Investigating the crystal engineering of the pillared paddlewheel metal–organic framework Zn2(NH2BDC)2DABCO

Abstract

The synthesis of Zn₂(NH₂BDC)₂DABCO was investigated with the hopes of producing a material with a high surface area. Despite considerable efforts to get reproducible results, replacing BDC with NH₂BDC was not trivial; the gas adsorption isotherms were inconsistent, resulting in different gas uptakes and large variation in hysteresis loops. Given this, we examined the gas adsorption isotherms (BET surface area and pore size distributions), the solution-phase NMR, and the powder X-ray diffractograms of our materials in order to puzzle out the underlying chemistry. From this data, we illustrate how 1D chains of Zn(H₂O)₂(NH₂BDC) are converted to partially pillared Zn₂(NH₂BDC)₂DABCO which is either amorphous or crystalline based on the NH₂BDC : DABCO ratio.