Structure of Zn(O₃PC₂H₄CO₂H)·0.5C₆H₅NH₂and XANES–EXAFS study of the intercalation of amines into Zn(O₃PR)·H₂O zinc alkylphosphonates

Abstract

On the basis of XANES–EXAFS experiments, neither the dehydration nor the subsequent n-alkylamine intercalation in Zn(O3PCH3)·H2O appears to be topotactic. On the contrary, the whole process consists of breaking Zn—O bonds present in the hydrated material, so that no bridging oxygen remains in the inorganic sheet. This hypothesis is supported by the structural determination of an aniline intercalate: Zn(O3PC2H4CO2H)·0.5C6H5NH2[orthorhombic, space group Pbcn, a= 29.880(6)Å, b= 8.526 (2)Å, c= 14.720 (3)Å, V= 3750.3(8)Å3, Z= 16, R= 0.043 and Rw= 0.047; 2063 observed reflections, I > 2σ(I)]. For steric reasons, only half of the zinc atoms are coordinated to aniline; the second half of the metal atoms that are not bound to the amine retain the environment present in the initial anhydrous phase.