Pinched-cone Calix[6]arene: New Synthesis of p- (1,1,3,3-tetramethylbutyl)calix[6]arene. Structure of its 1 : 3 Complex with Chloroform

A new method is described for the synthesis of p-(1,1,3,3-tetramethylbutyl)calix6]arene isolated ina 30 % yield. For the first time the crystal structure isgiven. The crystals are monoclinic, space group C2/c,a = 24.144(5) Å, b = 14.093(3) Å,c = 26.972(5) Å, = 93.36(3)^circ, V = 9162(3) ų, Z = 4. The macrocycle with C2symmetry presents the pinched-cone conformation. It crystallizes with three chloroform molecules, two of them are positioned in the cones shaped by the phenol moieties; the third chloroform is located in the cavity near the hydroxyl groups; this solvent molecule is disordered around the 2 axis. The packing of the complex is described.