Synthesis, crystal structure and thermal decomposition mechanism of the complex [Sm(p-BrBA)3bipy·H2O]2·H2O

A new binuclear samarium (III) complex [Sm(p-BrBA)3bipy·H2O]2·H2O (p-BrBA = p-bromobenzoic acid; bipy = 2,2′-bipyridine) has been synthesized and characterized by elemental analysis, UV, IR, molar conductance and TG-DTG techniques. The structure of the complex was established by single crystal X-ray diffraction. It crystallizes in triclinic, space group P1¯ with a = 8.2476(7) Å, b = 13.3483(10) Å, c = 15.9035(13) Å, α = 73.9160(10)°, β = 78.9630(10)°, γ =  74.4770(10)°, Z = 1, Dc = 1.947 g cm−3, F(000) = 910. The carboxylic groups are bonded to the samarium ion in two modes: bidentate bridging, monodentate. Each center Sm3+ ion is eight-coordinated by one 2,2′-bipyridine molecular, four bidentate bridging and a monodentate carboxylic group, as well as one water molecular. The coordination polyhedron around each Sm3+ ion can be described as bi-capped triangular prism geometry. The thermal decomposition behavior of the title complex in a static air atmosphere was investigated by TG-DTG and IR techniques.