Selective Reduction of Nitro Group in Aryl Halides Catalyzed by Silver Nanoparticles Modified with ß-CD.

In this paper, we first report the selective reduction of nitro group in aryl halides catalyzed by silver nanoparticles modified with ß-CD. Taking advantage of hydrophobic lumen and donor-acceptor behavior of ß-CD, the halogenated alkyl groups on the aromatic ring can be enveloped in the inner cavity that thereby inhibits the reduction of the halogen. For validating the mechanism proposed by us, different silver nanoparticles were applied in parallel experiments. In our experiments, UV-vis spectra and NMR spectra were used to characterize the selectivity. This strategy represents an outstanding improvement on the synthesis of halogenated aromatic amines in comparison with the traditional route, and greatly expands the application of silver nanoparticles in catalytic field.

Gold Nanoparticles Prepared by ß-CD and Dispersion Behavior in Oil/Water Mixed System.

In this paper, we report a green and controllable synthetic method of gold nanoparticles (AuNPs) by directly ß-CD reduction under mild conditions. Analysis of UV-vis spectra, along with TEM was applied to study the effects of experimental parameters on morphologies of the gold nanoparticles. The corresponding formation mechanism of the nanoparticles was evaluated by redox potential. In particular, compared with the traditional method of sodium citrate or ascorbic reduction, this method can facilely realize multi-dimensional regulation. On this basis, we further studied the dispersion behavior of the as-prepared gold nanoparticles in oil/water mixed system that would provide a possible strategy for optical sensor.

6-[4-(Diphenyl-amino)-phen-yl]quinoline 1-oxide.

In the title mol-ecule, C(27)H(20)N(2)O, a triphenyl-amine derivative of quinoline, the three benzene rings linked through an N atom form a propeller shape, with dihedral angles between the mean planes of pairs of rings of 75.57 (9), 55.68 (9) and 83.66 (9)°. The quinoline ring is essentially planar, with an r.m.s. deviation of the fitted atoms of 0.0155 Å, and forms a dihedral angle of 33.52 (8)° with the benzene ring to which it is bonded. Weak C-H⋯π inter-actions are also observed in the crystal structure.

5-(2-Meth-oxy-phen-yl)-1,3,4-thia-diazol-2-yl 2-meth-oxy-benzoate hemihydrate.

In the title compound, C(17)H(14)N(2)O(4)S·0.5H(2)O, the mol-ecule, with the exception of the two meth-oxy-phenyl groups, is nearly planar with an r.m.s. deviation of 0.0305 Å. The two 2-meth-oxy-phenyl rings make dihedral angles of 4.1 (3) and 2.3 (3)° with the thia-diazole ring. In the crystal, inter-molecular C-H⋯O and O-H⋯N hydrogen bonds link the mol-ecules.

Ethyl 2-(2-hy-droxy-5-nitro-phen-yl)acetate.

In the crystal structure of the title compound, C(10)H(11)NO(5), inter-molecular O-H⋯O hydrogen bonds link the mol-ecules into chains along the b-axis direction. Weak C-H.·O hydrogen bonds also occur.

Ethyl 5-methyl-imidazo[1,2-a]pyridine-2-carboxyl-ate.

The title compound, C(11)H(12)N(2)O(2), was synthesized from the reaction of 6-methyl-pyridin-2-amine and ethyl 3-bromo-2-oxopropionate. In the mol-ecular structure, the six- and five-membered rings are individually almost planar with r.m.s. deviations of 0.003 and 0.002 Å, respectively. The two rings are almost coplanar, the dihedral angle between their planes being 1.4 (3)°. Inter-molecular C-H⋯O and C-H⋯N hydrogen bonds are present in the crystal structure.

5-(4-Meth-ylphenyl)-1,3,4-thia-diazol-2-amine.

The title compound, C(9)H(9)N(3)S, was synthesized by the reaction of 4-methyl-benzoic acid and thio-semicarbazide. The thia-diazol ring adopts a planar conformation and makes a dihedral angle of 31.19 (18)° with the phenyl ring. In the crystal, mol-ecules are linked by N-H⋯N hydrogen bonds.

3-[4-(Trifluoro-meth-yl)phen-yl]propanoic acid.

In crystal of the the title compound, C(10)H(9)F(3)O(2), inversion dimers linked by pairs of O-H⋯O hydrogen bonds occur.

2-(4-tert-Butyl-phen-yl)-5-{3,4-dibutoxy-5-[5-(4-tert-butyl-phen-yl)-1,3,4-oxadiazol-2-yl]-2-thienyl}-1,3,4-oxadiazole.

In the title compound, C(36)H(44)N(4)O(4)S, the dihedral angles between the central thio-phene ring and the pendent oxadiazole rings are 12.7 (2) and 13.7 (2)°, and the dihedral angles between the oxadiazole rings and their adjacent benzene rings are 6.1 (2) and 17.5 (2)°. An intra-molecular C-H⋯O inter-action may help to establish the conformation.