Theoretical Insight on the S → O Photoisomerization of DMSO Complexes of Ru(II)

• Published in: The journal of physical chemistry. A, Molecules, spectroscopy, kinetics, environment, & general theory Molecules, spectroscopy, kinetics, environment, & general theory, 2009-10, Vol.113 (41), p.11002-11006
• Main Authors: Lutterman, Daniel A, Rachford, Aaron A, Rack, Jeffrey J, Turro, Claudia
• Format: Article
• Language: English
• Subjects: A: Molecular Structure, Quantum Chemistry, General Theory; Computer Simulation; Dimethyl Sulfoxide - chemistry; Isomerism; Models, Molecular; Molecular Structure; Organometallic Compounds - chemistry; Oxygen - chemistry; Photochemistry; Quantum Theory; Ruthenium - chemistry; Sulfur - chemistry
• ISSN: 1089-5639; 1520-5215
• DOI: 10.1021/jp903048n

Complexes of the type [Ru(tpy)(L)(dmso)] n+ (where tpy = 2,2′:6′,2′′-terpyridine; L = 2,2′-bipyridine (bpy), n = 2; N,N,N′,N′-tetramethylethylene diamine (tmen), n = 2; acetylacetonate (acac), n = 1; oxalate (ox), n = 0; malonate (mal), n = 0) were investigated by density functional theory (DFT). The results do not support a promoting role for the dσ* ligand field (LF) states during excited state S → O isomerization. Instead, the calculations show that the formation of a Ru(III) center is important in the isomerization, along with the identity of the ancillary bidentate ligand. The present work shows that the orbital contributions from the bidentate ligand to the HOMO, which is typically centered on the ruthenium, plays an important role in the photochemical and oxidative reactivity of the complexes.