Post-synthesis alkoxide formation within metal-organic framework materials: A strategy for incorporating highly coordinatively unsaturated metal ions

A new noncatenated metal-organic framework containing pendant alcohol functionalities was synthesized. The alcohols were then post-synthetically converted to either lithium or magnesium alkoxides, with the incorporated metals anchored far from nodes or carboxylate functionalities. The metal alkoxide sites can be obtained stoichiometrically while maintaining the permanent porosity and large surface area of the parent hydroxylated material. The incorporated metal ions are found to induce an unusual pattern of binding energetics for H ₂: isosteric heats of adsorption increase, rather than decrease, with increasing H ₂ loading. Additionally, at 1 atm and 77 K, uptake (at least with low Li ⁺ loading) is increased by two hydrogen molecules per Li ⁺.