Studies On Supra-molecular Structures Of Some Metal Complexes With Substituted-Benzoate

It has aroused chemists' interest since the discovery that the level of the benzene ring activation depends on the electronic property of the substituent (electron donating groups or electron-withdrawing groups). The key point of this present paper is the influence of different substituting groups on coordinate ability of the benzoic acid to form the transition metal complex, on the structure of complex, and on intermolecular interactions between the complexes.In this work a series of complexes with m-toluic acid anion, p-toluic acid anion, 4-nitrobenzoic acid anion, 3,5-dinitrobenzoic acid anion, 4-chlorobenzoic acid anion, imidazole and 1,10-phenanthroline were synthesized, their single crystals were successfully obtained and the three-dimensional structures were determined by X-ray diffraction method.The structure analysis indicated that, in these new complexes, some of the carboxyl groups attach the transition metals by the different ways, and some not attach transition metals. In the majority situation, the complexes form the mononuclear structure, and assembled to be one-dimensional, two-dimensional or three-dimensional supermolecular structure by intermolecular hydrogen bond interactions (to see Table 1).The following valuable results were obtained from these a series of the structures ofthe new complexes:1st, the methyl substituting group is electron donating group. It makes the electronic cloud density of carboxyl group oxygen atom of the benzoic acid to increase, strengthened the coordinate ability of benzoic acid regardless of another ligand is imidazole (monodentate ligand) or 1,10-phenanthroline (bidentate ligand). The coordinate ways of the carboxyl groups are the monodentate, the bridging and the chelate (tg15, tg44, tg36, tg12).2nd, the nitryl substituting group is electron-withdrawing group. It makes the electronic cloud density of carboxyl group oxygen atom of the benzoic acid to reduce, and causes the coordinate ability of the benzoic acid to weaken. The 4-nitrobenzoic acid anion attaches the transition metal by monodentate when the imidazole exists and it doesn't attach the transition metal when the 1,10-phenanthroline exists (tg13, tg16, tg17). It only exists by the anion or the drifters in the complex (tg28, tg29). The 3,5-dinitrobenzoic acid anion doesn't attach the transition metal when the imidazole exists. It only exists by the anion in the complex (tg14). Therefore, in competing reaction, the coordinate ability of substituted benzene formic acid: 3,5-dinitrobenzoic acid anion < 4-nitrobenzoic acid anion (monodentate ligand) < toluic acid anion (bidentate ligand).3rd, The following data are obtained when the theoretical calculation with Gaussian03w quantification computational procedure is worked on the carboxyl group and the carboxyl group oxygen atom of different substituted benzoic acid:These data are basically consistent to the coordinate situation of the substituted benzoic acids that are selected in this present paper. Except the 2,4,6-trinitrobenzoicacid and the benzoic acid, other five kinds of substituted benzoic acid are that this present work does with. Finally four single crystals are synthesized with the toluic acid, five single crystals are synthesized with the 4-nitrobenzoic acid, one single crystal is synthesized with the 3,5-dinitrobenzoic acid, and none single crystal is synthesized with the 2-nitrobenzoic acid or the 3-nitrobenzoic acid.