Syntheses, Structures And Properties Of Coordination Compounds Based On Dipyridylamine Ligands

Complexes have attracted much attention due to its broad application prospects in catalysis, photoelectricity materials, gas storage, biological activity and other fields. Coordination center and organic ligand play very important roles in structural building and property. Complexes based on dipyridylamine ligand have extensive researches and potential applications in catalysis, conductivity and optical properties. This thesis chose the symmetrical and asymmetrical dipyridylamine and its derivatives as ligands, synthesized a variety of different types of novel complexes, and discussed the relationship between the structure and properties of those complexes. Those complexes used in catalysis, electrochemistry and optical properties were also studied.(1) We chose dipyridylamine and its derivatives as basic ligand, aliphatic carboxylic acid, aromatic carboxylic acid and salicylic acid as co-ligand, synthesized seven nickel and nine cobalt mononuclear complexes. We have investigated the transesterification of phenyl acetate with methanol catalyzed by nine complexes under mild conditions, and explored the effects by different metal center, carboxylic acid ligands and catalyst quantity. Experimental results show that the catalytic reactivity of cobalt complexes are higher than homologous nickel complexes. Increasing the amount of cobalt catalyst can accelerate transesterification rate of catalytic reaction. Complexes with different carboxylic acid ligands have important effects on catalytic reactivity. Complexes with aliphatic acid ligand is better than those of aromatic acid ligand in the transesterification catalytic reaction.(2) Based on4-methyl-2,2’-dipyridylamine ligand, we synthesized nine nickel metal string complexes with different axial ligands. Some of those complexes were characterized by X-ray single crystal structure, IR, element analysis, ESI mass spectrometry, optical properties and electrochemical properties. Introduction of the four alkyl groups into the trimetal complexes improves solubility, increase stability, and make oxidations easier.(3) Asymmetric aza-boron-dipyridomethenes were synthesized from bromo-aza-dipyridomethene through reactions with phenylboronic acid, phenylacetylene, phenylethylene, respectively, by using the Suzuki-Miyaura, Hagihara-Sonogashira and Heck cross-coupling reaction protocols. Introducing conjugate group, we got three novel fluorescent dyes. These dyes were characterized by NMR, high-resolution mass spectrometry and X-ray single crystal diffraction structure characterization. DFT calculations have been carried out to explore the effect of the substituent. Crystal structure reveals that the three compounds exhibit π…π stacking interactions. Compared with the optical properties that have been reported for symmetrical aza-boron-dipyridomethenes in solution, the asymmetrical molecules exhibit large apparent Stokes shift and the emission spectra are strongly dependent on solvent polarity.