(C6H10N3O2)Zn2(HPO4)(PO4)·H2O: An inorganic network with biofunctional amino aciddl-histidine molecules

Abstract

A new layered zinc phosphate, (C₆H₁₀N₃O₂)Zn₂(HPO₄)(PO₄)·H₂O (denoted ZnPO-CJ36), has been synthesized solvothermally with biological molecule amino acidDL-histidine as both a template and a ligand. It is characterized by a combination of techniques such as FTIR, inductively coupled plasma (ICP), powder X-ray diffraction, thermogravimetric analysis and fluorescence spectroscopy, as well as single-crystal X-ray diffraction analysis. Its structure consists of double crankshaft chains linked by bridging oxygen atoms to form an infinite layer with 4- and 8-rings (denoted 4 × 8 net) parallel to the ab plane. The histidine molecules reside in the interlayer regions and coordinate to Zn atoms through bridging O_carboxyl atoms. It is noteworthy that the histidine molecules on one side of the sheet have the R absolute configuration while those on the other side of the sheet have the S absolute configuration. Extensive multipoint hydrogen bonds are formed involving histidine molecules, water molecules and inorganic sheets, and construct a pseudo-three-dimensional supermolecular structure. The compound exhibits photoluminescence upon photo-excitation at 220 nm.