Structures of dicobalt and dinickel 4,4′-biphenyldicarboxylate dihydroxide, M ₂(O₂CC₆H₄C₆H₄CO₂)(OH)₂, M = Co and Ni, and diammonium 4,4′-biphenyldicarboxylate from powder diffraction data

Abstract

The triclinic structures of poly[(μ4-4,4′-biphenyldicarboxylato)di-μ-hydroxido-dicobalt], [Co2(C14H8O4)(OH)2] n , and poly[(μ4-4,4′-biphenyldicarboxylato)di-μ-hydroxido-dinickel], [Ni2(C14H8O4)(OH)2] n , were established using laboratory X-ray powder diffraction data. These structures, as well as that of poly[(μ4-4,4′-biphenyldicarboxylato)di-μ-hydroxido-dimanganese], [Mn2(C14H8O4)(OH)2] n , were optimized using density functional techniques. The structure of diammonium 4,4′-biphenyldicarboxylate, 2NH4 +·C14H8O4 2−, was also solved using laboratory powder data. The Mn and Co compounds are isostructural: the octahedral MO6 groups share edges to form chains running parallel to the c-axis. These chains share corners (OH groups) to link into layers lying parallel to the bc plane. The hydroxyl groups do not participate in hydrogen bonds. The structure of (NH4)2BPDC consists of alternating layers of BPDC and ammonium ions lying parallel to the ab plane. Each hydrogen atom of the ammonium ions in (NH4)2BPDC participates in a strong N—H...O hydrogen bond.