Porous metal-organic framework with coordinatively unsaturated Mn(II) sites:sorption properties for various gases.

A 3D porous metal-organic framework generating 1D channels, [Mn(NDC)(DEF)]n (1), has been prepared from the solvothermal reaction of Mn(II) and 2,6-naphthalenedicarboxylic acid (H2NDC) in diethylformamide (DEF). When DEF molecules coordinating Mn(II), which occupy the channels, are removed from 1 by heating the crystal of 1 at 250 degrees C under vacuum for 18 h, structural change occurs as evidenced by X-ray powder diffraction patterns. Desolvated solid [Mn(NDC)]n (2), which contains coordinatively unsaturated Mn(II) sites, reveals remarkable sorption capabilities for N2, H2, CO2, and CH4 gases and exhibits type I sorption behavior indicative of permanent microporosity.