Molecular Crystals and Liquid Crystals, Vol.399, 29-42, 2003
The crystal structures of 1 : 1 molecular complexes of monoalkylammonium halides with rac-1,1'-bi-2-naphthol
The monoalkyltrimethylammonium halides CH3 (CH2 )(n-1) N+ (CH3)(3)X- (X=Br or Cl, when n=12, and X=Br, when n=16) and rac-1,1'-bi-2-naphthol (C20H14O2) have been found to form 1:1 crystalline complexes. In all the complexes, the host molecules are sandwiched between the BNP molecules in a similar manner. The bent tail region of the alkyl chains in all the host molecules are arranged in a uniquely interdigitated fashion. The bent conformation of the alkyl chains could be attributed to the effect of placing a naphthol plane almost normal to the long alkyl chain axis. The change of the counter anion in the host molecule does not show any significant variation in the packing arrangement observed in the complexes of 12TAB/BNP and 12TAC/BNP or 16TAB/BNP and 16TAC/BNP. The nonplanar shape of the BNP molecule affects the molecular packing of the alkyl chains. The BNP molecule adopts a cisoid conformation in all the complexes. Hydrogen bonds and C-H...pi interactions stabilize these crystal structures.