Conservation of vibrational coherence in ultrafast electronic relaxation The case of diplatinum complexes in solution

We report the results of ultrafast transient absorption studies of tetrakis amp; 956; pyrophosphito diplatinate II , [Pt2 amp; 956; P2O5H2 4]4 amp; 8722; Pt pop and its perfluoroborated derivative [Pt2 amp; 956; P2O5 BF2 4]4 amp; 8722; Pt pop BF2 in water and acetonitrile upon excitation of high lying lt;300 nm UV absorption bands. We observe an ultrafast relaxation channel from high lying states to the lowest triplet state that partly Pt pop in H2O, Pt pop BF2 or fully Pt pop in MeCN bypasses the lowest singlet excited state. As a consequence, vibrational wave packets are detected in the lowest triplet state and or the lowest excited singlet of both complexes, even though the electronic relaxation cascade spans ca. 2 and 1.3 eV, respectively. In the case of Pt pop BF2 , coherent wave packets generated by optical excitation of the lowest singlet 1A2u state also are reported. Overall, the reported dephasing times of the Pt Pt oscillator in the ground, singlet and triplet states do not depend much on the solvent or the molecular structur