X-ray transient absorption structural characterization of the3MLCT triplet excited state of cis-[Ru(bpy)2(py)2]2+

Elisa Borfecchia, Claudio Garino, Luca Salassa*, Tiziana Ruiu, Diego Gianolio, Xiaoyi Zhang, Klaus Attenkofer, Lin X. Chen, Roberto Gobetto, Peter J. Sadler, Carlo Lamberti

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

33 Scopus citations

Abstract

The excited state dynamics and structure of the photochemically active complex cis-[Ru(bpy)2(py)2]2+ have been investigated using optical transient absorption (OTA) and X-ray transient absorption (XTA) spectroscopy, and density functional theory (DFT). Upon light-excitation in aqueous solution cis-[Ru(bpy)2(py)2]2+ undergoes ultrafast dissociation of one pyridine ligand to form cis-[Ru(bpy)2(py)(H2O)]2+. OTA measurements highlighted the presence of two major time components of 1700 ps and 130 ps through which the system decays to the ground-state and evolves towards the photoproduct. XTA data were acquired after 150 ps, 500 ps, and 3000 ps from laser excitation (λexc = 351 nm) and provided the transient structure of the3MLCT state corresponding to the longer time component in the OTA experiment. In excellent agreement with DFT, XTA shows that the3MLCT geometry is characterized by an elongation of the dissociating Ru–N(py) bond and a shortening of the trans Ru–N(bpy) bond with respect to the ground state. Conversely, calculations show that the3MC state has a highly distorted structure with Ru–N(py) bonds between 2.77–3.05 Å.

Original languageEnglish (US)
Pages (from-to)6564-6571
Number of pages8
JournalJournal of the Chemical Society. Dalton Transactions
Volume42
Issue number18
DOIs
StatePublished - Mar 8 2013

ASJC Scopus subject areas

  • Chemistry(all)

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