Shi-Yong Zhang

Pd-Catalyzed Oxidative Homocoupling of Arylboronic Acids in Aqueous Ethanol at Room Temperature

The authors demonstrate for the first time that the Pd(OAc)2/N,O-ligands act as catalysts toward homocoupling of arylboronic acid in aqueous ethanol (95%) under mild conditions: at room temperature and under aerobic condition. Under the optimal reaction conditions, all reactions gave the homocoupling products in good to excellent yields.

Molecular Dynamics, Phase Transition and Frequency‐Tuned Dielectric Switch of an Ionic Co‐Crystal

Dielectric switches that can be converted between high and low dielectric states by thermal stimuli have attracted much interest owing to their many potential applications. Currently one main drawback for practical application lies in the non-tunability of their switch temperatures (TS ). We report here an ionic co-crystal (Me3 NH)4 [Ni(NCS)6 ] that contains a multiply rotatable Me3 NH+ ion and a solely rotatable one due to a more spacious supramolecular cage for the former one. This compound undergoes an isostructural order-disorder phase transition and it can function as a frequency-tuned dielectric switch with highly adjustable TS , which is further revealed by the variable-temperature structure analyses and molecular dynamics simulations. In addition, the distinct arrangements and molecular dynamics of two coexisting Me3 NH+ ions confined in different lattice spaces as well as the notable offset effect on the promoting/hindering of dipolar reorientation after dielectric transition provide a rarely observed but fairly good model for understanding and modulating the dipole motion in crystalline environment.

Structural phase transitions, dielectric bistability and luminescence of two bulky ion-pair crystals [N(C3H7)4]2[Ln(NO3)5] (Ln = Tb, Dy)

Two bulky ion-pair crystals [N(C3H7)4]2[Ln(NO3)5] (Ln = Tb or Dy) are synthesized and structurally characterized. Both compounds exhibit a dielectric bistable behaviour accompanied by a reversible structural phase transition above room temperature. In addition, the relatively rigid coordination configuration around the lanthanide ions makes the two ion-pair compounds function as promising green and yellow phosphors, respectively. The synthetic approach may be applicable to construct other multifunctional materials with dielectric bistability and luminescence based on large organic ammonium and lanthanide complex anions.

A two-fold interpenetrating porous metal–organic framework with a large solvent-accessible volume and selective sensing of nitroaromatic explosives

Abstract A cadmium(II) 3-D porous metal–organic framework, (Me2NH2)4[Cd2(TTCA)2Cl2]·7DMF·2Diox·6H2O (1) (TTCA = triphenylene-2,6,10-tricarboxylate, DMF = N,N-dimethylformamide, diox = 1,4-dioxane), has been synthesized through solvothermal conditions. Single-crystal X-ray analysis reveals that the structure of 1 has a two-fold interpenetrating framework with a large solvent-accessible volume of 52% per unit cell. The result of topological analysis shows that 1 is a (3,3)-connected 3-D network with {103} topology. Luminescence tests illustrate that 1 can selectively sense nitroaromatic explosives via a luminescence quenching mechanism.