Synthesis, crystal structure, spectroscopic, and photoreactive properties of a ruthenium(II)-mononitrosyl complex

Marine Tassé (1) , Hasan Shamran Mohammed (1) , Chloe Sabourdy (1) , Sonia Mallet-Ladeira (2, 1) , P.G. Lacroix (1) , Isabelle Malfant (1, 3)

1 LCC - Laboratoire de chimie de coordination
2 ICT - Institut de Chimie de Toulouse
3 UT3 - Université Toulouse III - Paul Sabatier

A compound of formula [RuIICl(NO)(Cl-py)4](PF6)2, in which Cl-py is the 4-chloropyridine, has been synthesized in four steps and fully characterized. It crystallizes in the P 1 ¯ triclinic space group as [RuIICl(NO)(Cl-py)4](PF6)2·1.25H2O. Upon irradiation at λ = 473 nm in the solid state, the N-bounded nitrosyl ligand (ground state GS: [RuII(NO)]) turns into O-bounded nitrosyl metastable state 1 (MS1: [RuII(ON)]). The population of the long-lived metastable RuII(ON) isomer is equal to 27% on powder samples, therefore 3 times less than that of the parent [RuIICl(NO)(py)4](PF6)2 derivative. Spectroscopy and TD-DFT studies are proposed to find a rational for this difference at the molecular level, which is tentatively related to different UV–visible spectra in the metastable RuII(ON) isomer. Surprisingly, and while the switching efficiency of [RuIICl(NO)(Cl-py)4](PF6)2 appears relatively modest, its capability for releasing the biologically active nitric oxide (NO) radical under irradiation in solution is find to be about 100 times that of the [RuIICl(NO)(py)4](PF6)2 derivative.

Domaines: Chimie de coordination

Marine Tassé, Hasan Shamran Mohammed, Chloe Sabourdy, Sonia Mallet-Ladeira, P.G. Lacroix, et al.. Synthesis, crystal structure, spectroscopic, and photoreactive properties of a ruthenium(II)-mononitrosyl complex. Polyhedron, 2016, 119, pp.350-358. ⟨10.1016/j.poly.2016.09.010⟩. ⟨hal-01935116⟩