60-35-5Relevant articles and documents
The 3rd degree of biomimetism: Associating the cavity effect, ZnII coordination and internal base assistance for guest binding and activation
Parrot,Collin,Bruylants,Reinaud
, p. 5479 - 5487 (2018)
The synthesis and characterization of a resorcinarene-based tetra(imidazole) ligand is reported. The properties of the corresponding ZnII complex are studied in depth, notably by NMR spectroscopy. In MeCN, acid-base titration reveals that one out of the four imidazole arms is hemi-labile and can be selectively protonated, thereby opening a coordination site in the exo position. Quite remarkably, the 4th imidazole arm promotes binding of an acidic molecule (a carboxylic acid, a β-diketone or acetamide), by acting as an internal base, which allows guest binding as an anion to the metal center in the endo position. Most importantly, the presence of this labile imidazole arm makes the ZnII complex active for the catalyzed hydration of acetonitrile. It is proposed that it acts as a general base for activating a water molecule in the vicinity of the metal center during its nucleophilic attack to the endo-bound MeCN substrate. This system presents a unique degree of biomimetism when considering zinc enzymes: a pocket for guest binding, a similar first coordination sphere, a coordination site available for water activation in the cis position relative to the substrate and finally an internal imidazole residue that plays the role of a general base.
Swift, E. H.,Butler, E. A.
, p. 146 - 153 (1956)
Measurement and calculation of the rate constant for the reaction of isopropyl isocyanate with hydroxyl radical
Parker, James K.,Espada-Jallad, Cyntia,Parker, Claudia L.,Witt, John D.
, p. 187 - 197 (2009)
The rate constant for the gas-phase reaction of hydroxyl radical with isopropyl isocyanate (IIC) has been measured, relative to toluene, in the T =287-321 K range at atmospheric pressure in air. Ultraviolet photolysis of methyl nitrite served as the sourc
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Paul
, (1937)
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EXAFS/FTIR Characterization and Selective Hydration of Acetonitrile on Silica-Supported *)4V6O19>
Yamaguchi, Masatsugu,Shido, Takafumi,Ohtani, Hiroko,Isobe, Kiyoshi,Ichikawa, Masaru
, p. 717 - 718 (1995)
Silica-supported *)4V6O19 exhibited high catalytic activities in the gas-phase hydration of acetonitrile towards acetamide at 350-473 K with selectivity of over 97percent and dehydrogenation of 2-propanol to acetone.EXAFS, XPS and FTIR studies suggested that thermal evacuation of silica-supported *)4V6O19> at 473 K led to the removal of the bridged oxygen atoms in the V6O19 framework.The resulting deoxygenated samples enhanced the acetonitrile hydration, while catalyzed the dehydration of 2-propanol to propene besides the dehydrogenation reaction, probably owing to the newly generated Lewis acid site.
Karrer,Haab
, p. 950,956 (1949)
Catalytic hydration of benzonitrile and acetonitrile using nickel(0)
Crestani, Marco G.,Arevalo, Alma,Garcia, Juventino J.
, p. 732 - 742 (2006)
The homogeneous catalytic hydration of benzo- and acetonitrile under thermal conditions was achieved using nickel(0) compounds of the type [(dippe)Ni(η2-NCR)] with R = phenyl or methyl (compounds 1 and 2, respectively), as the specific starting intermediates. Alternatively, the complexes may be prepared in situ by direct reaction of the precursor [(dippe)NiH]2 (3) with the respective nitrile. Hydration appears to occur homogeneously, as tested by mercury drop experiments, producing benzamide and acetamide, respectively. Addition of Bu4NI did not lead to catalysis inhibition, suggesting the prevalence of Ni(0) intermediates during catalysis. Hydration using analogous complexes of 3, such as [(dtbpe)NiH] 2 (4) and [(dcype)NiH]2 (5) was also addressed.
Unmasking the Action of Phosphinous Acid Ligands in Nitrile Hydration Reactions Catalyzed by Arene-Ruthenium(II) Complexes
Tomás-Mendivil, Eder,Cadierno, Victorio,Menéndez, María I.,L?pez, Ram?n
, p. 16874 - 16886 (2015)
The catalytic hydration of benzonitrile and acetonitrile has been studied by employing different arene-ruthenium(II) complexes with phosphinous (PR2OH) and phosphorous acid (P(OR)2OH) ligands as catalysts. Marked differences in activity were found, depending on the nature of both the P-donor and η6-coordinated arene ligand. Faster transformations were always observed with the phosphinous acids. DFT computations unveiled the intriguing mechanism of acetonitrile hydration catalyzed by these arene-ruthenium(II) complexes. The process starts with attack on the nitrile carbon atom of the hydroxyl group of the P-donor ligand instead of on a solvent water molecule, as previously suggested. The experimental results presented herein for acetonitrile and benzonitrile hydration catalyzed by different arene-ruthenium(II) complexes could be rationalized in terms of such a mechanism.
Half-Sandwich Iridium Complexes Based on β-Ketoamino Ligands: Preparation, Structure, and Catalytic Activity in Amide Synthesis
Wang, Yang,Guo, Wen,Guan, Ai-Lin,Liu, Shuang,Yao, Zi-Jian
, p. 11514 - 11520 (2021/07/31)
A series of β-ketoamino-based N,O-chelate half-sandwich iridium complexes with the general formula [Cp*IrClL] have been prepared in good yields. These air-insensitive iridium complexes showed desirable catalytic activity in an amide preparation under mild conditions. A number of amides with diverse substituted groups were furnished in a one-pot reaction with good-to-excellent yields through an amidation reaction of NH2OH·HCl with aldehydes in the presence of these iridium(III) precursors. The excellent catalytic activity, mild reaction conditions, and broad substrate scope gave this type of iridium catalyst potential for use in industry. All of the obtained iridium complexes were well characterized by different spectroscopy techniques. The exact molecular structure of complex 3 has been confirmed by single-crystal X-ray analysis.
Manganese-Pincer-Catalyzed Nitrile Hydration, α-Deuteration, and α-Deuterated Amide Formation via Metal Ligand Cooperation
Ben-David, Yehoshoa,Diskin-Posner, Yael,Kar, Sayan,Milstein, David,Zhou, Quan-Quan,Zou, You-Quan
, p. 10239 - 10245 (2021/08/24)
A simple and efficient system for the hydration and α-deuteration of nitriles to form amides, α-deuterated nitriles, and α-deuterated amides catalyzed by a single pincer complex of the earth-abundant manganese capable of metal-ligand cooperation is reported. The reaction is selective and tolerates a wide range of functional groups, giving the corresponding amides in moderate to good yields. Changing the solvent from tert-butanol to toluene and using D2O results in formation of α-deuterated nitriles in high selectivity. Moreover, α-deuterated amides can be obtained in one step directly from nitriles and D2O in THF. Preliminary mechanistic studies suggest the transformations contributing toward activation of the nitriles via a metal-ligand cooperative pathway, generating the manganese ketimido and enamido pincer complexes as the key intermediates for further transformations.
Metal-Free Solvent Promoted Oxidation of Benzylic Secondary Amines to Nitrones with H2O2
Adrio, Javier,Amarante, Giovanni Wilson,Granato, álisson Silva
, p. 13817 - 13823 (2021/10/01)
An environmentally benign protocol for the generation of nitrones from benzylic secondary amines via catalyst-free oxidation of secondary amines using H2O2 in MeOH or CH3CN is described. This methodology provides a selective access to a variety of C-aryl nitrones in yields of 60 to 93%. Several studies have been performed to shed light on the reaction mechanism and the role of the solvent.