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.
Formation of singlet molecular oxygen by the Radziszewski reaction between acetonitrile and hydrogen peroxide in the absence and presence of ketones
Brauer, Hans-Dieter,Eilers, Beate,Lange, Andreas
, p. 1288 - 1295 (2002)
Measurements of the infrared phosphorescence of singlet molecular oxygen (1O2) at 1270 nm have been used to demonstrate the formation of 1O2 by the Radziszewski reaction between acetonitrile and hydrogen peroxide. The kinetics of the Radziszewski reaction either alone or in the presence of ketones have been studied by this technique. The rate-determining step of the 1O2 formation of the reaction in the absence of ketones was found to be independent of both the concentration of acetonitrile and that of hydrogen peroxide. The kinetic data, the results of the volumetric measurements of the oxygen liberated and the results of the determination of the amount of 1O2 generated by the reaction are consistent with the assumption that the reaction between acetonitrile and hydrogen peroxide occurs via the heterolytic decomposition of the intermediate, peroxyacetimidic acid (PAIA), forming 1 mol acetamide and 0.5 mol 1O2 according to the stoichiometric equation: CH3CN + H2O2 → CH3C(=O)NH2 + 0.5 1O2. The rate constant of the heterolytic decomposition of PAIA was determined to be k8 = 1.2 × 10-3 dm3 mol-1 s-1 at T = 30°C. From the measurements at different pH values in the range 9.1 a(PAIA) value was estimated to be 11.1 at T = 30°C. The investigation of the reaction between acetonitrile and hydrogen peroxide by using N,N-dimethyl-4-oxopiperidinium nitrate as catalyst, has unequivocally shown that the rate of 1O2 formation is considerably enhanced by this ketone. For the ketone-catalysed decomposition of PAIA a rate law can be derived showing a first order dependence on the concentration of acetonitrile and hydrogen peroxide at a given pH. In accordance with the observed rate law are the results with acetonitrile in 50% acetone containing a tenfold excess of hydrogen peroxide at pH 8.2 and T = 60°C.
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
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.
Hydrolysis of N-(1-Aminoalkyl)amides
Loudon, G. Marc,Jacob, James
, p. 377 - 378 (1980)
The hydrolysis of the title compounds involves the expulsion of an amide anion as a leaving group at basic pH, and probably an amide enol (imidoacid) as a leaving group at acidic pH.
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.
Hydrolysis of Acetonitrile, Catalyzed by Octaacetatotetraplatinum(II). - High Reactivity of Coordination Sites Trans to the Pt-Pt Bond -
Yamaguchi, Tadashi,Adachi, Hisako,Ito, Tasuku,Sasaki, Yoichi
, p. 3116 - 3118 (1994)
The platinum(II) cluster, , catalyzes the hydrolysis of acetonitrile to acetamide in acetonitrile-water mixtures.Typical turnover number was 104 mol h-1 at 80 deg C.The catalyst was slowly deactivated by the accumulation of the less active acetamide-substituted species, as well as by its decomposition.
Hydration of Aliphatic Nitriles Catalyzed by an Osmium Polyhydride: Evidence for an Alternative Mechanism
Babón, Juan C.,Esteruelas, Miguel A.,López, Ana M.,O?ate, Enrique
, p. 7284 - 7296 (2021/05/29)
The hexahydride OsH6(PiPr3)2 competently catalyzes the hydration of aliphatic nitriles to amides. The main metal species under the catalytic conditions are the trihydride osmium(IV) amidate derivatives OsH3{κ2-N,O-[HNC(O)R]}(PiPr3)2, which have been isolated and fully characterized for R = iPr and tBu. The rate of hydration is proportional to the concentrations of the catalyst precursor, nitrile, and water. When these experimental findings and density functional theory calculations are combined, the mechanism of catalysis has been established. Complexes OsH3{κ2-N,O-[HNC(O)R]}(PiPr3)2 dissociate the carbonyl group of the chelate to afford κ1-N-amidate derivatives, which coordinate the nitrile. The subsequent attack of an external water molecule to both the C(sp) atom of the nitrile and the N atom of the amidate affords the amide and regenerates the κ1-N-amidate catalysts. The attack is concerted and takes place through a cyclic six-membered transition state, which involves Cnitrile···O-H···Namidate interactions. Before the attack, the free carbonyl group of the κ1-N-amidate ligand fixes the water molecule in the vicinity of the C(sp) atom of the nitrile.
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.
