Syntheses,structures And Properties Of Metal Complexes Based On 2-Hydroxy-3-Carboxy-5-Methoxybenzaldehyde,Its Aldehyde Oxime And 2-Hydroxy-4-Methoxybenzaldehyde Schiff Base

2-hydroxy-3-carboxy-5-methoxybenzaldehyde,2-hydroxy-3-carboxy-5-methoxy benzaldehyde oxime and 2-hydroxy-4-methoxybenzaldehyde Schiff base ligands contain multiple N,O atoms.The N,O atoms possess unpaired electrons,they not only act as coordinating atoms,but also play a bridging role,coordinated with metal cation to form multinuclear complexes.In this paper,we synthesized2-hydroxy-3-carboxy-5-methoxybenzaldehyde,2-hydroxy-3-carboxy-5-methoxy benzaldehyde oxime and 2-hydroxy-4-methoxybenzaldehyde Schiff base ligands.They reacted with different metal salts under different conditions and obtained 18 complexes with single crystal structures.The structures were characterized by X-ray single crystal diffraction,infrared spectroscopy,elemental analysis and XRD,and the magnetic properties of some complexes were also studied.It was found that partial metal complexes based on 2-hydroxy-3-carboxy-5-methoxybenzaldehyde,2-hydroxy-3-carboxy-5-methoxy benzaldehyde oxime and 2-hydroxy-4-methoxybenzaldehyde Schiff base showed good magnetic properties.The main sections of the thesis are as follows:1.Seven complexes were obtained from the reactions of2-hydroxy-3-carboxy-5-methoxybenzaldehyde?H₂L1?with different metal salts:[Mn₃?OH??L1?4?Py?5?H₂O?₂]·2Py·H₂O?1?,[MnCo₂?L1?4?Py?6?H₂O?₂]?2?,[Mn4Cd2?L1?8?Py?12?H₂O?₂]?3?,[Mn2Cd2?L1?4?Py?6?CH3CH₂O?₂]?4?,NMe4·[Mn₃?OH?₂?L1?4?4,4'-bipy?3]·2H₂O?5?,[Cd2?L1?₂?Py?6]·Py?6?,[Cu?L1??2,2'-biPy?]?7?.The three manganese ions of complex 1 show a “U” shaped structure,and the three manganese ions show six-coordinated tetragonal bipyramid conformation.The structure of the complex 2 is similar to that of the complex 1,which corresponds to two cobalt ions replaced the manganese ions at both ends of the complex 1.Complex 3 consists of A and B parts,each is a trinuclear core of Mn2Cd1.Complex 4 is heteronuclear metal complex of Mn2Cd2,both of manganese ions are six-coordinated tetragonal bipyramid configurations,while the two cadmium exhibit seven coordination pentagonal bipyramid configurations.Complex 5 is a complex of trinuclear manganese,and each structural unit forms aone-dimensional chain structure by 4,4'-bipyridine.The structure of complex 6 is dinuclear Cd,and each Cd cation exhibits tetragonal bipyramid conformation.Complex 7 is a mononuclear copper complex.Studies of magnetic properties indicate that the presence of dominate antiferromagnetic interaction between manganese ions in complex 1,further experiments show that complex 1 exhibits single molecule magnet behavior.The magnetic properties of complexes 2,3,4,5 show that the presence of significant antiferromagnetic interactions between the metal ions in the complexes.2.The reactions of 2-hydroxy-3-carboxy-5-methoxybenzaldehyde oxime?H3L2?with different metal salts produced three complexes:?NMe4?4·[Zn4?L2?₂?HL2?₂?OAc?₂]·DMF·H₂O?8?,?NMe4?₂·[Cu4?L2?₂?HL2?₂?H₂O?₂]·DMF·H₂O?9?,[Co₂?HL2?₂?2,2'-bipy?₂?H₂O?]·DMF·2H₂O?10?.Complexes 8 and 9 are all tetranuclear structures and structurally similar.Copper and zinc cations are five-coordinated tetragonal pyramid conformations,the adjacent molecules are connected by O···H-C interactions to form a2-D network structure,the difference is that the zinc cations are coordinated with the carboxylic acid anion in the vertex of tetragonal pyramid conformations,while the copper cations are coordinated with water molecules.Complex 10 is a complex of dinuclear cobalt.Both cobalt cations are six-coordinated tetragonal bipyramid conformations.The magnetic property of complex 9 was studied.The result shows that complex 9 exhibits antiferromagnetic interaction between copper ions.3.The reactions of 2-hydroxy-4-methoxybenzaldehyde Schiff base ligand?H₃L₃?with different metal salts afforded eight complexes: [Zn3?HL3?₂?OAc?₂?DMF?₂]?11?,NMe4·[Cu2?L3??SO4?]·CH3CN?12?,[Y6?L3?4??3-OH?4?CH3OH?₂?NO3?₂]?13?,[Gd6?L3?4??3-OH?4?CH3OH?₂?NO3?₂]?14?,[Er6?L3?4??3-OH?4?CH3OH?₂?NO3?₂]?15?,[Ho6?L3?4??3-OH?4?CH3OH?₂?NO3?₂]?16?,[Tb6?L3?4??3-OH?4?CH3OH?₂?NO3?₂]?17?,[Dy6?L3?4??3-OH?4?CH3OH?₂?NO3?₂]?18?.Complex 11 is a metal complex of trinuclear zinc,and three zinc ions are tetragonal bipyramid conformation with two coordination environments.Complex 12 is a dinuclear copper complex,the copper ions are all four-coordinated with square planar configuration.Complexes 13-18 are all hexanuclear lanthanide-based complexes and structurally similar,all lanthanide ions are in theeight-coordinated environment.The studies of magnetic properties indicated that the presence of dominant antiferromagnetic interactions between the lanthanide ions in complex 14;further experiments showed that the complex 18 displays single molecule magnets behavior.