Effect of ionising radiation on potassium pentacyanonitrosylruthenate (II): an electron spin resonance study

Amorphous potassium pentacyanonitrosylrufhenate (II) was synthesized and ch aracterized by UV, IR, X-ray diffraction and thermogravimetric analysis. El ectron Spin Resonance spectroscopy reveals the presence of paramagnetic rut henate (I) complexes and NO2 radicals in the X-irradiated diamagnetic salt. Spin-hamiltonian parameters of the [Ru(CN)(5)NO](3-) complex (g(perpendicu lar to)=2.0064, A(perpendicular to)(N-14) = 60.7 MHz, g(parallel to) = 1.99 9,A(parallel to) (N-14) = 77.3 MHz) support an electron capture in a pi* mo lecular orbital of the nitrosyl group mixed with d(xz) and d(yz) ruthenium orbitals as recently predicted by theoretical calculations. Silver ions, pr esent as impurities, are reduced to Ag(0) by X-irradiation and coordinate t o four magnetically equivalent nitrogens in a distorted site, giving rise t o a well resolved anisotropic ESR powder spectrum.