Lattice Imaging of Electro-Optically Active Poly(nonylbithiazole) (PNBT)

Dislocations in molecular crystals

Dislocations in molecular crystals remain terra incognita. Owing to the complexity of molecular structure, dislocations in molecular crystals can be difficult to understand using only the foundational concepts devised over decades for hard materials. Herein, we review the generation, structure, and physicochemical consequences of dislocations in molecular crystals. Unlike metals, ceramics, and semiconductors, molecular crystals are often characterized by flexible building units of low symmetry, thereby limiting analysis, complicating modeling, and prompting new approaches to elucidate their role in crystallography from growth to mechanics. Such considerations affect applications ranging from plastic electronics and mechanical actuators to the tableting of pharmaceuticals.

Growth actuated bending and twisting of single crystals

Crystals of a variety of substances including elements, minerals, simple salts, organic molecular crystals, and high polymers forgo long-range translational order by twisting and bending as they grow. These deviations have been observed in crystals ranging in size from nanometers to centimeters. How and why so many materials choose dramatic non-crystallographic distortions is analyzed, with an emphasis on crystal chemistries that give rise to stresses operating either on surfaces of crystallites or within the bulk.

Palladium-catalyzed regioselective oxidative coupling of indoles and one-pot synthesis of acetoxylated biindolyls

Mild conditions have been developed to achieve Pd-catalyzed homocoupling of indoles with excellent regioselectivity in the presence of Cu(OAc)(2) x H(2)O in DMSO at room temperature in high efficiency. This method provides a simple route to 2,3'-biindolyls from the electron-rich to moderately electron-poor indoles. The reaction tolerates the bromide substituent on indoles. In addition, a one-pot approach to C3-position acetoxylated biindolyls is realized via palladium catalysis by the use of AgOAc under oxygen atmosphere as oxidants.