Crystal structure of the 1:1 co-crystal 4-(di-methylamino)-pyridin-1-ium 8-hy-droxy-quinoline-5-sulfonate-N,N-di-methyl-pyridin-4-amine.

The asymmetric unit of the title compound is composed of two independent ion pairs of 4-(di-methyl-amino)-pyridin-1-ium 8-hy-droxy-quinoline-5-sulfonate (HDMAP+·HqSA-, C7H11N2 +·C9H6NO4S-) and neutral N,N-di-methyl-pyridin-4-amine mol-ecules (DMAP, C7H10N2), co-crystallized as a 1:1:1 HDMAP+:HqSA-:DMAP adduct in the monoclinic system, space group Pc. The compound has a layered structure, including cation layers of HDMAP+ with DMAP and anion layers of HqSA- in the crystal. In the cation layer, there are inter-molecular N-H⋯N hydrogen bonds between the protonated HDMAP+ mol-ecule and the neutral DMAP mol-ecule. In the anion layer, each HqSA- is surrounded by other six HqSA-, where the planar network structure is formed by inter-molecular O-H⋯O and C-H⋯O hydrogen bonds. The cation and anion layers are linked by inter-molecular C-H⋯O hydrogen bonds and C-H⋯π inter-actions.

Fabrication of Hyperbranched Photomechanical Crystals Composed of a Photochromic Diarylethene.

We report the fabrication of hyperbranched hollow crystals of 1,2-bis(2,5-dimethyl-3-thienyl)perfluorocyclopentene on a concave surface of the spherical glass substrate by sublimation and their practical photomechanical behaviors. The number of units of the branched structure of the hollow crystals composed of this compound is proportional to the substrate curvature of the substrate. Compared with the sublimation process of the same compound on the flat glass substrate, two kinds of the thin film domains are generated separately in the center and around the edge of the spherical glass substrate. Especially under the high relative humidity condition, the boundaries between these thin film domains move gradually around the edge through the center during as long as 6 h of sublimation time so that the hyperbranched hollow crystals are densely produced on the entire surface of the substrate. These hyperbranched hollow crystals can be prepared with the highly ordered molecular packing due to the very slow formation process of the crystalline walls of the hollow structures. Furthermore, the photo-induced bending behaviors in the few- and highly-branched hollow crystals have the practical roles in moving and bending the minute objects according to their characteristics of these branched shapes.