Synthesis And Optical Properties Of Phenyl-azo Schiff Base And Their Transition Metal Complexes

Azo compounds have attracted people's interest due to their properties on dyes and luminescent materials.Schiff bases are considerable concerned for their various structures and coordination abilities with transition/Lanthanide metals.The construction of new type azo schiff base complexes has become a subject of interest to chemists.In this paper,the transition metal complexes of two novel Schiff base compounds and their complexes with transition complexes were synthesized.The main work is as follows:(1)2-Hydroxy-3-methoxy-5-(phenyldiazenyl)benzaldehyde from aniline and o-Vanillin by diazo reaction and coupling reation.Then bis[5-(azobenzene)-methoxysalicylaldehyde]-ethylenediamine(H2La:C30H28N6O4)and bis-[5-(azobenzene)-methoxysalicylaldehyde]-1,3-propanediamine(E2Lb:C31H30N6O4)were synthesized by the condensation of 2-hyd roxy-3-methoxy-5-(phenyldiazenyl)benzaldehyde and 1,2-ethylenediamine(C2H8N2)or 1,3-propylenediamine.(2)The complexes ZnLa,CuLa,CoLa were prepared from the reaction of H2La(or H2Lb)with zinc acetate,copper acetate,cobalt nitrate(3)The melting points of the two kinds of azo Schiff base ligands and four kinds of transition metal metal complexes were measured.The results showed that the melting points of the six substances were all greater than 200? and they could be stably present at room temperature.The elemental analysis and FT-infrared Spectroscopy,nuclear magnetic resonance spectroscopy,mass spectrometry,and single crystal X-ray diffraction were used to determine their chemical structures.(4)The experiment of single-factor explored that the optimal reaction time for the synthesis of ligand H2La is about 30 min,and the best reaction temperature is 50?.(5)UV-Vis absorbance spectrum shows that the maximum absorption wavelengths of ligands and complexes both shift to the short-wave direction when acidified,which illustrated that azo schiff base has an acid-induced discoloration properitiy.(6)Fluorescence of ligands and complexes was found by fluorescence test.The polarity of the solvent affects the fluorescence intensity of the six substances,while acidic conditions reduce the fluorescence.