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New mixed-ligand complexes, [M2(BAMP)(bipy)2][MCl4]2, M=Co+2(1), Cu+2(2), [M2(TAMEN)(bipy)2][MCl4]2, M=Fe+2(3), Co2+(4), and [Fe2(TAMEN)(bipy)2][FeCl6]2 (5), where BAMP and TAMEN stand for the Mannich bases N,N′-bis(antipyryl-4-methylene)-piperazine and N,N′-tetra(antipyryl-4-methylene)-1,2-ethane-diamine, respectively, have been obtained and characterized by elemental analyses, conductometric and magnetic susceptibility measurements at room temperature, mass spectrometry, UV-Vis, infrared, and mass spectroscopy, and 1H NMR spectra for the ligands.

The synthesis of Schiff bases N,N′‐bis(4‐dodecyloxy‐benzylidene‐N‐propyl)‐piperazine (2) and N,N′‐bis‐[4‐(4′‐octyloxy‐benzoic)‐ester‐benzylidene‐N‐propyl]‐piperazine (6) in a multistep process is reported. The intermediates as well as the products were characterized by elemental analysis, melting point and IR, 1H and 13C‐NMR spectroscopy. The complex formation of these Schiff bases with copper(II) perchlorate resulted in disruption of the imino bond and yielded N,N′‐bis(3‐aminopropyl)piperazineperchloratocopper(II) perchlorate, Cu(L)(ClO4)2, where L stands for N,N′‐bis(3‐aminopropyl‐)piperazine. The nature of the complex is established by elemental analyses, IR and Raman spectroscopy and its structure by X‐ray diffraction measurements. The mesomorphic ordering of the ligands have been checked.

The new Schiff base N,N′-bis(4-decyloxysalicyliden-N-n-propyl)-piperazine (ZOPP) was designed and synthesized. Structures were confirmed by elemental analysis and IR, 1H-NMR spectroscopy. ZOPP can act as ligand through the two set of donor atoms (one set: two nitrogen atoms and one oxygen) situated on each side of the piperazine bridge. The nature of the complexes depends strongly on the metal to ligand molar ratio. Thus, starting from metal to ligand of 1 to 1 ratio, where M=Cu(II), Ni(II), binuclear complexes with a polymeric structure have been obtained, whereas at metal to ligand molar ratio of 2 to 1, discrete binuclear complexes were formed.

The new sulfide bridged-polynuclear complexes Cu2(VO)4- (C2O4)4S2L4ċnH2O, where for L=1, 10-phenanthroline, n=5 and for L=2, l0-bipyridine, n=7, have been synthesized and characterized by elemental and thermal analyses, electronic and IR spectroscopy. These data as well as magnetic moments and EPR spectra strongly support a structure in which four [VO(L)(C2O4)(H2O)] units act as ligands toward the two copper(II) centers through the oxalate anion. Each of the oxalate anions act as a tridentate ligand and the core of the complexes involve a copper-sulfide-copper moiety.

Mixed-ligand complexes of the type M2L(TAB)nX4 [L = N,N′-bis(4-antipyryl-methyl)piperazine (BAMP), or N,N′-tetra(4-antipyrylmethyl)-l,2-diaminoethane (TAMEN) and 2-aminobenzothiazole (TAB), X - NCS or CIO4, M - Co, n - 2, or M - Cu, n = 4] were synthesized and investigated. The IR and Raman spectra revealed that the ligands L are coordinated through the carbonyl oxygen atom of the antipyrine and the nitrogen atom of the piperazine or 1,2-ethanediaminc bridge, except in Cu2(TAMEN)(TAB)4(ClO4)4, in which case TAMKN is coordinated to the metal only through the carbonyl oxygen. Steric considerations explain the bonding of TAB through the exocyclic or endocyclic nitrogen.

The synthesis and properties of new cobalt, nickel and copper complexes of general formula M2(TAMEN)Cl4 [M = Co, Ni, Cu; TAMEN = N,N,′-tetra(4-antipyrylmethyl)-1,2-diaminoethane; antipyryl- = 2,3-dimethyl-1-phenyl-3-pyrazoline-5-one] and the 1H-NMR spectrum of the ligand TAMEN are reported. TAMEN bridges the two metal centres via two groups of donor atoms, each being formed of the carbonylic oxygens and a 1,2-diaminoethane nitrogen atom.