The rate of reduction of nitrite by trimethylamine-borane was followed by observing the decrease in nitrite absorbance under pseudo-first-order conditions. The reaction is acid-catalyzed and exhibits a first-order dependence on both amine-borane and total nitrite concentration. The molar equivalence of NaNO(2) to (CH(3))(3)NBH(3) = 2:1. Equimolar amounts of hydrogen and nitrous oxide are formed, and the molar ratio of nitrite reacted to N(2)O produced is 2:1. In concentrated HCl or H(2)SO(4), a correlation of rate with the Hammett acidity function, h(o), is observed. The reaction is subject to a pronounced inversesolvent isotope effect (k(D)()2(O)/k(H)()2(O) approximately 2.7) and a modest normal substrate effect (k((CH)()3())()3(N.BH)()3/k((CH)()3())()3(N.BD)()3 approximately 1.4). The reaction is first-order in H(3)O(+) in the region pH 0.7-2.7, but a second-order dependence is observed above pH 4 with the transition occurring at pH approximately pK(a) for HNO(2). Results are consistent with a mechanistic model involving preequilibration protonation of molecular nitrous acid followed by rate-limiting hydride attack on H(2)ONO(+) or free NO(+) to produce nitrosyl hydride as a reactive intermediate.
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http://dx.doi.org/10.1021/ic9601549 | DOI Listing |
Inorg Chem
March 2025
Department of Chemistry, Indiana University, Bloomington 47405, Indiana, United States.
While many mononuclear complexes for electrocatalytic NO reduction have been reported, there are few examples of dinuclear electrocatalysts. Here, we report on the electroreduction of NO by the dinuclear complex [Ni(tpmc)(NO)] (tpmc = 1,4,8,11-tetrakis-(2-pyridylmethyl)-1,4,8,11-tetraazacyclotetradecane) and a mononuclear analogue [Ni(cyclam)] (cyclam = 1,4,8,11-tetraazacyclotetradecane). Notably, the presence of the second metal ion in [Ni(tpmc)(NO)] shifts the onset of catalysis anodically by ca.
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March 2025
Key Laboratory for Green Chemical Technology of Ministry of Education, Haihe Laboratory of Sustainable Chemical Transformations, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300350, China.
This work reports a fully exposed palladium cluster catalyst that exhibits superior activity and selectivity for methyl nitrite (MN) carbonylation compared to atomically dispersed Pd catalysts and Pd nanoparticles. Mechanistic studies reveal that the distinct geometric structure of the fully exposed palladium cluster enables surface-mediated Langmuir-Hinshelwood reactions, efficiently producing dimethyl carbonate (DMC) while minimizing dimethyl oxalate (DMO) formation. In contrast, atomically dispersed Pd catalysts rely on Eley-Rideal mechanisms, leading to lower activity, while the continuous surface sites of Pd NPs promote DMO formation.
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Department of Molecular Environmental Biotechnology, Helmholtz Centre for Environmental Research - UFZ, Leipzig, Germany.
The anammox bacteria " Kuenenia stuttgartiensis" ( Kuenenia) are able to gain energy by combining ammonium and nitrite to produce nitrogen gas, which is an ecologically and technically significant activity process. In this reaction, nitric oxide serves as a recognized intermediate in the reduction of nitrite, which is subsequently combined with ammonium to produce hydrazine. However, the enzyme that converts nitrite to nitric oxide remains elusive.
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Department of Electrical and Biological Physics, Kwangwoon University, Wolgye-Dong, Seoul 01897, Republic of Korea.
The removal of surface residues from single-layer graphene (SLG), including poly(methyl methacrylate) (PMMA) polymers and Cl ions, during the transfer process remains a significant challenge with regard to preserving the intrinsic properties of SLG, with the process often leading to unintended doping and reduced electronic performance capabilities. This study presents a rapid and efficient surface treatment method that relies on an aqueous sodium nitrite (NaNO) solution to remove such contaminants effectively. The NaNO solution rinse leverages reactive nitric oxide (NO) species to neutralize ionic contaminants (e.
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China Railway Eryuan Engineering Group Co., Ltd, Chengdu, Sichuan 610031, PR China.
Bidirectional electron transfer biofilms (BETB) could efficiently reduce nitrate without accumulating nitrite, representing a promising biological electrochemical denitrification technology. This study utilized iron phthalocyanine modified carbon felt (FePc-CF) to enrich electroactive bacteria, constructing a long-term stable FePc-BETB. Its nitrate removal rate reached 91%, far exceeding the traditional nitrate-reducing biocathode (45%) and Con-BETB (46%).
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