Ye. Morozova et al., Protolytic properties and molecular structure of 2,8,14,20-tetramethyl-5,11,17,23-tetrakis(N-morpholino)methylcalix[4]resorcinolarene, RUSS J G CH, 71(1), 2001, pp. 119-125
The protolytic properties of 2,8,14,20-tetramethyl-5,11,17,23-tetrakis(N-mo
rpholino)methyicalix[4]resorcinolarene were studied by pH-potentiometric ti
tration. Its crystal and molecular structure was determined by single cryst
al X-ray diffraction and UV spectroscopy. In solution the macrocycle exists
as a zwitter-ion. In the crystal, the calixresorcinolarene molecule is in
the cone conformation; two pairs of the opposite morpholine substituents ar
e oriented inside and outside the macrocycle cavity and therefore show diff
erent acid properties.