ic070132u_si_014.cif (9.87 kB)

Synthesis and Characterization of Four Metal−Organophosphonates with One-, Two-, and Three-Dimensional Structures

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posted on 25.06.2007, 00:00 by Sanjit Konar, Jerzy Zoń, Andrey V. Prosvirin, Kim R. Dunbar, Abraham Clearfield
A series of metal-organic hybrid compounds were synthesized using two new phosphonic acids, pyridyl-4-phosphonic acid and p-xylylenediphosphonic acid (H2O3PCH2C6H4CH2PO3H2). The phosphonic acid ligands have been synthesized from their corresponding bromides following two different types of reactions. The reaction of pyridyl-4-phosphonic acid with three different divalent metal salts results in the formation of molecular structures of different dimensionality. The reaction of Cu(II) with the phosphonic acid under hydrothermal conditions yields a three-dimensional (3D) open framework structure having the molecular formula [Cu4(NC5H4−PO3)4(H2O)10] (1). The reactions with Mn(II) and Zn(II) salts with the same phosphonic acid resulted in a two-dimensional layered and a dinuclear compound with molecular formulas [Mn3(NC5H4−PO3)4(H2O)6(ClO4)2] (2) and [Zn2(NHC5H4−PO3H)2Cl4] (3), respectively. Compound 1 crystallizes in the triclinic crystal system having space group P1̄ with structural parameters a = 7.4564(15) Å, b = 9.1845(19) Å, c = 11.582(2) Å, α = 100.842(3)°, β = 104.303(3)°, γ = 94.774(3)°, and Z = 1. Compound 2 crystallizes in the triclinic crystal system, space group P1̄, with structural parameters a = 7.6871(14) Å, b = 10.576(2) Å, c = 14.470(3) Å, α = 81.340(3)°, β = 81.561(3)°, γ = 68.757(3)°, and Z = 2, whereas compound 3 crystallizes in a monoclinic crystal system with space group P2(1)/n. The structural parameters are as follows:  a = 8.4969 (5) Å, b = 9.3911 (5) Å, c = 12.3779 (6) Å, β = 90.860(17)°, and Z = 4. The pyridylphosphonate ligand shows different ligation behavior toward the three divalent metal ions. On the other hand, p-xylylenediphosphonic acid on reaction with Co(II) formed a 3D compound [Co2(O3PCH2C6H4CH2PO3)2(H2O)2] (4) with a layered and pillared structure. Compound 4 crystallizes in an orthorhombic crystal system with space group Pnma. The structural parameters are a = 21.744(4) Å, b = 5.6744(10) Å, c = 4.7927(9) Å, and Z = 4.