(C6H10N3O2)Zn2(HPO4)(PO4)·H2O: An inorganic network with biofunctional amino acid dl-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 Ocarboxyl 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.