Synthesis, Structures And Properties Of Tripodal Ligands And Their Metal Complexes

Tripodal ligand with a semi-rigid structure and three flexible side chains, it makes that it easy to form a suitable size cavity. Combined with rich and varied substituted type, the tripodal ligand shows particular selective coordinating capacity and flexible binding modes. Tripodal ligands and their complexes represent excellent application prospect in many aspects, such as optical, electrical, magnetic, catalytic, and gas adsorption, etc. In recent years, the study of tripodal ligands and their complexes is one of the most challenging fields in coordination chemistry and supramolecular chemistry. In this paper, we designed and synthesized several tripodal ligands with N, O atoms. The applications of these ligands in the fields of supramolecular chemistry including fluorescent sensor, water clusters and molecular self-assembly were investigated.The thesis includes the following four parts:1. A briefly introduce of the basic concept, research fields of supramolecular chemistry and applications of supramolecular complexes has made. The definition, classification of tripodal ligand and its applications in the fields of supramolecular chemistry, including coordination polymers, fluorescent sensor, water clusters and rare earth complexes were reviewed.2. A tripodal ligand (Tris[2-(8-chinolinyloxy)ethyl]amine) L was synthesized based on the 8-hydroxyquinoline platform. It has been developed as a new fluorescent sensor based on the chelation-enhanced fluorescence (CHEF) mechanism. In buffer solution, sensor L exhibits high selectivity for Cd2+-over other metal ions. Its sensing behavior toward Cd2+ was investigated by absorption and fluorescence spectroscopy. The binding mode of the Cd2+-L complex has been found to be 1:1 based on the fluorescence/absorption titration, ES1-MS and further confirmed by X-ray crystallography. Fluorescent imaging of Cd2+ in living cells was also demonstrated.3. The reaction of CoC(NO3)2·6H2O with a tripodal ligand leads to a new complex {[Co(L)]·2NO38H2O} (1), in which a novel infinite ID water tape is observed. It was confirmed by elemental analysis,1R spectroscopy and single-crystal X-Ray diffraction. This water tape consisting of (H2O)16 cluster units, and the neighboring water tapes are connected by free nitrate anions via hydrogen bonds into a 2D guest layer. These guest layers are sandwiched between the host layers, and formed a 3D supramolecular architecture.4. Two novel tripodal ligands containing N,O heteroatoms were synthesized, and the binding ability of these ligands with mercuric chloride were studied. Both these ligands were found to complexation with mercuric chloride by N, O atoms. These complexes were characterized by elemental analysis,IR spectroscopy and single-crystal X-Ray diffraction. The interactions of the complexes with calf thymus DNA have also been investigated using UV-Vis spectra, fluorescence spectra and viscosity measurements. Experimental results indicated that complexes 1 and 2 can bind to DNA via the intercalation binding mode.