Crystal structure, optical, magnetic, and photochemical properties of the complex pentakis(dimethyl sulfoxide)nitrosylchromium(2+) hexafluorophosphate

The nitrosyl complex [Cr(dmso)5(NO)](PF6)2 (1) (dmso = dimethyl sulfoxide) has been prepared by the solvolysis of [Cr(NCCH3)5(NO)](PF6)2 in neat dmso. The optical absorption spectrum of 1 in dmso shows maxima at 734, 567, 450, 413, and 337 nm. Continuous photolysis of 1 with λ = 365–580 nm light in dmso solution results in a release of NO with quantum yield, Φ, in the range 0.034–0.108 mol Einstein−1. Irradiation of a deoxygenated CH3CN solution of [Cr(NCCH3)5(NO)](PF6)2 in the presence of excess of [Fe(S2CNEt2)2] results in a transfer of NO to the iron centre as shown from the characteristic EPR spectrum of [Fe(S2CNEt2)2(NO)] with Aiso(14N) = 12.2 × 10−4 cm−1. The EPR parameters of 1 were determined: giso, g‖ and g⊥ : 1.96725, 1.91881(4) and 1.992763(2); Aiso(53Cr), A‖ (53Cr) and A⊥(53Cr): 22.8 × 10−4, 39 × 10−4 and 15.8 × 10−4 cm−1; Aiso(14N), A‖ (14N) and A⊥(14N): 5.9 × 10−4, 2 × 10−4 and 7.540(4) × 10−4 cm−1.