Reaching Milestones in the Oxygenation Chemistry of Magnesium Alkyls: towards Intimate States of O2 Activation and the First Monomeric Well-Defined Magnesium Alkylperoxide

Article abstract of DOI:10.1002/chem.201805180

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.

Full text of DOI:10.1002/chem.201805180

A Journal of
Accepted Article
Title: Reaching Milestones in the Oxygenation Chemistry of
Magnesium Alkyls: Towards Intimate States of O₂ Activation and
the First Monomeric Well-Defined Magnesium Alkylperoxide
Authors: Tomasz Pietrzak, Iwona Justyniak, Jiwon Victoria Park,
Michał Terlecki, Łukasz Kapuśniak, and Janusz Lewinski
This manuscript has been accepted after peer review and appears as an
Accepted Article online prior to editing, proofing, and formal publication
of the final Version of Record (VoR). This work is currently citable by
using the Digital Object Identifier (DOI) given below. The VoR will be
published online in Early View as soon as possible and may be different
to this Accepted Article as a result of editing. Readers should obtain
the VoR from the journal website shown below when it is published
to ensure accuracy of information. The authors are responsible for the
content of this Accepted Article.
To be cited as: Chem. Eur. J. 10.1002/chem.201805180
Link to VoR: http://dx.doi.org/10.1002/chem.201805180
Supported by

10.1002/chem.201805180
Chemistry - A European Journal
FULL PAPER
Reaching Milestones in the Oxygenation Chemistry of
Magnesium Alkyls: Towards Intimate States of O2 Activation and
the First Monomeric Well-Defined Magnesium Alkylperoxide
Tomasz Pietrzak,[a] Iwona Justyniak,[b] Jiwon Victoria Park,[c] Michał Terlecki,[a] Łukasz Kapuśniak[a] and
Janusz Lewiński*[a,b]
Abstract: 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 via 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-diketminate
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
Exceptional reactivity of main group metal-carbon bonds
towards dioxygen has lain at the heart of organometallic chemistry
since Frankland’s groundbreaking discovery in 1849.[1] Despite
decades of extensive research in the field, crucial factors
controlling the oxygenation reaction outcomes remain the subject
of lively discussions. Although the formation of the most frequently
encountered metal alkoxides via unstable alkylperoxide
intermediates has commonly been accepted, the latter species
have been elusive for almost 100 years. It was not until 1989
when the first dimeric indium[2] and, three years later, gallium[3]
alkylperoxides [(tBu)2M(µ-OOtBu)]2 were isolated and structurally
characterized from the controlled oxygenation of the homoleptic
tri(tert-butyl) metal derivatives. In later studies, the reactions of O2
with dialkylaluminium and alkylzinc complexes incorporating
monoanionic, bidentate ligands allowed for stabilization and
subsequent isolation of the first aluminium[4] and zinc[5,6]
alkylperoxides. Since that time, over a dozen examples of metal
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
alkylperoxides with non-redox-active metal centres, i.e. Li[7–9]
Na[8], K[8], Mg[10,11] Zn[12–17] Cd[18] Al[19,20] Ga[21] In[22,23]
incorporating variety of supporting ligands have been
,
(
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.
a
successfully synthesized. These compounds form typically
dimeric structures or higher aggregates with bridging
alkylperoxide moieties, however, to the best of our knowledge, a
handful of examples of terminal metal alkylperoxide have also
been described.[12,20,22] Moreover, despite the structural diversity
of isolated metal alkylperoxides with non-redox-active centres,
knowledge of their modes of further transformation still appears to
be fragmentary. Our group’s systematic studies on the reactivity
of zinc alkyls towards O2 have demonstrated that not only zinc
Introduction
alkylperoxides and alkoxides[15,17,24,25], but also zinc peroxide[26,27]
,
hydroxide[24,26,27], oxo[28,29] and even carboxylate[30] species can
be isolated from the controlled oxygenation of organozincs.
Furthermore, we have provided compelling evidence that a
variety of oxygenation products result from the decomposition of
(L)ZnOOR species mediated by the O-O bond scission. Recently,
we demonstrated that the observed diversity of the reaction
outcomes may be a distinguishing feature of a single reaction
system based on dinuclear alkylzinc complexes incorporating a
sterically encumbered bis(β-diketiminate) ligand.[24] In their
entirety, our results provided a basis for a new mechanism for
the oxygenation of organometallics with non-redox-active metal
centers, an inner-sphere electron-transfer mechanism (ISET).[16]
The crucial step of the ISET mechanism involves a non-specific
activation of an O2 molecule on the metal centre followed by
single electron transfer (SET) from the M-C bond to the O2
molecule (we note that the ISET mechanism nicely collaborates
[a]
T. Pietrzak, Ł. Kapuśniak, M. Terlecki, Prof. J. Lewiński
Faculty of Chemistry
Warsaw University of Technology
Noakowskiego 3, 00-664 Warsaw, Poland
E-mail: lewin@ch.pw.edu.pl
Dr. I. Justyniak, Prof. J. Lewiński
Institute of Physical Chemistry
Polish Academy of Science
Kasprzaka 44/52, 01-224 Warsaw, Poland
J. V. Park
[b]
[c]
Department of Chemistry
Massachusetts Institute of Technology
77 Massachusetts Avenue, Cambridge, Massachusetts 02139,
United States
Supporting information for this article is given via a link at the end of
the document.
This article is protected by copyright. All rights reserved.

10.1002/chem.201805180
Chemistry - A European Journal
FULL PAPER
Scheme 1. The oxygenation of the alkylmagnesium complex stabilized by the
β-diketoiminate ligand.
with our systematic studies on both the mentioned above
controlled oxygenation of organometallics with non-redox-active
metal centre as well as the reactivity of organozincs incorporating
non-innocent ligands, i.e.; stable nitoxide radicals[31], α-diimines[15]
and α-diketones[32]). Moreover, we have also emphasized the
essential role of the coordination state of the oxygenated
organoaluminum[33,34] and organozinc[5,15,16,24] compounds, as well
as the geometric requirements of an O2 molecule approaching the
metal centre.[33,34] Apart from the fundamental aspects, these
systematic studies have advanced rational design of metal
alkyl/air systems as radical initiators for organic reactions,[35–37]
stoichiometric[38,39] and catalytic asymmetric epoxidation of
enones[11,14,40] and pave the way to well-defined metal alkoxides
(not accessible via the classical alcoholysis path) as potential
initiators of cyclic esters polymerization[25,41] as well as to a new
approach for the preparation of semiconductor zinc oxide
quantum dots based on organozinc/air systems.[42–46]
Notably, the oxygenation chemistry of magnesium alkyls
has remained an undeveloped area of research due to difficulties
to control the respective reaction systems resulting from the
exceptional instability of MgOOR species. As early as the
beginning of the XXth century Bodroux[47] and Bouveault[48]
independently observed that oxygenation of RMgX compounds
afforded the corresponding ROH alcohols after the standard
workup procedure. Next, Wuyts postulated the formation of
magnesium alkylperoxide in the initial step of the oxygenation
process followed by its subsequent reduction by the parent Mg-R
complex with the formation of magnesium alkoxide.[49] In the late
‘60s, Davies and Roberts proposed the free-radical chain
mechanism of the oxygenation of organometallics with non-redox-
active metal center, and accordingly claimed that reactions of
RMgX with O2 occur via radical intermediates.[50,51] However, the
isolation and characterisation of magnesium alkoxides and
alkylperoxides via single-crystal X-ray diffraction has remained
challenging. A few examples of magnesium alkoxides has been
structurally authenticated only in the first decades of this
century[52–57]. The first example of magnesium alkylperoxide was
structurally characterized by Bailey and co-workers in 2003.[10]
This compound was obtained from the oxygenation of a
benzylmagnesium complex incorporating a β-diketiminate ligand
[(dipp)BDIMg(thf)Bn]
(
dippBDI
=
deprotonated
2-[(2,6-
diisopropylphenyl)amino]-4-[(2,6-diisopropylphenyl)-imino]pent-
2-ene). However, the resulting alkylperoxide [(dippBDI)Mg(μ-η2:η1-
OOBn)]2 was not isolated in pure form, but it co-crystallized with
the respective magnesium alkoxide [(dippBDI)Mg(µ-OBn)]2 in an
approximate ratio of 1:2. The authors suggested that the presence
of the metal alkoxide could be due to a metathesis reaction
between the resulting magnesium alkylperoxide and the parent
Mg-R complex. Recently, we reinvestigated the oxygenation
chemistry of magnesium alkyls stabilized by β-diketiminate
ligands and provided new insights into the reactivity of
magnesium alkylperoxide species. Our studies demonstrated that
the controlled oxygenation of [(dippBDI)MgBn(thf)] complex led
exclusively to the formation of magnesium alkylperoxide
[(dippBDI)Mg(μ-η2:η1-OOBn)]2 (Scheme 1).[11] This compound is
stable in the solid state, but easily transforms into the
corresponding magnesium alkoxide in a toluene solution at room
temperature. Notably, in the same work we also showed that the
This article is protected by copyright. All rights reserved.

10.1002/chem.201805180
Chemistry - A European Journal
FULL PAPER
stability of magnesium alkylperoxides in solution strongly
depends on the nature of the supporting N,N-ligands. In case of
the oxygenation of an alkylmagnesium complex supported by a
fluorinated β-diketiminate ligand, we isolated and structurally
characterized an alkylperoxide [(F3BDI)Mg(µ-OOtBu)]2 (F3BDI =
deprotonated
2-[(2,4,6-trifluorophenyl)amino]-[(2,4,6-trifluoro-
phenyl)imino]-pent-2-ene), which is stable in a toluene solution at
room temperature.[11] Moreover, we also demonstrated that the
direct reaction between the magnesium alkylperoxide
[(F3BDI)Mg(µ-OOtBu)]2 and the parent alkyl complex did not lead
to the respective magnesium alkoxide, i.e., the widely accepted
metathesis reaction did not occur on this occasion. Thus, we
anticipated that the observed formation of magnesium alkoxides
may result from an intramolecular rearrangement of the
alkylperoxide moiety in η2-alkylperoxide complexes.[11] The
resulting (L)MgOOR compounds were also found to be notably
more active as catalysts in the epoxidation of enones compared
to other various metal-based systems.[11,58–60]
Herein, we significantly advance the oxygenation chemistry
of magnesium alkyls supported by β-diketiminate ligands. Our
studies demonstrate that the controlled oxygenation of a well-
defined neo-pentylmagnesium complex results in the solvent-
dependent formation of a dimeric magnesium alkoxide or the first
example of monomeric magnesium alkylperoxide (Scheme 1).
The role of the coordination state of the metal centre during the
oxygenation of magnesium alkyls in the presence of donor ligands
is also addressed using low-temperature 1H NMR spectroscopy.
Figure 1. Molecular structure of 1; hydrogen atoms are omitted for clarity.
Selected bond lengths [Å] and angles [°]:Mg1–N1 2.006(5), Mg1–N2 2.033(5),
Mg1–C1 2.105(4); N1–Mg1–N2 93.06(12), N1–Mg1–C1 132.1(4), N2–Mg1–C1
134.5(4).
Results and Discussion
Synthesis and characterization of neo-pentylmagnesium
complexes incorporating a β-diketiminate ligand. In the
reported studies on the oxygenation magnesium alkyls supported
by a β-diketiminate ligand, we replaced the Mg-bond alkyl
substituent from benzyl to neo-pentyl. We note that the chemistry
of neo-pentylmagnesium derivatives is rather scare, and to the
best of our knowledge, there is only a handful of examples of
structurally characterized neo-pentylmagnesium complexes.[61–64]
The neo-pentylmagnesium complex, [(dippBDI)MgCH2CMe3] (1),
Figure 2. Molecular structure of 2; hydrogen atoms are omitted for clarity.
Selected bond lengths [Å] and angles [°]:Mg1–N1 2.082(2), Mg1–N2 2.070(2)),
Mg1–C1 2.132(2), Mg1–O1 2.092(2); N1–Mg1–N2 91.27(7), N1–Mg1–C1
123.8(9), N2–Mg1–C1 131.1(8), N1–Mg1–O1 101.8(7), N2–Mg1–O1 102.2(7).
and its solvated form
quantitatively prepared in equimolar reaction of (Me3CCH2)2Mg
and the dippBDI-H proligand in toluene or thf, respectively (dippBDI
[
dippBDIMgCH2CMe3(thf)] (2) were
geometrical parameters are essentially similar to that observed in
the previously reported analogous compounds, (dippBDI)MgtBu[65]
and (dippBDI)MgiPr[54]. Compound 2 crystallizes in the space group
P21 Its molecular structure with pseudo-tetrahedral geometry
.
=
deprotonated
2-[(2,6-diisopropylphenyl)amino]-4-[(2,6-
about the magnesium atom is depicted in Figure 2. The
MgCH2CMe3 moiety is chelated by the dippBDI ligand, andthe
magnesium atom is only slightly displaced from the CMgNN plane.
The coordination sphere of the metal center is completed by the
thf molecule.
diisopropylphenyl)-imino]pent-2-ene). These compounds are very
air- and moisture-sensitive and are soluble in hydrocarbon
solvents as well as toluene and thf. Both compounds were
characterized spectroscopically in solution and their molecular
structures in the solid state were determined by single crystal X-
ray diffraction analysis. The 1H NMR spectra of 1 and 2 are
relatively simple and featured a single set of signals characteristic
of the β-diketiminate ligand and the Mg-bound neo-pentyl group
(for more details, see Experimental Section). Colourless crystals
of 1 suitable for single crystal X-ray diffraction analysis were
isolated after storage of a toluene solution at 0 °C. The molecular
structure of 1 is shown in Figure 1. The complex exists as a
monomer with the three-coordinate magnesium centre and its
Oxygenation reactions
Synthesis and characterization of magnesium alkoxide and
alkylperoxide. The first attempts to isolate a crystalline product
resulting from the oxygenation of 1 with dry O2 conducted in a
wide temperature range from -78 °C to -20 °C in non-donor
solvents have failed. In all cases the formation of an amorphous
This article is protected by copyright. All rights reserved.

10.1002/chem.201805180
Chemistry - A European Journal
FULL PAPER
Figure 4. Molecular structure o 4; hydrogen atoms are omitted for clarity.
Selected bond lengths [Å] and angles [°]:Mg1–O1 1.908(3), Mg1–O2 2.176(3)
Mg1–O3 2.038(3), Mg1–N1 2.084(3), Mg1–N2 2.069(3), O1–O2 1.480(5), O2–
C1 1.432(6); O1–Mg1–N1 115.38(16), O1–Mg1–N2 126.88(16), O1–Mg1–O3
112.3(2), C1–O2–O1 109.7(4).
Figure 3. Molecular structure o 32; hydrogen atoms are omitted for clarity.
Selected bond lengths [Å] and angles [°]:Mg1–O1 1.983(2), Mg1–O1’ 1.992(2),
Mg1–N1 2.102(2), Mg1–N2 2.129(2), O1–C1 1.421(3); Mg1–O1–Mg1’ 97.99(7),
O1–Mg1–N1 114.98(8), O1–Mg1–N2 129.56(8), C1–O1–Mg1 125.77(15).
magnesium centre adopts distorted square pyramidal geometry
and its coordination sphere is completed by two nitrogen atoms
from the β-diketiminate ligand and the thf molecule. The Mg1-O1
bond in the terminal alkylperoxide ligand equals 1.908(3) Å, while
the peroxo O1-O2 bond length equals 1.480(5) Å and is longer
than those in the dimeric magnesium alkylperoxides
[(N,N)MgOOR)]2 incorporating β-diketiminate ligands.[11] To our
knowledge, compound 4 is the first example of monomeric
magnesium alkylperoxide.
phase was observed just after introduction of O2, likely due to
verypoor solubility of the resulting product(s). Next, the
oxygenation of 1 was conducted via a slow diffusion of pre-dried
air to a solution of 1 in toluene/CH2Cl2 mixture at -20 °C, which
allowed to isolate crystals of a magnesium neo-pentyloxide
[(dippBDI)Mg(µ-OCH2CMe3)]2 (32) suitable for X-ray diffraction
analysis (Scheme 1). Previously, the formation of analogous
magnesium alkoxides was reported for the oxygenation of well-
defined alkylmagnesium compounds [(dippBDI)MgnBu(thf)][53] and
dippBDIMgiPr[54]. Remarkably, dramatically different outcome was
observed when the reaction was conducted in thf as a donor
solvent. In this case the oxygenation of 1 by dry air at – 20 °C
followed by the crystallization at - 30 °C resulted in the formation
of a magnesium alkylperoxide [(dippBDI)MgOOCH2CMe3(thf)]
(4).[66] Compounds 32 and 4 were characterized spectroscopically
in solution and their molecular structure in the solid state was
determined by single crystal X-ray diffraction analysis. Compound
32 is poorly soluble in hydrocarbon solvents and toluene, and only
sparingly soluble in thf at ambient temperature. The 1H NMR
spectrum of 32 and 4 featured a single set of signals characteristic
of the Mg-bound neo-pentyloxide and the β-diketiminate ligand
(for details, see Experimental Section).
Towards the role of the coordination state of the magnesium
centre in the oxygenation of magnesium alkyls. As mentioned,
our previous results emphasized the essential role of the
coordination state of the metal centre in the oxygenation reaction.
For example, the four-coordinate zinc alkyl species do not display
reactivity towards dioxygen, in contrast to the three- coordinate
species, which react smoothly (Scheme 2A).[16,24] Remarkably,
the similar issue has not yet been resolved for alkylmagnesium
complexes.[10,11] Thus, another question which naturally arises as
to whether the initial attack of O2 during the oxygenation of 2
occurs on the three- or four-coordinate magnesium centre.
Nevertheless, this issue is rather challenging due to the lack of
univocal data concerning the coordination state of magnesium
alkyl complexes in donor solvents. The formation of the Lewis
acid-base adducts between magnesium alkyls supported by β-
diketiminates and various donor ligands is well documented in the
solid state.[67–69] In turn, in solution the molecular dynamics and
ligand exchange in [(dippBDI)MgR(L)]-type complexes were
particularly nicely demonstrated by Chisholm and co-workers.[68]
The authors showed that these complexes are kinetically labile
likely react through both a dissociative and an associative (with
the formation of the fifth-coordinate magnesium complex,
Compound 32 crystallizes in the space group P-1 as a
centrosymmetric dimer with the magnesium centres bridged by
neo-pentyloxide groups. The four-coordinate metal centres adopt
distorted tetrahedral geometry. The Mg-Mg separation is 2.999(2)
Å, while Mg-O bonds lengths fall in a narrow range of 1.983–1.992
Å. The observed geometric parameters for 32 are essentially
similar to that observed in the previously reported analogous
compounds [(dippBDI)Mg(µ-OR)]2.[10,11,53,54,67] Compound
4
crystallizes in space group P -1 as a monomeric moiety with a η2
-binding mode of the alkylperoxide ligand. The five-coordinate
This article is protected by copyright. All rights reserved.

10.1002/chem.201805180
Chemistry - A European Journal
FULL PAPER
analogous studies in the presence of a stronger Lewis base,
4-metylpyridine (py-Me) (for details, see Supporting Information).
Strikingly, in this case we do not observe any inhibition of the
reaction and the Lewis acid-base adduct between 1 and py-Me
reacts rapidly with O2 at - 80 °C (Figure 10S). Thus, the observed
oxygenation of the putative four-coordinate complex
[(dippBDI)MgCH2CMe3(py-Me)] in thf-d8 suggests that the
dissociation of the ligand from the four-coordinate magnesium
complex [(dippBDI)MgCH2CMe3(L)]is not likely required prior to the
effective attack of an O2 molecule on the metal centre and the
noncovalent activation of the O2 molecule, being the crucial step
in our mechanistic understanding (vide infra), can occur on either
the fourth or the fifth magnesium centre coordination site (Scheme
2B); we note that the latter case nicely resembles a five-
coordinate interchange activated complex, which have previously
been postulated by Chisholm and co-workers during the
associative ligand exchange (Scheme 3).[68]
Factors affecting the oxygenation reaction outcomes. The
rational synthesis of well-defined metal complexes with both
redox-active and non-redox-active metal centre, which can
efficiently drive the selective ground-state dioxygen (3O2)
activation has been a challenging goal. Although multi-electron
reductive activation of dioxygen is thermodynamically favourable,
this process is kinetically hindered due to a triplet spin ground
state of O2 and one-electron reduction with the formation of
superoxide anion is a highly endothermic reaction (−0.60 V vs
NHE in DMF).[70] In enzymes containing redox-active metal
centres such processes usually proceed through various subtle
O2 intermediates to circumvent unwanted radical reactions. In turn,
it has been commonly postulated that autooxidation of
organometallics with non-redox-active occur via radical-chain
mechanism; however, the source of the initial R· radical still
remains as an open question.[71] Our systematic studies on the
oxygenation of organozincs shed new light into the possible
pathways of these reactions. For example, it seems likely that the
kinetical inertness of O2 is bypassed through a non-covalent
activation on the metal centre followed by an electron transfer
from the M-C bond to the activated O2 molecule. Thus, this weak
interaction changes the electronic structure of O2 and facilitates
the single electron transfer from the M-C bond to O2. The
activation process strongly correlates with the coordination state
Scheme 2. The role of the coordination state of organozinc and
organomagnesium compounds on the oxygenation reaction.
Scheme 3. The postulated associative interchange process for the
[
dippBDIMgR(L)]-type complexes.
Scheme 3) interchange mechanism.
Inspired by the Chisholm’ investigations, in order to
determine the role of the coordination state of alkylmagnesium
compounds in the oxygenation process, we initially probed the
oxygenation of 1 solvated by thf molecules by low-temperature 1H
NMR studies. For this purpose, a solution of 2 in thf-d8 was placed
in J. Young valve NMR tube and cooled with liquid nitrogen. Next,
dry dioxygen was introduced and the sample was heated to
- 80 °C in NMR apparatus. Interestingly, the disappearance of the
signals attributable to the Mg-CH2tBu protons was immediately
observed, just after dissolving the sample (Figure 9S). Taking into
account that complex 2 is kinetically labile and may partly
dissociate even at low temperature, we also conducted the
Scheme 4. The proposed reaction pathways of the oxygenation of the three-coordinate complex 1, for the analogous reaction pathway of the oxygenation
process involving the respective four-coordinate species, see Figure 1S.
This article is protected by copyright. All rights reserved.

10.1002/chem.201805180
Chemistry - A European Journal
FULL PAPER
followed by purification according to the literature methods.[74]
Oxygenation reactions were carried out using atmospheric air dried
through an open-end adapter filled with anhydrous CaCl2.[11] NMR spectra
were acquired on a Varian Mercury 400 spectrometer at 298 K.
of the reacting organometallic molecule since the approaching O2
molecule requires activation by the metal centre of sufficient
Lewis acidity. Based on the aforementioned studies, we propose
the reaction pathways for the oxygenation of 1 as outlined in
Scheme 4 and Scheme 1S. It involves an initial attack of an O2
molecule on the magnesium centre (A) followed by its non-
covalent activation on the Mg centre (B). As was demonstrated,
both three- and four-coordinate magnesium centres may activate
an O2 molecule. Next, it is believed that the formation of this non-
covalent complex triggers the inner-sphere electron transfer to
form a radical pair (C). Subsequently, the triplet-to-singlet surface
crossing allows this radical pair to rearrange to an alkylperoxide
Synthesis of 1: A solution of dippBDI-H (418 mg, 1.000 mmol) in toluene
(7 mL) was cooled to -70°C, and (Me3CCH2)2Mg (2.20 mL of a 0.45 M
solution of toluene, 1 mmol) was slowly added using a syringe. The
reaction mixture was then stirred overnight at ambient temperature.
Compound 1 was obtained as colourless crystals after crystallization
overnight at 0°C (isolated yield 92%, 472 mg). Elemental analysis calcd
(%) for C34H52MgN2: C 79.59, H 10.21, N 5.46; found 78.93, H 10.11, N
5.61. 1H NMR(400 MHz, C7D8, 25 °C): δ = 7.13–6.99 (m, 6H; CHN-aryl), 4.92
(s, 1H; CH3CNCH), 3.13 (sept, JH-H = 6.9 Hz, 4H, CH(CH3)2), 1.67 (s, 6H,
CH3CN), 1.31 (d, JH-H = 6.9 Hz, 12H, CH(CH3)2), 1.15 (d, JH-H = 6.9 Hz,
12H, CH(CH3)2), 0.78 (s, 18H, MgCH2(CH3)3), - 0.06 ppm (s, 2H,
MgCH2(CH3)3).
Synthesis of 2: A solution of dippBDI-H (125 mg, 0.300 mmol) in THF (6
mL) was cooled to -70°C, and (Me3CCH2)2Mg (0.66 mL of a 0.45 M
solution of toluene, 0.300 mmol) was slowly added using a syringe. The
reaction mixture was then stirred for overnight at ambient temperature.
Compound 2 was obtained as colourless crystals after concentration of the
solution followed by the addition of pentane (2 mL) and crystallization
overnight at 0°C (isolated yield 88%, 154 mg). Elemental analysis calcd
(%) for C38H60MgN2O: C 77.99, H 10.33, N 4.79; found 77.41, H 10.27, N
4.94. 1H NMR(400 MHz, C7D8, 25 °C): δ = 7.13–6.99 (m, 6H; CHN-aryl), 4.78
(s, 1H; CH3CNCH), 3.74 (b, 4H, O(CH2,CH2)2), 3.26 (m, 4H, CH(CH3)2),
1.63 (s, 6H, CH3CN), 1.42 (b, 4H, O(CH2,CH2)2), 1.34 (d, JH-H = 6.9 Hz,
12H, CH(CH3)2), 1.22 (d, JH-H = 6.8 Hz, 12H, CH(CH3)2), 0.88 (s, 18H,
MgCH2(CH3)3), - 0.21 ppm (s, 2H, MgCH2(CH3)3).
species
[
and
finally
yielding
the
monomeric
dippBDIMgOOCH2CMe3] complex. The resulting magnesium
alkylperoxide appears to be unstable in a toluene/CH2Cl2 solution
and easily transforms to the respective magnesium alkoxide 32
under these conditions. Thus, the sterically hindered neo-pentyl
group does not sufficiently stabilize the alkylperoxide moiety and
an intramolecular rearrangement of the Mg-OOR species may
occur in non-donor solvents. Conversely, the presence of thf
efficiently stabilizes the nascent [dippBDIMgOOCH2CMe3] complex.
Undoubtedly, a remarkable observation of these studies is the
stabilization of the magnesium alkylperoxide 4 by thf. Thus, these
studies along with our earlier results for zinc alkylperoxide[16,24]
unambiguously prove that stabilization of the most unstable
oxygenation products is due to the increased electron density on
the metal centre.
Synthesis of 32: The Schlenk vessel with a solution of 1 (302 mg, 0.50
mmol) in 4 mL of a mixture of CH2Cl2 and toluene (1:1) was equipped with
an open-end adapter with anhydrous CaCl2 and placed in a freezer without
stirring for one hour. Afterwards, the adapter was changed to a glass
stopcock, and the reaction mixture was gently concentrated and stored at
- 30°C. Compound 32 was obtained as colourless crystals after
crystallization overnight at - 30°C (isolated yield 82%, 216 mg). Elemental
analysis calcd (%) for C68H104Mg2N4O2: C 77.18, H 9.91, N 5.29; found
76.81, H 9.78, N 5.44. The respective 1H NMR spectrum was obtained
upon heating of the sample. 1H NMR (400 MHz, C6D6, 25 °C): 7.35-6.95
(m, 12H; CHN-aryl), 4.77 (s, 2H; CH3CNCH), 3.35 (s, 4H, MgOCH2(CH3)3),
3.44, 3.15, 2.99 (m, 8H; CH(CH3)2), 1.53 (s, 6H; CH3CN), 1.44 (s, 6H;
CH3CN), 1.21 (d, 12H; CH(CH3)2), 1.17 (d, 12H; CH(CH3)2), 1.16 (d, 12H;
CH(CH3)2), 1.07 (d, 12H; CH(CH3)2), 1.00 (s, 18H; MgOCH2CH3)3) ppm.
Synthesis of 4: A solution of 1 (151 mg, 0.25 mmol) in thf (5 mL) was
oxygenated using a procedure similar to that employed in the synthesis of
compounds 3. Compound 4 was obtained as colourless crystals after
standard workup procedure (isolated yield 69%, 98 mg). Elemental
analysis calcd (%) for C38H60MgN2O3: C 73.95, H 9.80, N 4.54; found 73.52,
H 9.71, N 5.07. 1H NMR(400 MHz, C7D8, 25 °C): δ = 7.12–6.99 (m, 6H;
CHN-aryl), 4.84 (s, 1H; CH3CNCH), 3.54 (b, 4H, O(CH2,CH2)2), 3.43 (m, 2H,
CH(CH3)2), 3.28 (s, 2H, MgOOCH2(CH3)3), 3.04 (m, 2H, CH(CH3)2), 1.69
(s, 6H, CH3CN), 1.39 (b, 4H, O(CH2,CH2)2), 1.27 (b, 12H, CH(CH3)2), 1.19
(b, 12H, CH(CH3)2), 0.98 (s, 18H, MgCH2(CH3)3) ppm.
Conclusions
Our comparative studies on the reactivity of the well-defined neo-
pentylmagnesium complexes incorporating the β-diketiminate
ligand toward O2 represent another step forward to better
understand intimate steps of the oxygenation process, as well as
the factors controlling the character of oxygenation products. The
isolation of the magnesium alkoxide and the first monomeric
magnesium alkylperoxide not only nicely complement our
ongoing studies on the oxygenation chemistry of magnesium
alkyls[11], but also demonstrate that subtle changes in the reaction
system play a crucial role during the formation of the reaction
outcomes. We believe that the reported results pave the way for
organomagnesium/O2 reactions systems for various applications.
Experimental Section
All reactions involving air- and moisture-sensitive organometallic
compounds were conducted under argon atmosphere using standard
Schlenk techniques and glovebox techniques (MBraun UniLab Plus; < 0.1
ppm O2, < 0.1 ppm H2O). All solvents were purified by passage through
activated aluminum oxide (MBraun SPS) and stored over molecular sieves.
Deuterated solvents were dried over Na/K, distilled under argon
atmosphere prior to use and stored over molecular sieves. All Reagents
used in this study were of commercial grade and obtained from Sigma-
Aldrich Co. dippBDI-H[72] was synthesized according to the literature
methods. (Me3CCH2)2Mg was prepared by adding 1 equivalent of
Me3CCH2Li[73] in hexane to a Et2O solution of Me3CCH2MgCl[73] at 0°C
X-ray structure determination: The crystals of all complexes were
selected under Paratone-N oil, mounted on the nylon loops and positioned
in the cold stream on the diffractometer. The X-ray data for complexes 1,
2, 32, and 4 were collected at 100(2)K on a SuperNova Agilent
diffractometer using CuKα radiation ( = 1.54184 Å). The data were
processed with CrysAlisPro[75] The structures were solved by direct
methods and refined using the SHELXL97.[76] All non-hydrogen atoms
were refined with anisotropic displacement parameters. The hydrogen
atoms were introduced at geometrically idealized coordinates with a fixed
This article is protected by copyright. All rights reserved.

10.1002/chem.201805180
Chemistry - A European Journal
FULL PAPER
isotropic displacement parameter equal to 1.5 (methyl groups) times the
value of the equivalent isotropic displacement parameter of the parent
carbon.
Crystal data for 1, C34H52MgN2: M = 513.08, orthorhombic , space group
P n21a (no. 33), a = 18.4342(3) Å, b = 21.0337(5) Å c = 8.3459(2) Å, U =
3236.03(12) Å3, Z = 4, F(000) = 1128, Dc = 1.053 g cm-3, μ(Cu-Kα) = 0.078
mm–1, max = 70.9394 , 4253 unique reflections. Refinement converged at
R1 = 0.0788, wR2 = 0.2114 for all data and 347 parameters (R1 = 0.0714,
W. Ziller, Polyhedron 1992, 11, 477–486.
[4]
[5]
[6]
J. Lewiński, J. Zachara, E. Grabska, J. Am. Chem. Soc.
1996, 118, 6794–6795.
J. Lewiński, W. Marciniak, J. Lipkowski, I. Justyniak, J. Am.
Chem. Soc. 2003, 125, 12698–12699.
J. Lewiński, Z. Ochal, E. Bojarski, E. Tratkiewicz, I.
Justyniak, J. Lipkowski, Angew. Chem. Int. Ed. 2003, 42,
4643–4646.
wR2 = 0.2007 for 3819 reflections with Io > 2(Io)). The goodness-of-fit on
2
F2 was equal 1.129. A weighting scheme w = [2(Fo + (0.0418P)2
+
3.1964P]-1 where P = (Fo + 2Fc2 )/3 was used in the final stage of
refinement. The residual electron density = + 0.93 /- 0.52 eÅ-3. CCDC-
1860425
2
[7]
G. Boche, K. Möbus, K. Harms, J. C. W. Lohrenz, M.
Marsch, Chem. Eur. J. 1996, 2, 604–607.
[8]
H. Osseili, K.-N. Truong, T. P. Spaniol, D. Mukherjee, U.
Englert, J. Okuda, Chem. Eur. J. 2017, 23, 17213–17216.
W. Uhl, M. Reza Halvagar, M. Claesener, Chem. Eur. J.
2009, 15, 11298–11306.
Crystal data for 2, C38H60MgN2O: M = 585.19, monoclinic, space group P
21 (no. 4), a = 9.9050(2) Å, b = 16.4269(3) Å c = 11.6551(3) Å,  =
110.175(3) , U = 1780.03(7) Å3, Z = 2, F(000) = 644, Dc = 1.092 g cm-3,
μ(Cu-Kα) = 0.642 –1, max = 71.025 , 4568 unique reflections. Refinement
converged at R1 = 0.0387, wR2 = 0.1030 for all data and 392 parameters
[9]
[10]
P. J. Bailey, R. a Coxall, C. M. Dick, S. Fabre, L. C.
Henderson, C. Herber, S. T. Liddle, D. Loroño-González, A.
Parkin, S. Parsons, Chem. Eur. J. 2003, 9, 4820–4828.
T. Pietrzak, M. Kubisiak, I. Justyniak, K. Zelga, E. Bojarski,
E. Tratkiewicz, Z. Ochal, J. Lewiński, Chem. Eur. J. 2016,
22, 17776–17783.
(R1 = 0.0384, wR2 = 0.1026for 4525 reflections with Io > 2(Io)). The
2
goodness-of-fit on F2 was equal 1.029. A weighting scheme w = [2(Fo
+
(0.0418P)2 + 3.1964P]-1 where P = (Fo + 2Fc2 )/3 was used in the final
stage of refinement. The residual electron density = + 0.35 /- 0.43 eÅ-3.
CCDC-1860426
2
[11]
Crystal data for 32, C68H104Mg2N4O2: M = 1058.17, triclinic, space group
P -1/c (no. 2), a = 11.4803(7) Å, b = 13.0905(8) Å c = 13.5105(10)Å, α =
94.984(5) ,  = 113.360(6) , γ = 108.025(5) , U = 1720.7(2) Å3, Z = 1,
F(000) = 580, Dc = 1.021 g cm-3, μ(Cu-Kα) = 0.077–1, max = 71.8297, 6494
unique reflections. Refinement converged at R1 = 0.0649, wR2 = 0.1580
for all data and 356 parameters (R1 = 0.0567, wR2 = 0.1533 for 5470
[12]
[13]
D. Mukherjee, A. Ellern, A. D. Sadow, J. Am. Chem. Soc.
2012, 134, 13018–13026.
N. V. Kulkarni, A. Das, S. G. Ridlen, E. Maxfield, V. A. K.
Adiraju, M. Yousufuddin, H. V. R. Dias, Dalton Trans. 2016,
45, 4896–4906.
reflections with Io > 2(Io)). The goodness-of-fit on F2 was equal 1.063. A
2
weighting scheme w = [2(Fo2 + (0.0418P)2 + 3.1964P]-1 where P = (Fo
+
[14]
M. Kubisiak, K. Zelga, I. Justyniak, E. Tratkiewicz, T.
Pietrzak, A. R. Keeri, Z. Ochal, L. Hartenstein, P. W.
Roesky, J. Lewiński, Organometallics 2013, 32, 5263–
5265.
2Fc2 )/3 was used in the final stage of refinement. The residual electron
density = + 0.47 /- 0.31 eÅ-3. CCDC-18604427
Crystal data for 4·thf, C42H68MgN2O4 : M = 689.29, triclinic , space group
P -1 (no. 2), a = 9.0979(6) Å, b = 12.6442(7)Å c = 18.2954(10) Å, α =
76.574(5) ,  = 80.144(5) , γ = 85.909(5) , U = 2015.8(2) Å3, Z = 2,
F(000) = 756, Dc = 1.136 g cm-3, μ(Cu-Kα) = 0.694 mm–1, max = 55.089 ,
5053 unique reflections. Refinement converged at R1 = 0.1026, wR2 =
0.2178 for all data and 465 parameters (R1 = 0.0824, wR2 = 0.2093 for
4495 reflections with Io > 2(Io)). The goodness-of-fit on F2 was equal
1.095. A weighting scheme w = [2(Fo2 + (0.0418P)2 + 3.1964P]-1 where P
[15]
[16]
[17]
[18]
[19]
J. Lewiński, K. Suwała, M. Kubisiak, Z. Ochal, I. Justyniak,
J. Lipkowski, Angew. Chem. Int. Ed. 2008, 47, 7888–7891.
J. Lewiński, W. Śliwiński, M. Dranka, I. Justyniak, J.
Lipkowski, Angew. Chem. Int. Ed. 2006, 45, 4826–4829.
M. K. Leszczyński, I. Justyniak, J. Lewiński,
Organometallics 2017, 36, 2377–2380.
2
= (Fo + 2Fc2 )/3 was used in the final stage of refinement. The residual
electron density = + 0.90 /- 0.59 eÅ-3. CCDC-18604428.
A. L. Johnson, N. Hollingsworth, G. Kociok-Köhn, K. C.
Molloy, Angew. Chem. Int. Ed. 2012, 51, 4108–4111.
S. S. Kumar, S. Singh, H. W. Roesky, J. Magull, Inorg.
Chem. 2005, 44, 1199–1201.
Acknowledgements
[20]
[21]
W. Uhl, B. Jana, Chem. Eur. J. 2008, 14, 3067–3071.
W. Uhl, M. R. Halvagar, H. R. Bock, B. Jasper-Peter, M.
Layh, Zeitschrift für Naturforsch. B 2009, 64b, 1369–1374.
W. Uhl, B. Jana, Eur. J. Inorg. Chem. 2009, 2009, 3942–
3947.
The authors would like to acknowledge the National Science
Centre - Grant OPUS DEC-2017/27/B/ST5/02329 and Grant
PRELUDIUM DEC-2016/23/N/ST5/02081 (T.P.) for financial
support. Dr. M. Dutkiewicz is kindly acknowledged for his
invaluable help in the synthesis of bis(neo-pentyl)magnesium
compound.
[22]
[23]
[24]
B. Jana, C. Honaker, W. Uhl, J. Organomet. Chem. 2018,
856, 78–86.
T. Pietrzak, M. D. Korzyński, I. Justyniak, K. Zelga, A.
Kornowicz, Z. Ochal, J. Lewiński, Chem. Eur. J. 2017, 23,
7997–8005.
Keywords: magnesium • dioxygen • peroxides • main group
elements • oxygenation
[25]
[26]
[27]
Z. Wróbel, T. Pietrzak, I. Justyniak, J. Lewiński, Chem.
Commun. 2017, 53, 10808–10811.
[1]
[2]
E. Frankland, Liebigs Ann. Chem. 1849, 71, 171.
W. M. Cleaver, A. R. Barron, J. Am. Chem. Soc. 1989, 111,
8966–8967.
P. Sobota, R. Petrus, K. Zelga, Ł. Mąkolski, D. Kubicki, J.
Lewiński, Chem. Commun. 2013, 49, 10477–10479.
Ł. Mąkolski, K. Zelga, R. Petrus, D. Kubicki, P. Zarzycki, P.
[3]
M. B. Power, W. M. Cleaver, A. W. Apblett, A. R. Barron, J.
This article is protected by copyright. All rights reserved.

10.1002/chem.201805180
Chemistry - A European Journal
FULL PAPER
Sobota, J. Lewiński, Chem. Eur. J. 2014, 20, 14790–14799.
Soc. Dalt. Trans. 2000, 1655–1661.
[28]
J. Lewiński, W. Bury, M. Dutkiewicz, M. Maurin, I.
Justyniak, J. Lipkowski, Angew. Chem. Int. Ed. 2008, 47,
573–576.
[53]
[54]
M. H. Chisholm, K. Choojun, J. C. Gallucci, P. M. Wambua,
Chem. Sci. 2012, 3, 3445.
A. P. Dove, V. C. Gibson, P. Hormnirun, E. L. Marshall, J.
A. Segal, A. J. P. White, D. J. Williams, Dalton Trans. 2003,
3088–3097.
[29]
J. Lewiński, K. Suwała, T. Kaczorowski, M. Gałęzowski, D.
T. Gryko, I. Justyniak, J. Lipkowski, Chem. Commun. 2009,
119, 215–217.
[55]
D. Mukherjee, N. L. Lampland, K. Yan, J. F. Dunne, A.
Ellern, A. D. Sadow, Chem. Commun. 2013, 49, 4334–
4336.
[30]
[31]
[32]
[33]
J. Lewiński, M. Kościelski, K. Suwała, I. Justyniak, Angew.
Chem. Int. Ed. 2009, 48, 7017–7020.
K. Budny-Godlewski, D. Kubicki, I. Justyniak, J. Lewiński,
Organometallics 2014, 33, 5093–5096.
[56]
[57]
[58]
[59]
[60]
B. Conway, E. Hevia, A. R. Kennedy, R. E. Mulvey, S.
Weatherstone, Dalton Trans. 2005, 1532–44.
C. A. Moreno, D. L. Hughes, M. Bochmann, Polyhedron
2007, 26, 2523–2526.
I. Dranka, M. Kubisiak, I. Justyniak, M. Lesiuk, D. Kubicki,
J. Lewiński, Chem. Eur. J. 2011, 17, 12713–12721.
J. Lewiński, J. Zachara, P. Goś, E. Grabska, T. Kopeć, I.
Madura, W. Marciniak, I. Prowotorow, Chem. Eur. J. 2000,
6, 3215–3227.
Y. Minko, I. Marek, Org. Biomol. Chem. 2014, 12, 1535–
1546.
M. J. Porter, J. Skidmore, Chem. Commun. 2000, 1215–
1225.
[34]
J. Lewiński, J. Zachara, I. Justyniak, Chem. Commun.
2002, 1586–1587.
D. Diez, M. Nunez, A. Anton, P. Garcia, R. Moro, N.
Garrido, I. Marcos, P. Basabe, J. Urones, Curr. Org. Synth.
2008, 5, 186–216.
[35]
[36]
K. Yamada, K. Tomioka, Chem. Rec. 2015, 15, 854–871.
M. Kubisiak, K. Zelga, W. Bury, I. Justyniak, K. Budny-
Godlewski, Z. Ochal, J. Lewiński, Chem. Sci. 2015, 6,
3102–3108.
[61]
[62]
[63]
[64]
E. P. Squiller, R. R. Whittle, H. G. Richey, J. Am. Chem.
Soc. 1985, 107, 432–435.
[37]
[38]
[39]
[40]
[41]
[42]
[43]
T. Akindele, K. Yamada, K. Tomioka, Acc. Chem. Res.
2009, 42, 345–355.
E. P. Squiller, R. R. Whittle, H. G. Richey, Organometallics
1985, 4, 1154–1157.
D. Enders, J. Zhu, G. Raabe, Angew. Chem. Int. Ed.
English 1996, 35, 1725–1728.
J. Francos, P. C. Gros, A. R. Kennedy, C. T. O’Hara,
Organometallics 2015, 34, 2550–2557.
D. Enders, J. Zhu, L. Kramps, Liebigs Ann. 1997, 1997,
1101–1113.
P. R. Markies, G. Schat, O. S. Akkerman, F. Bickelhaupt,
W. J. J. Smeets, A. J. M. Duisenberg, A. L. Spek, J.
Organomet. Chem. 1989, 375, 11–20.
A. Raheem Keeri, I. Justyniak, J. Jurczak, J. Lewiński, Adv.
Synth. Catal. 2016, 358, 864–868.
[65]
[66]
V. C. Gibson, J. A. Segal, A. J. P. White, D. J. Williams, J.
Am. Chem. Soc. 2000, 122, 7120–7121.
During the synthesis of 3 and 4, we have not observed the
oxidation of the β-diketiminate ligand, athought this type of
reactivity has occasionally been encountered homoleptic
and heteroleptic metal complexes, for example, see: C.
Camp, J. Arnold, Dalton Trans. 2016, 45, 14462–14498; J.
Pahl, A. Friedrich, H. Elsen, S. Harder, Organometallics
2018, 37, 2901–2909.
L. Qin, J. Bai, Y. Zhang, X. Chen, J. Organomet. Chem.
2018, 871, 40–47.
E. Chwojnowska, M. Wolska-Pietkiewicz, J. Grzonka, J.
Lewiński, Nanoscale 2017, 9, 14782–14786.
M. Wolska-Pietkiewicz, K. Tokarska, A. Grala, A.
Wojewódzka, E. Chwojnowska, J. Grzonka, P. J. Cywiński,
K. Kruczała, Z. Sojka, M. Chudy, et al., Chem. Eur. J. 2018,
24, 4033–4042.
[44]
[45]
A. Grala, M. Wolska-Pietkiewicz, W. Danowski, Z. Wróbel,
J. Grzonka, J. Lewiński, Chem. Commun. 2016, 52, 7340–
7343.
[67]
[68]
[69]
[70]
[71]
[72]
L. Davin, W. Clegg, A. R. Kennedy, M. R. Probert, R.
McLellan, E. Hevia, Chem. Eur. J. 2018, 24, 14830–14835.
M. H. Chisholm, K. Choojun, A. S. Chow, G. Fraenkel,
Angew. Chem. Int. Ed. 2013, 52, 3264–3266.
M. S. Hill, D. J. MacDougall, M. F. Mahon, Dalton Trans.
2010, 39, 11129–11131.
A. M. Cieślak, M. V. Pavliuk, L. D’Amario, M. Abdellah, K.
Sokołowski, U. Rybinska, D. L. A. Fernandes, M. K.
Leszczyński, F. Mamedov, A. M. El-Zhory, et al., Nano
Energy 2016, 30, 187–192.
D. T. Sawyer, J. S. Valentine, Acc. Chem. Res. 1981, 14,
393–400.
[46]
M. K. Leszczyński, I. Justyniak, K. Zelga, J. Lewiński,
Dalton Trans. 2017, 46, 12404–12407.
J. M. Grévy, Encyclopedia of Inorganic Chemistry, Wiley,
Chichester, 2005.
[47]
[48]
[49]
[50]
F. Bodroux, Compt. Rend. 1903, 136, 158–159.
M. L. Bouveault, Bull. Soc. Chim. Fr. 1903, 29, 1051.
H. Wuyts, Compt. Rend. 1909, 134, 930.
A. G. Davies, B. P. Roberts, J. Chem. Soc. B Phys. Org.
1968, 1074.
M. Stender, R. J. Wright, B. E. Eichler, J. Prust, M. M.
Olmstead, H. W. Roesky, P. P. Power, J. Chem. Soc. Dalt.
Trans. 2001, 3465–3469.
[73]
[74]
R. R. Schrock, J. D. Fellmann, J. Am. Chem. Soc. 1978,
100, 3359–3370.
[51]
[52]
A. G. Davies, J. Chem. Res. 2008, 2, 361–375.
P. J. Bailey, C. M. E. Dick, S. Fabre, S. Parsons, J. Chem.
R. A. Andersen, G. Wilkinson, J. Chem. Soc. Dalt. Trans.
This article is protected by copyright. All rights reserved.

10.1002/chem.201805180
Chemistry - A European Journal
FULL PAPER
1977, 809.
[75]
[76]
Agilent Technologies, CrysAlisPro, Version 1.171.35.21b.
G. M. Sheldrick, Acta Crystallogr. Sect. A 2008, 64, 112–
122.
This article is protected by copyright. All rights reserved.

10.1002/chem.201805180
Chemistry - A European Journal
FULL PAPER
Entry for the Table of Contents (Please choose one layout)
Layout 1:
FULL PAPER
Solvent makes a difference! Probing
the oxygenation of a well-defined neo-
pentylmagnesium complex stabilized
Tomasz Pietrzak, Iwona Justyniak,
Jiwon Victoria Park, Michał Terlecki,
Łukasz Kapuśniak, Janusz Lewiński*
by
(
a
β-diketminate
ligand,
dippBDI)MgCH2CMe3, we report on the
Page No. – Page No.
isolation and structure characterization
of both a dimeric magnesium alkoxide
[(dippBDI)Mg(µ-OCH2CMe3)]2 and the
Reaching milestones in the
oxygenation chemistry of magnesium
alkyls: Towards intimate states of O2
activation and the first monomeric,
well-defined magnesium
first
example
of
monomeric
magnesium
alkylperoxide
[(dippBDI)Mg(thf)OOCH2CMe3] (dippBDI
= [(ArNCMe)2CH]- and Ar = C6H3iPr2-
2,6).
alkylperoxide
This article is protected by copyright. All rights reserved.