Structural Control of (1)A(2u)-to-(3)A(2u) Intersystem Crossing in Diplatinum(II,II) Complexes

0384550 - ÚFCH JH 2013 RIV US eng J - Článek v odborném periodiku
Durrell, A. C. - Keller, G. E. - Lam, Y. - Ch. - Sýkora, Jan - Vlček, Antonín - Gray, H. B.
Structural Control of (1)A(2u)-to-(3)A(2u) Intersystem Crossing in Diplatinum(II,II) Complexes.
Journal of the American Chemical Society. Roč. 134, č. 34 (2012), s. 14201-14207. ISSN 0002-7863. E-ISSN 1520-5126
Grant CEP: GA MŠMT(CZ) ME10124
Institucionální podpora: RVO:61388955
Klíčová slova: TRIPLET EXCITED-STATE * BINUCLEAR PLATINUM(II) PHOTOCHEMISTRY * ELECTRON-TRANSFER REACTIONS
Kód oboru RIV: CG - Elektrochemie
Impakt faktor: 10.677, rok: 2012

Analysis of variable-temperature fluorescence quantum yield and lifetime data for per(difluoroboro)tetrakis(pyrophosphito)diplatinate(II) ([Pt-2(mu-P2O5(BF2)(2))(4))(4-), abbreviated Pt(pop-BF2)), yields a radiative decay rate (k(r) = 1.7 X 10(8) s(-1)) an order of magnitude greater than that of the parent complex, Pt(pop). Its temperature-independent and activated intersystem crossing (ISC) pathways are at least 18 and 142 times slower than those of Pt(pop) [ISC activation energies: 2230 cm(-1) for Pt(pop-BF2); 1190 cm(-1) for Pt(pop)]. The slowdown in the temperature-independent ISC channel is attributed to two factors: (1) reduced spin-orbit coupling between the (1)A(2u) state and the mediating triplet(s), owing to increases of LMCT energies relative to the excited singlet; and (2) diminished access to solvent, which for Pt(pop) facilitates dissipation of the excess energy into solvent vibrational modes. The dramatic increase in E-a is attributed to increased P-O-P framework rigidity, which impedes symmetry-lowering distortions, in particular asymmetric vibrations in the Pt-2(P-O-P)(4) core that would allow direct (1)A(2u)-(3)A(2u) spin-orbit coupling.
Trvalý link: http://hdl.handle.net/11104/0214161