Construction of Two Microporous Metal–Organic Frameworks with flu and pyr Topologies Based on Zn4(μ3‑OH)2(CO2)6 and Zn6(μ6‑O)(CO2)6 Secondary Building Units

By employment of a tripodal phosphoric carboxylate ligand, tris­(4-carboxylphenyl)­phosphine oxide (H3TPO), two novel porous metal–organic frameworks, namely, [Zn4(μ3-OH)2(TPO)2(H2O)2] (1) and [Zn6(μ6-O)­(TPO)2]­(NO3)4·3H2O (2), have been synthesized by solvothermal methods. Complexes 1 and 2 exhibit three-dimensional microporous frameworks with flu and pyr topologies and possess rare butterfly-shaped Zn4(μ3-OH)2(CO2)6 and octahedral Zn6(μ6-O)­(CO2)6 secondary building units, respectively. Large cavities and one-dimensional channels are observed in these two frameworks. Gas-sorption measurements indicate that complex 2 has a good H2 uptake capacity of 171.9 cm3 g–1 (1.53 wt %) at 77 K and 1.08 bar, and its ideal adsorbed solution theory calculation predicts highly selective adsorption of CO2 over N2 and CH4. Furthermore, complexes 1 and 2 exhibit excellent blue emission at room temperature.