Two histidine-templated metal phosphate-oxalates: solvent-free synthesis, luminescence, and proton-conducting properties.

Two new histidine-templated metal phosphate-oxalates (MPOs) were prepared under solvent-free conditions. Single-crystal X-ray diffraction analysis reveals that they have layered and chainlike structures, respectively. Under ultraviolet light irradiation, the two MPOs exhibit blue luminescence originating from histidine templates. Their proton-conducting properties were also investigated under different conditions.