Hexaphenolic Rigid Cages Prepared by Self-Organization of C_3v Tridentates

Abstract

Coordination cages were composed by self-organization of rigid C-symmetric heptaarene tridentates and Pd(II) precursors. The heptaarene framework involves one mesitylene, three phenol, and three pyridine moieties, which were connected by Suzuki coupling reactions. The treatment of the tridentates with Pd(dppp)(OTf) or Pd(en)(NO) in a 2:3 molar ratio furnished coordination cages, which was ascertained by crystallography, H NMR and DOSY measurements, and ESI-TOFMS and UV-vis spectra. The cages have six phenolic hydroxy groups inside and were expected to incorporate hydrogen-bonding guest molecules such as saccharides. CD and DOSY measurements showed that octyl hexoside guests could be incorporated into the cage.

Saccharide Recognition by a Three‐Arm‐Shaped Host Having Preorganized Three‐Dimensional Hydrogen‐Bonding Sites

“…Monoyne 8 was converted into 10 by Sonogashira reaction with an excess amount of 2,6‐diiodo‐4‐(octyloxy)pyridine ( 9 ). On the other hand, triiodide 11 can be readily prepared by reported procedures [7a] . This triiodide 11 was subjected to Sonogashira reaction with ( tert ‐butyldimethylsilyl)acetylene followed by treatment with tetrabutylammonium fluoride (TBAF) to give 13 .…”

“…THF was freshly distilled from sodium benzophenone ketyl before use. Starting materials 9 , [13] 11 , [7c] and 14 [7a] and guest molecules oct‐α‐Glc , [14] oct‐β‐Gal , [14] oct‐β‐Man , [14] and oct‐β‐Fru [14] were prepared by reported procedures. Other commercially available reagents and solvents were used without purification.…”