Solvent- and Temperature-Induced Multiple Crystal Phases: Crystal Structure, Selective Adsorption, and Separation of Organic Dye in Three S-Containing {[Cd(MIPA)]n}n− Homologues

Three S-containing highly porous metal–organic frameworks, namely, [((CH3)2NH2)Cd(MIPA)]n·xG (n = 4 (1), 2 (2), 1 (3) G = guest of DMF/DMA and H2O), featuring with high adsorption capacities and high selectivity for methylene blue (MB), were successfully assembled by subtly varying the synthesis conditions including solvents and temperatures. Compounds 1–3 crystallize in P21/c, I2/a, and R3m, respectively. The anionic frameworks of them are homologues and multiple crystal phases of the {[Cd(MIPA)]n}n−. Compounds 1 and 2 demonstrate the same 3,6-connected binodal net (42·6)(48·64·83), encapulating ca. 18 A × 18 A hexagonal channels and three other types of micropous channels. Compound 3 shows a different topology of a 4,4-connected binodal net (43·62·8), which has the highest crystalline density, highest solvent-accessible void, and accessible special surface area, as well as the highest symmetry among them. Circular channel, ca. 13 A × 13 A, and two other types of micropore channels are found in six dire...