H. Balcar et al., METATHESIS POLYMERIZATION OF PHENYLACETYLENE BY TUNGSTEN ARYLOXO COMPLEXES, Collection of Czechoslovak Chemical Communications, 60(3), 1995, pp. 489-497
Catalytic activity of the tungsten aryloxo complexes WCl5(OAr) and WOC
l3(OAr), where Ar = 4-t-C4H9C6H4, 2,6-(t-C4H9)(2)C6H3, 2,6-Cl2C6H3, 2,
4,6-Cl3C6H2, and 2,4,6-Br3C6H2 in polymerization of phenylacetylene (2
0 degrees C, monomer to catalyst molar ratio = 1 000) was studied. The
activity of WCl5(OAr) as unicomponent catalysts increases with increa
sing electron withdrawing character of the -OAr ligand. Addition of tw
o equivalents of organotin cocatalysts (Me(4)Sn, Bu(4)Sn, Ph(4)Sn, Bu(
3)SnH) to WCl5(O-C6H2Cl3-2,4,6) has only slight positive effect (sligh
tly higher polymer yield and/or molecular weight of poly(phenylacetyle
ne)s was achieved). However, in the case of WOCl3(O-C6H3Cl2-2,6) catal
yst, it enhances the activity considerably by eliminating the inductio
n period, Poly(phenylacetylene)s prepared with the catalysts studied h
ave weight-average molecular weight ranging from 100 000 to 200 000. T
hey are trans-prevailing and have relatively low molar fraction of mon
omer units comprised in cyclohexadiene sequences (about 6%).