On the interplay of solvent and conformational effects in simulated excited-state dynamics of a copper phenanthroline photosensitizer. Issue 2 (13th December 2019)

• Record Type: Journal Article
• Authors: Levi, Gianluca; Biasin, Elisa; Dohn, Asmus O.; Jónsson, Hannes
• Is Part Of: Physical chemistry chemical physics. Volume 22:Issue 2(2019)
• Page Start: 748
• Page End: 757
• Publication Date: 2019-12-13
• Subjects: Chemistry, Physical and theoretical -- Periodicals; 541.3
• DOI: 10.1039/c9cp06086c
• Languages: English
• ISSNs: 1463-9076

Abstract

Abstract : QM/MM direct dynamics simulations in acetonitrile reveal the interplay between solvent and conformational effects in the photoinduced ultrafast flattening of a copper photosensitizer. Abstract : Copper(i ) bis-phenanthroline complexes represent Earth-abundant alternatives to ruthenium-based sensitizers for solar energy conversion and photocatalysis. Improved understanding of the solvent-mediated excited-state structural dynamics can help optimize their photoconversion efficiency. Through direct dynamics simulations in acetonitrile and excited-state minimum energy path calculations in vacuum, we uncover the mechanism of the photoinduced flattening motion of the prototypical system [Cu(dmphen)2 ] + (dmphen = 2, 9-dimethyl-1, 10-phenanthroline). We find that the ligand distortion is a two-step process in acetonitrile. The fast component (∼110 fs) is due to spontaneous pseudo Jahn–Teller instability and is largely solvent independent, while the slow component (∼1.2 ps) arises from the mutual interplay between solvent molecules closely approaching the metal center and rotation of the methyl substituents. These results shed new light on the influence of a donor solvent such as acetonitrile and methyl substituents on the flattening dynamics of [Cu(dmphen)2 ] + .