A New Inorganic−Organic Hybrid Zinc Phosphate Prepared with l-Histidine with an Unusual Stability in Water

• Published in: Crystal growth & design 2011-02, Vol.11 (2), p.396-404
• Main Authors: Mekhatria, Djilali, Rigolet, Séverinne, Janiak, Christoph, Simon-Masseron, Angélique, Hasnaoui, Mohammed Abdelkrim, Bengueddach, Abdelkader
• Format: Article
• Language: English
• Subjects: Chemical Sciences; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Inorganic compounds; Material chemistry; Materials science; Materials synthesis; materials processing; Physics; Structure of solids and liquids; crystallography; Structure of specific crystalline solids
• ISSN: 1528-7483; 1528-7505
• DOI: 10.1021/cg100952q

A new layered zinc phosphate (Mu-39) has been synthesized by hydrothermal treatment with biomolecules as original templates. It was synthesized with the l-histidine amino acid (C6H9N3O2). The structure was determined by a single crystal X-ray diffraction study combined with exhaustive solid-state NMR experiments. These last ones [1H → 13C HETCOR, 1H single quantum/double quantum (DQ), 31P, 1H → 31P CPMAS, 1H → 31P HETCOR] ascertained the formulation of Mu-39 as {[C6H10N3O2 +][Zn2(HPO4)(PO4)−]·H2O} n with a hydrogen phosphate and phosphate ligands, and ruled out partial protonation such as (H1−x PO4)(H x PO4). A 31P magic angle spinning (MAS) NMR study supported the almost complete racemization of l-histidine during the hydrothermal synthesis with only a small enantiomeric excess of 25% remaining. The compound crystallizes in the triclinic symmetry (space group P1̅) with a = 8.6109(6) Å, b = 9.0319(6) Å, c = 9.9523(7) Å, and α = 84.481(2)°, β = 83.279(2)°, γ = 74.652(2)°, V = 739.56(9) Å3, Z = 2. The inorganic layer is built up from four-membered rings sharing T−O−T bonds (T = Zn and P) and connected to each other in order to form ladders which are joined together via a Zn−O−P bond for creating eight-membered rings. The interest and the originality of this new zinc phosphate come especially from its unusual stability in aqueous solution.