Naraso Borjigin - Inorganic Chemistry

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      Publication Details (including relevant citation   information):

      Hybrid Organic−Inorganic Framework Structures: Influence of   Cation Size on Metal−Oxygen−Metal Connectivity in the Alkaline   Earth Thiazolothiazoledicarboxylates

      Authors: Eduardo H. L. Falco, Naraso, Russell K. Feller, Guang Wu, Fred   Wudl and Anthony K. Cheetham

      Inorg. Chem., 2008, 47 (18), pp 8336–8342




      Figure 1. Thermal ellipsoid plot (50% probability) of   I, with the atoms of one asymmetric unit (plus   an extra O1 and C1) labeled. Both Mg1 and the Thz center sit on   inversion centers. Hydrogen atoms are shown as white spheres.


      Figure 2. Chains of I viewed along the   propagation direction [1 −1 −1]. Element colors are the same as   in Figure   1.

      We report the synthesis of four organic−inorganic frameworks of   alkaline earth cations with the organic ligand   2,5-thiazolo[5,4-d]thiazoledicarboxylate   (C6N2S2O42−,   Thz2−). Structures with remarkably different   connectivities result when Mg2+, Ca2+,   Sr2+, and Ba2+ react with Thz2−.   Mg(Thz)(H2O)4 (I) forms a   1-D coordination polymer in which one carboxylate oxygen on each   terminus of the ligand connects individual MgO6  octahedra from their axial positions, while the remaining   equatorial sites are coordinated by water molecules.   Ca2(Thz)2(H2O)8  (II) forms a 1-D coordination polymer in which   dimeric clusters with 7-fold Ca coordination are connected via   the ligand in a linear fashion, with a second, uncoordinated   Thz2− providing charge balance.   Sr(Thz)(H2O)3 (III) has   1-D infinite inorganic connectivity built from edge-sharing   SrO7N polyhedra having one carboxylate oxygen and one   water molecule acting as M−O−M bridges.   Ba2(Thz)2(H2O)7  (IV) has 2-D inorganic connectivity based upon   face- and edge-sharing BaO9N polyhedra. One   carboxylate oxygen and all water molecules act as bridges between   each Ba2+ and its three neighbors. We shall discuss   the manner in which the increasing coordination requirements of   the cations (MgO6 < CaO7 <   SrO7N < BaO9N) lead to an increase in   inorganic connectivity through the series.

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