In Situ Synthesized Homochiral Spiroborate Ester Metal-Organic Framework with Mono-, Di-, and Trivalent Cations.

We report here a one-step method for synthesizing multi-component and in-situ-formed homochiral spiroborate-ester-based metal-organic framework CPM-B1. This unique material successfully integrates COF fragment spiroborate ester within the MOF and simultaneously incorporate homochirality and helicity. In addition, CPM-B1 is a rare example of framework materials that results from the cooperative assembly of three charge-complementary cations: +1 (lithium), +2 (cobalt), and +3 (boron). The sophistication of the co-assembly is further highlighted by the three structural roles of lithium ions. This unique structure contributes to its multi-functional properties such as ionic conductivity and catalytic activity for oxygen reduction reaction (by CPM-B1 carbonized material) and provides a new path to develop MOF materials with complex secondary building units and multi-functional applications.

Lock-and-Key and Shape-Memory Effects in an Unconventional Synthetic Path to Magnesium Metal-Organic Frameworks.

We report a new magnesium metal-organic framework (MOF) (CPM-107) with a special interaction with CO2 . CPM-107 contains Mg2 -acetate chains crosslinked into a 3D net by terephthalate. It has an anionic framework encapsulating ordered extra-framework cations and solvent molecules. The desolvated form is closed and unresponsive to common gasses, such as N2 , H2 , and CH4 . Yet, with CO2 at 195 K, it abruptly opens and turns into a rigid porous form that is irreversible via desorption. Once opened by CO2 , CPM-107 remains in the stable porous state accessible to additional gas types over multiple cycles or CO2 itself at different temperatures. The porous phase can be re-locked to return to the initial closed phase via re-solvation and desolvation. Such peculiar properties of CPM-107 are apparently linked to a convergence of factors related to both framework and extra-framework features. The unusual CO2 effect is currently the only available path to porous CPM-107 which shows efficient C2 H2 /CO2 separation.

Cooperative self-assembly of chiral L-malate and achiral succinate in the formation of a three-dimensional homochiral framework.

Chiral l-malate and achiral succinate ligands have been integrated into a three-dimensional homochiral framework by reacting transition-metal cations (Mn (2+)), l-(-)-malic acid ( l-H 2ma), succinic acid (H 2suc), and 4,4'-bipyridine (4,4'-bipy). Chiral l-malate bonds to Mn (2+) without using the -OH group, which is very unusual for malate. Such unusual bonding of chiral malate results from the cooperative effect of chiral malate and achiral succinate ligands during the self-assembly process, further assisted by the third complementary bipyridine ligand.