Synthesis, characterization and thermal decomposition of SbIII-M-SbIII type trinuclear complexes of ethylenediamine-N,N,N′,N′-tetraacetate (M: Co(II), La(III), Nd(III), Dy(III))

Four ethylenediamine-N,N,N',N'-tetraacetate complexes with Sb(III)-M-Sb(III) polynuclear structure (M=Co(II), La(III), Nd(III), Dy(III)) are synthesized. [Sb-2-mu(4)-(EDTA)(2)Co(H2O)(2)]center dot 5.15H(2)O is characterized by single crystal X-ray diffraction. The crystal structure of [Sb-2-mu(4)-(EDTA)(2)Co(H2O)(2)]center dot 5.15H(2)O belongs to monoclinic system, space group P2(1)/n, lattice parameters: a=6.9969(2), b=20.8705(4), c=10.8106(2) angstrom, beta=90.031(1)degrees, V=1578.66(6) angstrom(3), Z=2, M-r=1007.76, D-c=2.120 g cm(-3), F(000)=1001, mu=2.323 mm(-1), the final R=0.0235 and wR=0.0629 for 3480 observed reflections (I > 2 sigma(I)). The powder X-ray diffraction patterns of the complexes are also measured. Elemental analyses, FTIR spectra, TG-DSC and DTA of [Sb-2(EDTA)(2)Ln]NO3 center dot nH(2)O are performed. FTIR spectra reveal that the antimony and other metallic ions were connected through the carboxylate bridges. The thermal analysis can demonstrate the complex formation of the antimony, other metallic ions and EDTA. The possible pyrolysis reactions in the thermal decomposition process of the complexes, the experimental and calculated percentage mass losses are also given.