1005-01-2Relevant articles and documents
An infrared study on matrix-isolated benzoic acid
Reva, I. D.,Stepanian, S. G.
, p. 337 - 340 (1995)
The infrared spectra of benzoic acid and deuterobenzoic acid embedded in Ar matrices were obtained.The only benzoic acid conformer with syn position of O-H and C=O groups was found to fix in the matrices.We have demonstrated that both a raise of benzoic a
Combining Structural with Functional Model Properties in Iron Synthetic Analogue Complexes for the Active Site in Rabbit Lipoxygenase
Bonck, Thorsten,De Waal Malefijt, Matina Elo?se,Dobbelaar, Emiel,Kelm, Harald,Klein, Johannes E. M. N.,Krüger, Hans-J?rg,Rauber, Christian,Schmitz, Markus
, p. 13145 - 13155 (2021)
Iron complexes that model the structural and functional properties of the active iron site in rabbit lipoxygenase are described. The ligand sphere of the mononuclear pseudo-octahedral cis-(carboxylato)(hydroxo)iron(III) complex, which is completed by a tetraazamacrocyclic ligand, reproduces the first coordination shell of the active site in the enzyme. In addition, two corresponding iron(II) complexes are presented that differ in the coordination of a water molecule. In their structural and electronic properties, both the (hydroxo)iron(III) and the (aqua)iron(II) complex reflect well the only two essential states found in the enzymatic mechanism of peroxidation of polyunsaturated fatty acids. Furthermore, the ferric complex is shown to undergo hydrogen atom abstraction reactions with O-H and C-H bonds of suitable substrates, and the bond dissociation free energy of the coordinated water ligand of the ferrous complex is determined to be 72.4 kcal·mol-1. Theoretical investigations of the reactivity support a concerted proton-coupled electron transfer mechanism in close analogy to the initial step in the enzymatic mechanism. The propensity of the (hydroxo)iron(III) complex to undergo H atom abstraction reactions is the basis for its catalytic function in the aerobic peroxidation of 2,4,6-tri(tert-butyl)phenol and its role as a radical initiator in the reaction of dihydroanthracene with oxygen.
Ratusky
, p. 124,126 (1970)
Theoretical modeling of infrared spectra of benzoic acid and its deuterated derivative
Boczar, Marek,Szczeponek, Krzysztof,Wójcik, Marek J.,Paluszkiewicz, Czes?awa
, p. 39 - 48 (2004)
Theoretical simulation of the νs stretching band is presented for benzoic acid and its OD derivative at 300 K. The simulation takes into account an adiabatic coupling between the high-frequency O-H(D) stretching and the low-frequency intermolec
Mechanism of the reaction of an NHC-coordinated palladium(II)-hydride with O2 in acetonitrile
Knapp, Spring M. M.,Konnick, Michael M.,Stahl, Shannon S.
, (2020)
PdII-hydride species are important intermediates in many Pd-catalyzed aerobic oxidation reactions, and their reaction with molecular oxygen has been the subject of considerable previous study. This investigation probes the reactivity of trans-[(IMes)2Pd(H)(OBz)] (IMes = 1,3-dimesitylimidazol-2-ylidene) with O2 in acetonitrile, a polar coordinating solvent that leads to substantial changes in the kinetic behavior of the reaction relative the previously reported reaction in benzene and other non-coordinating solvents. In acetonitrile, the benzoate ligand dissociates to form the solvent-coordinated complex trans-[(IMes)2Pd(H)(NCMe)][OBz]. Upon exposure to O2, this cationic PdII–H complex reacts to form the corresponding PdII-hydroperoxide complex trans-[(IMes)2Pd(OOH)(NCCD3)][OBz]. Kinetic studies of this reaction revealed a complex rate law, rate = k1k2[3][OBz]/(k?1[CD3CN] + k2[OBz]) + k3[3][OBz], which is rationalized by a mechanism involving two parallel pathways for rate-limiting deprotonation of the PdII–H species to generate the Pd0 complex, Pd(IMes)2. The latter complex undergoes rapid (kinetically invisible) reaction with O2 and BzOH to afford the PdII-hydroperoxide product. The results of this study are compared to observations from the previously reported reaction in benzene and discussed in the context of catalytic reactivity.
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Buswell,Rodebush,Roy
, p. 2239,2242 (1938)
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Hydrogen isotope fractionation factors for N,N-dimethylbenzyl-ammonium ion and some related species: An unusually strong preference for deuterium over protium
Guo, Hong-Xun,Kresge, A. Jerry
, p. 295 - 298 (1997)
Deuterium fractionation factors were determined by the 1H and 13C NMR methods in aqueous solution for PhCH2NLMe2+ (φ = 1.47 ± 0.05), PhCH2OL (φ = 1.04 ± 0.06), PhCO2L (φ = 1.04 ± 0.08), and CH3CO2L (φ = 0.99 ± 0.02). The medium effect for transferring PhCH2NMe2 from H2O to D2O, Φ = 1.025 ± 0.003, was also determined by partitioning this substance between water and immiscible organic solvents, and a UV spectroscopic method was used to measure the solvent isotope effect on the acid ionization of PhCH2NLMe2+, (Qa)H/(Qa)D = 4.88 ± 0.16. This solvent isotope effect agrees well with the value predicted using the relevant fractionation factors, (Qa)H/(Qa)D = 4.38 ± 0.28. The unusually large value of φ for PhCH2NLMe2+ is attributed to stiffened bending vibrations of its N-L bond imposed by the tetrahedral structure of the ion and the bulk of its methyl groups.
Kinetics and mechanism of the oxidation of substituted benzaldehydes by hexamethylenetetramine-bromine
Gangwani,Sharma,Banerji
, p. 615 - 622 (2000)
The oxidation of thirty-six monosubstituted benzaldehydes by hexa-methylenetetramine-bromine (HABR), in aqueous acetic acid solution, leads to the formation of the corresponding benzoic acids. The reaction is first order with respect to HABR. Michaelis-Menten-type kinetics were observed with respect to aldehyde. The reaction failed to induce the polymerization of acrylonitrile. There is no effect of hexamethylenetetramine on the reaction rate. The oxidation of [2H]benzaldehyde (PhCDO) indicated the presence of a substantial kinetic isotope effect. The effect of solvent composition indicated that the reaction rate increases with an increase in the polarity of the solvent. The rates of oxidation of meta- and para-substituted benzaldehydes showed excellent correlations in terms of Charton's triparametric LDR equation, whereas the oxidation of ortho-substituted benzaldehydes correlated well with tetraparametric LDRS equation. The oxidation of para-substituted benzaldehydes is more susceptible to the delocalization effect but the oxidation of ortho- and meta-substituted compounds displayed a greater dependence on the field effect. The positive value of γ suggests the presence of an electron-deficient reaction center in the rate-determining step. The reaction is subjected to steric acceleration when ortho-substituents are present.
Steric control and the mechanism of benzaldehyde oxidation by polypyridyl oxoiron(IV) complexes: Aromatic: versus benzylic hydroxylation of aromatic aldehydes
Turcas, Ramona,Lakk-Bogáth, Dóra,Speier, Gábor,Kaizer, József
, p. 3248 - 3252 (2018)
The present study describes the first example of the hydroxylation of benzaldehydes by synthetic nonheme oxoiron(iv) complexes, where the reactivity, chemoselectivity, and mechanism were strongly influenced by the ligand environment of the iron center.
Tropylium-Catalyzed O-H Insertion Reactions of Diazoalkanes with Carboxylic Acids
Empel, Claire,Nguyen, Thanh Vinh,Koenigs, Rene M.
supporting information, p. 548 - 553 (2021/01/26)
Herein, we describe the application of a nonbenzenoid aromatic carbocation, namely tropylium, as an organic Lewis acid catalyst in O-H functionalization reactions of diazoalkanes with benzoic acids. The newly developed protocol is applicable to a wide range of diazoalkane and carboxylic acid substrates with excellent efficiency (43 examples, up to 99% yield).
METHODS FOR DEPOLYMERIZING POLYESTERS
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Paragraph 0011; 0044-0045; 0086, (2021/10/22)
A method for depolymerizing a polyester may comprise heating a polyester at a temperature and for a period of time in the presence of a supported metal-dioxo catalyst, optionally, in the presence of H2, to induce hydrogenolysis of ester groups in the polyester and provide monomers of the polyester.
