title: Solvent Effects on Nonradiative Relaxation Dynamics of Low-Energy Ligand-Field Excited States: A CuCl42-Complex.
abstract: Nonradiative relaxation dynamics of CuCl42-complexes photoexcited into the highest-energy ligand-field electronic state (2A1) is studied in acetonitrile, dichloromethane, and chloroform solvents, as well as in acetonitrile-water and in acetonitrile-deuterated water mixtures. Due to ultrafast internal conversion, this excited state directly converts to the electronic ground state in dichloromethane and chloroform. The nonradiative relaxation constant is similar in anhydrous acetonitrile. Addition of water to acetonitrile solutions efficiently quenches the excited ligand-field2A1state. The quenching is proposed to be due to the diffusion-controlled formation of an electronically excited pentacoordinated [CuCl4H2O]2-encounter complex or a short-lived exciplex of similar structure, in which the electronic excitation energy transfers into the O-H stretch of the coordinated H2O molecule. This is followed by the dissociation of the pentacoordinated species, resulting in the reformation of the ground-state CuCl42-and free H2O molecules.
authors.affiliation: Saint-Petersburg State University , 7/9 Universitetskaya nab., St. Petersburg 199034, Russia.
authors.forename: Andrey S
authors.identifier: 0000-0001-9390-1446
authors.initials: AS
authors.lastname: Mereshchenko
authors.affiliation: Saint-Petersburg State University , 7/9 Universitetskaya nab., St. Petersburg 199034, Russia.
authors.forename: Olesya S
authors.initials: OS
authors.lastname: Myasnikova
authors.affiliation: Saint-Petersburg State University , 7/9 Universitetskaya nab., St. Petersburg 199034, Russia.
authors.forename: Maxim S
authors.initials: MS
authors.lastname: Panov
authors.affiliation: Saint-Petersburg State University , 7/9 Universitetskaya nab., St. Petersburg 199034, Russia.
authors.forename: Vladimir A
authors.initials: VA
authors.lastname: Kochemirovsky
authors.affiliation: Saint-Petersburg State University , 7/9 Universitetskaya nab., St. Petersburg 199034, Russia.
authors.forename: Mikhail Yu
authors.initials: MY
authors.lastname: Skripkin
authors.forename: Darya S
authors.initials: DS
authors.lastname: Budkina
authors.forename: Alexander N
authors.initials: AN
authors.lastname: Tarnovsky