title: Excited-state equilibration over 30 A in a platinum(II) quinolinolate-bridge-platinum(II) porphyrin complex.
abstract: Long-range triplet excited-state equilibration occurs over a nanometric distance between platinum(II) 8-quinolinolate (3Ptq2 = 1.87 eV) and platinum(II) tetraphenylporphyrin (3PtTPP = 1.89 eV). The equilibrium is mediated by a fluorene-thiophene-fluorene bridge (3FTF = 1.92 eV) and is characterized by a double-exponential decay (tau1 = 39 +/- 4 ps; tau2 = 351 +/- 15 ps) that suggests the participation of three separate excited states: 3Ptq2, 3FTF, and 3PtTPP, respectively. Numerical simulation of the dual equilibrium allowed for estimation of the individual rate constants for each of the reversible steps (kET = 3.9 x 10(9)-4.1 x 10(10) s(-1)). As a result of rapid triplet-state equilibration, almost 50% of the excited-state energy is directed from the PtTPP chromophore toward Ptq2, in spite of a small endothermic barrier (0.03 eV).
authors.affiliation: Department of Chemistry and Center for Photochemical Sciences, Bowling Green State University, Bowling Green, Ohio 43403, USA.
authors.forename: Victor A
authors.initials: VA
authors.lastname: Montes
authors.forename: Michael A J
authors.initials: MA
authors.lastname: Rodgers
authors.forename: Pavel
authors.initials: P
authors.lastname: Anzenbacher