HIGH-RESOLUTION SOLID-STATE MAGIC-ANGLE-SPINNING NUCLEAR-MAGNETIC-RESONANCE STUDIES ON THE LAYERED ANTIMONY HYDROGEN PHOSPHATE, HSB(PO4)(2)CENTER-DOT-2H(2)O, AND ITS REACTION-PRODUCTS WITH TETRAKIS(PYRIDYL)IRON(II) CHLORIDE

The antimony hydrogen phosphate, HSb(PO4)(2) . 2H(2)O (denoted H1SbP2 . 2H(2)O), has been synthesised via the ion exchange of crystalline KS b(PO4)(2), (K1SbP2), with 9 M HNO3. Scanning electron microscopy (SEM) confirmed that the crystalline K1SbP2 as formed by the so-called 'dec k of cards' mechanism to give randomly orientated lamellae. The synthe sised H1SbP2 . 2H(2)O host material was studied using H-1 and P-31 mag ic angle spinning nuclear magnetic resonance (MAS NMR) techniques. Int ercalation studies were carried out using tetrakis(pyridyl)iron(II) ch loride, [Fe(py)(4)Cl-2]. H2O. The resulting products were analysed usi ng powder X-ray diffraction (PXRD) and P-31 MAS NMR techniques. The fo rmer suggested that the [Fe(py)(4)Cl-2]. H2O complex lost its water of crystallisation during the reaction and did not intercalate in its in tact state between adjacent layers of the H1SbP2 . 2H(2)O crystallites . P-31 MAS NMR data suggested that the H1SbP2 . 2H(2)O-[Fe(py)(4)Cl-2] reaction products contained phosphorus resonances which could be assi gned as belonging to (i) unaltered host H1SbP2 . 2H(2)O (protonated) p hosphate groups, (ii) phosphate groups bonded to the intercalating spe cies. In addition, a separate, Q(P)(3), resonance was also noted which was thought to arise from a chemically unaltered phosphate group of t he host H1SbP2 . 2H(2)O perturbed by the close proximity of the sorbed [Fe(py)(4)](2+) cationic species.