Despite the fact that extensive research has been carried out, the oxygenation of alkyl magnesium species still remains a highly unexplored research area and significant uncertainties concerning the mechanism of these reactions and the composition of the resulting products persist. This case study compares the viability of the controlled oxygenation of alkylmagnesium complexes supported by β-diketiminates. The structural tracking of the reactivity of (N,N)MgR-type complexes towards O at low temperature showed that their oxygenation led exclusively to the formation of magnesium alkylperoxides (N,N)MgOOR. The results also highlight significant differences in the stability of the resulting alkylperoxides in solution and demonstrate that [(BDI)Mg(μ-η :η -OOBn)] (in which BDI=[(ArNCMe) CH] and Ar=C H iPr -2,6) can be easily transformed to the corresponding magnesium alkoxide [(BDI)MgOBn] at ambient temperature, whilst [( BDI)Mg(μ-OOtBu)] (in which BDI=[(ArNCMe) CH] and Ar=C H F -2,4,6) is stable under similar conditions. The observed selective oxygenation of (N,N)MgR-type complexes to the corresponding (N,N)MgOOR alkylperoxides strongly contradicts the widely accepted radical-chain mechanism for the oxygenation of the main-group-metal alkyls. Furthermore, either the observed transformation of the alkylperoxide [(BDI)MgOOBn] to the alkoxide [(BDI)MgOBn] as well as the formation of an intractable mixture of products in the control reaction between the alkylperoxide [( BDI)MgOOtBu] and the parent alkylmagnesium [( BDI)MgtBu] complex are not in line with the common wisdom that magnesium alkoxide complexes' formation results from the metathesis reaction between MgOOR and Mg-R species. In addition, a high catalytic activity of well-defined magnesium alkylperoxides, in combination with tert-butyl hydroperoxide (TBHP) as an oxygen source, in the epoxidation of trans-chalcone is presented.

Reactions between O 2 and organometallics with non-redox-active metal centers have received continuous interest foro ver1 50 years, althoughs ignificant uncertainties concerningt he character and details of the actual mechanism of these reactions persist. Harnessingd inuclear threecoordinate alkylzinc derivatives of an N,N-coupled bis(b-diketimine) proligand (LH 2 )a sam odel system, we demonstrate for the first time that as light modification of the reaction conditions might have ad ramatic influence on the oxygenation reaction outcomes, leading to an unprecedented variety of products originating from as ingle reaction system,t hat is, partially and fully oxygenated zinc alkoxides,zinc alkylperoxides, and zinc hydroxide compounds. Our studies indicate that accessibility of the three-coordinate zinc center by the O 2 molecule, coupled with the lower reactivity of Zn-Me vs.

The epoxidation of enones by zinc alkylperoxides is a challenging task receiving considerable attention in contemporary research; however, until now no welldefined zinc alkylperoxide based systems have been described. Here, a new catalytic method of epoxidation of enones in the presence of zinc alkylperoxides supported by N,N-bidentate ligands and tert-butyl hydroperoxide is reported. A new dimeric zinc alkylperoxide complex supported by an aminotroponiminate ligand is also presented. The studied catalytic systems show high activity in the epoxidation of trans-chalcone, and in the case of a chiral catalyst with the (S,S)-N,N′-bis(1-phenylethyl)aminotroponiminate ligand a moderate enantioselectivity was achieved.

Over the past 150 years,acertain mythology has arisen around the mechanistic pathwaysofthe oxygenation of organometallics with non-redox-active metal centers as well as the character of products formed. Notably,t here is aw idespread perception that the formation of commonly encountered metal alkoxide species results from the auto-oxidation reaction, in whichaparent metal alkylc ompound is oxidized by the metal alkylperoxide via oxygen transfer reaction. Now, harnessing awell-defined zinc ethylperoxide incorporating a bdiketiminate ligand, the investigated alkylperoxide compounds do not react with the parent metal alkyl complex as well as Et 2 Zn to form az inc alkoxide.U pon treatment of the zinc ethylperoxide with Et 2 Zn, ap reviously unobserved ligand exchange process is favored. Isolation of az inc hydroxide carboxylate as ap roduct of decomposition of the parent zinc ethylperoxide demonstrates the susceptibility of the latter to OÀ Ob ond homolysis.Supportinginformation and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.

Despite decades of extensive studies on the reactivity of magnesium alkyls towards O2, the isolation and structural characterization of discrete products of these reactions still remains a challenge. Although the formation of the most frequently encountered magnesium alkoxides through unstable alkylperoxide intermediates has commonly been accepted, the latter species have been elusive for over 100 years. Probing the oxygenation of a seemingly simple well‐defined neo‐pentylmagnesium complex stabilized by a β‐diketiminate ligand, (dippBDI)MgCH2CMe3, we report on the isolation and structure characterization of both a dimeric magnesium alkoxide [(dippBDI)Mg(μ‐OCH2CMe3)]2 and the first example of monomeric magnesium alkylperoxide [(dippBDI)Mg(thf)OOCH2CMe3] (dippBDI=[(ArNCMe)2CH]− and Ar=C6H3iPr2‐2,6). The formation of monomeric magnesium alkylperoxide demonstrates a crucial role of an additional Lewis base for stabilizing the most elusive oxygenation products likely due to increasing of the electron density on the metal centre. Moreover, the 1H NMR studies at −80 °C revealed that the dissociation of a coordinated Lewis base from the solvated complex (dippBDI)Mg(L)CH2CMe3 (where L=thf or 4‐methylpyridine) is likely not required prior to the effective attack of an O2 molecule on the metal centre and the four‐coordinate alkylmagnesium complex reacts smoothly with O2 under these conditions. The results can be expected to aid future engineering of various organomagnesium/O2‐based reaction systems.

nation of zinc alkyls, 6-8 herein we describe the synthesis and Scheme 1 Representation of divergent solid-state product formation by the controlled oxygenation of alkylzinc complexes incorporating monoanionic X,Y-bidentate ligands.

The binding energy of the homogeneous metallic cluster consisting of N atoms can be expressed as [l, 21where BE(Me,) stands for the binding energy calculated per atom in the Me, cluster; E(MeN) and E(Me) denote the total energies of cluster and single atom, respectively. An analysis of the size effect, i.e. the dependence BE(Me,) = f ( N ) , directly from (1) is rather difficult and the use of the analytical cluster model (ACM) [3, 41 seems to be more convenient in this case.According to ACM the size effect 'of the binding energy of a three-dimensional metal cluster can be performed as The binding energy in homogeneous clusters, considered above, may be used as a background to the description of the size in heterogeneous clusters, i.e. in clusters consisting of at least two different types of components. A particular and simplest case of such clusters is an atom chemisorbed on a metallic substrate. In this note we confine ourselves to the case of atomic chemisorption of single oxygen and hydrogen atoms on 3d transition metal ')

While aluminum alkyls are often considered to be exemplary compounds of main-group organometallics and an in-depth understanding of their multifaceted chemistry is continually vital, the controlled oxygenation of organoaluminum complexes still remains a largely undeveloped area. In the course of our systematic studies on the relationship between the Lewis acidity of metal centers and noncovalent interactions in the secondary coordination sphere, we report the oxygenation of dialkylaluminum complexes incorporating a pyrrole–ester ligand, as purposefully selected dormant Lewis acidic octet-compliant model compounds, and the isolation and characterization of a new, dimeric aluminum tert -butylperoxide and an unique example of an aluminum oxoethoxide cluster. Our studies provide a more in-depth look at the diversity and complexity of the oxygenation chemistry of aluminum alkyls.