Photochemistry of Nitrosyl Metal Complexes. Laser Photolysis Studies of Nitrosylcobalt Schiff Bases in Ethanol and Toluene in the Temperature Range 160−300 K

(N,N‘-Disalicylideneethylenediaminato)cobalt(II), CoIIsalen, and (N,N‘-bis(1-methyl-3-oxobutylidene)ethylenediaminato)cobalt(II), CoIIacacen, in both ethanol and toluene react with nitric oxide to give the nitric oxide adducts, (NO)CoIIsalen and (NO)CoIIacacen. The laser photolysis studies revealed that (NO)CoIIsalen photodissociates NO to yield CoIIsalen with the quantum yields 1.0 ± 0.1 in ethanol and 0.6 ± 0.1 in toluene at 300 K. The transient product, CoIIsalen, undergoes the recombination reaction with NO to regenerate (NO)CoIIsalen with the rate constant 1.1 × 109 M-1 s-1. The quantum yields, φ, for photodissociation of NO from (NO)CoIIacacen are obtained as φ = 1.0 ± 0.1 and φ < 0.01 in toluene and ethanol, respectively. The quantum yields φ for both (NO)CoIIsalen and (NO)CoIIacacen are found to be markedly dependent on temperature:  the yield decreases with a decrease in temperature. The photodissociation mechanism of NO from (NO)CoIIsalen and (NO)CoIIacacen is discussed on the basis of the laser...