Determining Excited-State Structures and Photophysical Properties in Phenylphosphine Rhenium(I) Diimine Biscarbonyl Complexes Using Time-Resolved Infrared and X-ray Absorption Spectroscopies

Yuushi Shimoda, Kiyoshi Miyata, Masataka Funaki, Takumi Ehara, Tatsuki Morimoto, Shunsuke Nozawa, Shin Ichi Adachi, Osamu Ishitani, Ken Onda

Research output: Contribution to journalArticlepeer-review

Abstract

We have explored the structural factors on the photophysical properties in two rhenium(I) diimine complexes in acetonitrile solution, cis,trans-[Re(dmb)(CO)2(PPh2Et)2]+ (Et(2,2)) and cis,trans-[Re(dmb)(CO)2(PPh3)2]+ ((3,3)) (dmb = 4,4′-dimethyl-2,2′-bipyridine, Ph = phenyl, Et = ethyl) using the combination method of time-resolved infrared spectroscopy, time-resolved extended X-ray absorption fine structure, and quantum chemical calculations. The difference between these complexes is the number of phenyl groups in the phosphine ligand, and this only indirectly affects the central Re(I). Despite this minor difference, the complexes exhibit large differences in emission wavelength and excited-state lifetime. Upon photoexcitation, the bond length of Re-P and angle of P-Re-P are significantly changed in both complexes, while the phenyl groups are largely rotated by ∼20° only in (3,3). In contrast, there is little change in charge distribution on the phenyl groups when Re to dmb charge transfer occurs upon photoexcitation. We concluded that the instability from steric effects of phenyl groups and diimine leads to a smaller Stokes shift of the lowest excited triplet state (T1) in (3,3). The large structural change between the ground and excited states causes the longer lifetime of T1 in (3,3).

Original languageEnglish
Pages (from-to)7773-7784
Number of pages12
JournalInorganic chemistry
Volume60
Issue number11
DOIs
Publication statusPublished - Jun 7 2021

All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry

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