STRUCTURAL CONSEQUENCES OF COMPETING NONCOVALENT FORCES - THE OUT-OUTCONFORMATION OF THE DOUBLY PROTONATED [2.2.2]CRYPTAND

The reaction of [2.2.2]cryptand 1 with 2,6-dihydroxybenzoic acid (dhbH ) in toluene affords the complex [1-2H][(2,6-dhb)(2)]; its crystal str ucture exhibits the first solid state evidence of the out-out form of the doubly protonated macrobicycle and illustrates the role of C-H...O hydrogen bonds in providing additional stability to the cavity of the ligand.