PHOTOCHEMISTRY OF NITROSYL METAL-COMPLEXES - LASER PHOTOLYSIS STUDIESOF NITROSYLCOBALT SCHIFF-BASES IN ETHANOL AND TOLUENE IN THE TEMPERATURE-RANGE 160-300K

(N,N'-Disalicylideneethylenediaminato)cobalt(II), Co(II)salen, and thy l-3-oxobutylidene)ethylenediaminato)cobalt(II), Co(II)acacen, in both ethanol and toluene react with nitric oxide to give the nitric oxide a dducts, (NO)Co(II)salen and (NO)Co(II)acacen, The laser photolysis stu dies revealed that (NO)Co(II)salen photodissociates NO to yield Co(II) salen with the quantum yields 1.0 +/- 0.1 in ethanol and 0.6 +/- 0.1 i n toluene at 300 K. The transient product, Co(II)salen, undergoes the recombination reaction with NO to regenerate (NO)Co(II)salen with the rate constant 1.1 x 10(9) M(-1) s(-1). The quantum yields, phi, for ph otodissociation of NO from (NO)Co(II)acacen are obtained as phi = 1.0 +/- 0.1 and phi < 0.01 in toluene and ethanol, respectively. The quant um yields phi for both (NO)Co(II)salen and (NO)Co(II)acacen are found to be markedly dependent on temperature: the yield decreases with a de crease in temperature. The photodissociation mechanism of NO from (NO) Co(II)salen and (NO)Co(II)acacen is discussed on the basis of the lase r photolysis studies carried out in the temperature range 160-300 K. B unsen absorption coefficients of NO in ethanol and toluene at 300 K we re determined from kinetic analysis of the recombination reaction betw een NO and cobalt(II) Schiff bases.