Siloxy backbone

Silicone. Silicone elastomers have a siloxy backbone with methyl, vinyl, and phenyl groups attached. The elastomers are designated by their chemical composition, as follows methyl silicone (MQ), methyl vinyl silicone (VMQ), methyl phenyl silicone (PMQ), methyl phenyl vinyl silicone (PVMQ), and fluorovinyl methyl silicone (FVMQ). 

The TT-electron system-substituted organodisilanes such as aryl-, alkenyl-, and alkynyldisilanes are photoactive under ultraviolet irradiation, and their photochemical behavior has been extensively studied (1). However, much less interest has been shown in the photochemistry of polymers bearing TT-electron substituted disilanyl units (2-4). In this paper, we report the synthesis and photochemical behavior of polysiloxanes involving phenyl(trimethylsilyl)-siloxy units and silicon polymers in which the alternate arrangement of a disilanylene unit and a phenylene group is found regularly in the polymer backbone. We also describe lithographic applications of a double-layer system of the latter polymers. 

The sodium condensation reaction of a,co-bis(chlorosilyl)-substituted compounds and the coupling reaction of dilithio derivatives of compounds bearing 7t-electron systems with dichlorosilanes offer a convenient route to various silicon containing polymers. However, the polymers prepared by these methods always contain a small proportion of siloxy units in the polymer backbone, which would interrapt the electron delocalisation. Therefore, new synthetic routes to organosilicon polymers have been developed in which no alkali metal halide condensations are involved [6, 7]. We report syntheses of organosilicon... 

Thus (XX) reacts with phenol in pyridine to form diphenoxysilicon phthalocyanine (XXII), with benzyl alcohol to form (XXIII), and with triphenylsilanol to form (XXIV) (168,170, 200). These complexes sublime readily without decomposition (cf. corresponding aluminum derivatives). Bis(diphenylmethylsiloxy)silicon phthalocyanine, which melts before subliming, is one of the very few metal phthalocyanines which actually melt (873). The siloxy complex (XXIV) may also be prepared in benzyl alcohol, thus implying that the Si—O—Si(Pc)—0—Si backbone is more stable than C—O—Si(Pc)—O—C. The dibenzyloxy derivative (XXIII) reacts with diphenylsilanediol to form bis(benzyloxydiphenylsiloxy)silicon phthalocyanine (XXV). 

LiC104 complexes of several PEO-grafted polysiloxanes in which the backbone is derived from both homopoly(methyl hydrogen siloxane) and poly(methyl hydrogen siloxane-co-dimethyl siloxane) have been prepared [10]. The PEO used had low molecular weights of 300 to 550. The electrolytes had TgS of —54 to — 77°C, and room temperature conductivities up to 10 S cm have been measured Table 3.2 gives an example of one such complex. In these electrolytes, the PEO side chains promote solubility and dissociation of Li salts while the flexible siloxy main chain provides mobility to charge carrier ions. 

The possible effect of spatial order on carbazole groups has been a subject of discussion. Isotactic poly[2-(N-carbazolyl)ethyl acrylate] exhibits a room-temperature hole mobility of 1.7 x 10 m V s at 2xlO Vm which is considerably higher than that of the atactic polymer or PVK [80]. On the other hand, these values are very close to those obtained for NIPC/polycarbonate at a comparable concentration of the transport-active molecule, i.e, a system with no order. Experiments with other carbazole polymers have shown that changing the backbone (e.g. carbon vinyl to siloxy) [45], or spacing of carbazole groups from the chain, has only a secondary effect. 

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