POLYMORPHISM OF CRYSTALLINE HOST-GUEST COMPLEXES AND UNSOLVATED HOSTS.6. PSEUDO-DIMORPHISM OF COMPLEXES BETWEEN 1,1'-BINAPHTHYL-2,2'-DICARBOXYLIC ACID AND ETHANOL - X-RAY CRYSTAL-STRUCTURES OF THE BETA-FORM AND OF THE UNSOLVATED HOST COMPOUND

Depending on crystallization conditions, under ordinary conditions or from solution in ethanol at 60 degrees C, 1,1-binaphthyl-2,2'-dicarbox ylic acid (BNDA) yields pseudo-dimorphous inclusion complexes with eth anol: alpha-form with 1:2 and beta-form with 2:1 BNDA-ethanol host-gue st ratio, respectively. At 100 degrees C crystallized from ethanol, un solvated BNDA is obtained, All three structures are formed as a result of packing of infinite chains which are generated by different types of H-bonding. In the alpha-form, BNDA molecules are incorporated in 12 -membered loops involving host-guest-host (-H...2G...H-) type H-bonds while in the beta-form [triclinic (<P(1)over bar>), a = 9.982(3), b = 13.327(3), c = 14.544(3) Angstrom, alpha = 81.21(3), beta = 81.21(3), gamma = 88.76(3)degrees, Z = 4, R = 0.066 for 3713 reflections] four B NDA molecules are associated by H-bonds typical for dimers of carboxyl ic acids and these tetramers are incorporated into chains via the alph a-form mode of interaction, establishing -4H...2G...4H...2G- type of a ssociation in the chains. In the unsolvated BNDA [orthorhombic (Peen), a = 24.348(5), b = 11.165(2), c = 12.868(3) Angstrom, Z = 8, R = 0.12 8 for 849 observations] the structure is formed by chains of carboxyli c acid dimers only.