Unique assemblies of alternating positively and negatively charged layers, directed by hydrogen bonds, ionic interactions, and π-stacking in the crystal structures of complexes between mellitic acid (benzenehexacarboxylic acid) and five planar aromatic bases

摘要: Benzenehexacarboxylic acid, mellitic acid (MA), has been used as a core motif to study possible radial self-assembly using complementary aromatic bases. By mixing water solutions of the components, crystals salts MA with 4-aminopyridine (AP), 4-dimethylamino-pyridine (DM), 2,2′-bipyridine (DP), o-phenanthroline (PL), and melamine (ML) have obtained. The MA−n ions assembled in either extended sheets for MA−2 or ribbons MA−4 by direct hydrogen bonding between additionally through mediation bonds molecules that distribute negative charges throughout sheet ribbon. Most O atoms carboxyl groups five complexes rotated significantly out plane central benzene ring. There are multiple base molecules, two four, each ion complexes. NH+ moieties all bases make ⋅ O–C MA−n . planar generally arranged stacks which components range from being parallel, interplanar separations 3.5 A, having considerable tilt respect other nearest separation greater than 3.9 A. These geometric characteristics reflected color crystals. three-dimensional networking makes some very hard. Cell dimensions: 1, C32H30N8O12 2H2O, C2/c, =13.764(2) b =18.053(3) c =14.876(4) β =105.99(2)° 2, C26H26N4O12 3H2O, P21/n, =15.891(1) =10.444(1) =18.242(1) =97.00(1); 3, C64H44N8O24 ⋅7H2O, P21/c, =23.016(4) =15.241(2) =19.124(2) =100.60(1)° 4, C36H22N4O12, =14.581(1) =10.472(1) =20.607(2) =106.43(1); 5, C18H18N12O12 $$P\bar 1$$ , =8.257(2) =8.986(2) =9.383(1) α =98.60(1)°, =96.38(2)°, γ =117.07(1)°.