Structure of Zn(O3PC2H4CO2H)·0.5C6H5NH2 and 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)ų, Z= 16, R= 0.043 and R_w= 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.