Synthesis and polymerization of highly electrophilic monomers.

Abstract

The experimental results of the current work have two parts. First the synthesis, characterization, and spontaneous copolymerization of two highly electrophilic imines, tricyanomethanimine and methyl 3-aza-α, β-dicyanoacrylate. 1,1-Dichloro-2,2-dicyanoethylene or methyl 3,3-dichloro-2-cyanoacrylate reacted with excess sodium azide to give the corresponding diazides, which smoothly underwent thermolysis in solution to give a solution of the novel tricyanomethanimine or methyl 3-aza-α, β-dicyano-acrylate. Attempted isolation gave only oligomers, but reactions using solution of these imines succeeded. Cyclopentadiene and 2,3-dimethyl-1,3-butadiene afforded hetero Diels-Alder reactions. N,N-Dimethylaniline with tricyanomethanimine gave a p-substituted derivative, but with methyl 3-aza-α, β-dicyanoacrylate only a charge transfer complex was formed. Imines - p-methoxystyrene copolymers were obtained. These imines are as reactive as TCNE, but in contrast can also polymerize. Second, a new unsymmetrically substituted quinodimethane was synthesized, characterized, and copolymerized with electron donating monomers. Oxidation of the 1-cyano-1-phenylmethylene-4-cyano-4-ethoxycarbonylmethylene with MnO₂ gave mostly poly-7,8-dicyano-7-ethoxycarbonyl-8-phenylquinodimethane (DCEPQ), but depolymerization by sublimation yielded 45% of DCEPQ. This compound was a mixture of cis and trans isomers. It was homopolymerized by anionic initiation. High molecular weight copolymers of DCEPQ-styrene, DCEPQ-p-methylstyrene and DCEPQ-p-methoxystyrene(p-MeOSt) were formed spontaneously in 1,2-dichloroethane. All polymerizations occurred by a radical mechanism. High molecular weight polymers formed at low conversion. DCEPQ - p-MeOSt copolymerizations yielded alternating copolymers. From spontaneous polymerization of DCEPQ with NVC no copolymer was obtained. All of these polymerizations begin with a bond forming mechanism and propagate by polyaddition.