A new class of layered zirconium mixed phosphonates, zirconium (p-aminobenzy])phosphonate methylphosphonate, Zr(O3PCH2C6H4NH2) x(O3PCH3)2-x [abbreviated as Zr(pab)x(me)2-x], and its intercalated hydrochloride form, Zr(O3PCH2C6H4NH3Cl) x(O3PCH3)2-x [Zr(pabHCl)x(me)2-x], in a number of stoichiometric pendant group ratios, have been synthesized and characterized. For these materials, thermogravimetric analysis was able to identify and quantify, when present, loss of surface-adsorbed water, HCl units, methyl and p-aminobenzyl groups. 31P NMR indicated evidence of two types of phosphorus environments that tracked the stoichiometry but behaved differently in chemical shift variation (6.7-8.5 and 2.2-8.0 ppm). FT-IR measurements quantitatively accounted for relative mole fraction as the pendant group ratio was varied. Interlayer spacing measurements as a function of the stoichiometric ratio were carried out by XRD and corroborated by molecular mechanics calculations. The calculations show that interlayer pendant group conformations (rotations about the anchoring P-C bond and of the benzenoid ring) are responsible ford-space variational behavior. It is observed that while Vegard's law is obeyed to some extent, deviation from linearity can be understood in terms of packing forces.
All Science Journal Classification (ASJC) codes
- Physical and Theoretical Chemistry
- Inorganic Chemistry