Poly complexing agent

Table 15. Optical activity in toluene solution, in the absence of complexing agents poly-[(S)-2-methyl-butyI]-vinyl-ether (68) and of some...

Hydrolysis increases the terpolymer limiting viscosity number in water by a factor of up to 45. Other previously published data(66-68) show that these terpolymers are nonnewtonian viscosifiers, metal-ion complexing agents, and effective flocculators. These materials are still "small" molecules in aqueous solution, however, and do not function as effectively when used 1. as nonnewtonian viscosifiers or 2. drag reducing agents as do poly(l-amidoethylene-co-(sodium 1-carboxylatoethylene)) copolymers. 

Aime et al. took advantage of the different redox states of manganese and of the difference in the related relaxation properties to design a p02 responsive contrast agent. The adducts formed between Mn /Mnn tpps complexes and poly-P-cyclodex-trin have considerably different relaxivities depending on the redox state of the metal, itself determined by the partial oxygen pressure of the solution (tpps — 5,10,15,20-tetrakis-(p-sulfonato-phenyl porphinate) (243). 

Macrocyclic derivatives are of considerable importance in biological areas and as complexing agents, particularly for metals. Macrocyclic examples are given in MACROLIDES FROM CYCLIZATION OF w-BROMOCARBOXYLIC ACIDS 11-HYDROXYUNDECANOIC LACTONE and MACROCYCLIC POLY AMINES 1,4,7,10,13,16-HEX AAZ ACYCLOOCT ADE-... 

The Effects of Complexing Agents. Cai et al.66 replaced the sodium counterion of MX-DNA with various aliphatic amine cations, e.g. spermine cation, and alkyltrimethylammonium cation as well as polymeric amine cations, such as poly-L-lysine and polyethylenimine to vary the separation between DNA duplexes. The radiation-produced electrons from the complexing agents readily transfer to the more electron affinic DNA. 

Helary and Fontanille 1781 have studied the influence of the tertiary amine crown molecule tetramethyltetraazocyclotetradecane (TMTA) upon the propagation of poly(styryl)lithium in cyclohexane at 20 °C using a rapid calorimetric procedure. The complexing agent, employed at a [TMTA] [Li] ratio of unity, caused a shift of the absorption maximum from 326 to 345 nm, indicating an increase in interionic separation it was presumed that, under these conditions, there is no aggregation... 

Laeubli, M. and Kampus, B. (1995) Selectivity Enhancement on a Poly (butadiene-maleic acid) Coated Cation Phase Induced by Ethylene Oxide-based Complexing Agents, J. Chromatogr. A 706, 103-107. 

We first describe the NMR parameters for the duplex to strand transition of the synthetic DNA poly(dA-dT) (18) with occasional reference to poly(dA-dU) (24) and poly(dA- brdU) and the corresponding synthetic RNA poly(A-U) (24). This is followed by a comparison of the NMR parameters of the synthetic DNA in the presence of 1 M Na ion and 1 M tetramethylammonium ion in an attempt to investigate the effect of counterion on the conformation and stability of DNA. We next outline structural and dynamical aspects of the complexes of poly(dA-dT) with the mutagen proflavine (25) and the anti-tumor agent daunomycin (26) which intercalate between base pairs and the peptide antibiotic netropsin (27) which binds in the groove of DNA. 

The purine(3 -5 Ipyrimidine and the pyrimidine(3 -5 )purine phosphodiester linkages are partially resolved in the proflavine and daunomycin intercalation complexes with poly(dA-dT) with the phosphodiester at the intercalation site shifting to low field. This suggests that these intercalating agents exhibit a sequence specificity in their complexes with alternating purine-pyrimidine polynucleotides. 

Three different ways have been developed to produce nanoparticle of PE-surfs. The most simple one is the mixing of polyelectrolytes and surfactants in non-stoichiometric quantities. An example for this is the complexation of poly(ethylene imine) with dodecanoic acid (PEI-C12). It forms a solid-state complex that is water-insoluble when the number of complexable amino functions is equal to the number of carboxylic acid groups [128]. Its structure is smectic A-like. The same complex forms nanoparticles when the polymer is used in an excess of 50% [129]. The particles exhibit hydrodynamic diameters in the range of 80-150 nm, which depend on the preparation conditions, i.e., the particle formation is kinetically controlled. Each particle consists of a relatively compact core surrounded by a diffuse corona. PEI-C12 forms the core, while non-complexed PEI acts as a cationic-active dispersing agent. It was found that the nanoparticles show high zeta potentials (approximate to +40 mV) and are stable in NaCl solutions at concentrations of up to 0.3 mol l-1. The stabilization of the nanoparticles results from a combination of ionic and steric contributions. A variation of the pH value was used to activate the dissolution of the particles. 

The use of supramolecular interactions to bind a pharmaceutically active drug noncovalently to a polymer in order to achieve slow release was presented by Puskas et al. [96]. Here, a side-chain functionahzed poly(styrene) bearing thymine moieties (Fig. 20) was prepared and complexed with phenol as a complexing agent. The release of the bound phenol was studied in aqueous buffer solution, revealing a slow desorption within 4.5 hours from the polymer. Thus, this system is adaptable for slow release of drugs from polymeric matrices. 

The control of the Eu redox stability is certainly a key issue for an eventual MRI contrast agent application. With the exception of cryptate complexes of Eu such as Eu (2.2.2) + and Eu (2.2.1) +, the complexation with poly(amino carboxylates) diminishes the redox stability of the Eu state, as compared to the aqua ion (some representative redox potentials are -0.63 V (Eu(H20) ) -0.21 V (Eu(2.2.2)2+) -0.82 V (EuODDA) -1.00 V (EuTETA -) -1.18 V (EuDO-TA ) -1.35 V (EuDTPA )) [111, 112]. Macrocyclic ligands that match in size with the larger Eu ion have a stabilizing effect of the reduced state, whereas carboxylate coordinating groups seem to be unfavorable in this respect. 

Polyvinylamine and its derivatives have been also used for the complexation of metal ions in homc eneous phase . Introduction of various chelating poups into polyvinylamine has been drown to result in a greater selectivity for complexation than polyvinylamine itself. Thus, poly(vinylaminodiacetate) has been found to be a selective complexing agent for copper and poly(N-methyl-N-vinylthiourea) for mercury ... 

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