122-66-7Relevant academic research and scientific papers
Highly efficient and selective photocatalytic hydrogenation of functionalized nitrobenzenes
Yang, Xiu-Jie,Chen, Bin,Zheng, Li-Qiang,Wu, Li-Zhu,Tung, Chen-Ho
, p. 1082 - 1086 (2014)
We report a simple but efficient photocatalytic nitrobenzene reduction method employing eosin Y as the photocatalyst and TEOA as the reducing agent. With green LED light irradiation, the nitro group in the nitrobenzenes containing other reducible groups was chemoselectively reduced into an amino group, and the corresponding anilines were isolated in quantitative yields. The photoinduced electron transfer mechanism suggests that the high chemoselectivity originates from the better electron-withdrawing ability of the nitro group.
Catalytic Hydrogenation of Azobenzene in the Presence of a Cuboidal Mo3S4Cluster via an Uncommon Sulfur-Based H2Activation Mechanism
Guillamón, Eva,Oliva, Mónica,Andrés, Juan,Llusar, Rosa,Pedrajas, Elena,Safont, Vicent S.,Algarra, Andres G.,Basallote, Manuel G.
, p. 608 - 614 (2021)
Azobenzene hydrogenation is catalyzed under moderate conditions by a cuboidal Mo3(μ3-S)(μ-S)3 diamino complex via a cluster catalysis mechanism. Dihydrogen activation by the molecular [Mo3(μ3-S)(μ-S)3Cl3(dmen)3]+ cluster cation takes place at the μ-S bridging atoms without direct participation of the metals in clear contrast with classical concepts. The reaction occurs with the formation of 1,2-diphenylhydrazine as an intermediate with similar appearance and disappearance rate constants. On the basis of DFT calculations, a mechanism is proposed in which formation of 1,2-diphenylhydrazine and aniline occurs through two interconnected catalytic cycles that share a common reaction step that involves H2 addition to two of the bridging sulfur atoms of the catalyst to form a dithiolate Mo3(μ3-S)(μ-SH)2)(μ-S) adduct. Both catalytic cycles have similar activation barriers, in agreement with the experimental observation of close rate constant values. Microkinetic modeling of the process leads to computed concentration-time profiles in excellent agreement with the experimental ones providing additional support to the calculated reaction mechanism. Slight modifications on the experimental conditions of the catalytic protocol in combination with theoretical calculations discard a direct participation of the metal on the reaction mechanism. The effect of the ancillary ligands on the catalytic activity of the cluster fully agrees with the present mechanistic proposal. The results herein demonstrate the capability of molybdenum sulfide materials to activate hydrogen through an uncommon sulfur based mechanism opening attractive possibilities toward their applications as catalysts in other hydrogenation processes.
Photocatalysis Enabling Acceptorless Dehydrogenation of Diaryl Hydrazines at Room Temperature
Sahoo, Manoj K.,Saravanakumar, Krishnasamy,Jaiswal, Garima,Balaraman, Ekambaram
, p. 7727 - 7733 (2018)
Aromatic azo compounds are privileged structural motifs, and they exhibit a myriad of pharmaceutical as well as industrial applications. Here, we report a catalytic acceptorless dehydrogenation of diarylhydrazine derivatives to access a wide variety of aryl-azo compounds with the removal of molecular hydrogen as the sole byproduct. This distinctive reactivity has been achieved under dual catalytic conditions by merging the visible-light active [Ru(bpy)3]2+ as the photoredox catalyst and Co(dmgH)2(py)Cl as the proton-reduction catalyst. The reaction proceeds smoothly under very mild and benign conditions and operates at ambient temperature. This dual catalytic approach is highly compatible with many different functional groups and has a broad substrate scope. We have also demonstrated the reversible hydrogen storage and release phenomenon on hydrazobenzene/azobenzene couple to show the utility of these compounds as hydrogen storage materials. Further diversification of azobenzene was shown by a transition-metal-catalyzed azo-group-directed ortho-C-H bond functionalization.
Dissociative cycloelimination, a new selenium based pericyclic reaction
Henriksen,Jakobsen
, p. 2448 - 2449 (2001)
The stereospecific oxidation of hydrazine into cis-diimide and the catalytic disproportionation of hydrogen peroxide effected by selenoxides are suggested to involve a dissociative cycloelimination from an intermediary selenurane.
Aryldiazonium Salts Serve as a Dual Synthon: Construction of Fully Substituted Pyrazoles via Rongalite-Mediated Three-Component Radical Annulation Reaction
Wang, Miao,Tang, Bo-Cheng,Xiang, Jia-Chen,Chen, Xiang-Long,Ma, Jin-Tian,Wu, Yan-Dong,Wu, An-Xin
, p. 8934 - 8937 (2019)
A highly efficient rongalite-mediated three-component radical annulation reaction to furnish fully substituted pyrazoles from aryldiazonium salts and α,β-unsaturated aldehydes or ketones under metal- and oxidant-free conditions at room temperature has been developed. In this transformation, aryldiazonium salts served as the precursor of both the aryl and aryl hydrazine units. Mechanistic investigations indicated that rongalite could act as a radical initiator and reducing reagent simultaneously in the reaction.
μ-imido, μ-(η2,η2-N,N-hydrazido) and μ-(η1-C:η2-C,N-isocyanido) dinuclear (fulvalene)zirconium derivatives
Gonzalez-Maupoey, Marta,Rodriguez, Gema M.,Cuenca, Tomas
, p. 2057 - 2063 (2002)
Treatment of the chloro (fulvalene)zirconium(III) compound [Zr(η5-C5H5)(μ-Cl)]2 [μ-(η5,η5-C10H8)] with an equimolar amount of azobenzene in toluene, under extremely anhydrous conditions, gives the μ-[bis(imido)] derivative [Zr(η5- C5H5)(μ-NPh)]2[μ-(η5, η5-C10H8)] (1). However, when this reaction is carried out under insufficiently dry conditions a mixture of the previously reported μ-oxo complex [Zr(η5- C5H5)Cl]2(μ-O)[μ-(η5, η5-C10H8)] and 1,2-diphenylhydrazine is obtained. When the chloro(fulvalene)zirconium(III) compound reacts with benzo[c]cinnoline the μ-(η2,η2-N,N-hydrazido) complex [Zr(η5-C5H5)Cl]2[μ- (NC6H4C6H4N)][μ (η5,η5-C10H8)] (2a) is obtained, which rearranges to the thermodynamically more stable 2b. Addition of an equimolar amount of RNC (R = nBu, C6H11) to a toluene solution of [Zr(η5-C5H5)(μ-Cl)]2 [μ-(η5,η5-C10H8)] gives [Zr(η5- C5H5)Cl]2(μ-CNR)[μ- (η5,η5-C10H8)] [R = nBu (3), C6H11 (4)]. Reaction of [Zr(η5-C5H5)Cl]2(μ-CNtBu) [μ-(η5,η5-C10H8)] with 1 equiv, of PhCH2MgCl or (PhCH2)2Mg(THF)2 afforded the monobenzyl derivatives [Zr(η5-C5H5)]2 (CH2Ph)(Cl)(μ-CNtBu) [μ-(η5,η5-C10H8)] (5 and 6). When this reaction was carried out with 2 equiv. or an excess of PhCH2MgCl, a mixture of the monobenzyl and dibenzyl compounds [Zr(η5- C5H5)]2(CH2Ph)(Cl) (μ-CNtBu)[μ-(η5,η5- C10H8)] (5) and [Zr(η5-C5H5) (CH2Ph)]2(μ-CNtBu)[μ-(η5, η5-C10H8)] (7) is obtained. Similar reactions with 1 or 2 equiv. of (CH3)3SiCH2Li afford a mixture of the monoalkyl and dialkyl compounds [Zr(η5-C5H5)]2 [CH2Si(CH3)3](Cl)(μ-CNtBu) [μ-(η5,η5-C10H8)] (8) and {Zr(η5-C5H5)[CH2Si (CH3)3]}2(μ-CNtBu) [μ-(η5,η5- C10H8)] (9) compounds. Moreover, methylation of [Zr(η5- C5H5)Cl]2(μ-CNnBu) [μ-(η5,η5-C10H8)] gives the analytically pure tetramethyl derivative [Zr(η5-C5H5) (CH3)]2(μ-CNnBu) [μ-(η5,η5-C10H8)] (10), whereas [Zr(η5-C5H5)Cl]2(μ- CNC6H11)[μ-(η5, μ5-C10H8)] reacts with MeLi to give a mixture of the monomethyl derivatives [Zr(η5C5H5)]2 (CH3)(Cl)(μ-CNC6H11)[μ- (η5,η5-C10H8)] (11 and 12), as well as the dimethyl compound [Zr(η5-C5H5) (CH3)]2(μ- CNC6H11)[μ-(η5, η5-C10H8)] (13). Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002.
N=N bond cleavage of azobenzene through Pt/TiO2 photocatalytic reduction
Tada, Hiroaki,Kubo, Masanobu,Inubushi, Yoichi,Ito, Seishiro
, p. 977 - 978 (2000)
TiO2 photocatalytic 2e--reduction of azobenzene to hydrazobenzene is found to occur at λ(ex) > 300 nm while loading of nanometer-sized Pt particles on TiO2 induces N=N bond cleavage via 4e--reduction; only photoisomerization occurs in the absence of TiO2.
Highly efficient and selective photocatalytic reduction of nitroarenes using the Ni2P/CdS catalyst under visible-light irradiation
Gao, Wen-Zheng,Xu, Yong,Chen, Yong,Fu, Wen-Fu
, p. 13217 - 13220 (2015)
A highly efficient and selective heterogeneous photocatalytic system for nitro reduction to amino organics was established using CdS, Ni2P and Na2S/Na2SO3 as a photosensitizer, a cocatalyst and a sacrificial electron donor in aqueous solution, respectively. Two competing pathways for photocatalytic H2 production and nitro reduction were found. Also, the reduction of nitroarenes to aniline was confirmed to proceed through both the direct and condensation routes.
Using a Nitrophenol Cocktail Screen to Improve Catalyst Down-selection
Shultz, Lorianne R.,Hu, Lin,Feng, Xiaofeng,Jurca, Titel
, p. 1627 - 1631 (2020)
The catalytic reduction of 4-nitrophenol (4NP) with excess NaBH4 is the benchmark model for quantifying catalytic activity of nanoparticles. Although broadly useful, the reaction can be very selective. This can lead to false positives and negatives when utilized for catalyst down-selection from a broader materials candidate pool. We report a multi-nitrophenol cocktail screening methodology incorporating 4NP and other amino-nitrophenols, utilizing Ag, Au, Pt, and Pd nanoparticles on carbon support. The reduction of the cocktail proceeds with no deleterious side reactions on the time-scale tested. The resulting kinetic rates provide an improved correlation of relative catalyst activity when compared to performance with other reducible moieties (e. g. azo bonds), or when compared to solely 4NP screening.
The benzidine and diphenyline rearrangements revisited. 1-14C and 1,1′-13C2 kinetic isotope effects, transition state differences, and coupled motion in a 10-atom sigmatropic rearrangement
Subotkowski, Witold,Kupczyk-Subotkowska, Lidia,Shine, Henry J.
, p. 5073 - 5076 (1993)
KIE were measured for 1-14C-and 1,1′-13C2-labeling in the acid-catalyzed rearrangement of hydrazobenzene (1) to benzidine (2) and diphenyline (3). Small KIE were found for forming 2, but none were found for the formation of 3. The results are consistent with concerted formation of 2 and nonconcerted formation of 3. KIE were remeasured for 4-14C-, 4,4′-13C2-, and 15N,15N′-labeling and were found to differ in magnitude from KIE reported earlier. The results are, nevertheless, consistent with the concerted formation of 2 and nonconcerted formation of 3. The differences in transition states for these two processes are discussed. Quantitative measurements of product distributions gave 85% 2 and 15% 3.
