Study On Supramolecular Chemistry Characteristics Of Some Thiosemicarbazones And Derivatives

Eight novel chalcone-thiosemicarbazones are designed and synthesized for the first time. The supramolecular chemistry characteristics of 4-chlorochalcone thiosemicarbazone (CCT), one of these reagents, are investigated systematically at first. The results indicate that CCT can form stable colored complexes with Hg²⁺, Cu²⁺, Pd²⁺ and Ag⁺, etc. in solutions. A new spectrophotometric method to determine trace copper has been developed (ε₃₉₄ 3.76 × 10⁴ L ·mor^-1·cm^-1) based on its good coordinate performance with copper. The predominant advantage of this method is that it has high sensitivity and satisfied selectivity without extraction or adding a large amount of organic solvents. It is also found that CCT has hydrogen bonding interactions with protic solvents, p-CD and fluoride anion. Furthermore, it has excellent recognition ability to fluoride anion, but it cannot detect the presence of other anions. So it has remarkable property to be used as colorimetric sensor for anions.Based on the above-mentioned researches, the micro-environmental effects and the spectral properties of eight chalcone thiosemicarbazones are studied theoretically. The changes of the spectrum in various solvents and acidity are examined in detail, respectively. The differences of the spectral properties of chalcone thiosemicarbazone derivatives with various substituents are discussed. Meanwhile, quantum chemical method is employed to investigate chalcone thiosemicarbazone derivatives for the first time. Geometry optimizations of tautomers are performed at HF/6-31G level. The most stable configurations are confirmed and the results keep the same with the experiments. The geometry, total atomic charge and bonding Mulliken population of the most stable configurations are calculated, and the results prove that hydrogen-bonding infractions exists. Substituent effects and the relative stability of the tautomers are discussed in theory.