title: Probing the fate of lowest-energy near-infrared metal-centered electronic excited states: CuCl(4)(2-) and IrBr(6)(2-).
abstract: Ultrafast transient absorption spectroscopy is used to investigate the radiationless relaxation dynamics of CuCl4(2-) and IrBr6(2-) complexes directly promoted into their lowest-energy excited metal-centered states upon near-infrared femtosecond excitation at 2000 nm. Both the excited CuCl4(2-) (2)E and IrBr6(2-) (2)Ug'(T2g) states undergo internal conversion to the ground electronic states, yet with significantly different lifetimes (55 fs and 360 ps, respectively) despite the fact that the (2)E and (2)Ug'(T2g) states are separated by the same energy gap (∼5000 cm(-1)) from the respective ground state. This difference likely arises from the predominance of the Jahn-Teller effect in a Cu(2+) ion and the spin-orbit coupling effect in an Ir(4+) ion. The approach documented in this work may be used for elucidating the role of low-energy metal-centered states in relaxation cascades of a number of coordination compounds, allowing for design of efficient light-triggered metal complexes.
authors: Department of Chemistry and the Center for Photochemical Sciences, Bowling Green State University, Bowling Green, Ohio 43403, United States.
authors: Sergey M
authors: SM
authors: Matveev
authors: Department of Chemistry and the Center for Photochemical Sciences, Bowling Green State University, Bowling Green, Ohio 43403, United States.
authors: Andrey S
authors: AS
authors: Mereshchenko
authors: Department of Chemistry and the Center for Photochemical Sciences, Bowling Green State University, Bowling Green, Ohio 43403, United States.
authors: Maxim S
authors: MS
authors: Panov
authors: Department of Chemistry and the Center for Photochemical Sciences, Bowling Green State University, Bowling Green, Ohio 43403, United States.
authors: Alexander N
authors: AN
authors: Tarnovsky
mesh_terms: D065966:Absorption, Physicochemical; D003300:Copper / Q000737:chemistry*; D004583:Electrons; D007259:Infrared Rays; D007495:Iridium / Q000737:chemistry*; D011789:Quantum Theory; D013816:Thermodynamics
chemical_list: D007495:Iridium; D003300:Copper; C029892:cupric chloride