Catalytic Synthesis Of Titanyl Salicylate Complexes By Ionic Liquid Under Water

Coordination chemistry is developed on the basis of inorganic chemistry, which has penetrated into all branches of chemistry, chemical engineering, etc. It is interrelated with organic chemistry, analytical chemistry, physical chemistry, polymer chemistry and other disciplines and influences each other, and the relationship of the coordination chemistry and the life sciences, materials science and medicine and other disciplines are getting closer. The rapid development of organometallic chemistry broadens people’s understanding of coordination compounds. Among of the organometallic chemistry, the titanocene complexes show outstanding performances in catalysising organic synthesis of olefin polymerization, isomerization hydrogenation, and anticancer property and other aspects, which have revealed many significant potential applications; salicylic acid derivatives also served a pivotal role in the life activities. Ionic liquids are a class of materials which possess low melting point, less volatile, good solubility, stable property, controllable structure and other excellent qualities. It has an attractive prospect in many fields, such as extraction and separation in chemical reaction. Based on these ideas, the paper centres on the synthesis of salicylate titanocene complexes in aqueous media by ionic liquids catalysis:Firstly, we have preparated a series of imidazole ionic liquids, optimized the best conditions for this reaction, used the FI-IR,1HNMR and other testing means for measuring the structure of the salicylate titanocene complexes, and researched meticulously all of the data, and finally presumed the reaction mechanism through experimental comparison and UV-Vis electronic absorption spectra. As described belows:1. With the help of related references, we prepared the3-ethyl-l-methyl-imidazolium bromide,3-ethyl-l-methylimidazolium tetrafluoroborate,3-ethyl-l-methy-limidazolium hexfluorophosphate,l-methyl-3-propylimidazolium bromide,1-methyl-3-propylimidazolium tetrafluoroborate,1-methyl-3-propylimidazolium hexfluorophosphate,3-butyl-1-methylimidazoliumbromide,3-butyl-1-methyl-imidazoliu m tetrafluoroborate,3-butyl-1-methylimidazolium hexfluorophosphate. After separation and purification, we carried out Fourier transform infrared FT-IR,1H-NMR nuclear magnetic resonance analysis on these ionic liquids. Data indicate that the product is consistent with the design and the structure of anion and cation has an influence on the property of ionic liquids.2. By optimizing the reaction conditions, we determined an amount of0.4mmol of the ionic liquid3-ethyl-l-methylimidazolium bromide, and molar ratio of titanocene dichloride to salicylic acid derivative is1:1.3, the volume ratio of deionized water and chloroform is1:3, the reaction can get the best yield. Based on the different result in ionic liquids, it is the conclusion that mainly affecting factors for the reaction include the structure of ionic liquids and water molecules, which have slight impact on the structure of ionic liquids. Under this condition, we synthesized five kinds of salicylate titanocene complexes, they are:thiosalicylate titanocene complexes,5-chlorosalicylate titanocene complexes,3,5-dichlorosalicylate titanocene complexes,3,5,6-trichlorosalicylate titanocene complexes and5-bromosalicylate titanocene complexes. Using FI-IR,1HNMR and other detection methods to characterize and analysis their structures, the results showed that:the five complexes are mononuclear forms of TiⅣ and geometries at titanium atoms are distorted tetrahedrons, the coordinate numbers are four. We selected the means to preparated thiosalicylate titanocene, after5times recycling catalysis, the yield remains high.3. Through1H NMR and UV-Vis electronic absorption spectra, we presumed the reaction mechanism. it is the possible mechanism that the ionic liquid came into the organic phase from the aqueous phase to activate titanocene dichloride to form activated intermediates titanocene hydrated ions, which react with salicylic acid derivatives to synthesis salicylate titanocene complexes. chloride ions leave from the organic phase to form the HC1was absorbed by water which accelerate further the the rate of reaction. In generally, for the reason of the solubility of the ionic liquids in water is higher than that in the trichloromethane, it was collected in the aqueous phase.