Photolysis of [(η5-C5H5)M(CO)2NO]+, where M = Mn and Re, in inert ionic matrices: Evidence for nitrosyl linkage isomerism

The photochemistry of [(η5-C5H5)M(CO)2NO]BF4, where M=Mn and Re, and [(η5-C5H4Me)Mn(CO)2NO]PF6 has been examined in frozen ionic matrices, NEt3OctPF6, at ca. 90 K. In each case visible light initiates transformations of the nitrosyl ligand to isonitrosyl and η2-NO linkage isomers as evidenced by their characteristic IR absorptions. Continued irradiation in the UV results in CO loss as reported by earlier workers. Comparisons with the photochemistry of the Group VI analogues, (η5-C5H5)M(CO)2NO, suggest that some features observed in these earlier studies may need to be reinterpreted.