The synthesis of trans-(Me3CO)3WCCH=CHCW(OCMe3)3, cis,cis-(Me3CO)3WCCH=CHCCCH=CHCW(OCMe3)3, and related metal-capped ene ynes, and evaluation of them as catalysts for preparing polydiacetylenes

Article abstract of DOI:10.1016/0022-328X(88)89027-2

Reaction of 0.5 equiv. of trans-5-decene-3,7-diyne with W(CEt)(OCMe3)3 yields trans-(Me3CO)3W<*>CCH=CHC<*>W(OCMe3)3 (2) via the intermediate trans-(Me3CO)3W<*>CCH=CHC<*>CEt (1), while the reaction of 1 equiv. of cis-5-decene-3,7-diyne with W(CEt)(OCMe3)3 yields cis,cis-(Me3CO)3W<*>CCH=CHC<*>CCH=CHC<*>W(OCMe3)3 (4) via cis-(Me3CO)3W<*>CCH=CHC<*>CEt (3).Reaction of additional cis- or trans-5-decene-3,7-diyne with either 2 and/or 4 results in decomposition.Bipyridyl adducts of related metal-capped oligomers have been prepared and are more stable, but they are too insoluble to serve as intermediates in polymerization reactions.Reaction of 0.5 equiv. of 1,4-dibutynylbenzene with W(CEt)(OCMe3)3 yields (Me3CO)3W<*>C(1,4-C6H4)C<*>W(OCMe3), while reaction of 1 equiv. of 1,2-dipentynylbenzene with W(CEt)(OCMe3)3 yields (Me3CO)3W<*>C(1,2-C6H4)C<*>C(1,2-C6H4)C<*>W(OCMe3)3.Addition of 4 or more equiv. of 1,4-dibutynyl- or 1,2-dipentynyl-benzene to W(CEt)(OCMe3)3 results in formation of a yellow intractable product in less than 50percent yield.It appears that either instability or insolubility of the growing polymers in this general class will limit their utility as catalysts.