Spectroscopic and electrochemical properties of a new nitrosyl-complex of Ru(II): trans-[Ru(NO){(CH 3CH 2) 2PCH 2CH 2P(CH 2CH 3) 2} 2Cl](PF 6) 2

Abstract

A new ruthenium nitric oxide complex with the bidentate phosphine, 1,2-bis(diethylphosphino)ethane (depe), has been synthesized and characterized by UV–Vis, infrared, EPR, NMR, electrochemical techniques and X-ray structure determination. The electronic spectrum showed a typical band of dπ→pπ* charge-transfer (CT) transition, assigned to Ru(II)NO transition, and the vibrational spectrum exhibited a peak of nitrosyl ligand at ( ν NO=1851 cm −1). A model structure for this complex has been proposed based on 1H, 1H{ 31P}, 31P{ 1H}, 13C{ 1H}, COSY 1H 1H{ 31P}, J-Resolved, HSQC, HMBC, HSQC 1H 13C{ 31P} and 1H 13C HSQC/ 1H 1H TOCSY spectral data, and confirmed by X-ray diffraction. The nitrosonium character for the NO ligand become evident through both electron paramagnetic resonance and X-ray data (angle RuNO=177.4(3)°). The reversible monoeletronic process at E 1/2=0.040 V versus SHE was assigned to the ligand NO +/NO redox couple. Under treatment with Cd(Hg) solutions containing the [Ru(NO)(depe) 2Cl](PF 6) 2 yields a signal in the EPR spectrum ( g ⊥=1.99 and g //=1.88) which fitted quite well with the simulated spectra of coordinated NO species.