Alkyne metathesis polymerization

Although alkyne metathesis has been used in polymerization reactions, these applications are not nearly as well advanced as those involving ROMP or ADMET polymerization of alkenes. Further discussion of alkyne metathesis polymerizations is beyond the scope of this text. 

This chapter will cover both the synthesis and basic principles of modern, well-defined metal alkyhdenes related to their use in ROMP, ADMET-polymerization and alkyne metathesis polymerization. The term well-defined is limited to catalytic systems, usually metal alkyhdenes, that are characterized by a uniform and stoichiometric composition and for which the actual propagating species is well known and characterized. Consequently, the entire chemistry of standard binary or ternary systems such as WCl6/AlEt2Cl/ethanol has been neglected. Where ap-phcable, general aspects of the preparation of advanced materials via ROMP and alkyne-polymerization will be mentioned briefly. 

The tungsten alkylidyne complex (t-BuO)3W(C-t-Bu) [130-132] is capable of catalyzing alkyne metathesis polymerization of cyclic alkynes. In addition, it can be used in acyclic diene metathesis (ADIMET) [133, 134]. The synthesis of the corresponding Mo-compound Mo(CCH2SiMe3)(OAd)3 (Ad=adamantyl) has been reported by C.C. Cummins et al. [135]. Though the active species is not known yet, a mixture of Mo(CO)6 and 4-chlorophenol is nowadays used for purposes of convenience [136]. 

I 6 Alkyne Metathesis Polymerization (ADIMET) and Macrocyclization (ADIMAC)... 

Table 6.1 Summary of catalyst systems utilized in alkyne metathesis polymerization.

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