Tripodal carboxylate MOFs with Co(II): Transmetallation and gas sorption studies

A homochiral coordination polymer of cobalt(II) and L-serine

A one-dimensional chiral cobalt(II) coordination polymer, namely, catena-poly[[[(S)-2-amino-3-hydroxypropanoato-κ²N,O¹]cobalt(II)]-μ-(S)-2-amino-3-hydroxypropanoato-κ⁴O¹,O³:N,O^1'], [Co(C₃H₆NO₃)₂]_n or Δ-[Co(L-Ser-κ²N,O)₂]_n (L-Ser = L-serine) (1), has been synthesized and characterized using elemental and thermal analyses, IR spectroscopy and single-crystal and powder X-ray diffraction techniques. The asymmetric unit of 1 consists of two serine anions which are coordinated to a Co²⁺ ion to give three chelate rings. These extend the structure into a helical chain with pendant chelate rings which participate in interchain hydrogen bonding. The ability of 1 to undergo transmetallation was evaluated. Among a range of divalent metal ions, only copper(II) partially replaced cobalt(II).

A window-space-directed assembly strategy for the construction of supertetrahedron-based zeolitic mesoporous metal-organic frameworks with ultramicroporous apertures for selective gas adsorption

Despite their scarcity due to synthetic challenges, supertetrahedron-based metal-organic frameworks (MOFs) possess intriguing architectures, diverse functionalities, and superb properties that make them in-demand materials. Employing a new window-space-directed assembly strategy, a family of mesoporous zeolitic MOFs have been constructed herein from corner-shared supertetrahedra based on homometallic or heterometallic trimers [M3(OH/O)(COO)6] (M3 = Co3, Ni3 or Co2Ti). These MOFs consisted of close-packed truncated octahedral cages possessing a sodalite topology and large β-cavity mesoporous cages (∼22 Å diameter) connected by ultramicroporous apertures (∼5.6 Å diameter). Notably, the supertetrahedron-based sodalite topology MOF combined with the Co2Ti trimer exhibited high thermal and chemical stability as well as the ability to efficiently separate acetylene (C2H2) from carbon dioxide (CO2).