Ultrafast electronic, infrared, and X-ray absorption spectroscopy study of Cu() phosphine diimine complexes

• Published in: Faraday discussions Vol. 244; pp. 391 - 41
• Main Authors: Appleby, Martin V, Cowin, Rory A, Ivalo, Iona I, Peralta-Arriaga, Samantha L, Robertson, Craig C, Bartlett, Stuart, Fitzpatrick, Ann, Dent, Andrew, Karras, Gabriel, Diaz-Moreno, Sofia, Chekulaev, Dimitri, Weinstein, Julia. A
• Format: Journal Article
• Language: English
• Published: England Royal Society of Chemistry 11.08.2023
• Subjects: Absorption spectroscopy; Coordination; Copper; Diimide; Distortion; Dynamic structural analysis; Electron states; Excitation; Infrared spectroscopy; Oxygen production; Phosphines; Singlet oxygen; Spectroscopic analysis; Spectrum analysis; X ray absorption
• ISSN: 1359-6640; 1364-5498
• DOI: 10.1039/d3fd00027c

The study aims to understand the role of the transient bonding in the interplay between the structural and electronic changes in heteroleptic Cu( i ) diimine diphosphine complexes. This is an emerging class of photosensitisers which absorb in the red region of the spectrum, whilst retaining a sufficiently long excited state lifetime. Here, the dynamics of these complexes are explored by transient absorption (TA) and time-resolved infrared (TRIR) spectroscopy, which reveal ultrafast intersystem crossing and structural distortion occurring. Two potential mechanisms affecting excited state decay in these complexes involve a transient formation of a solvent adduct, made possible by the opening up of the Cu coordination centre in the excited state due to structural distortion, and by a transient coordination of the O-atom of the phosphine ligand to the copper center. X-ray absorption studies of the ground electronic state have been conducted as a prerequisite for the upcoming X-ray spectroscopy studies which will directly determine structural dynamics. The potential for these complexes to be used in bimolecular applications is confirmed by a significant yield of singlet oxygen production. The study aims to understand the role of the transient bonding in the interplay between the structural and electronic changes in heteroleptic Cu( i ) diimine diphosphine complexes.