Fengli Bei

Synthesis, Crystal Structure and Stability Studies of Dithiocarbamate Complexes of Some Transition Elements (M=Co, Ni, Pd)

Single-crystal x-ray structure determinations have been recorded at 295 K for the dithiocarbamate metal compounds [Co(Et2dtc)3], [Co(nPr2dtc)3], [Pd(iPr2dtc)2] and [Pd(Et2dtc)2]. The stability constants(K) in EtOH of dialkyldithiocarbamate metal complexes [M(R2dtc)n] (M=Co, Ni, Pd. R=Me, Et, iPr, nPr. n=2, 3. dtc=dithiocarbamate) are determined by UV-vis data. The stability of the metal complexes increases in the order: Co<Ni<Pd. The effects of alkyl groups on the stability of [M(R2dtc)2] (M=Ni and Pd) increase in the order: Me<Et<nPr<iPr, and [Co(R2dtc)3] decrease in the order: Et>iPr>nPr>Me. The results obtained from this study confirm that the stability due to alkyl groups may be partly attributed to changes in the residual positive charge and also partly to steric hindrance of branched alkyl-groups. The comparison between the solid and solution states shows that the [M(R2dtc)2] (M=Pd, Ni) complexes have similar changes in M-S distance and stability with change in alkyl group. [M(iPr2dtc)2] has the shortest M-S distance and the highest stability in solution.

Room-Temperature Synthesis of Self-Assembled Sb2S3 Films and Nanorings via a Two-Phase Approach

The freestanding Sb(2)S(3) films were easily synthesized at the interface of water and toluene at room temperature, where Na(2)S and (C(2)H(5)OCS(2))(3)Sb (xanthate, O-ethyldithiocarbonate) acted as sulfur and antimony source, respectively. After 3 h of aging, the Sb(2)S(3) films with a flat surface toward organic side and rough surface toward aqueous side were assembled by sheaflike Sb(2)S(3) nanowires. The Sb(2)S(3) nanorings formed by end-to-end connection of the bundled nanowires appeared in the water layer when the reaction time reached 24 h. The Sb(2)S(3) nanorings showed higher photocatalytic activity for methyl orange degradation under visible light than the Sb(2)S(3) films owing to broader spectrum response and better aqueous dispersion.

Crystal structure and characterization of 1,2-N,N-disallicydene-phenylamineato nickel(II) complex

A new complex has been synthesized and characterized by elemental analysis, IR, TGA, and single-crystal X-ray analysis. The crystal is orthorhombic and the space group is chiral (P212121) with a = 6.620(3) Å, b = 17.300(4) Å,, c = 5.450(1) Å,, α = 90°, β = 90°, γ = 90°, z = 4. In the crystal lattice, the molecules create a two-dimensional network structure through hydrogen bonds. The C–H⋅⋅⋅O intermolecular hydrogen bonds connect the title complex to form a supermolecular structure.

Nucleation of polyaniline nano-/macrotubes from anilinium composed micelles.

A mechanistic study on the nucleation of polyaniline nanotubes (PANI-NT) through template-free method is explored by in situ solution-state (1)H NMR experiments via a careful analysis of the spectral evolution of the major species in the course of the reaction. Before polymerization, aniline and salicylic acid have assembled into loosely packed micelles due to electrostatic interactions and the proton exchange reaction between aniline and anilinium. A three-stage polymerization with a formation, accumulation of aniline dimers, as well as a generation of phenazine-like oligomers is observed, which can be attributed to the monomer transformation from neutral aniline molecules to anilinium cations and the significantly lowered pH in the reaction. Strong π-π stacking interactions from the phenazine-like oligomers facilitate the intermolecular aggregation which initiates the formation of PANI-NT. At first, such aggregates, locating at the outermost layer of anilinium composed micelles, shield in situ formed protons from releasing into the aqueous bulk but into the micelle instead. Due to the continuously increased charge in the micelle, a sphere-to-rod structural transition occurs which leads the oligomer aggregates to be sheathed at the exterior of the rod. Further consumption of anilinium in the micelle leaves the internal cavity while the fusion between the micelles elongates the length of the tubes. Our work demonstrates that (i) loosely packed anilinium composed micelles, highly mobile monomers within the micelle, and efficient blockage of the proton-releasing to the aqueous bulk are three key factors for the generation of tubular structures; and (ii) dynamic NMR line shape analysis provides a new perspective for resolving the formation profile of nanostructured polymers.

Bis(2-benzyl-1H-benz­imidazole-N3)dichorozinc(II)

In the title compound, [ZnCl2(C14H12N2)2], the environment around the Zn atom is distorted tetrahedral formed by two Cl atoms and two tertiary N atoms of the 2-benzyl-1H-benzimidazole ligands. N-H...Cl intermolecular hydrogen bonds link the molecules into infinite chains in the [101] direction.