Poly 4-vinylpyridine Derivatives

Poly(4-vinylpyridine) Derivatives.—There have been no mechanistic studies of reactions using this polymer, although, as reported later, there have been several examinations of poly(vinylpyridine)s acting as polymer supports. 

There have been several studies of the thermodynamics of binding to poly(vinylpyrrolidone).  

Poly(vlnylimidazole) Derivatives.—The hydrolysis of esters catalysed by imidazole-containing polymers has been reviewed.  

Radical polymerization of (14) and the subsequent removal of the benzyl group produces water-soluble polymers containing imidazole-4-carbohydroxamic acid residues. The hydrolysis of 4-nitrophenyl acetate catalysed by this polymer proceeds faster than that catalysed by imidazoles or carbohydroxamic acid but slower than that catalysed by the monomeric analogue. The hydrolysis of 4-nitrophenyl acetate is catalysed by the bifunctional hydroxamic acid (IS) and 

Water-soluble terpolymers of 4(5)-vinylimidazole, acrylamide, and alkenones catalyse the hydrolysis of esters. The hydrophobic side chains of the polymer may be varied by using different alkenone monomers. Increasing the size of the terpolymer side chain increases the reaction rate. The same weight percent of apolarity appears to be more effective when concentrated in fewer, but longer side chains than a larger number of shorter side chains. In the presence of excess ester substrate deacylation is inhibited.  

---

Nishikawa H, Tsuchida E. Complexation and form of poly(vinylpyridine) derivatives with copper(II) in aqueous solutions. J Phys Chem 1975 79 2072-2077. 

Typical of these materials are the poly(vinyl thioethers), the poly(vinyl isocyanates), the poly(vinyl ureas) and the poly(alkyl vinyl ketones). Methyl isopropenyl ketone and certain vinylpyridine derivatives have been copolymerised with butadiene to give special purpose rubbers. 

Kirsh et al. 42) prepared apolar derivatives of poly(4-vinylpyridine) by benzylation. With nitrophenyl acetate as the substrate the benzylated catalyst is 100 times more effective than 4-ethylpyridine. A double-displacement mechanism was observed. The rate constants for deacylation of the acylpoly(vinylpyridine) derivatives were about 4 x 10" /sec. The comparable value for a-chymotrypsin is 8 x 10 /sec. The factor of 20 seems small, but it should be kept in mind that deacetylation of a-chymotrypsin is very slow compared with the deacylation reactions involving the natural substrates of the enzyme. 

Kargin and his co-workers (98) have prepared polymeric derivatives of the cytostatic agent sarcolysin by alkylation of poly(vinylpyridine). Simultaneous alkylation with cetyl bromide yields copolymers with the following structure of chain [JO]. 

The effects of alkyl spacer length between both charged moieties with different substitution at, and with different hybridization of, the quat-ernized nitrogen were studied for a series of poly(carboxybetaines) derived from poly(4-vinylpyridine) and poly(vinylbenzyl chloride) by capillary electrophoresis, charge titration, and FTIR spectroscopy. A strong pH-and structure-dependent shift in electrophoretic mobihties is revealed for... 

Poly[(vinylpyridine)Os(bipyridine)2Cl ] derivative based redox hydrogels (A)... 

II. BLOCK COPOLYMERS FOR NANOFABRICATION A. Poly(2-vinylpyridine) Derivatives... 

Figure 1. Effect of dodecyl group content on reduced viscosity of poly 4-vinylpyridine) derivatives in 0,0226 M KBr at 25 C. Key J, PEB 2, 6.7% polysoap 3, 13.6% polysoap 4, 28.5% polysoap 5, 37.9% polysoap. Reproduced from ref. 7. Copyright 1956 American Chemical Society.)...

Conclusive evidence for a guiding influence of the poly(4-vinylpyridine) derivatives is provided by directly comparing exp.3 of Table 12 and exp.2 of Table 13. The reagents and the conditions were identical in these experiments except for the template molecule. When the condensation was carried out in the presence of the template molecule with Ade side groups, the major dinucleotide was pUpU. 

---