Ionothermal synthesis, structures, properties of cobalt-1,4-benzenedicarboxylate metal–organic frameworks

Eight kinds of 1-methyl-3-alkylimidazolium halide [RMI]X (R=ethyl (E), propyl (P), butyl (B) and amyl (A); MI = imidazolium; X= Cl−, I−) ionic liquids (ILs) were used as reaction media and obtained a series of 2D [RMI]2[Co3(BDC)3X2] frameworks through the ionothermal reactions of 1,4-benzenedicarboxylic acid (H2BDC) with Co(NO3)2·6H2O. The 2D [RMI]2[Co3(BDC)3X2] frameworks exhibit a same (3,6) topology network with [RMI]+ cations locating in the interlayer space. [RMI]+ cations play a template role in the structure constructions, whose influence combining with the effect of X− anions pass to the TG behaviors. The decomposition temperatures of the [RMI]2[Co3(BDC)3X2] frameworks decrease with the alkyl chains in [RMI]+ cations, and the compounds containing Cl− show higher thermal stabilities than those with I−. However, compounds 1–8 exhibit two similar broad emissions at ca. 380 and 390 nm, assigned to ILCT. The RMI+ templates and the X− anions do not exert their influence on the fluorescence.

Eight 2D [RMI]2[Co3(BDC)3X2] compounds were synthesized through ionothermal reactions. [RMI]+ cations play a template role in the structure constructions, and tune the TG behaviors combining with the effect of X− anions.Figure optionsDownload as PowerPoint slide