Construction,Characterization And Properties Of New Schiff Base Compounds And Metal Complexes

Schiff base compounds have been the focus of the research,which have certain pharmacological and physiological activity.Hydrazone compounds are a class of Schiff base compounds which formed by the condensation of hydrazide with aldehyde or ketone.However,the synthesis of Schiff base compounds has the existence of problem of low yield.As a hydrogen bond type organic catalysts,urea type catalyst can activate the substrate of the carbonyl group(C=O)and form a double hydrogen bonding interaction which catalyzing the reaction effectively.In this paper,1,5-diphenylcarbazide catalyst was synthesized through phenylhy--drazine and urea as raw materials.The influence of the amount of catalyst on the yield of Schiff base compounds were discussed.4-Hydroxy benzaldehyde benzoyl hydrazone(3a),4-hydroxy benzaldehyde-2-hydroxy benzoyl hydrazone(3b),4-hydroxy benzaldehyde-4--hydroxy benzoyl hydrazone(3c),4-hydroxy benzaldehyde-3,4,5-trihydroxy benzoyl hydrazone(3d),4-hydroxy-3-methoxy benzaldehyde benzoyl hydrazone(3a'),4-hydroxy--3-methoxy benzaldehyde-2-hydroxy benzoyl hydrazone(3b'),4-hydroxy-3-methoxy benzaldehyde-4-hydroxy benzoyl hydrazone(3c'),4-hydroxy-3-methoxy benzaldehyde--3,4,5-trihydroxy benzoyl hydrazone(3d')were respectively obtained by condensation reaction of 4-hydroxy benzaldehyde and 4-hydroxy-3-methoxy benzaldehyde with benzoyl hydrazine(2a),2-hydroxy benzoyl hydrazine(2b),4-hydroxy benzoyl hydrazine(2c)and3,4,5-trihydroxy benzoyl hydrazine(2d),which using 1,5-diphenylcarbazide as catalyst.The compounds were characterized by elemental analysis,infrared spectrum(IR),nuclear magnetic resonance hydrogen spectrum(1H NMR),scanning electron microscopy(SEM)and thermogravimetric analysis(TGA).Transition metal complexes were obtained by hydrothermal synthesis of Schiff base compounds and transition metal(Zn,Cu,Co,Ni,Mn)with the second pyridine ligand(py).PH and electrical conductivity of transition metal complexes and ligands were measured.The pH test results show that: the pH of 4-hydroxy benzaldehyde series Schiff base compounds(3a~3d)ranges from 5.57 to 7.43.The pH of its metal complexes ranges from4.67 to 6.96.The pH of 4-hydroxy-3-methoxy benzaldehyde series of Schiff base compounds(3a'~3d')ranges from 5.89 to 7.15.The pH of its metal complexes ranges from4.73 to 6.75.The conductivity test results show that: the range of electrical conductivity of4-hydroxy benzaldehyde series Schiff base compounds(3a~3d)are 6.40~10.33 ?s/cm.The scope of the electrical conductivity of metal complexes are 0.43×102~1.07×103 ?s/cm.The rage of electrical conductivity of 4-hydroxy-3-methoxy benzaldehyde series of Schiff base compounds(3a'~3d')are 3.13~10.67?s/cm.The range of electrical conductivity of the metal complexes are 0.85×102~1.04×103?s/cm.On the other hand,4-hydroxy benzaldehyde benzoyl hydrazone(3a)and 4-hydroxy--3-methoxy benzaldehyde benzoyl hydrazone(3a')were developed into single crystal.The tests for crystal structure shown that 3a belongs to the orthorhombic system with space group Pbca;3a' belongs to the tetragonal system with space group I41/a.The compound crystal can maintain a certain stability by one-dimensional chain of the compound formed through weak interactions and hydrogen bonds.