Synthesis, Thermal Stability, and Magnetic Properties of a Manganese(II) Coordination Framework Containing Bistriazolate Ligands

Comparative study of metal-organic frameworks synthesized via imide condensation and coordination assembly

A series of metal-organic frameworks (1-XDI) have been synthesized by imide condensation reactions between an amine-functionalized pentanuclear zinc cluster, Zn4Cl5(bt-NH2)6, (bt-NH2 = 5-aminobenzotriazolate), and organic dianhydrides (pyromellitic dianhydride (PMDA), naphthalenetetracarboxylic dianhydride (NDA), 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA) and 4,4'-(hexafluoroisopropylidene)diphthalic anhydride (HFIPA)). The properties of the 1-XDI MOFs have been compared with analogues (2-XDI) prepared using traditional coordination assembly. The resulting materials have been characterized by ATR-IR spectroscopy, acid-digested 1H NMR spectroscopy, elemental analysis, and gas adsorption measurements. N2 adsorption isotherm data reveal modest porosities and BET surface areas (30-552 m2 g-1). All of the new 1-XDI and 2-XDI MOFs show selective adsorption of C2H2 over CO2 while 2-PMDI and 2-BPDI exhibit high selectivity toward C3H6/C3H8 separation. This study establishes imide condensation of preformed metal-organic clusters with organic linkers as a viable route for MOF design.