Hybrid inorganic-organic frameworks containing magnesium: Synthesis and structures of magnesium squarate, diglycolate, and glutarate, and potassium magnesium cyclobutanetetracarboxylate

摘要

Four new magnesium containing metal-organic hybrid compounds have been synthesized in an effort to prepare low-density materials for hydrogen storage. The compounds were prepared hydrothermally and characterized using single crystal X-ray diffraction. Three of these compounds are analogs of known transition metal structures with squarate (I, Pn-3n, a = 16.276(5) A), diglycolate (II, P2_12_12_1, a = 6.860(1) A, b = 9.993(1) A, c = 10.884(1) A, R_1 = 0.0341), and glutarate (III, R-3, a = 10.744(2) A, c = 28.677(5) A, Rx = 0.0554) ligands; the fourth is a novel structure using cyclobutanetetracarboxylate (IV, Pccn, a = 9.382(1) A, b = 14.410(2) A, c = 8.725(1) A, R_1 = 0.0465) which contains potassium as well as magnesium cations.