Photochemistry of tricarbonyl(η-cyclopentadienyl)methylmolybdenum in frozen gas matrices at 12 K. Infrared spectroscopic evidence for the formation of dicarbonyl(η-cyclopentadienyl)methylmolybdenum and dicarbonyl(η-cyclopentadienyl)(dinitrogen)methylmolybdenum

Abstract

Infrared spectroscopic evidence, including ¹³CO lebelling and energy-factored CO force-field fitting, is presented to show that on photolysis of [Mo(η⁵-C₅H₅)(CO)₃(CH₃)] at high dilution in CH₄, Ar, CO, and N₂ matrices at 12 K new species [Mo(η⁵-C₅H₅)(CO)₂(CH₃)] and [Mo(η⁵-C₅H₅)(CO)₂(N₂)(CH₃)] are produced. The reversibility of the reaction [Mo(η⁵-C₅H₅)(CO)₃(CH₃)]⇌[Mo(η⁵-C₅H₅)(CO)₂(CH₃)]+ CO is interpreted as confirming the existence of a reduced co-ordination number species as the intermediate in the substitution reactions of [Mo(η⁵-C₅H₅)(CO)₃(CH₃)]. The results are discussed in relation to the mechanisms of thermal and photochemical solution reactions.