Figure 1.
a) The coordination environment of gallate ligand and MO6. M purple, C black, O red, H white. b) Perspective view of the structure along the c axis showing the triangular main channels and the regular branched channels leaning against the main ones. The H atoms are omitted for clarity. c) Diagram of the fusiform branched channels. Only ethylene can favorably enter the cavity because the limiting aperture size of M-gallate (3.47 × 4.85 Å2 for Ni-gallate, 3.56 × 4.84 Å2 for Mg-gallate, and 3.69 × 4.95 Å2 for Co-gallate) matches well with the smallest cross-section size of C2H4 (3.28 × 4.18 Å2), but is smaller than that of C2H6 (3.81 × 4.08 Å2). The C atoms in C2H4 and C2H6 are particularly presented in orange. d),e) Accessible Connolly surface calculated with a Connolly radius of 1.0 Å. The quasi-discrete cavities of the fusiform branched channels are restrained by the narrow pore windows. f) Diagram of the zigzag channels. The zigzag channels in different layers are colored by purple and orange, respectively.