Synthesis,Characterization,Crystal Structure And Spectral Properties Of Aminoacetophenone Schiff Base Ligands And Their Metal Complexes

Two new intermediates were synthesized by reacting 4-aminoacetophenone with O-benzylhydroxylamine hydrochloride and hydroxylamine hydrochloride.The two intermediates reacted with salicylaldehyde containing different substituents to obtain four Schiff bases organic ligands,they are:1-（4-{[（3-methoxy-2-hydroxyphenyl）methine]amino}phenyl）ethanone O-benzylhydroxylamine oxime ligand（HL¹）,1-（4-{[（5-methoxy-2-hydroxyl-phenyl）methine]amino}phenyl）ethanone O-benzylhydroxylamine oxime ligand（HL²）,1-（4-{[（5-methyl-2-hydroxyphenyl）methine]amino}phenyl）ethanone hydroxylamine oxime ligand（HL³）,1-（4-{[（2-hydroxyphenyl）methine]amino}phenyl）ethanone hydroxylamine oxime ligand（HL⁴）;The four ligands are reacted with transition metal salts such as Zn（OAc）₂·2H₂O,Cu（OAc）₂·H₂O,Co（OAc）₂·4H₂O,The seven Schiff base metal complexes were obtained.The chemical composition and structure of the Schiff metal complex were determined by X-ray single crystal diffraction.And the following single crystal data were obtained:[Zn（L¹）₂],[Co（L¹）₂],HL²,[Zn（L²）₂],[Cu（L³）₂],[Zn（L⁴）₂],[Cu（L⁴）₂]and[Co（L⁴）₂].Elemental analysis,infrared spectrum and UV-Vis spectrum were used to characterize Schiff base organic ligands and their metal complexes.The obtained Schiff base transition metal complexes are similar in structure and are mononuclear four-coordinated.The coordination ratio of metal ion to the ligand is 2:1.According to the measurement of fluorescence spectrum,it was found that after adding Zn（Ⅱ）ion to the ligand,the fluorescence was significantly enhanced.The coordination between the ligand and Zn（Ⅱ）ion increased the rigidity of the ligand,thereby enhancing the fluorescence;after adding Cu（Ⅱ）,Co（Ⅱ）the ion,the fluorescence is quenched.Since the d-electron layers of Cu（Ⅱ）and Co（Ⅱ）ions are not fully filled,d-d transitions will occur,and the energy of d-d transitions is low.The fluorescence quenching is shown.Complex 1:Empirical formula,C₄₆H₄₂ZnN₄O₆,Formula weight,812.20,monoclinic,C2/c,a=17.1669（9）?,b=15.6008（10）?,c=29.9436（17）?,α=90.00°,β=99.934（2）°,γ=90.00°,Z=8,V=7899.2（8）?³,R₁=0.0999,wR₂=0.1893;Complex 2:Empirical formula,C₄₆H₄₂CoN₄O₆,Formula weight,805.76,triclinic,P-1,a=11.5614（4）?,b=12.0566（4）?,c=15.0657（5）?,α=75.5470（11）°,β=77.0137（12）°,γ=88.7316（13）°,Z=2,V=1980.27（12）?³,R₁=0.0555,wR₂=0.1211;Crystal 3:Empirical formula,C₃₂H₂₂2 N₂O₃,Formula weight,374.42,orthorhombic,P2₁2₁2₁,a=5.9839（5）?,b=7.7192（6）?,c=41.204（3）?,α=90.00°,β=90.00°,γ=90.00°,Z=4,V=1903.3（3）?³,R₁=0.0485,w R₂=0.1250;Complex 4:Empirical formula,C₄₆H₄₂ZnN₄O₆,Formula weight,812.20,monoclinic,P2₁/c,a=13.3297（5）?,b=11.6426（4）?,c=25.6821（10）?,α=90.00°,β=95.3010（10）°,γ=90.00°,Z=4,V=3968.6（3）?³,R₁=0.0555,wR₂=0.1163;Complex 5:Empirical formula,C₃₂H₃₀CuN₄O₄,Formula weight,598.16,triclinic,P-1,a=10.651（6）?,b=11.321（6）?,c=12.992（7）?,α=107.989（15）°,β=94.684（14）°,γ=104.694（14）°,Z=1,V=1419.3（13）?³,R₁=0.0878,wR₂=0.2036;Complex 6:Empirical formula,C₃₀H₂₆ZnN₄O₄,Formula weight,571.92,monoclinic,C2/c,a=16.0747（4）?,b=19.2092（4）?,c=16.7140（5）?,α=90.00°,β=93.1240（10）°,γ=90.00°,Z=8,V=5153.3（2）?³,R₁=0.0337,wR₂=0.0849;Complex 7:Empirical formula,C₃₀H₂₆CuN₄O₄,Formula weight,570.09,monoclinic,P2₁/c,a=15.5861（8）?,b=10.6367（4）?,c=7.9536（4）?,α=90.00°,β=104.220（2）°,γ=90.00°,Z=2,V=1278.18（10）?³,R₁=0.0401,w R₂=0.1154;Complex 8:Empirical formula,C₃₀H₂₆CoN₄O₄,Formula weight,565.48,monoclinic,C2/c,a=16.0520（5）?,b=19.1890（5）?,c=16.7292（4）?,α=90.00°,β=93.0640（10）°,γ=90.00°,Z=8,V=5145.6（2）?³,R₁=0.0400,wR₂=0.0932;...