Influence of ligands on the fac⇌Δhνmer isomerization in [RuCl3(NO)(P–P)] complexes, [P–P = R2P(CH2)nPR2 (n = 1–3) and R2P(CH2)POR2, PR2–CHCH–PR2, R = Ph and (C6H11)2P-(CH2)2-P(C6H11)2]

[RuCl3(NO)(P–P)], [P–P = R2P(CH2)nPR2 (n = 1–3) and R2P(CH2)POR2, PR2–CHCH–PR2, R = Ph and (C6H11)2P-(CH2)2-P(C6H11)2] were obtained and characterized by 31P {1H} NMR, IR spectroscopies and cyclic voltammetry. The structures of fac-[RuCl3(NO)(P–P)], P–P = dppm (1), dppe (2), c-dppen (3) and dppp (4), mer-[RuCl3(NO)(dcpe)] (6a) and mer-[RuCl3(NO)(dppmO)] (7) have been determined by X-ray diffraction. Photochemical isomerization of fac- to mer-[RuCl3(NO)(P–P)] was observed under white light in a CH2Cl2 solution and in solid state. The isomerization processes were followed by IR and 31P {1H} spectra. The mer-[RuCl3(15NO)(dppb)] isomer was used for the definition of the phosphorus atoms in the structure of the complex in solution. The electrochemical study shows that the oxidation/reduction processes observed in these complexes are dependent on both the isomer (fac or mer) and the solvent. In CH2Cl2, the NO+ reduction potentials are less negative for the mer-isomers than for the fac ones, while in CH3CN solvent these potentials are, in general, very close for both isomers.

Complexes with general formula mer-[RuCl3(NO)(P–P)] were obtained and characterized from photoisomerization reactions of the respective fac-[RuCl3(NO)(P–P)] isomers. The spectroscopy, electrochemical and structural characterizations are presented aiming to unravel the different electronic properties of the NO+ ligand in each isomer type.Figure optionsDownload as PowerPoint slide