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.