Polymer complex, complexation/dissociation

The stability of the enzyme-polymer complex and its dissociation upon the variation of pH depends on the structural and other physico-chemical properties of CP and enzyme molecule. Thus, a Biocarb-T heteroreticular biosorbent (Fig. 26) is characterized by a stability of its complex with ot-amylase (under the condition of its stabilization) in acid solutions and a complete dissociation of the complex during isolation of the active enzyme at pH 7-8. 

It is known that organoboron halide-imidazole complexes dissociate diming equilibrium 56 however, charges disappear upon dissociation. In such a matrix, mobile ions should not originate from the matrix. Therefore, the polymer electrolytes composed of boron halide-imidazole complexes were considered to be appropriate for selective ion transport. 

Interestingly, the Fe2+ ion in the core can be easily removed by base, the complex dissociates and the individual polymer dimers can be analyzed. Block copolymers of 2-ethyl-2-oxazoline with other substituted oxazolines have also been made [121]. Ru2+(4,4 dichloromethyl-2,2 bipyridine)3 has also been used as the multifunctional initiator for the ATRP of styrene at 110°C [122], It is interesting to note that the Cu+ ions necessary for the polymerization reaction are solubilized via complexation with other bipyridine species. 

Change of Association-Dissociation Interactions in Polymer Complexes... 

A template polymer complex, which incorporates N-benzyl-D-valine with almost 100 % stereospecificity, has been synthesized by copolymerization of A-P2-[Co (R,R )-A, /V -bis(4-(vinylbenzyloxy)salicylidene]-l,2-diaminocyclohexane -(A-benzyl-D-valine)], styrene, and divinylbenzene, followed by dissociation of the coordinated amino acid 115). 

The interaction of macromolecules has a cooperative nature33, i.e. the formation and dissociation of polymer complexes occur within a narrow range of oligomer molecular weight, solvent composition, pH, etc. 

A further dependence of the intrinsic viscosity on the content of water-dimethyl sulfoxide mixed solvent for the PVP-MAA/St copolymer system76 has been found the viscosity increases already beyond 30 vol-% of DMSO in the mixture. This indicates the dissociation of the polymer complex. At the same time, in the PMAA-PVP system27, the compact structure of the complex remains intact up to 70 vol-% content of DMSO, i.e. these complexes are very stable to the organic solvent. 

The stability of complexes formed in non-aqueous media against the destructive action of organic solvents has been studied (DMSO). The PAA-PVP polycomplex retains its compact structure up to 40 vol-% content of DMSO in the mixture with methanol (Fig. 16, curve 2) this follows from the low values of the intrinsic viscosity. A further increase of the DMSO content results in a sharp rise of the viscosity i.e. the complex dissociates. That the complex breaks down in pure DMSO is confirmed by the following facts the intrinsic viscosity of the PAA-PVP system is an additive function of the viscosity of individual polymers in this solvent while in methanol [ 7] of the PAA-PVP system is close to the viscosity of globular proteins. It is of interest that... 

The first example for Method 2 was reported by Nishide and co-workers, who polymerised a metal complex of 1-vinylimidazole with l-vinyl-2-pyrollidone and divinylbenzene [8]. The metal-vinylimidazole complex was copolymerised, cross-linked with l-vinyl-2-pyrollidone by y-ray irradiation and the template metal ion was removed by treating the polymer complex with an acid. These poly(vinyl-imidazole) (PVI) resins adsorbed metal ions more effectively than the PVI resin prepared without the template. The number of adsorption sites and the stability constant of the Ni(II) complex were larger for the PVI resin prepared with the Ni(II) template, as seen by the smaller dissociation rate constant of Ni(II) from the resin. 

Some complexes dissociate fully in solution (e.g., 7r-allyl nickel tri-fluoroacetate) whence [63] Rp cc [C2][M]. Donor solvents (triphenyl-phosphite, nitrobenzene) can also coordinate with the metal and influence catalyst dissociation with effects on rate and polymer molecular weight the structure of the polymer may also be affected [173]. 

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