In the crystals of 4,7-dihalobenzo[c][1,2,5]chalcogenadiazoles, the molecules are connected by two competing secondary bonding interactions: chalcogen bond (ChB) and halogen bond (HaB). Because the strengths of ChB and HaB change according to the kind of chalcogen (E: S, Se, Te) and halogen (X: Cl, Br, I), their relative contributions in determining the crystal packing can also change. Six newly determined crystal structures as well as 3 previously reported structures can be categorized into two groups: ChB-dominant and HaB-dominant structures. HaB in which X = I is strong enough to dictate the crystal packing of compounds with E = S and Se, but not where E = Te, whereas HaB in which X = Cl or Br has little effect on ChB-dominant molecular networks in crystals. The observed changing contributions of ChB and HaB may be useful for designing new supramolecular synthons for crystal engineering.

Biomass was dissolved in ionic liquids under non-thermal atmospheric pressure plasma irradiation. On plasma irradiation, the amount of dissolved biomass in the ionic liquids increased from 15 to 29 mg for bagasse and from 26 to 36 mg for Japanese cedar. The high solubility is attributed to the deconstruction of the lignin network by active chemical species generated by the plasma. Selective extraction of cellulose from biomass was observed under the plasma irradiation.

We synthesized planar chiral cyclophanes with multiple pairs of helical conformations that were generated by twisting at the interlayer. Three- and four-layer cyclophanes preferred a homochiral form with a single...