Structures, Magnetic And Fluorescence Properties Of Polynuclear Complexes Based On Hydroxyl- And Nitrogen-Rich Ligands

Polynuclear complexes and supramolecular coordination assemblies have attracted extensive attention due to the potential applications in the fields of catalysis, gas adsorption, optical, electrical, and magnetic materials. The selection of suitable organic ligands is extremely important in the design of coordination compounds with novel structures. In this dissertation, a series of hydroxyl-and nitrogen-rich ligands and their metal complexes were designed and synthesized. Crystal structures, luminescence and magnetic properties of these complexes were systemically studied. The main contents are listed as follows:1. By the reaction between amino glycerol and 2-hydroxy-1,3-phthalaldehyde with different substituents, we obtained coordination compounds [Cu(HL')]2 (1) and [Ni7(OH)2(OCH3)4(H2L2)2(MeOH)2(H2O)2](ClO4)2·10H2O (2). The organic ligands involved in these two complexes are tridentate mono-Schiff base H3L1 and multidentate mono-Schiff base H5L2. X-ray crystal structure measurements revealed that, complex 1 has alkoxo-bridged binuclear Cu(II) coordination structure; and complex 2 is a centrosymmetric heptanuclear Ni(II) complex with a unique face-sharing hexadruple defective cubane structure. Variable temperature magnetic measurements revealed that ferromagnetic and antiferromagnetic exchange interactions coexist in complex 2.2. By the reaction between serinol and 2-hydroxy-1,3-phthalaldehyde with different substituents, with NaN3 added as the co-ligand in some cases, we obtained crystals [Cu2(H3L3)N3]n(ClO4)n-2nH2O (3), [Cu2(H3L4)Cl2(H2O)]·H2O (4), [Cu2(H3L4)N3]n(ClO4)n-2nH2O (5) and [Cu(HL5)]4 (6). The organic ligands involved in these complexes are multidentate bis-Schiff bases H5L3 and H5L4, and tridentate mono-Schiff base H3L5, respectively. X-ray crystal structure measurements revealed that, complexes 3 and 5 have binuclear Cu(II) coordination structures with mixed phenoxo and azido-bridges; complex 4 also has a binuclear Cu(II) coordination structure, with mixed phenoxo and chloro-bridges; and complex 6 is a tetranuclear Cu(II) complex with a cubane structure formed by the bridging of alkoxo-O atoms.3. By the reaction between 1,3-bis(2-aminoethylamino)-2-hydroxy propane and 2-hydroxy-1,3-phthalaldehyde with different substituents, with NaN3 and NaSCN added as the co-ligands, we obtained crystals of [Zn4L6Cl4]-2DMF (7), [Zn4L7Cl4]-3H2O (8), [Zn4L8Cl4]-H2O (9), and [Na(H2O)5][Cu8(H2L8)2(ClO4)(O)4(S2)2] (10) by the solvothermal method. The organic ligands involved in these complexes are three similar hydroxyl-and nitrogen-rich macrocyclic Schiff base type compartmental compounds, namely H4L6, H4L7 and H4L8. X-ray crystal structure measurements revealed that, complexes 7,8 and 9 are all alkoxo-and phenoxo-bridged tetranuclear Zn(II) complexes, and the Zn(II) ions possess the same coordination environments; In complex 10, a perchlorate utilizes all its oxygen atoms to bridge two tetranuclear units, affording a novel octanuclear Cu(II) coordination structure. Finally, the fluorescence measurements on Zn(II) complexes 7-9 revealed that, when zinc ion was added to the solution of H4L7, the fluorescence was significantly enhanced, which demonstrates that H4L7 may be utilized to design sensors for the detection of zinc ion.In summary, in this dissertation, based on the design of novel ligands, we synthesized a series of novel Ni(II), Cu(II) and Zn(II) coordination compounds, including heptanuclear Ni(II) and octanuclear Cu(II) complexes with unique structures. Preliminary magnetic and fluorescence studies of some of the complexes were performed.