Wen-Xin Dai

Encapsulating Naphthalene in an Electron-Deficient MOF to Enhance Fluorescence for Organic Amines Sensing

Host-guest encapsulation of electron-rich naphthalene molecules into a weakly emissive porous metal-organic framework based on π-electron-deficient (π-acidic) naphthalene diimide tectons leads to orange-emissive crystals, which can be used to sense strongly basic organic amines in a fast response, high photostability, and tunable sensitivity. Moreover, such host-guest inclusion crystals are also a good photochromic probe for the detection of weakly basic N-methyl-2-pyrrolidone and N,N-dimethylformamide molecules.

Introduction of holes into graphene sheets to further enhance graphene–TiO2 photocatalysis activities

Holey graphene sheets-involved TiO2 samples have been successfully prepared using appropriate H2O2 to etch carbon sheets during hydrothermal preparation of graphene–TiO2 composites. Due to the introduction of holes, the permeation ability of these graphene sheets may increase, which is beneficial for light adsorption by the composites and the interactions between reactants. As a result, holey graphene–TiO2 hybrids exhibit enhanced photocatalytic reduction of nitro-aromatics into the corresponding amino-aromatics compared with that of traditional graphene-involved ones, indicating that holey graphene sheets would be promising graphene derivatives to further optimize the photoactivity of graphene-involved composites.

Discrete polynuclear manganese nanorods: syntheses, crystal structures and magnetic properties

Shape-anisotropic nanomaterials with uniform lengths and widths have attracted much interest but few of them are involved in self-assembled manganese complexes. The combination of two redox-active acylthiosemicarbazide ligands with Mn3+ cations leads to two discrete polynuclear Mn nanorods, pentanuclear [Mn5(L3)6][Mn0.7(DMF)1.4(H2O)2.8] (1a) and trinuclear Mn3(L4)3·2DMF (2), whose L3 and L4 represent N-(5-(2-hydroxyphenyl)-1,3,4-oxadiazol-2-yl)benzamide and N-(5-(2-hydroxyphenyl)-1,3,4-oxadiazol-2-yl)-propionamide, respectively, which are in situ synthesized from their acylthiosemicarbazide derivatives in the presence of Mn3+ cations, while the latter are reduced into divalent ones in rod-like moieties. For each pentanuclear anion in 1a, the charge is balanced by a solvated trivalent manganese cation, which can be replaced by two tetramethylammonium cations to yield pure valence compound 1b. Moreover, the magnetic studies reveal all of them possess antiferromagnetic properties.