The use of ionic liquids in the synthesis of zinc imidazolate frameworks

Abstract

Four zinc imidazolate materials has been synthesized under ionothermal conditions using ionic liquids; [Zn(C₂O₄)(C₃N₂H₄)], P2₁/a (1); [Zn(CH₃COO)(C₃N₂H₃)], Ima2 (2); [Zn₄(C₃N₂H₄)(C₃N₂H₃)₈], P (3) and [Zn(C₃N₂H₃)₂], I4₁ (4). Compounds 1 and 4 have already known structures, but have been synthesised for the first time using ionothermal methods. Compounds 2 and 3 are novel and have been synthesized for the first time in this work. The syntheses of 3 and 4 take place under almost exactly the same conditions, except that a lower synthesis temperature leads to a proportion of terminal imidazolate units in the structure of 3 while a slightly higher temperature leads to all bridging imidazolate units in 4.