Functional organic-inorganic colloids modified by iodoxybenzoic acid

A simple strategy for the modification of polymers having hydroxyl or amino groups on their surfaces by o-iodoxybenzoyl (IBX) groups is described. The synthetic route involves modification of 5-hydroxy-2-iodobenzoic acid with 3-isocyanatopropyltriethoxysilane in nonaqueous solvent followed by conjugation of the resulting triethoxysilanylpropylearbamoyloxyiodobenzoic acid with the -OH groups of the polymers via sol-gel reaction in the presence of water. The formation of silica conjugated to the polymer creates organic-inorganic particles. The iodobenzoic groups on the particle surfaces are further oxidized by Oxone tetrabutylammonium salt into IBX. The IBX-modified poly(vinyl alcohol) and microcrystalline cellulose were shown to be capable of hydrolyzing diisopropyl fluorophosphate (DFP), an analogue of sarin and soman, at pH 7.4 with the apparent second-order rate constants (k '') of 4.6 x 10(-2) and 2.7 x 10(-2) M-1 s(-1), respectively. The IBX-cellulose and IBX-PVA suspensions accelerated chlorpyrifos degradation 26- and 122-fold compared to the corresponding unmodified cellulose and PVA suspensions, respectively. Approximately 43-fold acceleration of the chlorpyrifos oxon degradation was measured in the IBX-PVA suspensions compared to the corresponding PVA Solutions. The IBX-modified particles were capable of oxidizing the thiophosphate (P=S) group to the corresponding oxon (P=O). The developed modification route is appropriate for a wide variety of surfaces for chemical defense applications.