TRANSIENT SPECIES IN THE PULSE-RADIOLYSIS OF CYCLOHEXANE SOLUTIONS OF GROUP-VI METAL-CARBONYLS

Pulse radiolysis of cyclohexane solutions of hexacarbonyls of chromium, molybdenum and tungsten yields transient visible absorptions with λmax, respectively, at 505 nm, 410 nm, 415 nm assigned by comparison with photochemical data, to the related pentacarbonyl. The following reactions: M(CO)6+e-solv→M(CO)6-M(CO)6-+C6H+12→M(CO)5+CO+C6H12 have been identified as the main mechanism responsible for pentacarbonyl formation by pulse radiolysis. In argon saturated solutions pentacarbonyls decay by first order kinetics; the rates are independent of radiation doses and hexacarbonyl concentration but somewhat affected by the origin of cyclohexane used. Hypotheses on the product are advanced. Reaction of pentacarbonyls with cyclohexane, hydrogen, nitrogen and carbon oxide are detected and reaction rates measured. Spectra of transient M(CO)5C6H10 and M(CO)5N2 are reported. © 1979.