Studies on water-soluble artificial receptors containing chiral side chains derived from carbohydrates. 2. Formation of diastereomeric inclusion complexes between optically active cyclophane TCP44 and chiral aromatic guests in acidic aqueous solutions

Systematic H-1 NMR investigations on the formation of diastereomeric comple xes of optically active cyclophane host TCP44 and chiral aromatic guests in acidic aqueous or mixed aqueous/methanolic solutions are described. inclus ion of chiral aromatic guests into the cavity led to enantiomeric splitting of the guest proton signals, particularly those of the protons near the ch iral center. The chiral recognition was quantitatively evaluated for 1-hydr oxy-arylacetic acids and 1-arylethanols on the basis of the stability const ants and complexation shifts of 1:1 complexes, determined by 1H NMR titrati on experiments. A possible mode of chiral recognition is discussed.