Solvent-directed Structure Variation from Mononuclear to Bis-methoxo-bridged Binuclear Copper (II) Compound: Crystal Structures and Proton-conduction

Abstract

In ethanol, the reaction of 2-(methylthio)-4-(pyridin-2-yl)pyrimidine) with Cu(NO3)2 (2-MTPP) yielded a mononuclear Cu(II) coordination compound [(C10H9N3S)2CuNO3]NO3.H2O. In contrast, a discrete bis-methoxo-bridged binuclear Cu(II) coordination compound resulted when ethanol was substituted by methanol. [(C10 H9 N3S)2CuNO3]NO3.H2O and [(C10 H9 N3S)(CH3O) CuNO3]2 have been structurally investigated by single crystal X-ray diffraction. In [(C10H9N3S)2CuNO3]NO3.H2O, uncoordinated nitrate anions and water guest molecules form an interesting one-dimensional hydrogen-bonded chain that is accommodated into an open rhomboidal channel constructed by [Cu(NO3)(2-MTPP)2]+ cations. In [(C10H9N3S)(CH3O)CuNO3]2, binuclear molecules are arrayed in a linear fashion via C–H…O hydrogen bonding interactions. Moreover, [(C10H9N3S)2CuNO3]NO3.H2O has a proton-conductive property with a room-temperature conductivity of 4.96×10−8 S cm−1.