Preparation and proton transport property of N,N′- diethyldithiooxamidatocopper coordination polymer

A novel proton-conductive copper coordination polymer, (H5C2)2dtoaCu (R2dtoaH2 = dithiooxamide derivatives), was synthesized. From X-ray powder diffraction measurements, the crystal structure of (H5C2)2dtoaCu was found to be similar to that of a two-dimensional (2-D) coordination polymer (HOH4C2)2dtoaCu. This title coordination polymer was revealed to be a proton conductor by the relative humidity (RH) dependence of AC conductivity measurements. The proton conductivity (σp) was 4.2 × 10−6 S cm−1 under the RH of 100% and the ionic transport number was more than 0.99. The σp of (HOH4dtoaCu was two orders of magnitude higher than that of (H5C2)2dtoaCu, which would be derived from the existence of-OH groups in the alkyl substituent R.