Effect of small concentrations of water on ethylbenzene oxidation with molecular oxygen catalyzed by iron(II, III) acetylacetonate complexes with 18-crown-6

The Role H-Bonding and Supramolecular Structures in Homogeneous and Enzymatic Catalysis

“…After our work in article [29], it was found that the probability of transforming the β-diketone ligand of the iron complex via analogy with the action of FeARD or Fe-Dke-1 increases in an aquatic environment. This is consistent with the data obtained in our previous works [27,28].…”

“…The reaction products are as follows: (OAc) − chelate ligand and methylglyoxal (see Scheme 1, wherein the complex [Fe(acac) 2 •18C6] acts as an example): The important role of H-bonds in the formation of active forms of catalysts was established via the addition of small amounts of water (~10 −3 mol litre −1 ) to the {ML 1 n + L 2 } (M=Fe) systems. It was discovered that the addition of small amounts of water leads to an increase in the initial rates of RH oxidation and an increase in the parameter SPEH in the course of the reaction [3,27,28]. The observed decrease in the parameter (SPEH)max in the case of catalysis by complexes Fe(acac)2•18C6 might be explained by the decrease in the stationary concentration intermediates Fex II (acac)y(OAc)z(18C6)n(H2O)m due to the acceleration of the conversion of these reactive intermediates into the final product Fe(OAc)2.…”

Oxidation of 4­brometylbenzene by ozone in acetic acid

“…Hydroxylation of the aromatic ring led to the formation of 4-hydroxyethylbenzene. The catalytic effect of a small amount of water (~10 -3 mol/l), added to the reaction of oxidation of ethylbenzene by molecular oxygen, which is catalyzed by the system {Fe (III) (acac) 3+18-crown-6 (18C6)}, was revealed in paper [15]. An increase in the rate of the reaction and a change in the direction of oxidation were observed.…”

Visible-Light-Promoted Iron-Catalyzed N-Arylation of Dioxazolones with Arylboronic Acids

“…Interestingly, the yields of 3da and 3ea were remarkably increased to 71% and 85%, respectively, when oxygen-containing ligand (18-crown-6) was added. 23 Halides (F, Cl, and Br) were well-tolerated and delivered the corresponding products with good yields (3ha−3ja). Dioxazolones that contain a substituted group at the meta or ortho position of the aryl ring were also successfully involved under the standard conditions, affording the desired products 3ka− 3oa in satisfactory to excellent yields (57%−98%).…”

“…However, the reactions of dioxazolones ( 1d and 1e ) bearing a MeO or EtO substituent on the para positions of the benzene ring provided the corresponding products 3da and 3ea with 49% and 56% yields, respectively. Interestingly, the yields of 3da and 3ea were remarkably increased to 71% and 85%, respectively, when oxygen-containing ligand (18-crown-6) was added . Halides (F, Cl, and Br) were well-tolerated and delivered the corresponding products with good yields ( 3ha – 3ja ).…”