Reversed‐phase high‐performance liquid chromatography [LiChrosorb RP‐18,UV detection at 254 nm and acetonitrile‐water (86:14,v/v) as mobile phase] was applied to studies of the host–guest complexation of tetraalkylcalix[4]resorcinareneoctols and their upper rim phosphoryl, sulfonyl and dialkylaminomethyl derivatives with some aromatic guests in the mobile phase. It was shown that the formation of the inclusion complexes results in changes in the retention of aromatic guests and improves their separation. Stability constants of the complexes were calculated from the dependences of the l/k′ values of the aromatic guest on the concentration of the calix[4]resorcinarene in the mobile phase. The molecular structure of 4,6,16,18‐tetrahydroxy‐10,12,22,24‐tetrakis(dipropoxyphosphoryloxy)‐2,8,14,20‐tetramethylcalix[4]resorcinarene (12) was determined. Crystal data for 12 are P21/n, a  =  16.708(9) Å, b  =  18.683(6) Å, c  =  20.243(5) Å, β  =  95.75(3)°, V  =  6287(4) Å3 and Z  =  4. Compound 12 exists in a boat conformation, in which two opposite unsubstituted resorcinol rings of the macrocyclic skeleton lie in the plane formed by four methine bridges and two diphosphorylated rings are perpendicular to the plane. © 1998 John Wiley & Sons, Ltd.

The crystal structure of 25,27-dihydroxy-26,28-bis(diethoxyphosphoryloxy)-tert-butylcalix[4]arene (1) (hexane solvate, 1:1) was determined by x-ray crystallography. The crystal data are P2 1 /n, a = 12.652(1) Å , b = 12.564(2) Å , c = 18.781(4) Å , b = 105.56(1)°, V = 2876.0(8) Å 3 , Z = 2. In this complex the molecule adopts a 1,2-alternate conformation. Both the calixarene and hexane molecules are centrosymmetric. The phenol units in the asymmetric part of the calix are inclined with respect to the main macrocyclic plane by 115.46(6)°and 128.01 (7)°for the phosphorylated and the non-phosphorylated ring, respectively. Self-inclusion of the ethyl chains in the halfcavities is observed. One intramolecular O-H…O and several intermolecular C-H…O hydrogen bonds are present. In the 1 H NMR spectrum one average AX spin system for methylene bridge protons can be interpreted as fast (on the NMR time-scale) interconversion of non-phosphorylated phenol fragments.

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