Effect of Light Exposure on UV‐Vis Spectrum of [( n BuCp) 2 ZrCl 2 ] Based Catalyst

UV‐vis spectroscopic study revealed that vinylcyclohexane interaction with zirconocene catalyst is enhanced on light exposure. If oxygen is present it interacts with the catalyst, hindering vinylcyclohexane interaction and consequently lowering the catalyst activity. The catalyst activity can be recovered with light exposure if low O 2 concentrations are used since in light the zirconocene‐vinylcyclohexane interaction is favoured over the zirconocene‐O 2 interaction. Moreover, 1 H NMR studies of the reaction products showed that the structures of the vinylcyclohexane‐based species produced with light irradiation were identical to the species produced in dark. This indicates that light exposure of the catalytic system does not change the reaction mechanism.Absorption spectrum of [( n BuCp) 2 ZrCl 2 ]/MAO/VCH. (a) reaction in dark, (b) reaction with irradiation, (c) reaction with O 2 treatment in dark and (d) reaction with O 2 treatment with irradiation.