Quaternary pyridinium polymers

Quaternary pyridinium polymers can show biological activity when bound to surfaces, e.g., poly(4-vinyl pyridine)-modified glass surfaces which were modified using different alkyl bromide derivatives. Suitable polymers for antibacterial applications not only exhibit antibacterial activity, but also non-toxicity to human cells (i.e., selectivity). 

Polymers exhibiting quaternary nitrogen functionalities have commonly been used as biocidal agents [13-21], A number of polymeric disinfectants containing quaternary pyridinium groups, either in the backbone or as pendent groups, have been prepared and exhibit good antibacterial activity. 

Work has been performed in which the quaternary pyridinium functionality was attached to 7-oxanorbornene-5,6-exo-dicarboximide-functionalised monomers which were subsequently polymerised using a Grubbs catalyst (Grubbs catalysts are a series of transition metal carbene complexes used as catalysts for olefin metathesis). The polymer series, a-f, and quaternised polymer, a , (Figure 9.1 and Table 9.1) was designed to study the effect of the hydrophobic alkyl substituent on the antibacterial and haemolytic activities of polymers using dimethylformamide (DMF) as the solvent. 

Similar to the biguanide structures, Dizman et al. created l,4-diazabicyclo[2.2.2]octane (DABCO)-based stmctures carrying two quaternary ammonium charges with butyl and hexyl alkyl extensions (C12). The monomer was assembled by multiple nucleophilic substitution reactions. Polymers were formed by free radical polymerization in water. These polymers, much like the biguanide acrylate and pyridinium polymers, combined hydrophobidty and cationic charge on the same monomer. One difference is that the cationic charge was also separated from the backbone of the polymer by a long alkyl chain. As with the pyridine polymers, the hexyl alkyl monomers were found to be the most effective biocides. 

Quaternary pyridinium-type PAF composites with AgCl have been introduced as antimicrobials to kill bacteria efficiently. PAF-50 with AgCl loaded in the pore displays excellent antibacterial properties, even better than commonly used antibacterial materials. Formation of a dispersion with various solvents and compatibility with a large number of polymers, such PAFs can lead to large scale industrial production for different medicinal applications. 

Another approach to the preparation of water soluble polymers has utilized quaternary pyridinium units. Reaction of aromatic aldehydes with poly(5-vinyl-2-methyl pyridinium methosulfate) provide polymers bearing styrylpyridinium units [29]. 

A compound prepared and first described as nicotinium dichromate (NDC) by Palomo et al.,379 was later shown by X-ray-crystal analysis380 to be a betainic mixed anhydride of nicotinic and chromic acid (NACAA). Because of its unique structure, it deserves a close scrutiny of its oxidative properties.381 Replacement of the chloride anion in the quaternary ammonium resin, Dowex 1-X8, for the dichromate anion, leads to a polymer supported dichromate, which is able to make selective benzylic oxidations.382 Finally, poly[vinyl(pyridinium dichromate)] (PVPDC), a polymeric analogue of PDC, must be mentioned whose use in the oxidation of alcohols allows for a very easy work-up.383... 

Pyridinium and quaternary ammonium resins react with chromium trioxide, producing polymer-supported complex chromates that oxidize alcohols, and provide a very facile work-up.427... 

Gelbard et al. have prepared a numbor of neutral and acidic supported ammonium chromates. Neutral resins woe found to be generally more effective dian acidic resins. The large differences in leactiviQr between different unbound, soluble alkylammonium chromates (Section 2.7.6.1) are not so pronounced with the polymer-supported oxidants. Some commoits about the reactivity of these supported oxidants woe made (i) quaternary ammonium salts are more reactive than the tertiary pyridinium chromates (ii) the reactivity of a conqilex chromate XCtOr was found to increase as the basicity of X decreases. Best... 

In conclusion, it was demonstrated that the use of ILs as intercalating agents of layered silicates was developed by using quaternary alkylammonium. However, the use of these ILs is limited by their low thermal stability, which implies to focus on more thermostable ILs based on pyridinium, imidazolium, and phosphonium cations. Nevertheless, does the addition of such highly thermostable IL surfactants improve the dispersion of nanofillers in polymer matrices as well as the final properties of the resulting nanocomposites ... 

On the other hand, cationic polymer brushes grafted on PET surfaces could prevent microbial infection in industrial and medical fields, such as alkyl pyridinium or quaternary ammonium moieties. Gen et al. grafted copolymerized with 4-vinylpyridine (4VP) and subsequently quaternized with hexylbromide [53,54], and N-hexyl-N -(4-vinylbenzyl)-4,4 -bipyridinium bromide chloride (HVV) [55] onto PET films for enhancing antibacterial properties. The PET films were pretreated by argon plasma to form surface... 

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