Subtle Stereochemical Effects Influence Binding and Purification Abilities of an Fe^II₄L₄ Cage

Abstract

A tetrahedral Fe II 4 L 4 cage assembled from the coordination of triangular chiral, face-capping ligands to iron(II). This cage exists as two diastereomers in solution, which differ in the stereochemistry of their metal vertices, but share the same point chirality of the ligand. The equilibrium between these cage diastereomers was subtly perturbed by guest binding. This perturbation from equilibrium correlated with the size and shape fit of the guest within the host; insight as to the interplay between stereochemistry and fit was provided by atomistic well-tempered metadynamics simulations. The understanding thus gained as to the stereochemical impact on guest binding enabled the design of a straightforward process for the resolution of the enantiomers of a racemic guest.

Mechanically Interlocked Water-Soluble Pd6 Host for the Selective Separation of Coal Tar-Based Planar Aromatic Molecules

“…Encouraged by the capability of interlocked cage to encapsulate a higher percent of AN2 over AN1 , another round of separation experiment was performed using the guest mixture obtained from the first round of separation . It was observed from the 1 H NMR of the extracted guest that after two rounds of separation, the selectivity of AN2 increased to 98%, which was similar to the purity of the commercially available AN2 (Figure ).…”

Chiral cage materials with tailored functionalities for enantioselective recognition and separation

“…In 2019, a chiral tetrahedral cage was successfully generated by Zhang et al via coordination-driven selfassembly [111] , as the L9 could be positioned on each face in a clockwise or counterclockwise direction and the octahedral vertices of the tetrahedron could be Δ or Λ partial chirality. Racemic cryptophane (rac-CRY) was added to the solution of C12 to form a "cage in cage" complex [Figure 10A].…”

Enantioselective Self‐Assembly of a Homochiral Tetrahedral Cage Comprising Only Achiral Precursors

“…An alternative, more efficient "chiral memory" [10] strategy is a more efficient approach to synthesize chiral cage compounds containing only achiral precursors, as developed by a few groups including Raymond [11] and Nitschke. [12] In this method, chiral coordinative cages containing chiral building blocks are obtained in an enantiomerically pure form. When the chiral components are replaced with achiral counterparts, the metal-ligand complexation within the cage frameworks helps "remember" the handedness, even though all the chiral building blocks were removed.…”