Disubstituted diacetylenes

According to publications (68LA113 71CAS1731 72BSF4781), disubstituted diacetylenes react with diazomethane to form both 3- and 4-acetylenyl-substituted... 

The synthesis can be conducted both in solution and without solvents. The reaction in solvent (e.g., methanol, ethanol, dioxane, dimethylformamide) is recommended for volatile 1,3-diynes and amines in this case the pyrroles are purer and the yield is higher. With disubstituted diacetylenes, ammonia and primary alkyl- and arylamines produce 1,2,3-trisubstituted pyrroles under the same conditions (65CB98 71MI1). Since disubstituted diacetylenes are readily obtained by oxidative coupling of acetylenes (98MI2), this reaction provides a preparative route to a wide range of pyrroles. 

The reaction of disubstituted diacetylenes with hydrazine hydrate was reported by Darbinyan et al. (70AKZ640). In the first stage the addition of hydrazine to the terminal carbon atom of the diacetylene system is analogous to that of primary amines to diacetylene (69ZC108 69ZC110). With monosubstituted diacetylenes (R = H), hydrazine adds to the terminal triple bond. This leads to the formation of vinylacetylenic hydrazine 22 which cyclizes to dihydropyrazole 23 subjected to further isomerization to the pyrazole 25. It is possible that hydrazine 22 undergoes hydration to the ketone 24 which can easily be cyclized to the pyrazole 25... 

Phenylarsine with symmetric disubstituted diacetylenes ( -LiBu, benzene) forms arsoles 79 in 33-83% yield (68TL3257). 

Disubstituted diacetylenes react with benzyl azide upon long heating in toluene (12-16 h, yield 67-70%) (82ZOR1619). Comparison of the reactivity and... 

An important example of the solid state polymerization of disubstituted diacetylenes is 1,6-bis(2,4-dinitro-phenoxy)-2,4-hexadiyne (DNP) shown in Figure 9 - DNP is unique among known diacetylenes... 

In addition to studies of diacetylene single crystals, current research, activities are focused on studies of the second X and third x order nonlinear optical responses of disubstituted diacetylene polymer films as active optical guided wave structures. Diacetylene polymers possess X values comparable to germanium(j 7). In the first stage, three major questions are being addressed ... 

Studies of the solid state photopolymerization of deposited multilayer films reveal that uv induced photopo1ymerizati0n of disubstituted diacetylenes... 

Monosubstituted acetylenic compounds can be oxidatively dimerized by air at room temperature in the presence of copper salts in a pyridine-methanol solution. This method has been applied to a wide variety of acetylenic compounds and gives high yields in disubstituted diacetylenic compounds (equation 264).590... 

Representative for systems exhibiting sigmoidal conversion curves Fig. 1 shows experimental results for the rate constant of the reaction of TS, evaluated from thermal and y-polymerization data according to K = (1 — X) dX(t)/dt, and normalized to the rate constant in the low conversion limit. It is obvious, that at low conversion K depends on X, contrary to what is to be expected for a simple first order reaction. The functional form of KPC) is different for the two modes of polymerization. The overall increase of K with increasing X reveals an autocatalytic reaction enhancement. A measure for its efficiency is the ratio K(X = 0.5)/K(X = 0) which tirnis out to be about 200 for TS under thermal polymerization conditions. This effect is often observed with disubstituted diacetylenes albeit with different kinetic... 

Bloor, D. The polymerization of disubstituted diacetylene crystals. In Developments in crystalline polymers. Bassett, D. C. (ed.). Barking Applied SciencePubUshers 1982, pp. 151-193... 

Besides single crystals, disubstituted diacetylene polymer thin films can be obtained for waveguide applications by evaporation, solidification, or deposition of the diacetylene monomers by the Langmuir-Blodgett approach, which allows film thicknesses to be controlled at the molecular level. These diacetylene films can be patterned using selective polymerization techniques such as developed for... 

The crystal structure of poly[l,2-bis(4-methoxy benzene sulphonyl methyl)-l-butene-3-ynylene] has been determined " since it is central to the topochemical polymerization of disubstituted diacetylenes, e.g. 

Theoretical and experimental studies of the polymerization kinetics of disubstituted diacetylenes are reviewed The problem of relating kinetics measured by macroscopic methods to the microscopic processes occuring in the solid-state is discussed. Areas of controversy and those deserving more detailed study are identified. 

Whereas several pyroelectric diacetylenes were identified, uniform ferroelectric phases seem to be rather the exception, according to our experience with many new substitutions of diacetylenes [92]. The ferroelectric low-temperature phase of the symmetrically disubstituted diacetylene DNP, i.e. l,6-bis(2,4-dinitrophenoxy)-2,4-hexadiyne (Tab. 9.2), turned out to be one of the rare and interesting exceptions [93-98]. 

H. Winter, E. Dormann The pyroelectric phase transition of DNP", a disubstituted diacetylene single crystal, in A. Blumen et al. (eds.) Dynamical processes in condensed molecular systems, World Scientific Publishing Co., 214 (1990)... 

The Fresh-Check is based on a solid state polymerization. The TTI function is associated with the property of disubstituted diacetylene crystals (R-is based on a solid state polymerizatiom Tcontrofled solid-state reaction proceeding via 1,4-addition polymerization, which leads to a highly colored polymer (Patel et al., 1976, Patel and Yee, 1980). During polymerization, the crystal stracture of the monomer is retained and the polymer crystals remain chain aligned and are effectively one-dimensional in their optical properties (Patel and Yang, 1983). The color response of the TTI can be observed in terms of a decrease in reflectance. 

Fig. 2.11 Schematic representation of the solid-state polymerization of a symmetrical disubstituted diacetylene monomer. Typical R groups are —CH2—O—SO2—Cf H4—C// and —CH2—O—CO-NH-C6H5.

The approach to a similar level of understanding for polymers has been hindered by the structural complexity of the majority of polymeric materials, A notable exception to this is a subset of the polymers based on disubstituted diacetylenes, which are available in the form of macroscopic single crystals. The fact that these polymers have conjugated backbones adds considerably to their value as model materials, particularly in view of the interest in other less perfect conjugated polymers, such as polyacetylene, which can be doped to obtain high electrical conductivity,... 

The starting point for the preparation of polydiacetylene crystals (hereafter referred to as PDAs] is the synthesis of disubstituted diacetylenes. The synthetic routes to these compounds are well established [9] and will not be discussed here typical examples are given in Figure 1, The abbreviations given in the figure will be used to refer to particular materials below. The solid-state polymerization of the monomers proceeds... 

---