Synthesis, Structure And Magnetic Properties Of Chiral Schiff Base Complexes

15new complexes have been synthesized by using chiral double Schiff-base ligands and chiral salicylaldehyde Schiff-base ligands with the transition metal ions in this paper. The crystal structures were detected by X-ray diffraction analyses, and magnetic properties of part complexes were well-defined. These research results have great significant that can enrich the theory of chiral polynuclear metal complexes with Schiff-base ligands. Not only for designing new chiral polynuclear nickel and copper complexes, but also for researching complexes’structure, magnetism and the relationship between them. The main results of this paper are as follows:1. Five pairs of new chiral Schiff-base ligands were prepared, and two pairs of them were chiral double Schiff-base ligands (R-HL1or S-HL1、R-HL2or S-HL2) while three pairs of them were chiral salicylaldehyde Schiff-base ligands (R-HL3or S-HL3、R-HL4or S-HL4、R-HL5or S-HL5)2. Six tetranuclear nickel(II) complexes synthesized by using chiral double Schiff-base ligands, R-HLi or S-HL1reaction with Ni2+while using different bridged ligands. Complexes1、2have no chirality which crystallized in P21/c centred space group of monoclinic while3、4crystallized in P6s22chiral space group of hexagonal and5、6in C2chiral space group of monoclinic. Magnetic measurements show that magnetism occur in these complexes.2and3have a similar magnetic behavior, both of them changed from a weak ferromagnetic into a weak antiferromagnetic interaction, and characterized by obvious antiferromagnetism.6is a typical antiferromagnetic compound.3. Through different bridged ligands, three pairs of multinuclear copper(II) complexes were synthesized by using chiral double Schiff-base ligands, R-HL2or S-HL2reaction with Cu2+.7、8are dinuclear. copper complexes wPhich have crystallized in P212121chiral space group of orthorhombic.9、10crystallized in the same space group with7、8, but9、10are polymers which tncore as a unit.11、12are hexanuclear and belong to P43212chiral space group of tetragonal. Magnetic measurements show that dinuclear copper is typical of the antiferromagnetic compound, tncore and hexanuclear copper have the same magnetic behavior which from a weak antiferromagnetic to a weak ferromagnetic, and characterized by obvious antiferromagnetism.4. Three tetranuclear copper(II) complexes were synthesized through the coordinating reaction of the chiral salicylaldehyde Schiff-base ligands R-HL3or S-HL3、R-HL4or S-HL4、 R-HL5or S-HL5and Cu2+. None of these complexes have chirality,13crystallized in P-1centred space group of triclinic,14in C2/c and15in P21/c centred space group of monoclinic. Magnetic measurement show that13is a typical antiferromagnetic compound.