Soluble diacetylenes

Poly(diacetylenes) also exhibit large %(3) values in resonant modes. Optical phase conjugation (DFWM) was demonstrated at 532 nm in solutions of a soluble diacetylene polymer, with %(3) 5 x 10-12 esu. 136) No... 

Disordered samples of polydiacetylenes can be prepared by a number of routes. First, the less perfectly polymerizing crystals can be obtained in a fibrilar form due to disruption of the crystal lattice by internal strain, e,g, (120). Secondly, similar samples can be obtained by the removel of unreacted monomer from partially polymerized crystals. Thirdly, single crystals can be deformed mechanically. Fourthly precipitates in the form of films or powders can be obtained for soluble diacetylenes and finally the solutions of such soluble materials can be studied directly. 

The need for increased stabilities and for controllable permeabilities and morphologies led to the development of polymerized surfactant vesicles [55, 158-161]. Vesicle-forming surfactants haw been functionalized by vinyl, methacrylate, diacetylene, isocyano, and styrene groups in their hydrocarbon chains or headgroups. Accordingly, SUVs could be polymerized in their bilayers or across their headgroups. In the latter case, either the outer or both the outer and inner surfaces could be polymerized separately (Fig. 38). Photopolymerization links both surfaces selective polymerization of the external SUV surface is accomplished by the addition of a water-soluble initiator (potassium persulfate, for example) to the vesicle solution. 

As an example of an asymmetric membrane integrated protein, the ATP synthetase complex (ATPase from Rhodospirillum Rubrum) was incorporated in liposomes of the polymerizable sulfolipid (22)24). The protein consists of a hydrophobic membrane integrated part (F0) and a water soluble moiety (Ft) carrying the catalytic site of the enzyme. The isolated ATP synthetase complex is almost completely inactive. Activity is substantially increased in the presence of a variety of amphiphiles, such as natural phospholipids and detergents. The presence of a bilayer structure is not a necessary condition for enhanced activity. Using soybean lecithin or diacetylenic sulfolipid (22) the maximal enzymatic activity is obtained at 500 lipid molecules/enzyme molecule. With soybean lecithin, the ATPase activity is increased 8-fold compared to a 5-fold increase in the presence of (22). There is a remarkable difference in ATPase activity depending on the liposome preparation technique (Fig. 41). If ATPase is incorporated in-... 

As utilized in the synthesis of PPV-based polymers, soluble precursor routes have been developed for the synthesis of various heterocyclic Jt-conjugated polymers. The two most widely employed of these methods for heterocycle formation, shown in Scheme 66, center around ring closure of pre-polymers containing diacetylene 65 or 1,4-diketone units 66 [335-339]. The synthesis of heterocyclic structures from 1,4-diketones has been a known transformation in organic chemistry for decades. While once mainly used for monomer preparation through various cyclizations, it is now being employed to make heterocycle-containing polymers and copolymers [340-342]. 

Upon exposure to heat, UV- or y-radiation diacetylenes are converted from a soluble monomer crystal which is transparent if pure, i.e., free of residual polymer, to a deeply colored polymer crystal. With a few exceptions, the latter is insoluble in all common solvents. The color arises from the lowest n-electron transition of the conjugated polymer backbone, which has its maximum near 600 nm. It is of excitonic origin 48-50) carries an oscillator strength of the order unity. Both insolubility and optical... 

Polymeric Systems.—Absorption, fluorescence excitation, and emission spectra of soluble poly(diacetylene) at room and liquid nitrogen temperature has been recorded for different solvents. The excimer-to-monomer emission ratio for polystyrene depends upon the polymer molecular weight but is independent of the solvent. Monolayer films of the 27-carbon-chain-length alkyldiace-... 

Cyclophanes are the class of synthetic receptors that have a hydrophobic cavity. Water-soluble cyclophane can make organic compounds soluble in water via the formation of inclusion complex. Anderson et al. synthesized rod-like organic compounds in water in the presence of water-soluble cyclophanes, and obtained corresponding rotaxanes. When oxidative coupling of an acetylenic derivative in the presence of a cyclophane, an oligorotaxane having an axle with a conjugated structure was dominantly obtained rather than non-complexed diacetylene.[187,188] (Scheme 31). This rotaxane is a prototype of insulated molecular wire that is expected as an electric wire in a molecular device. 

Many aspects of the preparation and properties of polydiacetylenes are the subject of lively debate. This review presents recent results that bear on some of these controversies. First the relationship of diacetylene monomer crystal structure and solid-state reactivity is discussed. Secondly the temporal evolution of solvato-chromio transitions of soluble polydiacetylenes is displayed. Optical and Raman spectra reveal the occurrence of an intermediate form of the polymer. A model compatible with these results is described. 

Tachibana, H., Yamaka, Y., Sakai, H., Abe, M., and Matsumoto, M. Structural and Morphological Changes and Polymerization Behaviors of Diacetylene Langmuir-Blodgett Films on Adding Water Soluble Polyallylamine in the Subphase. Polymer 42, 1995 (2001). Nishiyama, K., Kurihara, M. A., and Fujihira, M. Photochromism of Amphiphilic Azobenzene Derivative in its Langmuir-Blodgett Films Prepared as Polyion Complex with Ionic Polymers. Thin Solid Films 179, All (1989). 

Another example is poly(propiolic anhydride), which was easily synthesized from the corresponding diacetylene. Though this polymer is soluble and relatively stable to air oxidation, the polymer had a low molecular weight and underwent a side reaction with the solvent.2 ... 

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