Inorganic-organic hybrid materials of p,p '-diphenylmethylenediphosphinic acid (H2PCP) with magnesium and calcium ions: Synthesis and characterization of [Mg(Hpcp)(2)], [Mg(Hpcp)(2)(H2O)(4)], [Mg(pcp)(H2O)(3)](H2O), [Ca(Hpcp)(2)] and [Ca(pcp)(H2O)] c

摘要

The pp'-diphenylmethylenediphosphinic acid (H(2)pcp) reacts with MOW or CaCl2 center dot 6H(2)O to give the anhydrous hybrid material [Mg(Hpcp)(2)] or [Ca(Hpcp)(2)]. Both the Mg and Ca derivatives, which are isomorphous, present polymeric 1D structural arrays, where the metal ions are doubly bridged by two Hpcp(-) ligands. When the reaction is carried out with Mg(OH)(2) (or Ca(OH)(2)), hydrate metal complexes of the aprotic form pcp(2-) are obtained, namely the hybrids [Mg(pcp)(H2O)(3)] center dot (H2O) and [Ca(pcp)(H2O)]. The magnesium compound presents a hydrogen bonding 2D layered structure, where the water molecules play the important role of cementing together the ID chains of metal ions bridged by phosphinate ligands. Differently a 2D layered architecture of the calcium derivative is built up by dimeric units of calcium metals bridged by pcp(2-) ligands, without the action of the water molecule, whose role is limited to stabilize the layer itself. From the mother solution affording the anhydrous [Mg(Hpcp)(2)] complex, the hydrate [Mg(Hpcp)(2)(H2O)(4)] can be isolated, which is a monomeric complex trapped in a closed 2D net of hydrogen bondings. The solid compounds were characterized by X-ray studies and thermogravimetric analysis. (c) 2006 Elsevier B.V. All rights reserved.