A simple strategy for pyridine visual sensing by the in-situ formation of tetranuclear copper iodine pyridine microcrystalline film on copper foil

A visual pyridine sensing method has been developed based on the in-situ formation of a [CuIL]4 (L = pyridine) microcrystal film on a copper foil upon exposure to pyridine solution. The film displays strong yellow color which can be observed by the naked eye under UV light. The formation of microcrystal film was characterized by scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, fluorescence spectroscopy, and Raman spectroscopy.