Poly cyano group terminated

Pyrolysis products from organometallic phosphazenes can give nano-structured materials. Mixtures of AuCllPPhs) and poly[2,2 -dioxy-l,l -biphenylphosphazene] were pyrolyzed by heating the sample at 10 °C/min. to 800 °C, which was held for 2 hours under a flow of air. Characterization of the products by X-ray diffraction revealed a nanostructured Au material. Additional experiments were performed with metal centers directed bound to the phosphazene substrate. Structure (43) shows a phosphazene linear polymer substituted with 2,2 -biphenol and 4-hydroxyphenylacetonitrile pendant groups, with ruthenium coordinated to the terminal cyano groups. 

The photoreduction of aromatic ketones by polymeric systems having tertiary amine end groups provides an ele nt way for the preparation of block copolymers with high efficiency [138]. The method consists of the synthesis of the bifimctional azo-derivative 4,4 -azobis (iV,i -dimethylaminoethyl-4-cyano pentanoate) (ADCP), successively used as fiee radical thermal initiator for the preparation of tertiary amine-terminated poly(styrene). 

A variety of CEs with tailorable physico-chemical and thermo-mechanical properties have been synthesized by appropriate selection of the precursor phenol [39,40]. The physical characteristics like melting point and processing window, dielectric characteristics, environmental stability, and thermo-mechanical characteristics largely depend on the backbone structure. Several cyanate ester systems bearing elements such as P, S, F, Br, etc. have been reported [39-41,45-47]. Mainly three approaches can be seen. While dicyanate esters are based on simple diphenols, cyanate telechelics are derived from phenol telechelic polymers whose basic properties are dictated by the backbone structure. The terminal cyanate groups serve as crosslinking sites. The polycyanate esters are obtained by cyanation of polyhydric polymers which, in turn, are synthesized by suitable synthesis protocols. Thus, in addition to the bisphenol-based CEs, other types like cyanate esters of novolacs [37,48], polystyrene [49], resorcinol [36], tert-butyl, and cyano substituted phenols [50], poly cyanate esters with hydrophobic cycloaliphatic backbone [51], and allyl-functionalized cyanate esters [52] have been reported. 

Synthesis. Poly(benzyl ether) dendrimers with amino groups at the periphery were obtained from cyano-terminated precursors by modifications of known methods (75). 

The loss of 44 5 uma was also observed in the mass spectrum of poly-BFl synthesized by anionic polymerization with PhLi as the initiator (Fig. 39), recorded using the dithranol as matrix. In this case, the difference between the two most intense peaks belonging to each cluster is about 77 Da, suggesting that the most intense peaks correspond to the macromolecular chains terminated with a phenyl group (Ph) at one end, as expected since PhLi was used as initiator [23]. Since very similar mass spectra were recorded using other matrices, such as CHCA (a-cyano-4-hydroxycinnamic acid), DCTB [tra/25-2-[3-(4-t rt-butylphenyl)-2-methyl-2-pro-penylidene]malononitrile], and HABA [2-(4-hydroxylphenylazo)benzoic acid], the question about the loss of a compound with a mass 44 5 requires appropriate investigations by means of post-source decay (PSD) and CID (collision induced dissociation) MALDI-TOF/TOF tandem mass spectrometry methods. 

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