Detection of the EPR Spectra of NO^• in Ruthenium(II) Complexes

Abstract

The EPR of NO. can be detected in the liquid and solid states when crystal fields are sufficient to remove the axial symmetry and separate the (pi*)x and (pi*)y orbitals by a few hundred reciprocal centimeters. The theory of the EPR spin Hamiltonian of bound NO. is reviewed, further developed, and then applied to the observed frozen-liquid spectra of NO. bound to Ru(II) obtained from RuIINO+ complexes by reduction. Comparisons to earlier reports on the observation of the EPR spectra of NO. are made.