1,2-Bis-crown-5-calix[4]arene

The title compound, 13,16,19,22,25,39,42,45,48,51-decaoxahexacyclo[35.15.1.1 11,27 .0 5,52 .0 7,12 .0 26,31 .O 33,38 ]-tetrapentaconta-1 (52),2,4,7(12),8,10,26(31),27,29,33(38),34,36-dodecaene, C 44 H 52 O 10 , is a potent and selective alkali metal carrier. Two half-independent molecules are observed in the solid state and they have the «pinched-cone» conformation of the studied calixarenes