Investigation of the solvent free isomerisation of cis -Mo(CO) 4 L 2 [L = PPh 2 Et, PPh 3 , PPh 2 Me, and P( m -tolyl) 3 ] by diffuse reflectance infrared Fourier transform spectroscopy and thermal methods
Thermal analysis of cis -Mo(CO) 4L2 (L = PPh 2Et, PPh 3, PPh 2Me and P( m-tolyl) 3) revealed that they undergo cis to trans isomerisation under solventless conditions. For L = PPh 3 and P( m-tolyl) 3, the reaction occurred in the solid state. For L = PPh 2Et and PPh 2Me the reaction occurred in the melt and was followed by trans isomer solidification. The rate of the solid state isomerisation of cis -Mo(CO) 4(PPh 3)2 was investigated by diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and the results showed that the reaction was first order. A thermomicroscopic investigation of cis -Mo(CO) 4(P( m-tolyl) 3)2 revealed that the isomerisation was surface-initiated.