The Stabilities of N−Cl Bonds in Biocidal Materials

Abstract

N-halamine chemistry has been a research topic of considerable importance in these laboratories for over two decades. N-halamine compounds are useful in preparing biocidal materials. There are three N-Cl moieties available in cyclic N-halamine compounds: imide, amide, and amine. The stabilities toward the release of free halogen have been experimentally shown to decrease in the order amine > amide > imide. In this work, this generalization has been tested theoretically at the level of B3LYP/6-31+G(d) and using the conductor-like polarizable continuum aqueous solvation model with UAKS cavities. Excellent accord was observed between theory and experiment. It was also found that the imide and amide N-halamine stabilities on hydantoin rings could be reversed with substitution patterns at the 5 position.

Antimicrobial efficacy and light stability of N-halamine siloxanes bound to cotton

“…The rates of inactivation of the bacteria are related to the stabilities toward direct transfer of the Cl + moiety to the cells. Therefore, in general amide N-halamines can kill bacteria more rapidly than do amine N-halamines (Tsao et al 1990;Akdag et al 2006;Qian and Sun 2004). Thus chlorinated 1 and 2 siloxanes demonstrated bacterial inactivation more rapidly than cotton swatches coated with chlorinated 3 and 4 siloxanes because they have amide N-halamine functionalities, while 3 and 4 siloxanes have amine N-halamine groups.…”

Fabrication and evaluation of electrospun nanofibrous antimicrobial nylon 6 membranes

“…These results agree well with our expectations based upon both the molecular structures and the amount of available chlorine. Since the inactivation of microorganisms depends on the nature of N-Cl groups, according to the dissociation rate of Nhalamines: imide > amide > amine type halamine, the higher the dissociation constant, the more rapid is the biocidal action [35]. CDMH has both an N-choloroimide and N-chloroamide group, CTMIO has an N-chloroamide and N-chloroamine group while CDDMH only has an N-chloroamide group, but we doubled the weight of CDDMH containing nylon 6 membranes for the comparison so that the only factor that might affect the antimicrobial rate would be the structural difference.…”

Antimicrobial N-brominated hydantoin and uracil grafted polystyrene beads

“…These include cellulose [4,[9][10][11], nylon [12], PET [13,14], Kraton rubber [15], and various surface coatings [14][15][16][17][18][19][20][21][22][23]. To date, however, the most important N-halamine polymers developed are the N-halogenated polystyrenehydantoins [24][25][26], because of their potential for economical disinfection of potable water, thus improving world health [24,[27][28][29][30][31].…”