Hydro/Solvothermal Synthesis and Structures of New Zinc Phosphates of Varying Dimensionality

2002-09-21T00:00:00Z (GMT) by Srinivasan Natarajan
Hydro/solvothermal reactions of ZnO, HCl, H<sub>3</sub>PO<sub>4</sub>, 1,4-diazacycleheptane (homopiperazine), and H<sub>2</sub>O under a variety of conditions yielded three new organic−inorganic hybrid materials, [C<sub>5</sub>N<sub>2</sub>H<sub>14</sub>][Zn(HPO<sub>4</sub>)<sub>2</sub>]·<i>x</i>H<sub>2</sub>O (<i>x</i> = ∼0.46), <b>I</b>, [C<sub>5</sub>N<sub>2</sub>H<sub>14</sub>][Zn<sub>3</sub>(H<sub>2</sub>O)(PO<sub>4</sub>)<sub>2</sub>(HPO<sub>4</sub>)], <b>II</b>, and [C<sub>5</sub>N<sub>2</sub>H<sub>14</sub>][Zn<sub>2</sub>(HPO<sub>4</sub>)<sub>3</sub>]·H<sub>2</sub>O, <b>III</b>. While <b>I</b> has a one-dimensional structure, <b>II</b> possesses a two-dimensional layered structure, and <b>III</b> has a three-dimensional structure closely related to the ABW zeolitic architecture. All the compounds consist of vertex linking of ZnO<sub>4</sub>, PO<sub>4</sub>, and HPO<sub>4</sub> tetrahedral units. The fundamental building unit, single four-membered ring (S4R), is present in all the cases, and the observed differences in their structures result from variations in the connectivity between the S4R units. Thus <b>I</b> has a corner-shared S4R forming an infinite one-dimensional chain, <b>II</b> has two corner-shared chains fused through a 3-coordinated oxygen atom forming a strip and a layer with eight-membered apertures, and <b>III</b> has S4R units connected via oxygen atoms to give rise to channels bound by eight T atoms (T = Zn, P) in all crystallographic directions. Crystal data:  <b>I</b>, monoclinic, space group = <i>P</i>2<sub>1</sub>/<i>n</i> (No. 14), <i>a</i> = 8.6053(3) Å, <i>b</i> = 13.7129(5) Å, <i>c</i> = 10.8184(4) Å, β = 97.946(1)°, <i>V</i> = 1264.35(8) Å<sup>3</sup>, <i>Z</i> = 4; <b>II</b>, monoclinic, space group = <i>P</i>2<sub>1</sub>/<i>c</i> (No. 14), <i>a</i> = 11.1029(1) Å, <i>b</i> = 17.5531(4) Å, <i>c</i> = 8.2651(2) Å, β = 97.922(2)°, <i>V</i> = 1595.42(5) Å<sup>3</sup>, <i>Z</i> = 4; <b>III</b>, monoclinic, space group = <i>P</i>2<sub>1</sub> (No. 4), <i>a</i> = 8.0310(2) Å, <i>b</i> = 10.2475(3) Å, <i>c</i> = 10.570(3) Å, β = 109.651(1)°, <i>V</i> = 819.24(3) Å<sup>3</sup>, <i>Z</i> = 2.