or 4-dimethylaminopyridine (dmap) (3), were obtained from nanosecond flash-quench spectroscopic data (quenching constants, kq, for 3ZnTPP/1-3 are 3.0 × 109, 1.5 × 10 9, and 1.1 × 109 M-1 s-1, respectively). Values of kq for reactions of 3ZnTPP∗ with 1-3 and Ru3(μ3-O)(μ-CH3CO2)6(CO)(L)2 [L = cpy (4), py (5), dmap (6)] monomeric analogues suggest that photoinduced electron transfer is the main pathway of excited-state decay; this mechanistic proposal is consistent with results from a photolysis control experiment, where growth of characteristic near-IR absorption bands attributable to reduced (mixed-valence) Ru3O-cluster products were observed.
AB - Transient absorption decay rate constants (kobs) for reactions of electronically excited zinc tetraphenylporphyrin (3ZnTPP) with triruthenium oxo-centered acetate-bridged clusters [Ru3(μ3-O)(μ-CH3CO2)6(CO)(L)]2(μ-pz), where pz = pyrazine and L = 4-cyanopyridine (cpy) (1), pyridine (py) (2), or 4-dimethylaminopyridine (dmap) (3), were obtained from nanosecond flash-quench spectroscopic data (quenching constants, kq, for 3ZnTPP/1-3 are 3.0 × 109, 1.5 × 10 9, and 1.1 × 109 M-1 s-1, respectively). Values of kq for reactions of 3ZnTPP∗ with 1-3 and Ru3(μ3-O)(μ-CH3CO2)6(CO)(L)2 [L = cpy (4), py (5), dmap (6)] monomeric analogues suggest that photoinduced electron transfer is the main pathway of excited-state decay; this mechanistic proposal is consistent with results from a photolysis control experiment, where growth of characteristic near-IR absorption bands attributable to reduced (mixed-valence) Ru3O-cluster products were observed.
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U2 - 10.1021/jp511213p
DO - 10.1021/jp511213p
M3 - Article
C2 - 25494985
AN - SCOPUS:84934935133
SN - 1520-6106
VL - 119
SP - 7473
EP - 7479
JO - Journal of Physical Chemistry B
JF - Journal of Physical Chemistry B
IS - 24
ER -