Organometallic photochemistry in supercritical fluids: Reactions of cyclopentadienyl carbonyl and phosphine carbonyl complexes of manganese with dinitrogen

Abstract

UV photolysis has been used to generate dinitrogen compounds by substitution of CO groups by N 2 in supercritical fluid solvents (scXe, scCO 2 and scC 2H 6) containing high pressures of N 2. Compounds include Cp'Mn(CO) 2L (Cp′  C 5H 4Me; L  PMe 3- x Ph x , x = 0 to 3). A semi-quantitative comparison of the photolysis of Cp★Mn(CO) 3 (Cp★  C 5Me 5) and N 2 in ScXe and scCO 2 indicates that there is little difference between the effectiveness of the photolysis in these two supercritical solvents. The Timney Ligand Effect approach is used to rationalise the fact that some of the ν(CO) and ν(NN) bands of Cp★Mn(CO) 2(N 2) and Cp★Mn(CO)(N 2) 2 are nearly coincident.