Synthesis of isostructural metal-organic frameworks, CPO-27s, with ultrasound, microwave, and conventional heating: Effect of synthesis methods and metal ions

Isostructural MOFs such as CPO-27-Zn, CPO-27-Co and CPO-27-Ni were synthesized with US (ultrasound), MW (microwave) and CE (conventional electric) heating from the very similar reactant mixtures to understand the effect of the synthesis methods and metal ions on the synthesis rates and on the physicochemical properties of the obtained MOFs. The porosities (surface area and micropore volume) and synthesis rates both for nucleation and crystal growth are on the order of US > MW > CE synthesis. The crystal sizes are on the order of US < MW <CE and this may be the reason of the low porosity of the CPO-27-Co obtained by conventional electric heating. The synthesis kinetics of the three CPO-27s shows the importance of the lability of the metal ions in the synthesis rates (both in nucleation and crystal growth) of the MOFs. Therefore, it can be suggested that labile metal ions, compared with inert ions, may be treated mildly (a low temperature or a short reaction time) for the synthesis of isostructural MOFs with the same ligand material.