THE CRYSTAL-STRUCTURE OF THE INCLUSION COMPLEX OF CYCLOMALTOHEPTAOSE (BETA-CYCLODEXTRIN) WITH 4-TERT-BUTYLBENZOIC ACID

The crystal of the 1:1 complex of cyclomaltoheptaose (beta-cyclodextri n, beta CD) with 4-tert-butylben zoic acid is triclinic P1 with a = 18 .244(3), b = 15.476(3), c = 35.417(2) Angstrom; alpha = 102.94(1), bet a = 113.08(1), gamma = 99.69(2)degrees; V = 3740(1) Angstrom(3); and Z = 2. The final R was determined to be 0.0932 for 8111 observed reflec tions (MoK alpha radiation). Two independent molecules of PCD form a d imer, via hydrogen bonds involving the O-3n atoms, that encloses two m olecules of 4-tert-butylbenzoic acid. The guest molecules penetrate th e beta CD cavities to different depths. There are 26.8 water molecules , distributed over 30 sites, which form a dense water network surround ing the dimers.