Transient metal-centered states mediate isomerization of a photochromic ruthenium-sulfoxide complex

• Published in: Nature communications 2018-05, Vol.9 (1), p.1989-9, Article 1989
• Main Authors: Cordones, Amy A., Lee, Jae Hyuk, Hong, Kiryong, Cho, Hana, Garg, Komal, Boggio-Pasqua, Martial, Rack, Jeffrey J., Huse, Nils, Schoenlein, Robert W., Kim, Tae Kyu
• Format: Article
• Language: English
• Subjects: 639/638/440/94; 639/638/911/406/939; Atomic structure; Charge transfer; Chemical reactions; Chemical Sciences; Data analysis; Data processing; Density functional theory; Electronic structure; Humanities and Social Sciences; INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; Isomerization; Ligands; Metals; Molecular chains; Molecular structure; multidisciplinary; Nuclear reactions; Nuclei; or physical chemistry; Photochromism; Ruthenium; Science; Science (multidisciplinary); Theoretical and; Time dependence; X ray spectra
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-018-04351-0

Ultrafast isomerization reactions underpin many processes in (bio)chemical systems and molecular materials. Understanding the coupled evolution of atomic and molecular structure during isomerization is paramount for control and rational design in molecular science. Here we report transient X-ray absorption studies of the photo-induced linkage isomerization of a Ru-based photochromic molecule. X-ray spectra reveal the spin and valence charge of the Ru atom and provide experimental evidence that metal-centered excited states mediate isomerization. Complementary X-ray spectra of the functional ligand S atoms probe the nuclear structural rearrangements, highlighting the formation of two metal-centered states with different metal-ligand bonding. These results address an essential open question regarding the relative roles of transient charge-transfer and metal-centered states in mediating photoisomerization. Global temporal and spectral data analysis combined with time-dependent density functional theory reveals a complex mechanism for photoisomerization with atomic details of the transient molecular and electronic structure not accessible by other means. An essential open question in functional transition metal complexes is the relative roles of charge-transfer and metal-centered excited states. Here the authors identify the important role of metal-centered excited states in the linkage photoisomerization of a photochromic Ru-sulfoxide complex.