Photochemistry of fac-[Re(bpy)(CO)3Cl]

Shunsuke Sato, Yasuo Matubara, Kazuhide Koike, Magnus Falkenström, Tetsuro Katayama, Yukihide Ishibashi, Hiroshi Miyasaka, Seiji Taniguchi, Haik Chosrowjan, Noboru Mataga, Naoto Fukazawa, Shinya Koshihara, Ken Onda, Osamu Ishitani

Research output: Contribution to journalArticle

44 Citations (Scopus)

Abstract

The photochemistry of fac-[Re(bpy)(CO)3Cl] (1 a; bpy=2,2'-bipyridine) initiated by irradiation using <330 nm light has been investigated. Isomerization proceeded in THF to give the corresponding mer-isomer 1 b. However, in the presence of a small amount of MeCN, the main product was the CO-ligand-substituted complex (OC-6-24)-[Re(bpy)(CO) 2Cl(MeCN)] (2 c; bpy=2,2'-bipyridine). In MeCN, two isomers, 2 c and its (OC-6-34) form (2 a), were produced. Only 2 c thermally isomerized to produce the (OC-6-44) form 2 b. A detailed investigation led to the conclusion that both 1 b and 2 c are produced by a dissociative mechanism, whereas 2 a forms by an associative mechanism. A comparison of the ultrafast transient UV-visible absorption, emission, and IR spectra of 1 a acquired by excitation using higher-energy light (e.g., 270 nm) and lower-energy light (e.g., 400 nm) gave detailed information about the excited states, intermediates, and kinetics of the photochemical reactions and photophysical processes of 1 a. Irradiation of 1 a using the higher-energy light resulted in the generation of the higher singlet excited state with τ<fs, from which intersystem crossing proceeded to give the higher triplet state (;bsupesup&HES(1)). In THF, ;bsupesup&HES(1) was competitively converted to both the triplet ligand field (;bsupesup&LF) and metal-to-ligand charge transfer (;bsupesup&MLCT) with lifetimes of 200a;fs, in which the former is a reactive state that converts to [Re(bpy)(CO);bsubesub (1 c) within 10a;ps by means of a dissociative mechanism. Re-coordination of CO to 1 c gives both 1 a and 1 b. In MeCN, irradiation of 1 a by using high-energy light gives the coordinatively unsaturated complex, which rapidly converted to 2 c. A seven-coordinate complex is also produced within several hundred femtoseconds, which is converted to 2 a within several hundred picoseconds. Time on our side: Photochemical ligand substitution and isomerization of fac-[Re(bpy)(CO) ;bsubesub&Cl] (bpy=2,2'-bipyridine) with high-energy light are reported. The combination of steady-state irradiation, time-resolved (TR)-UV-visible, TR-IR, and TR-emission experiments gave detailed information on not only various excited states but also short-lived intermediates (see scheme).

Original languageEnglish
Pages (from-to)15722-15734
Number of pages13
JournalChemistry - A European Journal
Volume18
Issue number49
DOIs
Publication statusPublished - Dec 3 2012

All Science Journal Classification (ASJC) codes

  • Catalysis
  • Organic Chemistry

Fingerprint Dive into the research topics of 'Photochemistry of fac-[Re(bpy)(CO)<sub>3</sub>Cl]'. Together they form a unique fingerprint.

  • Cite this

    Sato, S., Matubara, Y., Koike, K., Falkenström, M., Katayama, T., Ishibashi, Y., Miyasaka, H., Taniguchi, S., Chosrowjan, H., Mataga, N., Fukazawa, N., Koshihara, S., Onda, K., & Ishitani, O. (2012). Photochemistry of fac-[Re(bpy)(CO)3Cl]. Chemistry - A European Journal, 18(49), 15722-15734. https://doi.org/10.1002/chem.201202734