Ionothermal synthesis and proton conductive behaviors of an organic-inorganic hybrid nickel dihydrogen phosphate

A new organic-inorganic hybrid solid, namely, (2-Hmim)2 center dot Ni(H2PO4)4(4,4 '-bpy), were prepared under ionothermal conidtions, where 2-Hmim = 2-methylimidazolium and 4,4 '-bpy = 4,4 '-bipyridine. This compound has a chain-like structure with nickel dihydrogen phosphate clusters bridged by 4,4 '-bpy ligands. It features an unprecedented hydrogen-bonded zeolitic GIS framework constructed from H2PO4 units. The temperature- and humidity-dependent proton conductive behaviors of this compound were also investigated.