Design, Synthesis, Structure And Properties Of Complexes With Bridging Schiff Base Ligands

Bridged complexes have become one of the most active fields of coordination chemistry due to novelty structures and diversity function. Azide ion, phenanthroline and thiocyanate ion are able to participate with a variety of coordination mode, and also transfer the magnetic coupling effectively, so they are often used as small auxiliary-ligands to construct molecule-based magnetic materials. In addition, it is one of the most effective strategy to introduce the multifunctional groups, which are both bridged and chelating metal ions, such as hydroxyl, carboxyl and amide groups, etc, in order to constructing some novel structure and unique features complexes.Based above reasons, we have synthesized seven schiff base ligands, through reacting with transition metal or rare earth metal salt, then reintroduction of some bridged ligands, such as azide ion, phenanthroline, thiocyanate and halogen ions, and 12 novel complexes have been successfully synthesized. The main content as following:(1) Through condensing N-methyl-1,3-propanediamine and 3-carboxysalicylidene, one schiff base H3L1((E)-2-hydroxy-3-((3-(methylamino)propylimino)methyl)benzoic acid) has been synthesized. Using the ligand, copper(II) salts, cobalt(Ⅱ) salt and some suitable ancillary ligand, we have synthesized four dual-core and quad-core complexes of transition metal [Cu2(L1)2 Cl2e·2H2O (1), [Cu2(L1)2(SCN)2] (2), [CO4(L1)2(N3)4(H2O)4]·2CH3OH(3) and [Co4(L1)2(N3)4(H2O)4]·2DMF·0.5H2O(4), and tested their crystal structure and properties.(2) Through condensing tris(hydroxymethyl)aminomethane,2-amino-2-ethyl-1,3-propanediol 2-amino 4-methylphenol and 3-carboxysaIicylidene, respectively. Three novel schiff base H5L2((E)-2-hydroxy-3-(( trimethylol asian aminomethane)methyl)benzoic acid), H4L3((E)-2-hydroxy-3-((dimethylol ethylimino methane)methyl)benzoic acid) and H3L4((E)-2-hydroxy-3-((2-imino-4-methylphenol)methyl)benzoic acid)have been synthesized. Using these ligand and cobalt(II) salt, we have synthesized three new complexes of cobalt [Co4(HL2)2(N3)2(CH3OH)2(H2O)2]·4CH3OH(5), [Co4(L3)2(N3)2(CH3OH)2(H2O)2]-2C H3OH-2H2O(6) and [Co4(L4)2(CH3OH)8]-4CH3OH·2H20-2Cl(7), and tested their crystal structure and properties.(3) A schiff base ligand H3L6((E)-2-hydroxy-3-((phenylimino thiourea)methyl)benzoic acid) has been synthesized through 4-phenyl-3-thiosemicarbazide and 3-carboxysalicylidene. Then through condensing thiosemicarbazide and 3-carboxysalicylidene,5-methyl-3-carboxysalicylidene, respectively. Another two Schiff base ligand H3L5((E)-2-hydroxy-3-((asian thiosemicarbazide)methyl)benzoic acid) and H3L7((E)-2-hydroxy-5-methyl-3-((asian thiosemicarbazide)methyl)benzoic acid) have been synthesized. Using H3L5, copper(Ⅱ) salts, and Gadolinium(Ⅲ) salt, a 3d-4f different metal three nuclear complexes [Cu2Gd(L5)2(DMF)4(NO3)]-DMF(8) has been synthesized, the reaction of H3L6, H3L7 and transition metal copper(II) salts, cobalt(Ⅱ) salt, we have synthesized four complexes [Cu(H2L6)(Phen)](9), [Ni(H2L6)(Phen)(CH3OH)](10), [Co(H2L7)2]-4CH3CH2OH(11) and [Cu(H2L7)(NCS)]H2O(12), and tested its crystal structure and properties.