Synthesis of Single Isomeric Complexes with Dissymmetric Structures Using Macrocyclic Homooligomers

Abstract

Bottom‐up chemical synthesis to construct intricate molecules has been a profound challenge. An effective approach is to utilize organic ligands and metal ions, but the formation of a single product among other possible candidates has proven difficult for dissymmetric structures. We now report the synthesis of single isomeric complexes with dissymmetric structures using the mismatch in the coordination valences of macrocyclic homooligomers and metal ions. A series of amide‐cyclodextrin derivatives possessing multiple 2,2′‐bipyridyl (bpy) groups forms mononuclear complexes whose specific three bpy groups are linked in the fac‐Λ configuration. The intermolecular coordination of the β‐cyclodextrin metal complex produces a dissymmetric cyclodextrin trimer as a single isomer, whose initially equivalent 21 (=7×3) bipyridylamide‐pyranose units are placed in different environments. Furthermore, we realize chiral recognition of amino acid anions utilizing the distinctive amide groups arranged on the unsymmetrically fixed scaffold.

Solvent-dependent fac/mer-isomerization and self-assembly of triply helical complexes bearing a pivot part

“…Useful but limited strategies have been reported. The electronic and structural properties of ligands, such as the trans influence, 1 steric hindrance, 2 π–π interaction, 3 tripodal structures, 4 and their combination, 5 have been successfully applied to control the isomerism. It is worth noting here that the ligands usually dominate the isomeric equilibrium.…”

Cyclodextrins with Multiple Pyrenyl Groups: An Approach to Organic Molecules Exhibiting Bright Excimer Circularly Polarized Luminescence

“…In this work, we utilized the CyD derivative hexakis(2,3‐di‐ O ‐methyl‐6‐amino‐6‐deoxy)‐α‐cyclodextrin ( Amine‐CyD ) containing amino groups at the C‐6 position and methoxy groups at the C‐2 and C‐3 positions as the starting material (Scheme 1). The amino groups of Amine‐CyD enable selective and facile modification through amide bond formation, while the methoxy groups suppress undesired side reactions and increase the solubility in organic solvents [30] . Amine‐CyD was conjugated with 1‐pyrenecarboxylic acid by a condensation reaction using 4‐(4,6‐dimethoxy‐1,3,5‐triazin‐2‐yl)‐4‐methylmorpholinium chloride ( DMT‐MM ) [31] to afford PCD‐C0 in good yield (58 %; Scheme 1).…”

Cyclodextrins with Multiple Pyrenyl Groups: An Approach to Organic Molecules Exhibiting Bright Excimer Circularly Polarized Luminescence

“…Theamino groups of Amine-CyD enable selective and facile modification through amide bond formation, while the methoxy groups suppress undesired side reactions and increase the solubility in organic solvents. [30] Amine-CyD was conjugated with 1-pyrenecarboxylic acid by acondensation reaction using 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride (DMT-MM) [31] to afford PCD-C0 in good yield (58 %; Scheme 1). Thes ingle X-ray crystal structure showed that the pyrene units conjugate with the cyclodextrin scaffold through amide bonds (Figure S1).…”