7250-68-2Relevant articles and documents
Oxidative dehydrogenation of hydrazines and diarylamines using a polyoxomolybdate-based iron catalyst
Huang, Lei,Qiu, Shiqin,Wei, Yongge,Xie, Jingyan,Yu, Han,Zeng, Xianghua,Zhao, Weizhe
supporting information, p. 7677 - 7680 (2021/08/09)
We report an efficient method for the oxidative dehydrogenation of hydrazines and diarylamines in aqueous ethanol using Anderson-type polyoxomolybdate-based iron(iii) as a catalyst and hydrogen peroxide as an oxidant. A series of azo compounds and tetraarylhydrazines were obtained in moderate to excellent yields. The reaction conditions and substrate scopes are complementary or superior to those of more established protocols. In addition, the catalyst shows good stability and reusability in water. The preliminary mechanistic studies suggest that a radical process is involved in the reaction.
Anion recognition in aqueous solution by cyclic dinuclear square cage-shaped coordination complexes
Fu, Cai-Ye,Li, Yu-Qian,Chen, Lu,Wang, Yun-Guang,Lin, Li-Rong
supporting information, (2019/07/02)
Three cyclic dinuclear complexes, namely [M2(H2L)2](ClO4)4 [M = Co2+ (1), Ni2+ (2), Zn2+ (3), H2L = (1,2)-bis-N'-(pyridin-2-ylmethylene)benzohydrazide hydrazine, C26H22N8O2], containing amide and hydrazine groups were synthesized and characterized. Each central metal ion is coordinated with two oxygen atoms and four nitrogen atoms from carbonyl, and pyridine and imine, respectively. The metal ion is six-coordinated and has a slightly deformed octahedral geometry. X-ray crystallographic analyses showed that all the three cyclic dinuclear complexes crystallize in the orthorhombic system, and belong to the C222 space group, with two molecules in each unit cell. The cyclic dinuclear molecule is linked by two H2L ligands with a Z-form-HN-NH-bridge, nearly forming a square coordination cage with edges of length around 8.4 ?. The cyclic dinuclear complexes can recognize acetate and fluoride anions in an acetonitrile solution containing 60% volume water. Recognition is governed by electrostatic interactions in cooperation with the cage structure effect with the mechanism of anion displacement reaction. The results show that the recognition of anions in acetonitrile aqueous solution is an exothermic and entropy-reducing reaction. This suggests that the enthalpy change plays an important role in the presence of highly polar water and highlights the importance of positively charged cage structure effect. A color change from light yellow to dark yellow was clearly observed for complex 3 on addition of acetate or fluoride anions in acetonitrile aqueous solution containing 60% water. Complex 3 can be used for colorimetric “naked eye” recognition of acetate or fluoride anions in acetonitrile aqueous solution. Theoretical calculations based on time dependent density functional theory (TD-DFT) show the agreement between the theoretical results and experimental data.
Conversion of anilines into azobenzenes in acetic acid with perborate and Mo(VI): correlation of reactivities
Karunakaran,Venkataramanan
, p. 375 - 385 (2019/02/14)
Azobenzenes are extensively used to dye textiles and leather and by tuning the substituent in the ring, vivid colours are obtained. Here, we report preparation of a large number of azobenzenes in good yield from commercially available anilines using sodium perborate (SPB) and catalytic amount of Na2MoO4 under mild conditions. Glacial acetic acid is the solvent of choice and the aniline to azobenzene conversion is zero, first and first orders with respect to SPB, Na2MoO4 and aniline, respectively. Based on the kinetic orders, UV–visible spectra and cyclic voltammograms, the conversion mechanism has been suggested. The reaction rates of about 50 anilines at 20–50?°C and their energy and entropy of activation conform to the isokinetic or Exner relationship and compensation effect, respectively. However, the reaction rates, deduced by the so far adopted method, fail to comply with the Hammett correlation. The specific reaction rates of molecular anilines, obtained through a modified calculation, conform to the Hammett relationship. Thus, this work presents a convenient inexpensive non-hazardous method of preparation of a larger number of azobenzenes, and shows the requirement of modification in obtaining the true reaction rates of anilines in acetic acid and the validity of Hammett relationship in the conversion process, indicating operation of a common mechanism.
