Di-tert-butyl phosphate as synthon for metal phosphate materials via single-source coordination polymers [M(dtbP)2]n (M = Mn, Cu) and [Cd(dtbP)2(H2O)]n (dtbp-H = (tBuO)2P(O)OH)

Reaction of M(OAc)(2).xH(2)O (M = Mn, Cu, or Cd) with di-tert-butyl phosphate (dtbp-H) in a 1:2 molar ratio in methanol followed by slow crystallization of the resultant solid in MeOH/THF medium results in the formation of three new polymeric metal phosphates [M(dtbP)(2)](n) [M = Mn, 1 (beige); M = Cu, 2 (blue)] and [Cd(dtbP)(2)(H2O)](n), 3 (colorless)] in good yields. The formation of [Mn(dtbP)21, (1) proceeds via tetrameric manganese phosphate [Mn-4(O)(dtbP)(6)] (4), which has been isolated in an analytically pure form. Perfectly air- and moisture-stable compounds 1-4 were characterized with the aid of analytical, thermoanalytical, and spectroscopic techniques. The molecular structures of 1-3 were further established by single-crystal X-ray diffraction studies. Crystal data for 1: C32H72-Mn2O16P4, monoclinic, P2(1)/c, a = 19.957(4) Angstrom, b = 13.419(1) Angstrom, c = 18.083(2) Angstrom, beta = 91.25(2)degrees, Z = 4. Crystal data for 2: C16H36CUO8P2, orthorhombic, Pccn, a = 23.777(2) Angstrom, b = 10.074(1) Angstrom, c = 10.090(1) Angstrom, Z = 4. Crystal data for 3: C48H114Cd3O27P6, triclinic, P (1) over bar, a = 12.689(3) Angstrom, b = 14.364(3) Angstrom, c = 22,491(5) Angstrom, alpha = 84.54(3)degrees, beta = 79.43(3)degrees, gamma = 70.03(3)degrees, Z = 2. The diffraction studies reveal three different structural forms for the three compounds investigated, each possessing a one-dimensional coordination polymeric structure. While alternating triple and single dtbp bridges are found between the adjacent Mn2+ ions in 1, uniform double dtbp bridges across the adjacent Cu2+ ions are present in 2. The cadmium ions in the structure of 3 are pentacoordinated. Thermal analysis (TGA and DSC) indicates that compounds 1-3 convert to the corresponding crystalline metaphosphate materials M(PO3)(2), in each case at temperatures below 500 degreesC. Similarly, the thermal decomposition of 4 results in the formation of Mn(PO3)(3) and Mn2P2O7. The final materials obtained by independent thermal decomposition of bulk samples have been characterized using I R spectroscopic, powder diffraction, and N-2 adsorption studies.