Synthesis of novel conducting polymers by transition metal catalysts

Abstract

Dipropargyl derivatives as monomers were prepared by a Grignard reagent of propargylbromide with dichlorosilane derivatives or various esters. The structure of monomers was identified by various spectroscopic analyses. Polymerization was attempted by various transition metal catalyst system. A molybdenium complex was found to be a particularly effective catalyst for the cyclopolymerization of dipropargyl derivatives. H-NMR, C-NMR, IR, UV-visible and Raman spectroscopies showed that poly (dipropargyl derivatives) possess polyene structures having 6-membered cyclic recurring units in the polymer backbone. Resulting cyclopolymers were soluble in common organic solvents and their solubility was depended on the nature of substituents. The oxidative stability of poly(dipropargyl derivatives) increased with increasing bulkiness of substituents. The thermal stability of cyclopolymers having aromatic substituent were more stable than those having aliphatic substituent. The electrical conductivity of cyclopolymers increased from the undoped level of $10^{-13}$ -$10^{-11}$ Scm$^{-1}$ (insulator) to a maximum value $10^{-13}$ -$10^{-2}$ Scm$^{-1}$ (semiconductor) by various electron acceptor doping. The changes in X-ray, IR, UV-visible, EPR and the activation energy for the conduction by doping were also investigated. Dehydration and isomerization of poly(dipropargyl-carbinol derivatives) with functional hydroxy group gave the good thermal stable polymer having the structure of poly(5-substituted-m-xylene).