Solvent-induced configuration mixing and triplet excited-state inversion: insights from transient absorption and transient dc photoconductivity measurements - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Physical Chemistry Chemical Physics Année : 2009

Solvent-induced configuration mixing and triplet excited-state inversion: insights from transient absorption and transient dc photoconductivity measurements

, , , (1) , , ,
1
Chunxing She
  • Fonction : Auteur
Aaron-A. Rachford
  • Fonction : Auteur
Xianghuai Wang
  • Fonction : Auteur
Sébastien Goeb
Ala'A-O. El-Ballouli
  • Fonction : Auteur
Felix-N. Castellano
  • Fonction : Auteur
Joseph-T. Hupp
  • Fonction : Auteur

Résumé

Solvent-induced excited-state configuration mixing in a Pt(II) diimine chromophore with phenylene ethynylene containing acetylide ligands, [Pt(tBu2bpy)(PE3)2] (1), was characterized by nanosecond transient absorption spectroscopy and transient dc photoconductivity (TDCP). The mixing is a result of closely spaced triplet charge transfer (3CT) and intraligand-localized (3IL) triplet energy levels that are finely tuned with solvent polarity as ascertained by their parent model chromophores [Pt(tBu2bpy)(PE1)2] (2) and [Pt(P2)(PE3)2] (3), respectively. The absorption difference spectrum of the mixed triplet state is dramatically different from those of the 3CT and 3IL state model chromophores. The 3CT, 3IL and configuration-mixed triplet states led to distinct TDCP signals. The TDCP response is of negative polarity for 3CT excited states but of positive polarity for 3IL excited states. TDCP transients for 1 in mixed solvents are a combination of signals from the 3IL and 3CT states, with the signal magnitude depending on the polarity of solvent composition. The fraction of 3CT state character in the configurationally mixed excited state was quantified by TDCP to be [similar]0.24 in pure benzene, while it decreased to [similar]0.05 in 20 : 80 (v : v) benzene–CH2Cl2. The charge transfer fraction appears to increase slightly to ~0.11 in the lower polarity 20 : 80 n-hexane–CH2Cl2 medium. TDCP is shown to be a useful tool for the identification of the lowest excited state in electrically neutral metal–organic chromophores.

Domaines

Chimie

Dates et versions

hal-03343403 , version 1 (14-09-2021)

Identifiants

Citer

Chunxing She, Aaron-A. Rachford, Xianghuai Wang, Sébastien Goeb, Ala'A-O. El-Ballouli, et al.. Solvent-induced configuration mixing and triplet excited-state inversion: insights from transient absorption and transient dc photoconductivity measurements. Physical Chemistry Chemical Physics, 2009, 11 (38), pp.8586 - 8591. ⟨10.1039/b908977b⟩. ⟨hal-03343403⟩
5 Consultations
0 Téléchargements

Altmetric

Partager

Gmail Facebook Twitter LinkedIn More