A new mechanism of the Atherton–Todd reaction is discussed. The first step of the reaction between diesters of H-phosphonic acid and carbon tetrachloride in the presence of a base is a salt formation between carbon tetrachloride and the base [amine·Cl]+CCl3−. The trichloromethanide anion [CCl3−] deprotonates dialkyl H-phosphonate to form chloroform and dialkyl phosphonate anion [(RO)2P(O)]−. The latter anion reacts with the chlorine cation to furnish dialkyl chlorophosphate.
31 March 2023 in Polymer Degradation and Stability
Well-defined linear and multi-arm star polymer structures were used as the templates for in situ synthesis and stabilization of silver nanoparticles (AgNPs). This approach led to hybrid nanomaterials with high stability and antibacterial activity to both Gram-positive and Gram-negative bacterial strains. The ecologically friendly so called “green” synthesis of nanomaterials was performed through AgNPs preparation in the aqueous solutions of star and linear poly(N,N′-dimethylaminoethyl methacrylate)s (PDMAEMAs); the process was followed with time. The size, shape, and zeta potential of the obtained hybrids were determined. To our knowledge, this is the first time that the antibacterial activity of PDMAEMA hybrid nanomaterial against Bacillus subtilis, Escherichia coli and Pseudomonas aeruginosa was investigated and assessed by minimum inhibitory concentration (MIC) and minimum biocidal concentration (MBC). Completely quaternized with ethyl bromide, star and linear PDMAEMAs were used in comparative biological tests. The modification of the polymers with in situ-formed AgNPs increased the antibacterial properties against all studied strains of bacteria by several times in comparison to non-modified polymers and quaternized polymers. These results yield novel nanohybrid materials that can be useful for applications in medicine and biology.