Photoinduced and Thermal Linkage Isomerizations of an Organometallic Ionic Liquid Containing a Half-Sandwich Ruthenium Thiocyanate Complex

Metal complexes with thiocyanate (SCN^-) ligands typically exhibit S- or N-coordinated linkage isomers. In this study, to explore ionic liquids that exhibit stimuli-responsiveness based on linkage isomerization, we synthesized an ionic liquid containing a cationic half-sandwich thiocyanate complex, [Ru(C₆H₆)(NCS)L]Tf₂N (L = N-hexyl-2-pyridinemethanimine, Tf₂N = bis(trifluoromethanesulfonyl)amide anion). The as-synthesized ionic liquid was a 0.7:0.3 mixture of N- and S-coordinated isomers, presenting as an extremely viscous liquid exhibiting a glass transition at 0 °C. Isomerization from the N- to the S-coordinated isomer occurred upon UV photoirradiation or heating, although thermal isomerization was accompanied by significant decomposition. The N- and S-coordinated isomers were separated into brown and orange liquids, respectively, using gel permeation chromatography. Each isomer exhibited a small solvatochromic absorption shift in organic solvents, with different solvent dependences observed for the two isomers.

Nuclearity versus oxidation state in the catalytic efficiency of MnII/III azo Schiff base complexes: computational study on supramolecular interactions and phenoxazinone synthase-like activity

Supramolecular interactions of a mononuclear Mn(iii) and a tetranuclear Zn(ii)–Mn(ii) complexes and their comparative bio mimetic catalytic activity have been reported.