Cyclic Interconversion Among Molecular Salts And Related Photoluminescence Properties Via Mechanochemistry

At present, developing low-pollution or pollution-free products and processes has become a great challenge as the polution in our society is more and more serious. in the sense that it not only pursuits the high efficiency and high selectivity, but also pursuits "green" in the reaction process. The solid-state synthesis, as an alternative "green" method, has attained increasing interest in recent years. People pay more attention to this method because of its advantage which manipulated easily, quickly and quantitatively and without involving environmentally unfriendly solvents. Mechanochemistry refers to reactions, normally of solids, induced by the input of mechanical energy, such as by grinding in ball mills. Using solid state synthesis method for preparation of supramolecular co-crystals by controlling appropriate stoichiometric amounts of the co-crystal reactants while the traditional solution method cannot. In the solid state synthesis process, the individual molecules of each reactants have to be freed from the original lattice and rearranged themselves with other molecules to form a crystal lattice in solid-state.In this paper, we have prepared series rates of supramolecular co-crystalsby(4,4-diaminodiphenylmethane and 5-sulfosalicylic acid dihydrate) by the solid-state grinding. We have obtained the following result and conclusions:(1) We get A1B1·H2O,A1B2 and A2B1·H2O co-crystal by grinding with the different stoichiometric of reactants A·2H2O and B. However, the co-crystal of A2B1·H2O can be only get by grinding. We only get A2B1 by different methods which are different solution, temperature and p H.(2) These co-crystals were characterized by X-ray single-crystal diffraction, PXRD.(3) We have studied systematically the cyclic interconversion among three different molecular salts via neat grinding, fore example, one mol B put into A1B1·H2O to conform A1B2,one mol A·H2O were put into conform A1B1·H2O.This promote the development of supramolecular chemistry theory according experimental support.(4)We study the effects of solid fluorescent materials and different ratios co-crystal, using theoretical calculation qualitatively illustrates the red shift of reasons in solid state fluorescent.