SYNTHESIS OF ASYMMETRIC DIYNES, DIFFERING IN NUMBER OF METHYLENE FRAGMENTS AND THEIR ABILITY TO SOLID STATE POLYMERIZATION
Authors: Tanaseichuk Boris S. , Pryanichnikova Margarita K. , Burtasov Alexey A. 
Published: February 2019

Asymmetric conjugate diynes are of considerable interest because of their ability to solid state polymerization to form polymers with an ordered tough polyene structure. The capacity of conjugated diynes to such polymerization is determined by the presence and nature of the substituents in the side chain diynes and the degree of their distance from the diacetylenic fragment. To evaluate the effect of the distance a bulky substituent of conjugate diyne′s fragment for ability of asymmetric diacetylenes ordered solid state polymerization were prepared 4 alkildiinil′s ether of p-hydroxybenzaldehyde with varying degrees of distance diyne′s fragment from the benzene ring.Synthesis of alkildiinil′s esters of p-hydroxybenzaldehyde was carried out in two stages. At the first stage by alkylation of p-hydroxybenzaldehyde of corresponding of toluenesulfonate′s terminal alkynol or ω-bromalkines in the presence of sodium ethoxide was prepared monoalkinil′s ether of p-hydroxybenzaldehyde, in which the terminal triple bond is separated from the phenoxyl′s fragment 1, 2, 3 and 4 methylene′s groups. Use as a alkylating agent of toluenesulfonate′s terminal alkynols, which differ in low volatility compared ω-bromalkines, gives a fairly high (~ 60%) the yield of desired products. At the second stage according to the method of Kadio-Chodkiewich the condensation-3-brompropin-2-ol with the corresponding monoalkinil′s esters of p-hydroxybenzaldehyde were alkildiynil′s ethers of p-hydroxybenzaldehyde, which have a terminal triple bond is separated from the benzene′s ring 1, 2, 3 and 4 methylene′s groups. The effect of the degree of remoteness of the conjugate diyne′s fragment from the bulk p-formilfenoksil′s substituents on these compounds ability to solid state polymerization under UV irradiation was studied by the asymmetric diynes. About the polymerization rate was judged visually by a color change. All investigated diynes exhibited the ability to solid state polymerization. The rate of it was largely dependent of the number of methylene′s fragments, separating p-formilfenoksil′s ring from diyne′s fragment. If the irradiation of diynes containing 3 or 4 methylene′s fragments, color change of almost colorless to dark brown occurred within 5-6 h, then diynes containing 1 or 2 of the methylene′s fragments was required for 24 h. It goes to show that the increase the length of the methylene′s chain, postpones surround p-formilfenoksil′s fragment from a paired diyne′s fragment, eases the solid state polymerization. However, the absence of the bright color of the polymer characteristic polydiacetylene′s ordered structures indicates that, polymerization was not well-ordered in out case.Thus, the results showed that administration of methylene′s fragments, causing varying degrees of remoteness of the conjugate diyne′s fragment from the bulk p-formilfenoksil′s fragment, has a significant impact on the ability of asymmetric conjugate diynes to solid state polymerization under UV irradiation. The increase in the degree of remoteness promotes their solid state polymerization, those namely the structure of asymmetric diynes determines their behavior in the polymerization process.