Abstract
Thirteen organic-inorganic hybrid compounds based on short-chain diammonium [NH3—
(CH2) n—NH3] metal chlorides MCl4 (M: Co, Mn, Fe) were successfully synthesized and
characterized. Eleven of these structures were previously determined and two were novel;
therefore, it was meaningful for this work to redetermine the structures with high precision.
The redetermined structures that have been published in the CSD have not been
determined at low temperature previously.
The single crystal X-ray diffraction analysis confirmed, as previously reported, that Co
perovskites with chain length n = 3 and 5 crystallize in monoclinic crystal systems P21/n
and P 21/c, respectively. For n>5, Co complexes crystallize in triclinic 𝑃1̅
. In the Co
complexes the inorganic anion is present as [CoCl4]2-, where the Co (II) is coordinated by
four Cl‒ ions in an isolated tetrahedral geometry. The organic and inorganic layers are
linked via N—H···Cl hydrogen bonds to form an infinite 2D network. The Mn perovskites
crystallize in monoclinic crystal systems P21/n or P21/c for the even numbered
diammonium cation chains and in orthorhombic crystal systems for the odd numbered
diammonium cation chains (n = 2‒5). In Mn complexes, the Mn is coordinated by six Cl‒
anions in an octahedral geometry and the inorganic layer of anions comprised of [MnCl4]−2
extends through corner-shared octahedra to form a 2D polymeric structure. The Fe
organic-inorganic hybrids form species with unusual and varied inorganic anion
composition. Mogul geometrical analysis flagged unusual bond lengths of Fe1—O1 (2.190
Å) on C2Fe and C5—C6 (1.584 Å) on C6Fe, and in the Mn perovskites, however, they
were no relatable Mn species in the CSD to compare the Mn species to. The crystal
structures have been confirmed further using FTIR, NMR, TGA/DSC and PXRD.