Structure of Zn(O3PC2H4CO2H)center dot 0.5C(6)H(5)NH(2) and XANES-EXAFS study of the intercalation of amines into Zn(O(3)PR)center dot H2O zinc alkylphosphonates

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). O.5C(6)H(5)NH(2) [orthorhombic, space group Pbcn, a=29.880(6) Angstrom, b=8.526(2) Angstrom, c=14.720(3) Angstrom, V=3750.3(8) Angstrom(3), Z=16, R=0.043 and R(w)=0.047; 2063 observed reflections, I>2 sigma(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.