Novel Conjugated Polymer Containing Aromatic Ring and Selenium in Backbone. Kinetics of the Addition Reaction as the Model for Addition Polymerization

Abstract

ABSTRACT:The addition reaction mechanism of benzeneselenol to ethynylbenzene was studied as a model for the addition polymerization (so called polyaddition) of 1,4-benzenediselenol to 1,4-diethynylbenzene. The addition reaction occurred without an appreciable side reaction in the presence of AIBN and an adduct of the anti-Markownikoff's structure ( 0-Se-CH = CH---0) was quantitatively obtained. The addition reaction is very similar to the addition polymerization of 1,4-benzenediselenol to 1,4-diethynylbenzene from the point of the geometrical structure of the polymer chain. A kinetic study showed that a rate-determining step of the addition reaction was the addition step of the benzeneseleno radical to ethynylbenzene. The results were compared with those of the addition reaction of benzenethiol to ethynylbenzene. By the competitive addition reaction, ethynylbenzene had 80 times higher reactivity than styrene toward benzeneselenol at 60°C in benzene.KEY 1,4-benzenedithiol (BDT) to 1,4-diethynylbenzene (DEB) proceeded rapidly in solution 4 or in solid state 7 under UV-irradiation. A conjugated linear polymer of the antiMarkownikoff's structure was obtained. The thin polymer film obtained by the solid state polymerization had a layer structure. The layer structure of polymer films increased or decreased reversibly by irradiation of the characteristic light. 8 In the previous paper,9 the authors investigated the synthesis of the conjugated polymer containing selenium by the addition polymerization of 1,4-benzenediselenol (BDSe) to DEB as shown in eq I. The polymerization of BDSe to DEB was carried out by UV-irradiation in toluene at 60°C under The authors reported studies on the conjugated polymer containing sulfur by addition polymerization (so called polyaddition) of dithiol monomers to diethynyl monomers. 4 -6

Novel Conjugated Polymer Containing Aromatic Ring and Selenium in Backbone. Kinetics of Substituent Effect on the Addition Reaction of Benzeneselenols to Ethynylbenzenes as a Model for Addition Polymerization

“…3 The reaction was carried out by introducing each solution into a reaction vessel by the syphon method. The reaction temperature was maintained at 58°C.…”

“…3 The adducts syntheses of various BSes and EBs were carried out with AIBN initiator at 60°C in benzene under nitrogen atmosphere. p-Chloro, p-methyl, and p-methoxy derivatives of BSe and EB were used as a monomer.…”

“…1 (1) In the previous study, 3 as a model for the addition polymerization the addition reaction of benzeneselenol (BSe) to ethynylbenzene (EB) was investigated (eq 2). The addition reaction initiated with 2,2'-azobisisobutyronitrile (AIBN) preferentially occurred Q-C =CH+ HSe-0 to the literature.…”

“…The reaction proceeded by a radical mechanism and the rate-determining step of the reaction was estimated as the addition step of benzeneseleno radical to EB. 3 In this article, to make clear the transition state of the reaction in detail substituent effects on the addition reactions of various BSes to EBs were investigated mainly by a kinetic method. The experimental data were compared with the energy levels of HOMO, SOMO, and LUMO calculated by CAChe system (PM3).…”

Novel Conjugated Polymer Containing Aromatic Ring and Selenium in Backbone. Side Reactions in the Addition Polymerization of Benzenediselenol to Diethynylbenzene

“…However, the side reactions in the addition polymerization have been scarcely investigated so far except for cases of the model addition reaction. 5 In this article, the authors made quantitative analysis of irregular units in the polymer by Raman spectroscopy. For assignment of characteristic absorption bands in Raman spectrum, three model compounds were used.…”