RING-OPENING METATHESIS POLYMERIZATION OF NORBORNENE BY WCL6 - FORMATION OF WCL5 AND WCL4 AND THEIR CATALYTIC ACTIVITY

Reaction between WCl6 and norbornene in benzene and cyclohexane, respe ctively, was investigated using UV/VIS, ESR and XPS spectroscopy in or der to establish the main reaction products on the tungsten side and t heir relation to the initiation of ring opening metathesis polymerizat ion (ROMP) of norbornene. The tungsten compounds: WCl5, insoluble WCl4 and soluble tungsten species having four chlorine atoms bound to tung sten, [WCl(4)L(n)] were found to be the main products. The catalytic a ctivity of the respective compounds in ROMP of norbornene was found to decrease in the order: WCl5>WCl6 much greater than WCl4 approximate t o[WCl(4)L(n)]. The polynorbornenes prepared with both WCl4 and [WCl(4) L(n)] possess higher content of cis double bonds in comparison with po lymers prepared with WCl6 and WCl5 catalysts.