Mechanically Flexible Crystals of Benzene Derivatives with Halogen or Methyl Groups

Thedeformation of molecular crystals and their mechanical propertiesare of interest in materials science. Herein, the single crystalsof simple benzene derivatives with bromo, iodo, and methyl substituentswere prepared, and we examined the effect of the substituents on theflexibility of crystals by single-crystal structural analysis, nanoindentationtest, and density functional theory (DFT) calculation. The crystalsof benzene derivatives can be classified into three types: crystalsthat bend in one direction, crystals that bend in two directions,and crystals that do not bend, depending on the member of the halogenand methyl groups. In addition, DFT calculation also revealed theisotropic and anisotropic mechanical properties of bendable crystals. Single crystals of simple benzene derivativeswith bromo,iodo, and methyl substituents were prepared, and we investigated theeffect of the substituents on the flexibility of these crystals. Thecrystals of benzene derivatives can be classified into three types:crystals that bend in one direction, crystals that bend in two directions,and crystals that do not bend, depending on the member of the halogenand methyl groups. In addition, DFT calculation and nanoindentationtest revealed the isotropic and anisotropic mechanical propertiesof bendable crystals.