A three-dimensional (3D) manganese (II) coordination polymer: Synthesis, structure and catalytic activities

A new Mn (II)-containing coordination polymer, [Mn-6(Ipa)(6)(ad)center dot 6H(2)O] (1; Ipa = isophthalate ligand; ad = adenine), was synthesized by reacting hydrated manganese nitrate with isophthalic acid and adenine under solvothermal reaction conditions. Polymer 1 was characterized using single-crystal X-ray diffraction analysis and other techniques such as Fourier transform infrared spectroscopy, elemental analyses and powder X-ray diffraction. The solid-state structure of 1 confirmed the formation of a three-dimensional framework structure based on Mn-6 secondary building units. Phase purity of bulk 1 and its thermal stability were investigated. Polymer 1 was evaluated for its performance as a heterogeneous catalyst for the Henry (nitroaldol) reaction of nitromethane with several aldehydes. The recyclability of 1 and heterogeneity of the reaction were also explored. A plausible mechanism for such reaction is proposed. To the best of our knowledge, polymer 1 represents the first example of a Mn (II)- and adenine-containing coordination polymer as well as the first example of a Mn (II)-containing coordination polymer that has been employed for the Henry reaction.