Diacetylene polymers

Sundar and Keller have reported the synthesis of linear boron-silicon-diacetylene polymers (31) (Fig. 21) using phenylboron dichloride (PBD) as the source for boron.50 The compositions of the thermally stable boron-silicon-diacetylene copolymers 31a-d are summarized in Figure 21. These polymers were observed to possess exceptional thermooxidative stabilities. 

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 ... 

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... 

Polymeric species Pt(X"Bn3)2 =C (C=C)m-C C and Pt(X Bn3)2-(C=C) 6H4-(C=C) -ju (m = 0, 1) have been synthesized. The absorption and emission spectra of these complexes showed extended tt-electron conjngation throngh the metal sites on the chain, with a lower itt-itt energy gap for the triacetylenic than for the diacetylenic polymers. Well-resolved vibronic stracture associated with the v(C=C) frequency was observed in both the absorption and emission spectra, indicating strong electron-phonon coupling for these polymers. 

Fig. 20.14 AFM images of a flat Au surface (left) with adsorbed diacetylenic polymer, then coated with deposited Ag particles (right). In the lower panel, the SERS of the polymer is shown. Exciting line 647.1 nm...

Diacetylenic polymers can be obtained by irradiating the monomer units adsorbed on gold surfaces with UV light [24]. The irradiation induces polymerization between adjacent diacetylenic chains resulting in formation of CC single, double, and triple bonds, as shown in the scheme in Fig. 20.25. 

Ijadi-Maghsoodi and Barton reported that replacement of SiR2 building blocks with disilane units Si2R4 in the above mentioned silylene acetylene or diacetylene polymers reduces the amount of graphitic carbon in the resulting... 

SCHEME 18.12 Synthesis of silylene acetylene ( polyalkynylsilanes , left and right) or diacetylene polymers ( polybutadiynylsilanes , middle) by metathesis of dichlorosilanes and dilithium reagents of acetylene, silylenediacetylene and butadiyne, respectively. ... 

Figure 8. Top, optical absorption and the corresponding prompt fluorescence spectra of diacetylene polymer molecules middle, excitation and the corresponding delayed emission spectra and bottom, transient absorption for a partially polymerized (broad line) and fully polymerized (narrow line) diacetylene crystal.

In addition to the [2+2] photodimerization of divinylbenzenes, the most significant solid-state reaction that provides a route to highly crystalline polymers is the top-ochemical polymerization of diacetylenes. The reaction, reported and investigated by Baughman and Wegner, produces a poly diacetylene polymer via a 1,4-addition... 

The preparation of several propargyl monomers and diacetylene polymers. and their initial characterization as radiation cured coatings for corrosion protection is discussed in the present report. 

Phase-matched second harmonic generation in single crystal polymers was first observed in 2-methyl-4-nitroaniline substituted diacetylene polymers. Subsequently, a number of other diacetylene structures... 

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... 

B. Tieke, H.-J. Graf, G. Wegner, B. Naegele, H. Ringsdorf, A. Banerjie, D. Day, and J. B. Lando, Polymerization of mono- and multilayer forming diacetylenes. Polymer Science. Pofymere. 255 36 (1977). 

Sahoo. P.K. Swain. S.K. Synthesis of zirconocene-acetylene and zirconocene-diacetylene polymer. J. Polym. Sci., Part A Polym. Chem. 1999. 37, 3899-3902. 

Finally, silarylene-siloxane-diacetylene polymers were reported by Hom-righausen and KeUer in 2000 [28], as precursors to high temperatiue elastomers. They were obtained as follows ... 

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