RETRACTED: Pyrazole-3-carboxylic Acid Manganese Complex: Syntheses and Its highly Efficient Heterogeneous Catalysis for the Epoxidation of Alkenes (Retracted Article)

One inorganic-organic hybrid manganese complex Mn(Hpca)(2)(phen)center dot 3H(2)O (1) based on pyrazole-3-carboxylic acid (H(2)pca) and phenanthroline (phen) has been synthesized and fully characterized by single-crystal X-ray diffraction (SXRD), powder X-ray diffraction (PXRD), infrared spectroscopy (IR), thermal gravity analysis (TGA) and elemental analyses. Complex 1 crystallizes in the monoclinic system, space group P2(1)/c with Z = 4, a = 10.3170(9), b = 13.1061(12), c = 17.6919(15) angstrom, V = 2272.1(3) angstrom(3), F(000) = 1052, D-c = 1.495 g/cm(3), mu = 0.635 mm(-1), the final R = 0.0428 and wR = 0.0853. In the crystal structure, the mononuclear Mn2+ center was coordinated by two Hpca(-) and one phen ligands, and shows a distorted {MnO2N4} octahedral coordination geometry. In the supermolecular structure, the independent units are entrained within several hexanuclear chair-like water clusters by the O-H center dot center dot center dot O and N-H center dot center dot center dot O hydrogen bonding interactions and finally form the three-dimensional framework. Notably, as a robust heterogeneous catalyst, complex 1 exhibits excellent catalytic performance in the epoxidation of alkenes with peroxyacetic acid as the oxidant (Conv. up to 97.7%, Sele. up to 98.9%). Additionally, the catalyst can be reused without losing its activity after three runs catalytic cycle.