SYNTHESIS AND CHARACTERIZATION OF LAYERED ZINC BIPHENYLYLENEBIS(PHOSPHONATE) AND 3 MIXED-COMPONENT ARYLENEBIS(PHOSPHONATE) PHOSPHATES/

Layered zinc 4,4'-biphenylylenebis(phosphonate), Zn-2(O3PC12H8PO3). 2H (2)O (I), has been synthesized and its structure solved and refined by using X-ray powder diffraction data. The compound crystallizes in the space group Pnn2 with a = 27.904(1) Angstrom, b = 4.8273(3) Angstrom, c = 5.6450(2) Angstrom, and Z = 2. The zinc atoms in this compound ha ve distorted octahedral geometry. The phosphonate oxygens bind to zinc through chelation and bridging similar to those found in zinc phenylp hosphonate and zinc phenylenebis(phosphonate) reported earlier. The wa ter oxygen atom occupies the sixth coordination site. This paper also reports three mixed zinc arylenebis(phosphonate)/phosphate compounds. Zn-2(O3PC6H4PO3)(0.75)(HPO4)(0.5). 2.5H(2)O (II), Zn-2(O3PC12H8PO3)(0. 75) (HPO4)(0.5). 2.5H(2)O (III), and Zn(HO(3)PC(12)HsPO(3)H)(0.82)(HPO 4)(0.18) (IV). Their structures were characterized by X-ray diffractio n, IR spectroscopy, solid state P-31 NMR spectroscopy, and TGA. It was found that the structures of compounds II and III are similar to thos e of their corresponding parent phosphonates but compound IV contains a different type of metal-phosphonate framework. BET measurements show that the surface areas of these phosphonates have been largely increa sed after introducing phosphate groups, mainly however due to mesoporo sity.