Construction and Application of a Non-Enzyme Hydrogen Peroxide Electrochemical Sensor Based on Eucalyptus Porous Carbon.

Natural eucalyptus biomorphic porous carbon (EPC) materials with unidirectional ordered pores have been successfully prepared by carbonization in an inert atmosphere. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscope (SEM) were employed to characterize the phase identification, microstructure and morphology analysis. The carbon materials were used to fabricate electrochemical sensors to detect hydrogen peroxide (H2O2) without any assistance of enzymes because of their satisfying electrocatalytic properties. It was immobilized on a glassy carbon electrode (GCE) with chitosan (CHIT) to fabricate a new kind of electrochemical sensor, EPC/CHIT/GCE, which showed excellent electrocatalytic activity in the reduction of H2O2. Meanwhile, EPC could also promote electron transfer with the help of hydroquinone. The simple and low-cost electrochemical sensor exhibited high sensitivity, and good operational and long-term stability.

Synthesis, characterization and anti-proliferative activity of heterocyclic hypervalent organoantimony compounds.

Three heterocyclic hypervalent organoantimony chlorides RN(CH2C6H4)2SbCl (2a R = t-Bu, 2b R = Cy, 2c R = Ph) and their chalcogenide derivatives [RN(CH2C6H4)2Sb]2O (3a R = t-Bu, 3b R = Cy, 3c R = Ph) were synthesized and characterized by techniques such as (1)H NMR, (13)C NMR, X-ray diffraction, and elemental analysis. It is found that the anti-proliferative activity detected over these compounds can be attributed to the coordination bond between the antimony and nitrogen atoms of these compounds. Moreover, a preliminary study on mechanistic action suggests that the inhibition effect is ascribable to cell cycle arrest and cell apoptosis.

Synthesis and structures of hypervalent organoantimony and organobismuth chlorides containing asymmetric C,E,C-chelating (E = O, S) ligands.

Two asymmetric tridentate C,E,C-chelating ligand precursors, 1-Br-2-[(2'-BrC6H4CH2E)CH2]C10H6 (E = O (1), E = S (2), were prepared in good yield. Lithiation of the two precursors was achieved by a reaction with n-BuLi, and was followed by treatment with SbCl3 or BiCl3 in a 1: 1molar ratio to give four air-stable hypervalent organoantimony and organobismuth chlorides with an asymmetric C,E,C-chelating ligand (E = O, S), i.e. (C6H4CH2OCH2C10H6)SbCl (3), (C6H4CH2SCH2C10H6)SbCl (4), (C6H4CH2OCH2C10H6)BiCl (5) and (C6H4CH2SCH2C10H6)BiCl (6). These compounds were characterized by NMR spectroscopy, elemental analysis and melting point determination. X-ray structure analysis of compounds 3-6 revealed that the donor atoms (O, S) are strongly coordinated to the metal atoms (Sb, Bi). Compounds 3-6 exhibit chirality and crystallize as racemic mixtures.

Synthesis and Structure of Organobismuth Chlorides and Triflates Containing (C,E)-Chelating Ligands (E=O, S) and Their Catalytic Application in the Allylation of Aldehydes with Tetraallyltin.

Four air-stable hypervalent organobismuth compounds with (C,O)- or (C,S)-chelating ligands, namely, R2 BiCl (R=2-(MeECH2 )C6 H4 ; E=O (3), S (4)), [2-(MeOCH2 )C6 H4 ]2 BiOTf (5), and [{2-(MeSCH2 )C6 H4 }2 Bi][OTf] (6; OTf=triflate) were successfully synthesized. The structures of compounds 3-6 were determined by single-crystal X-ray diffraction. Compound 6 comprises the [2-(MeSCH2 )C6 H4 ]2 Bi+ cation and the OTf- anion. Compounds 5 exhibited good catalytic efficiency and reusability for the allylation reaction of different aldehydes with tetraallyltin in methanol to give the corresponding homoallylic alcohols in excellent yields.

12-Chloro-6-cyclo-hexyl-5,6,7,12-tetra-hydro-dibenzo[c,f][1,5]aza-stibocine.

In the title organometallic complex, [Sb(C(20)H(23)N)Cl], the central anti-mony-containing part of the complex exhibits a pseudo-trigonal-bipyramidal geometry, where two C atoms and a lone electron pair of the Sb atom exist at the equatorial positions, while the N and Cl atoms are located at the apical positions, and a transannular inter-action exists between the Sb and N atoms on 1,5-aza-stibocine. Inter-molecular C-H⋯Cl hydrogen bonds are also observed.

Effect of butterfly-shaped sulfur-bridged ligand and counter anions on the catalytic activity and diastereoselectivity of organobismuth complexes.

In the direct Mannich reaction and synthesis of α,ß-unsaturated ketones, the use of organobismuth complexes as catalysts leads to high diastereoselectivity and products of single trans conformation. In this paper, we illustrate the relationship between structure and catalytic activity as well as diastereoselectivity of organobismuth complexes having a 5,6,7,12-tetrahydrodibenz [c,f][1,5]thiobismocine framework as well as bearing a butterfly-shaped sulfur-bridged ligand and tunable anions. With the exposed bismuth center acting as a Lewis acid site and the uncoordinated lone pair electrons of sulfur as a Lewis base site, the cationic organobismuth complexes work as bifunctional Lewis acid/base catalysts. Due to the steric influence of the butterfly-shaped structure and synergistic effect of Lewis acid and Lewis base centers, the complexes can direct substrate attack in organic synthesis. By adjusting the electron-withdrawing ability of the counter anions, the S-Bi bond strength can be regulated, leading to a significant change in Lewis acidity and Lewis basicity as well as catalytic activity. Through synergistic modulation of the above effects, one can control the diastereoselectivity of the organobismuth complexes for the generation of a single diastereoisomer.

6-Cyclo-hexyl-6,7-dihydro-dibenzo[c,f][1,5]aza-bis-mocin-12(5H)-yl(N→Bi) trifluoro-methane-sulfonate.

In the title compound, [Bi(C(20)H(23)N)(CF(3)SO(3))], the Bi(III) ion shows a distorted pseudo-trigonal-bipyramidal geometry, with two C atoms and a lone electron pair of the Bi atom in equatorial positions and the N and O atoms at the apical positions. The cyclo-hexyl group is disordered over two orientations with site-occupancy factors of 0.600 (14) and 0.400 (14).