Organically pillared layered zinc hydroxides

The two organically pillared layered zinc hydroxides Zn₂(OH)₂(ndc)], CPO-6, and Zn₃(OH)₄(bpdc)], CPO-7, were obtained in hydrothermal reactions between 2,6-naphthalenedicarboxylic acid (ndc) and zinc nitrate (CPO-6) and 4,4′biphenyldicarboxylate (bpdc) and zinc nitrate (CPO-7), respectively. In CPO-6, the tetrahedral zinc atoms are connected by two μ₂-OH groups and two carboxylate oxygen atoms, forming infinite layers extending parallel to the bc-plane. These layers are pillared by ndc to form a three-dimensional structure. In CPO-7, the zinc hydroxide layers are containing four-, five- and six coordinated zinc atoms, and the layers are built like stairways running along the 001] direction. Each step is composed of three infinite chains running in the 010] direction. Both crystal structures were solved from conventional single crystal data. Crystal data for CPO-6: Monoclinic space group P2₁/c (No. 14), a=11.9703(7), b=7.8154(5), c=6.2428(4) Å, β=90.816(2)°, V=583.97(6) Å³ and Z=4. Crystal data for CPO-7: Monoclinic space group C2/c (No. 15), a=35.220(4), b=6.2658(8), c=14.8888(17) Å, β=112.580(4)°, V=3033.8(6) Å³ and Z=8. The compounds were further characterized by thermogravimetric- and chemical analysis.