Synthesis and characterization of novel multi-functional polymers by transition metal catalysts

Abstract

Part I. Cyclopolymerization of 1,6-Heptadiyne Derivatives by Metathesis Catalysts : This thesis deals with the effects of the size and the type of substituents on the fine and conformational structure, environmental stability and optical properties for the poly(1,6-heptadiynes) with substituents. A variety of 1,6-heptadiyne monomers were polymerized to give organo-soluble polymers in high yield with $MoCl_5$-based catalysts. From a series of ## values of the resulting polymers, it was found that the incorporation of the bulkier substituent into the 4-position of 1,6-heptadiyne enforces the conjugated polyene into more planar structure as indicated by the bathochromic shift of maximum absorption bands resulting from the $\pi$-$\pi^*$ transition of the conjugated polymer backbone. It appears that the chain twisting of the substituted poly(1,6-heptadiynes) is primarily determined by the steric bulk of the substituent group at 4-position rather than by that at the point of attatchment to the polymer chain which usually decreases the effective conjugation length-coplanarity- of the polymer ##-system. When an extremely bulky substituent was introduced at 4 position, the resulting polymer tends to have mostly one size ring, five- membered ring. The poly 5c (## = 606 nm) with an extremely bulky substituent such as tert - butyldiphenylsiloxymethyl group is environmentally very stable. This stability, reluctance to the backbone toward air oxidation, is thought to be due to the effective shielding of highly conjugated backbone by the bulky substituents. The nonlinear optical properties of the resulting polymers were evaluated by degenerate four wave mixing experiment. The ## values were increased with increasing the steric bulk of the substituents at 4-position. These unusual optical behavior could be explained by the trans-cis structure (in case of all five-membered ring structure) or transoid-cisoidal conformation (in case of all six-membered ring structure) firstly pro...