Synthesis and Crystal Structure of a New Lanthanum(Ⅲ) 4-Cyanobenzoate Complex

A new dinuclear La(Ⅲ) complex [La2(4-cba)4[H(4-cba)2]2(phen)2(H2O)4] (4-Hcba = 4-cyanobenzoic acid and phen = 1,10-phenanthroline) 1 has been synthesized by solvothermal reaction in an ethanol/water mixed solution at 100 ℃ and structurally characterized by single- crystal X-ray diffraction. Crystallographic data: C88H58La2N12O20, Mr = 1881.28, triclinic P(1), a = 7.518(3), b = 17.033(6), c = 17.551(6)(A), α = 115.333(4), β = 92.9910(10), γ = 99.366(5)°, V = 1985.3(12) (A)3, Z = 1, Dc = 1.574 g/cm3, F(000) = 944 μ = 1.145 mm-1, the final R = 0.0281 and wR = 0.0686 for 6708 reflections with Ⅰ ＞2σ(Ⅰ). In 1, two nine-coordinated La(Ⅲ) ions are connected by two 4-cba ligands in a syn-syn bidentate coordination mode, and the other six 4-cba ligands terminate the La(Ⅲ) ions, resulting in an isolated dinuclear structure. Two different types of intramolecular hydrogen bonds, asymmetrical O-H…O and symmetrical O…H…O, exist in the crystal. The title complex molecules are connected through hydrogen bonds and weak π-πstacking interactions to generate a 2-D layered network. The thermogravimetric analysis of 1 has also been discussed.