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International audienceLinking of the trinuclear pivalate fragment Fe2CoO(Piv)6 by the redox-active bridge Ni(L)2 (compound 1; LH is Schiff base from hydrazide of 4-pyridinecarboxylic acid and 2-pyridinecarbaldehyde, Piv– = pivalate) led to formation of a new porous coordination polymer (PCP) {Fe2CoO(Piv)6}{Ni(L)2}1.5 (2). X-ray structures of 1 and 2 were determined. A crystal lattice of compound 2 is built from stacked 2D layers; the Ni(L)2 units can be considered as bridges, which bind two Fe2CoO(Piv)6 units. In desolvated form, 2 possesses a porous crystal lattice (SBET = 50 m2 g–1, VDR = 0.017 cm3 g–1 estimated from N2 sorption at 78 K). At 298 K, 2 absorbed a significant quantity of methanol (up to 0.3 cm3 g–1) and chloroform. Temperature dependence of molar magnetic susceptibility of 2 could be fitted as superposition of χMT of Fe2CoO(Piv)6 and Ni(L)2 units, possible interactions between them were taken into account using molecular field model. In turn, magnetic properties of the Fe2CoO(Piv)6 unit were fitted using two models, one of which directly took into account a spin–orbit coupling of CoII, and in the second model the spin–orbit coupling of CoII was approximated as zero-field splitting. Electrochemical and electrocatalytic properties of 2 were studied by cyclic voltammetry in suspension and compared with electrochemical and electrocatalytic properties of a soluble analogue 1. A catalytic effect was determined by analysis of the catalytic current dependency on concentrations of the substrate. Compound 1 possessed electrocatalytic activity in organic halide dehalogenation, and such activity was preserved for the Ni(L)2 units, incorporated into the framework of 2. In addition, a new property occurred in the case of 2: the catalytic activity of PCP depended on its sorption capacity with respect to the substrate. In contrast to homogeneous catalysts, usage of solid PCPs may allow selectivity due to porous structure and simplify separation of product

Such reactions lead to the formation of valuable chlorotrifluoro-or tetrachloroethylenes. It was found that a silver cathode has a promoting effect on the investigated processes compared with the other materials (GC, Pt). The optimum reaction conditions within the present investigation were determined.The processes involved in the electrochemical activation of Freons and their use in the synthesis of important organic products have attracted the attention of many research workers in recent years [1][2][3][4][5][6][7]. A promising feature of the electrochemical conversion of Freons is their use as sources of fluoroalkyl groups in the fluoroalkylation of various organic substrates [1].Another no less important development is the dehalogenation of Freons C-2, including the process involving the use of various electron transfer mediators [2-7] and leading to the formation of fluorine-containing ethylenes, which are valuable products for the synthesis of fluoroplastics, biologically active substances, and other products. At the same time, in spite of the appeal of such processes, many important aspects of their realization remain unclear or have been poorly developed. This concerns, primarily, the effect of the cathode material, the nature of the electrolyte, and other factors on such processes.In the present work we studied the electrochemical activation of Freons F113 (CF 2 ClCFCl 2 ), F113B2 (CF 2 BrCFClBr), and F114B2 (CF 2 BrCF 2 Br) at various electrodes, i.e., at platinum as a material widely used in electrochemical investigations, at glassy carbon as a material not exhibiting significant specific adsorption of halogen-containing compounds [8,9], and at silver for which such an effect can be clearly observed in certain halogen-containing compounds [9][10][11][12][13][14][15][16]. EXPERIMENTALThe Freons were dried with calcium chloride for 12 h and were then distilled at atmospheric pressure. Dimethylformamide (DMF), dehydrated with calcium chloride for 6 h and double distilled under vacuum with intermediate drying by 4A molecular sieves, was used as solvent. The indifferent electrolyte was LiBF 4 , which was dried under vacuum at 100°C for 24 h and further dried in a muffle furnace at 110°C just before the experiment. The electrochemical experiments were carried out with a computerized setup based on an EP 20A potentiostat in an undivided three-electrode cell with platinum, silver, or glassy carbon (GC) point working electrodes of 2 mm diameter and a platinum auxiliary electrode. The concentration of the Freons in the voltammetric experiments amounted to 0.02 M, and the concentration of the indifferent electrolyte was 224 0040-5760/06/4204-0224

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