Synthesis Of Novel Hydrazone Receptors And The Recognition Properties

Molecular recognition is the process that host molecular form binding with guest molecular selectively and produce some special function, which is an important research area in supramolecular chemistry. The anion recognition, as an important part of molecular recognition, has been given great attention from many specialists. We have synthesized some novel hydrazone tweezers receptors and studied on their anion recognition properties. The major contents are as follows:Researches in the development of anion recognition were briefly reviewed, which contain the following topics: (i) the principle of molecular recognition, the significane of anion recognition, the structural characteristics of anions impact on receptor design; (ii) the development of anion recognition properties hydrazone receptors.1. A series of novel tripodal colorimetric anion sensors based on hydrazone–CH=N^-NH^- groups have been synthesized and their recognition behavior with anionic guests have been studied. In DMSO solutions, sensors 1&2 show colorimetric responses for F^-, H₂PO₄^- and AcO^-, while in DMSO/H₂O (9:1, v/v) solutions, sensor 1 show single selectivity for AcO^-. 1H NMR titration confirm that the tripodal sensors could bind anions through the collaboration of three hydrazone groups and anions resided in the central cavity of the sensors.2. A colorimetric anions receptor bearing phenol OH and NH groups is synthesized, and the binding properties of the receptors with anions such as F^-, CI^-, Br^-, I^-, CH₃COO^-, H₂PO₄^-, HSO₄^- and ClO₄^- are studied by UV–VIS absorption spectroscopy. The results show that the receptor has a better selectivity for I^- , Br^- and could bind F^-,CH₃COO^-,H₂PO₄^-. To add F^-, CH₃COO^- or H₂PO₄^- to the DMSO solution of receptor, red shift of the receptor UV^-VIS absorption band has been observed, while to add Br^-or I^- to the DMSO solution of receptor, it is blue shift of the receptor UV^-VIS absorption band that has been observed.