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Abstract

Reaction between WCl₆ and norbornene in benzene and cyclohexane, respectively, was investigated using UV/VIS, ESR and XPS spectroscopy in order to establish the main reaction products on the tungsten side and their relation to the initiation of ring opening metathesis polymerization (ROMP) of norbornene. The tungsten compounds: WCl₅, insoluble WCl₄ and soluble tungsten species having four chlorine atoms bound to tungsten, [WCl₄L_n] were found to be the main products. The catalytic activity of the respective compounds in ROMP of norbornene was found to decrease in the order: WCl₅ > WCl₆ >> WCl₄ ~ [WCl₄L_n]. The polynorbornenes prepared with both WCl₄ and [WCl₄L_n] possess higher content of cis double bonds in comparison with polymers prepared with WCl₆ and WCl₅ catalysts.

Keywords: Ring opening metathesis polymerization; Norbornene; Tungsten chlorides.