H. Balcar et Z. Bastl, RING-OPENING METATHESIS POLYMERIZATION OF NORBORNENE BY WCL6 - FORMATION OF WCL5 AND WCL4 AND THEIR CATALYTIC ACTIVITY, Collection of Czechoslovak Chemical Communications, 61(9), 1996, pp. 1353-1359
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.