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we should take into account not only their hydrophobic properties but also the efficiency of substrate solubilization as well as the reactivity of the oximate group in the surfactant micelles.The unflagging interest during recent decades in the synthesis and reactivity of surfactants with nucleophilic functional groups is a consequence of a number of factors. Firstly, microheterogeneous systems derived from functional detergents serve, to some extent, as models for studying the action of hydrolytic enzymes, which provides for the investigation of various features of enzymatic catalysis in simpler systems. The increase in the reaction rate in micelles of functional surfactants in comparison with water may reach factors of 10 2 -10 7 , which makes such systems comparable in efficiency with enzyme systems [1,2]. The observed effects are largely a function of the role of the microenvironment of that part of the micelles, in which the chemical reaction proceeds and the hydrophobic binding of the substrate by the micelle core [1][2][3][4]. Secondly, the intensive study of the reactivity of functional detergents has had and still has marked applied significance related to the decomposition and utilization of environmental toxicants, in particular the highly toxic esters of organophosphorus acids [1,[5][6][7][8].Modification of functional surfactants in order to obtain highly efficient supernucleophilic systems requires us to establish the factors responsible for the micelle effects of detergents. In previous work [9], we showed that, in the case of surfactants with an oximate group, nucleophilicity is directly related to the acid-base properties of the oximate group. In this instance, as in the case of oximes, which do not form micelles, the Brönsted catalysis equation is not linear and has an inflection point at pK a » 8.5-9.0 [9, 10]. Since the concentration of the substrate in the micellar pseudophase makes the major contribution to the increase in the observed reaction rate [10], the hydrophobic properties of the functional surfactants have fundamental importance in the manifestation of their micellar effects [1,[11][12][13].

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Dimeric (gemini) surfactants containing hydroxyl functional groups have been synthesized and studied. These new surfactants have low critical micelle formation concentrations (<5·10 -5 mol/L) and Krafft temperatures (£0°C). Depending on the pH of the medium, the alkaline hydrolysis of 4-nitrophenyl diethyl phosphonate, which is a model of organophosphorus ecotoxicants, proceeds 20-80 times more rapidly in the presence of gemini surfactant micelles than in water.The enormous interest in recent decades concerning the preparation and study of dimeric (gemini) surfactants and derived organized molecular systems has been due to the unique physicochemical characteristics of these compounds [1, 2], primarily, their anomalously low critical micelle concentrations (CMC » 10 -5 -10 -6 mol/L), which are one or two orders of magnitude less than for the corresponding monomeric surfactants, more efficient lowering of the surface tension of aqueous solutions, better solubilization of compounds with low solubility in water, and micelle polymorphism [2].Gemini surfactants may be seen as a promising basis for organized molecular systems corresponding to the requirements of "green chemistry" for the detoxification and utilization of toxic phosphorus acid esters [3]. The decomposition of ecotoxicants should be carried out under mild conditions using inexpensive and nontoxic solvents. Water is the preferred solvent from this viewpoint but most organophosphorus compounds have low aqueous solubility. This problem may be solved using surfactant additives providing for the solubilization of hydrophobic substrates and an increased rate of nucleophilic substitution reactions, including alkaline hydrolysis. While the effect of monomeric surfactants on the rate of acyl group transfer reactions has been studied in considerable detail [3][4][5], the reactivity of nucleophilic reagents in the presence of gemini surfactant micelles has been studied much less extensively [2,6,7].In the present work, we studied the effect of new gemini surfactants I and II on the rate of alkaline hydrolysis of 4-nitrophenyl diethyl phosphonate (NPDEPS), which is a model analog of highly toxic organophosphorus pesticides and chemical warfare agents. The micellar effects of I and II are comparable to those for cetyltrimethylammonium bromide (CTAB), which is a monomeric surfactant.New gemini surfactants I and II feature a bridging unit (spacer) functionalized by hydroxyl groups. Modification of the spacer by the introduction of hydroxyl groups improves the solubility of these compounds in water since gemini surfactants with the general formula m-s-m [2] have relatively high Krafft temperatures and low solubility in water, which hinders both the 108 0040-5760/11/4702-0108

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