Addition of phenylacetylene to a magnesium complex of monoiminoacenaphtheneone (dpp-mian)

Article abstract of DOI:10.1039/c5dt03174e

In the presence of formic acid, acenaphthenequinone (AQ) reacts with one molar equivalent of 2,6-diisopropylaniline in toluene to give monoiminoacenaphtheneone (3, dpp-mian) in good yield. Reduction of compound 3 with an excess of magnesium in thf results in green crystalline amido-alcoholate [(dpp-mian)Mg(thf)₂]₂ (4). Crystallization of complex 4 from toluene affords a blue tetramer [(dpp-mian)Mg(thf)]₄ (5). Reactions of compounds 4 and 5 with phenylacetylene proceed with C-C bond formation between the alkyne and the dpp-mian ligand to give the monomeric alkynyl-magnesium derivative [(dpp-mian)(PhCCH₂)Mg(CCPh)₂(thf)]₂ (7). Hydrolysis of complex 5 gives metal-free dpp-mian(PhCCH₂)H (8). Reaction of 7 with acetylacetone yields [{dpp-mian(PhCCH₂)}Mg(acac)]₂ (9). Compounds 3-5 and 7-9 have been characterized by IR and NMR spectroscopy; molecular structures of 3, 5, 7, 8 and 9 have been determined by single crystal X-ray analysis.

Full text of DOI:10.1039/c5dt03174e

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Addition of phenylacetylene to a magnesium
complex of monoiminoacenaphtheneone
Cite this: DOI: 10.1039/c5dt03174e
(dpp-mian)†‡
D. A. Razborov, A. N. Lukoyanov, E. V. Baranov and I. L. Fedushkin*
In the presence of formic acid, acenaphthenequinone (AQ) reacts with one molar equivalent of 2,6-diiso-
propylaniline in toluene to give monoiminoacenaphtheneone (3, dpp-mian) in good yield. Reduction of
compound 3 with an excess of magnesium in thf results in green crystalline amido-alcoholate [(dpp-
mian)Mg(thf)2]2 (4). Crystallization of complex 4 from toluene affords a blue tetramer [(dpp-mian)Mg-
(thf)]4 (5). Reactions of compounds 4 and 5 with phenylacetylene proceed with C–C bond formation
between the alkyne and the dpp-mian ligand to give the monomeric alkynyl-magnesium derivative [(dpp-
mian)(PhCvCH2)Mg(CuCPh)2(thf)]2 (7). Hydrolysis of complex 5 gives metal-free dpp-mian(PhCvCH2)H
(8). Reaction of 7 with acetylacetone yields [{dpp-mian(PhCvCH2)}Mg(acac)]2 (9). Compounds 3–5 and
7–9 have been characterized by IR and NMR spectroscopy; molecular structures of 3, 5, 7, 8 and 9 have
been determined by single crystal X-ray analysis.
Received 17th August 2015,
Accepted 24th October 2015
DOI: 10.1039/c5dt03174e
www.rsc.org/dalton
Introduction
From 1983 to 2002 Frühauf et al. reported in a series of
papers1 on cycloaddition reactions between unsaturated sub-
stances and transition metal complexes of neutral 1,4-diaza-
1,3-diene (dad) or 1,4-dihetero-1,3-diene ligands. Iron and
ruthenium complexes with ketoimino ligands react for
instance with activated alkynes to form stable cycloadducts
(Scheme 1).
Scheme 1 Frühauf’s cycloaddition reactions.
A notable feature of these reactions is the addition of the
substrate not only to the metal centre but also to the ligand
resulting in a carbon–carbon bond. Similar cycloadducts have
been obtained reacting aromatic ketones with zirconium2a and
samarium2b complexes of the dad dianion. Comparable
addition reactions involving main group metal complexes are
limited to a few examples. Among them are reactions of anti-
mony amido-alkoxide with CF3–CuC–CF3 3a and of a platinum
gallyl complex with tBu–CuP3b (Scheme 2).
In 2010 we have found that (dpp-bian)Ga–Ga(dpp-bian) (1)
Scheme 2 Addition of CF3–CuC–CF3 and tBu–CuP to antimony and
gallium derivatives respectively.
(dpp-bian
=
1,2-bis[(2,6-diisopropylphenyl)imino]ace-
naphthene) easily reacts even with non-activated alkynes
affording cycloadducts4 (Scheme 3).
Remarkable for this dpp-bian gallium metal–organic
system is the reversibility of the alkyne addition. It can be com-
pared with the π coordination of organic molecules by tran-
sition metals. Dialanes (L)Al–Al(L) (L = dpp-bian,5a or dad5b)
are even more active in the cycloaddition of alkynes. The
mononuclear (dpp-bian)AlEt(Et2O)6a and (dpp-bian)Ga(S2-
G. A. Razuvaev Institute of Organometallic Chemistry, Russian Academy of Sciences,
Tropinina str. 49, 603137 Nizhny Novgorod, Russian Federation.
E-mail: igorfed@iomc.ras.ru; Fax: +7 831 4627495; Tel: +7 831 4629631
†Dedicated to Prof. A. L. Buchachenko on the occasion of his 80th birthday.
‡Electronic supplementary information (ESI) available: Crystallographic, NMR
and UV-Vis spectroscopic data. CCDC 1419025–1419030. For ESI and crystallo-
graphic data in CIF or other electronic format see DOI: 10.1039/c5dt03174e
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dianion; and (iii) the reactivity of magnesium dpp-mian com-
plexes towards phenylacetylene.
Results and discussion
(2,6-Diisopropylphenylimino)acenaphtheneone (3, dpp-mian):
synthesis and characterisation
In dpp-bian bulky 2,6-iPr2C6H3 groups ensure efficient shield-
ing of the nitrogen atoms. Thus, only in the bian plane
enough space is left for interaction with the metal. This pre-
vents formation of complexes, in which dpp-bian acts as a
bridging ligand. Further, it provides the unique reactivity of
dpp-bian metal complexes. Hence, we started the synthesis of
dpp-substituted monoiminoacenaphtheneone 3 (dpp-mian).
In contrast to the reported procedure12a we mixed acenaphthene-
quinone (AQ), 2,6-diisopropylaniline and formic acid
(catalytic amount) in toluene at once and refluxed the mixture.
After complete dissolution of AQ the mixture was cooled to
ambient temperature. Unreacted AQ and dpp-bian formed
were filtered off. From the filtrate the solvent was removed in a
vacuum and the crude product was extracted with diethyl
Scheme 3 Reversible addition of alkynes to digallane 1.
ether. Orange crystalline
3 was isolated in 80% yield
Scheme 4 Addition of PhCuCH to (dpp-bian)Mg(thf)3 (2).
(Scheme 5). As impurity it contains 5 mol% of dpp-bian. Ana-
lytically pure 3 can be prepared by repeated extraction with
diethyl ether. Although Kim’s procedure12a for the preparation
of 3 resulted in compound 3 in high yield (84%) the reported
method is both solvent and time consuming compared to our
approach. Thus, we used only 150 mL of toluene as a solvent
to react 10 g of AQ with aniline, while in the reported synthe-
sis12a 600 mL of methanol were used to prepare 3 starting
from 3.2 g of acenaphthenequinone.
CNMe2)6b also react with alkynes to produce cycloadducts.
Furthermore, the latter complex reversibly adds to conjugated
methylvinylketone.6b Alteration of the main group metal co-
ordinated by the dpp-bian dianion changes the reactivity of
the complex. For instance, the magnesium complex (dpp-bian)-
Mg(thf)3 (2) behaves in contrast to digallane 1 like a frustrated
Lewis pair7 when reacted with PhCuCH. The reaction affords
a magnesium alkynyl derivative supported with an amido–
amino chelating ligand (Scheme 4).8
The ability of complex 1 to “coordinate” PhCuCH allows
hydroamination and hydroarylation of the latter with anilines
and 1-naphthol in the presence of 1 as the catalyst.4b,6b More-
over, complex 1 catalyses the addition of anilines to carbodi-
imides.9 In its turn the magnesium complex 2 serves well as
the catalyst for ROP of lactide10 and hydroamination/cycliza-
tion of amino-olefins.11 But, the wide usage of compounds 1
and 2 as catalysts is limited by their instability in air. Search-
ing for more robust metal complexes with redox-active ligands
we studied the reactions of (2,6-diisopropylphenylimino)ace-
naphtheneone12 (3, dpp-mian) with different metals and
metal-containing reagents. While transition metal complexes
with neutral dpp-mian,12b,c,d and related Ar-mian13 ligands
have been reported, crystallographically authenticated main
group metal complexes with these ligands are unknown. It
should be noted that reactions of dpp-mian with Grignard
reagents have been reported14 recently but no metal contain-
ing derivative of dpp-mian could be isolated. Here we report:
(i) the modified synthesis of dpp-mian; (ii) preparation of the
first metal complexes containing dpp-mian in the form of a
The strongest absorptions in the IR spectrum of dpp-bian
are the CvN stretching vibrations at 1671, 1652, and
1642 cm−1 15
In compound 3 they are shifted to lower wave-
.
numbers (1658, 1602, and 1589 cm−1). The stretching
vibrations of CvO cause absorption at 1726 cm−1, which is
the most intensive one in the IR spectrum. Compound 3 is
moderately soluble in organic media. Crystals of 3 obtained
from toluene have been studied by X-ray single crystal analysis.
The key bond distances and angles in 3 are within the range of
those values reported earlier.12b However, in contrast to the
structure reported12b crystals of 3 obtained by us are free of
any lattice content. It is worth noting that in 3 due to the
Scheme 5 Synthesis of dpp-mian (3).
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restricted rotation around the N–C(ipso Ph) bond the 2,6-
iPr2C6H3 ring stands orthogonal to the heterodiene moiety.
Reduction of dpp-mian with magnesium
Reaction of dpp-mian with magnesium proceeds in thf at
reflux. The reaction rate strongly depends on whether the
metal was activated or not. Thus, addition of a catalytic
amount of iodine to magnesium allows reduction of dpp-mian
to its dianion within 30 minutes. In the course of the reaction
the colour of the solution turned from red-orange to dark
green. The product (dpp-mian)Mg(thf)2 (4) is poorly soluble in
thf and precipitates as a green microcrystalline solid from the
reaction mixture. Complex 4 has been separated from the
metal by extraction with hot thf. Dissolution of crude 4 in
toluene at 110 °C led to a blue solution. The solvent was evap-
orated and the residue was dissolved in toluene again. This
evaporation/dissolution process was repeated three times. The
compound [(dpp-mian)Mg(thf)]4 (5) was isolated in the form
of blue crystals from the concentrated toluene solution
(Scheme 6).
Fig. 1 Molecular structure of compound
drawn at 30% probability; hydrogen as well as carbon atoms of 2,6-di-
isopropyl groups and thf molecules are omitted for clarity).
5
(thermal ellipsoids are
Complexes 4 and 5 have been characterized by IR and NMR
spectroscopy. The X-ray analysis of the crystals of 4 has been
attempted several times. Unfortunately, they do not diffract
satisfactorily. Taking into account the composition of com-
pound 4 we suggest that in the solid state it has a dimeric
structure with μ2-O-bridges and a five-coordinated magnesium
atom. Crystals of compound 5 suitable for X-ray analysis have
been obtained from toluene. According to the X-ray data
complex 5 is a tetramer with a slightly distorted cuboid core
Mg4O4 (Fig. 1). The latter is assembled via μ3-bridging oxygen
atoms of the dpp-mian ligand. Each magnesium atom in 5 has
a coordination number of five. For comparison, the mag-
nesium atom in complex 215 is also five-coordinated. The bond
lengths in the ketoiminate fragment point to the dianionic
state of dpp-mian. Compared to neutral dpp-mian the C–O
and C–N bonds in 5 are significantly elongated (average C–O
and C–N bonds are 1.399 and 1.383 Å), but very close to C–N
bond lengths in 215 (1.401(6) and 1.378(7) Å), which contains a
dpp-bian dianion. The 1H NMR spectrum of compound 2 in
thf-d8 consists of two doublet signals that arise from non-
equivalent methyl groups (in pairs in each isopropyl substitu-
ent).15 This non-equivalence is caused by restricted rotation of
fragments around N–C(ipso) and C(iPr)–C(ipso) bonds. The
four methine protons in compound 2 produce only one septet
1
signal. According to the H NMR spectra dissolution of 4 and
5 in thf-d8 results in only one and the same species: the 1H
NMR spectra of 4 and 5 consist of two doublets and one septet
(see the ESI‡). In contrast, the 1H NMR spectrum of compound
5 in C6D6 reveals four doublets (δ 1.37, 1.04, 0.89 and
0.34 ppm) and two septets (δ 3.99 and 3.64 ppm) (see the
ESI‡). This indicates that complex 5 retains its tetrameric
structure in benzene.
Reactions of complexes 4 and 5 with phenylacetylene:
synthesis, molecular structure and solution behaviour of
[(dpp-mian)(PhCvCH2)Mg(CuCPh)2(thf)]2 (7)
Both 4 and 5 readily react with PhCuCH in thf or toluene at
80 °C. The NMR monitoring has shown that 4 and 5 reacted
completely within 8 h to give at least two products in each
case. Workup of the reaction mixture formed in toluene using
4 as the starting material gives compound [(dpp-mian)-
(PhCvCH2)Mg(CuCPh)2(thf)]2 (7) as pink crystals in 38%
yield when crystallised from toluene.
We suggest that complex 7 is a result of protonation of the
Mg–C bond with an alkyne followed by the formation of the
cycloadduct [(dpp-mian)(PhCvCH2)Mg(thf)] (6) (Scheme 7).
This suggestion is supported by the fact that the reaction of
[(dpp-mian)GaI]2 with PhCuCH resulted in a cycloaddition
product, which was isolated and crystallographically character-
ized. These data will be published elsewhere. The reaction
Scheme 6 Synthesis of complexes 4 and 5. The acenaphthene part of
the ligand in the formula of 5 is omitted.
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Scheme 7 Formation of [(dpp-mian)(PhCvCH2)Mg(thf)] (6) and [(dpp-
mian)(PhCvCH2)Mg(CuCPh)2(thf)]2 (7).
Fig. 3 The 1H NMR spectra of complex 7 in C6D6 (200 MHz, 293 K): (a)
dissolved at 293 K and stored at ambient temperature for 7 days; (b)
after heating at 80 °C for 8 hours.
Fig. 2 Molecular structure of compound
7 (thermal ellipsoids are
drawn at 30% probability; hydrogen as well as carbon atoms of 2,6-di-
isopropyl groups and thf molecules are omitted for clarity).
Fig. 4 The 1H NMR spectra of complex 7 in thf-d8 (200 MHz, 293 K): (a)
dissolved at 293 K and stored at ambient temperature for 7 days; (b)
after heating at 80 °C for 8 hours.
between 5 and PhCuCH in thf also produces 7, which has
been isolated from thf. According to single crystal X-ray ana-
lysis complex 7 is a centrosymmetric dimer with a planar
Mg2O2 core (Fig. 2). The only difference between the crystals of
compound 7 obtained from toluene or from thf is the solvent
molecules present in the unit cells (toluene and thf
correspondingly).
Owing to the asymmetry of the formed ligand all its
protons should be different. Thus, four non-equivalent methyl
groups and two non-equivalent methine protons give rise to
four doublets and to two septets respectively in the 1H NMR
spectrum of complex 7 (Fig. 3a). For 7 days at 20 °C the spec-
trum remains unchanged. But, heating of the sample to 80 °C
results in an additional set of NMR signals (Fig. 3b).
As evident from the integration of the signals two species
are present in solution in nearly equal amounts. In thf-d8
complex 7 behaves similarly (Fig. 4). Both samples (C6D6 and
thf-d8) attain the steady-state after 8 h of heating (80 °C). The
spectra shown in Fig. 3a and 4a both consist of signals above
9 ppm. In order to assign a corresponding signal in the spec-
trum shown in Fig. 4a we have carried out the COSY NMR
experiments (see the ESI‡). Based on the spectroscopy data we
conclude that the signal at δ 9.07 ppm (dd, 1H) belongs to the
proton of the naphthalene ring in the position next to the
chiral centre C(13). Its multiplicity reflects coupling to two
neighbouring protons in the six-membered ring, whereas its
low-field shift is caused by the close proximity to the chiral
centre C(1). Several hypotheses have been considered in order
to understand the solution behaviour of compound 7. Elimin-
ation of PhCuCH from complex 7 to give compound 6 in the
course of heating should be probably excluded since the
signals of free phenylacetylene (e.g. singlet at δ 2.77 ppm) are
absent in the spectra (Fig. 3b and 4b). The next hypothesis is
based on the observation that one form of compound 7
present in both C6D6 and thf-d8 shows remarkable differences
of the chemical shifts of the NMR signals that correspond to
methine protons of the iPr groups (C6D6: septets δ 3.96 and
2.74 ppm; thf-d8: septets δ 3.69 and 2.59 ppm). This splitting
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Scheme 8 Formation of metal-free compound 8.
Scheme 9 Synthesis of the acetylacetonate derivative 9.
signals (each 1H) centred at δ 6.77 and 5.25 ppm. In the spec-
trum of 7-homo in C6D6 these protons produce the signals
(1H) at δ 7.90 and 5.82 ppm (Fig. 3b). Formation and stability
of homo- and heterochiral dimers of methylzinc alkoxides
have been studied in detail by Noyori and co-workers.16 They
found that in solution as well as in the solid state, the hetero-
chiral dimers are more stable than the homochiral isomers. In
the case of compound 7 inter-conversion between diastereo-
mers requires dissociation of the dimers into monomers. As
mentioned above the reaction of [(dpp-mian)GaI]2 with phenyl-
acetylene resulted in a cycloaddition product. It is worth
Fig. 5 Molecular structure of compound
8 (thermal ellipsoids are
drawn at 30% probability; hydrogen atoms except for H(1) are omitted mentioning that this product is present in the crystal as a
for clarity).
homochiral dimer.
In order to gain more insight into the diastereomerisation
process we attempted substitution of the phenylethynyl ligand
in complex
7 by an acetylacetonate-anion. The reaction
between complex 7 and acetylacetone (acacH) proceeds in
toluene at 100 °C and is completed within 1 h. The colourless
compound (dpp-mian)(PhCvCH2)Mg(acac)2 (9) has been
isolated from the mother liquor in 39% yield (Scheme 9).
According to single crystal X-ray analysis complex 9 is a
centrosymmetric dimer with a planar Mg2O2 core (Fig. 6). Due
to the constraints caused by the chelating ligands the coordi-
nation environment of the metal atoms in 9 is somewhat
different from that found in compound 7. It is more like a
may indicate the close proximity of a chiral centre to the
above-mentioned protons. This might be the case when
PhCuCH adds across the C–N–Mg fragment in 4 or 5, thus
making the carbon atom bound to the chiral nitrogen.
In order to detect such a species we hydrolysed the NMR
samples of complex 7 in C6D6 and thf-d8. In both cases the
NMR spectra indicate the presence of the only product –
metal-free compound (dpp-mian)(PhCvCH2)H (8), which has
also been obtained in a bench experiment and isolated in the
form of yellow crystals (22%) from hexane (Scheme 8).
1
In the H NMR spectrum of 8 in CDCl3 (see the ESI‡) the
CH2 protons appear as two doublets (each 1H) at δ 6.20 and
5.66 ppm (J = 1.0 Hz). Most probably the proton of the OH
group results in a singlet signal at δ 3.42 ppm. The structure of
compound 8 (Fig. 5) has been determined by single crystal
X-ray analysis. The unit cell (Z = 4) consists of two pairs of
enantiomers. The structure of 8 corresponds to that of 7: the
vinyl group is connected to the carbon atom bound to oxygen.
The N(1)–C(1) bond is 1.2730(16) Å and corresponds to a C–N
double bond. Taking into account the solid state structure and
the NMR spectroscopy data we suggest that in solution
complex 7 may exist as two diastereomers: R,S-diastereomer
(heterochiral dimer, 7-hetero), which is also present in the
solid state (Fig. 2) and the 1 to 1 mixture of R,R- + S,S-
diastereomers (homochiral dimers, 7-homo), which exists only
in solution.
Diastereotopic protons in the H2CvCPh fragment in the 1H
NMR spectrum of 7-hetero in C6D6 (Fig. 3a) give rise to two
Fig. 6 Molecular structure of compound
drawn at 30% probability; hydrogen atoms are omitted for clarity).
9 (thermal ellipsoids are
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trigonal bipyramid: atoms O(1) and O(3) are located in the with phenylacetylene represents a homochiral dimer in the
axial positions, O(1′), O(2) and N(1) are situated in an equator- crystalline state. These recent results will be published
ial plane.
elsewhere. As shown by the synthesis of compound 9 the
Another difference between 7 and 9 concerns the angle acac spectator ligand affects not only the coordination environ-
N(1)–Mg–O(1′): in the latter this angle (139°) is nine degrees ment of the central atom but also the ability of the dimer to
smaller compared to that in compound 7 (148°). Furthermore, dissociate in solution into monomers. In conclusion, two
the difference between Mg–N(1) bond lengths in 7 (2.308(1) Å) other research projects involving dpp-mian as the ligand have
and 9 (2.255(1) Å) is remarkable. On the other hand, Mg–O(1) been conducted in our group. These involve preparation of
bonds in 7 and 9 are similar (7: 2.049(1) Å; 9: 2.025(1) Å). main group metal complexes with neutral dpp-mian ligands
Bearing in mind the features of the molecular structure of 9 (Ga, Sb, Sn, Ti, and Co derivatives) as well as a detailed study
we studied its solution behaviour. We have found that complex of the reduction of dpp-mian with alkali metals to produce
9 does not possess any dynamics neither in C6D6 nor in thf-d8. dpp-mian polyanions. The results of these projects will be
The diastereotopic protons of the H2CvCPh fragment in the published elsewhere. In the future we intend to study the
1H NMR spectrum of 9 in C6D6 give rise to two signals (each catalytic activity of compounds 4 and 5 in organic synthetic
1H) centred at δ 6.98 and 5.50 ppm. The acetylacetonate ligand reactions involving phenylacetylene and some other
results in two singlets at δ 5.16 (1H) and 1.54 ppm (6H). As in unsaturated substrates.
the case of compound 7 the isopropyl groups in complex 9
give rise to two septets (δ 3.38 and 3.09 ppm) and to four doub-
lets (δ 1.77, 1.35, 1.02 and 0.61 ppm). Finally, hydrolysis of
complex 9 yields compound 8.
Experimental
General procedures
All manipulations were carried out in a vacuum or under nitro-
gen by using Schlenk techniques. The solvents were distilled
Conclusions
from sodium benzophenone prior to use. The deuterated sol-
We have modified Kim’s procedure12a for the synthesis of vents used for the NMR measurements were dried with
monoiminoacenaphtheneone
3 (dpp-mian). Our method sodium benzophenone at ambient temperature and were, just
allows preparation of 3 with a yield comparable to that prior to use, condensed under vacuum into the NMR tubes
reported by the Korean team but using lower amounts of the already containing the respective compounds. Acenaphthene-
solvent. In our case the reaction proceeds faster due to the quinone and 2,6-diisopropylaniline were purchased from
higher boiling temperature of toluene compared to methanol Aldrich. Melting points were measured in sealed capillaries.
1
and gave compound 3 in 80% yield already in a couple of The H NMR spectra were recorded on Bruker DPX-200 NMR
hours. Reduction of 3 in thf with magnesium and crystallisa- and Bruker Advance III 400 spectrometers; IR spectra – on a
tion of the product either from thf or toluene allowed the syn- FSM-1201 spectrometer. The yields of compounds 4, 5, 7, 8
thesis of the first metal complexes with dpp-mian dianions – and 9 were calculated on the amount of the dpp-mian used in
compounds [(dpp-mian)Mg(thf)2]2 (4) and [(dpp-mian)Mg- the syntheses.
(thf)]4 (5), respectively. As other main group metal complexes
(E)-2-(2,6-Diisopropylphenylimino)acenaphthylene-1(2H)-
with dpp-bian ligand compounds 4 and 5 are reactive towards one (3, dpp-mian). A mixture of acenaphthenequinone (10.0 g,
phenylacetylene. However, in contrast to (dpp-bian)Mg(thf)3 55 mmol), 2,6-diisopropylaniline (9.75 g, 55 mmol) and formic
reactions of 4 and 5 with phenylacetylene proceed via cyclo- acid (0.6 g, 13 mmol) was refluxed in toluene (150 mL) for 2 h.
addition but not as acid–base interactions. On the other hand, After cooling to ambient temperature the solution was filtered.
cycloadducts have been obtained recently in the reactions of From the filtrate all volatiles were removed under vacuum and
alkynes with dpp-bian gallium complexes.3 These data demon- the residue was extracted with diethyl ether. Compound 3 pre-
strate a variety of chemical properties of the main group metal cipitated from diethyl ether as a crystalline orange solid. Yield
complexes of non-innocent ligands. Owing to the high reactiv- 15.7 g (80%). According to NMR data product 3 contains as
ity of the magnesium–carbon bond the cycloadduct 6 reacts impurity dpp-bian (5%), which can be removed by further
with a second equivalent of phenylacetylene to give acetylenide extraction. M.p. 177 °C. Anal. calcd for C24H23NO: C 84.42,
[(dpp-mian)(PhCvCH2)Mg(CuCPh)2(thf)]2 (7). An interesting H 6.79; Found: C 84.52, H 6.76. 1H NMR (200 MHz, CDCl3,
finding here is the diastereomerisation of 7 in solution. Thus, ppm): 8.19 (dd, 2H, arom, 7.1 and 8.2 Hz), 7.99 (d, 1H, arom,
crystallisation of compound 7 from solution makes prefer- 8.2 Hz), 7.83 (dd, 1H, arom, 7.1 and 8.2 Hz), 7.41 (dd, 1H,
ences for the heterochiral dimer 7-hetero, which structure has arom, 7.1 and 8.2 Hz), 7.27 (s, 3H, arom), 6.62 (d, 1H, arom,
been determined by single crystal X-ray analysis. Being dis- 7.1 Hz), 2.84 (sept, 2H, CH
̲
solved in benzene or thf 7-hetero isomerizes partially to the (CH3)2, 6.8 Hz), 0.90 (d, 6H, CH(CH3 2
̲
̲
homochiral dimer 7-homo. Obviously, inter-conversion (50.32 MHz, CDCl3, ppm): 189.52, 160.55, 146.52, 143.05,
between 7-hetero and 7-homo requires dissociation of the 135.18, 132.26, 131.04, 130.84, 129.48, 129.00, 128.29, 128.13,
dimers into monomers. Interestingly, the cycloaddition 127.63, 125.07, 123.55, 123.33, 122.14, 28.39, 23.40. IR (Nujol,
product obtained by reacting a dpp-mian gallium derivative cm−1): ν = 1986 w, 1905 w, 1852 w, 1726 s, 1658 s, 1623 w,
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1602 m, 1589 m, 1488 w, 1436 m, 1420 m, 1362 m, 1348 w, w, 453 m. UV-VIS (toluene, 293 K): 310 (sh), 325, 340 (sh), 475,
1329 w, 1273 s, 1218 w, 1196 w, 1178 w, 1150 w, 1123 w, 570, 640 nm.
1067 m, 1049 w, 1027 s, 939 w, 912 m, 832 m, 812 w, 782 s, 753
[(dpp-mian)(PhCvCH2)Mg(CuCPh)2(thf)]2 (7). Heating of
s, 698 w, 671 w, 645 w, 606 w, 577 w, 551 w, 525 m, 505 w, a mixture of complex 4 (0.41 g, 0.78 mmol) and phenyl-
463 m, 453 w. UV-VIS (toluene, 293 K): 365 (sh), 395 (sh), acetylene (0.31 g, 3.0 mmol) in toluene (25 mL) at 80 °C for 8 h
460 nm.
caused a change of the colour of the reaction mixture from
[(dpp-mian)Mg(thf)2]2 (4). A solution of dpp-mian (0.34 g, blue to light-violet. After cooling to ambient temperature the
1.0 mmol) in thf (30 mL) was added to magnesium shavings volatiles were removed from the mixture under vacuum. The
(5 g) activated prior to use with iodine (10 mg). In the course remaining solid was dissolved in toluene (10 mL) at heating.
of reflux (30 min) the reaction mixture turned green. The solu- Crystallization at ambient temperature gave complex 7·C7H8 as
tion was cooled to ambient temperature and decanted from an light-pink crystals. Yield 0.22 g (38%). M.p. 200–210 °C (dec.).
excess of magnesium. Crude product 4 was obtained as a Anal. calcd for C102H102Mg2N2O4: C 83.42, H 7.00; Found:
green crystalline solid on removal of the volatiles from thf solu- C 83.39, H 7.05. 1H NMR (200 MHz, C6D6, ppm): 10.25 (dd,
tion in a vacuum. Yield 0.43 g (84%). M.p. 179 °C. Anal. calcd 1H, arom, 6.8 and 1.0 Hz), 7.70 (t, 1H, arom, 7.1 Hz), 7.45 (d,
1
for C32H39MgNO3: C 75.37, H 7.71; Found: C 73.09, H 7.84. H 1H, arom, 8.3 Hz), 7.40–6.85 (m, 26H, arom), 6.77 (1, 1H,
NMR (200 MHz, thf-d8, ppm): δ 7.31–6.92 (m, 9H, arom), 6.87 PhCvCH
(d, 1H, arom, 8.1 Hz), 6.80 (dd, 1H, arom, 6.9 and 8.1 Hz), 7.0 Hz), 5.25 (s, 1H, PhCvCH
6.66–6.53 (m, 2H, arom), 6.37 (d, 1H, arom, 6.7 Hz), 5.62 (d, 1H, CH(CH3)2, 6.8 Hz), 3.00 (sept, 1H, CH
1H, arom, 6.7 Hz), 3.69 (sept, 2H, CH(CH3)2, 6.8), 2.29 (s, 3H, (s, 12H, C6H5CH3), 1.63 (d, 3H, CH(CH3)2, 6.8 Hz), 1.51 (d, 3H,
C6H5CH3), 1.19 (d, 6H, CH(CH3)2, 6.8 Hz), 0.91 (d, 6H, CH CH(CH3)2, 6.8 Hz), 1.31 (s, 4H, thf), 1.14 (d, 3H, CH(CH3)2, 6.8
(CH
3)2, 6.8 Hz). 13C NMR (50.32 MHz, CDCl3, ppm): 153.23, Hz), 0.19 (d, 3H, CH(CH3)2, 6.8 Hz). IR (Nujol, cm−1): ν = 3056
̲
̲
̲
̲
̲
̲
̲
̲
̲
̲
̲
̲
̲
145.66, 145.02, 140.21, 138.21, 135.78, 129.72, 128.94, 128.03, w, 2077 w, 1941 w, 1738 w, 1649 m, 1636 w, 1614 w, 1591 m,
127.16, 126.69, 126.37, 126.08, 124.89, 123.61, 122.76, 121.03, 1482 w, 1345 w, 1327 w, 1257 w, 1232 w, 1200 m, 1185 w, 1171
118.69, 109.89, 68.26, 28.71, 26.43, 26.00, 24.31, 21.51. IR w, 1102 m, 1081 m, 1058 w, 1033 m, 1010 w, 993 w, 924 m,
(Nujol, cm−1): ν = 3055 w, 3023 w, 2726 w, 2676 w, 1800 w, 910 m, 903 w, 885 m, 852 w, 833 m, 815 w, 803 w, 785 m,
1734 w, 1693 w, 1657 m, 1602 w, 1587 w, 1552 w, 1515 w, 1422 755 m, 705 m, 692 m, 682 w, 672 w, 645 w, 610 w, 581 w, 560
w, 1341 m, 1246 m, 1214 m, 1188 w, 1173 m, 1144 w, 1128 m, w, 548 w, 533 m, 515 w, 505 w, 486 w, 468 w. 1H NMR
1103 w, 1072 m, 1026 m, 999 w, 954 w, 937 w, 911 m, 888 w, (400 MHz, thf-d8, ppm): 9.07 (dd, 1H, arom, 6.5 and 1.0 Hz),
877 w, 830 w, 805 m, 780 w, 767 m, 754 w, 728 m, 695 m, 670 7.88 (dd, 1H, arom, 8.2 Hz), 7.82–7.76 (m, 2H, arom), 7.67 (s,
w, 622 w, 604 m, 569 m, 523 m, 499 m, 465 m. UV-VIS (THF, 1H), 7.61–7.48 (m, 2H, arom), 7.33–7.09 (m, 9H, arom),
293 K): 320, 345 (sh), 445, 730 nm.
[(dpp-mian)Mg(thf)]4 (5). Complex 4 (prepared from 0.34 g 2H, arom), 6.66–6.54 (m, 2H, arom), 6.08 (d, 1H, arom, 7.0
(1.0 mmol) of dpp-mian as described above) was dissolved in Hz), 5.41 (s, 1H, PhCvCH), 3.69 (sept, 1H, CH(CH3)2, 6.8 Hz),
toluene (30 mL) at 110 °C. In 30 min the mixture was cooled to 3.67–3.55 (m, 4H, thf), 2.59 (sept, 1H, CH(CH3)2, 6.8 Hz), 2.32
ambient temperature and the solvent was removed completely (s, 3H, C6H5CH3), 1.85–1.71 (m, 4H, thf), 1.42 (d, 3H, CH
under vacuum. Dissolution of the residue and evaporation of (CH3)2, 6.8 Hz), 0.92 (d, 3H, CH(CH3)2, 6.8 Hz), 0.67 (d, 3H,
the solvent were repeated three times. Crystallization from CH(CH3)2, 6.8 Hz), −0.11 (d, 3H, CH(CH3 2
) , 6.8 Hz). 13C NMR
7.09–6.97 (m, 2H, arom), 6.82 (d, 1H, arom, 7.3), 6.78–7.66 (m,
̲
̲
̲
̲
̲
̲
̲
̲
toluene (10 mL) at ambient temperature gave product 5 as blue (100.62 MHz, thf-d8, ppm): 156.44, 155.84, 147/35, 146.47,
crystals. Yield 0.41 g (78%). M.p. >250 °C (dec.). Anal. calcd for 145.87, 143.47, 142.74, 142.67, 141.01, 140.84, 140.54, 139.77,
1
C
140H156Mg4N4O8: C 79.32, H 7.42; Found: C 78.38, H 7.29. H 138.61, 137.70, 133.57, 132.95, 132.92, 132.73, 132.21, 132.14,
NMR (200 MHz, C6D6, ppm): 7.30–6.93 (m, 12H, arom), 131.69, 131.55, 131.41, 131.05, 130.69, 130.45, 130.12, 130.00,
6.90–6.75 (2H, arom), 6.28 (d, 1H, 6.7 Hz), 3.99 (sept, 1H, 129.84, 129.72, 129.55, 129.30, 129.07, 128.95, 128.56, 128.14,
CH
6.7 Hz), 2.11 (s, 6H, C6H5CH3
1.04 (d, 3H, CH(CH3)2, 6.7 Hz), 1.03 (br s, 4H, thf), 0.89 (d, 3H, 124.08, 123.92, 121.92, 117.4, 111.77, 110.85, 89.08, 88.62,
CH(CH3)2, 6.7 Hz), 0.34 (d, 3H, CH(CH3 2
) , 6.7 Hz). 13C NMR 68.39, 29.74, 29.25, 28.95, 28.25, 26.66, 26.55, 24.53, 24.45,
̲
̲(CH3)2, 128.01, 127.77, 127.71, 126.97, 126.73, 126.61, 126.50, 126.21,
̲
̲
̲
̲
̲
(50.32 MHz, CDCl3, ppm):149.74, 147.56, 146.92, 144.19, 21.65. Product 7·C4H8O was obtained under the same con-
138.50, 137.54, 135.32, 128.98, 126.68, 126.43, 125.34, 124.35, ditions reacting complex 4 (0.43 g, 0.84 mmol) and phenyl-
123.96, 123.50, 119.47, 110.05, 28.23, 27.94, 26.39, 26.33, acetylene (0.31 g, 3.0 mmol) in thf (30 mL). Yield 0.29 g (48%).
25.24, 24.77, 22.90, 21.06. IR (Nujol, cm−1): ν = 3055 w, 3025 w, M.p. 185–190 °C. Anal. calcd for C48H51MgNO3: C 80.72, H
1932 w, 1864 w, 1808 w, 1736 w, 1657 m, 1619 w, 1604 w, 7.20, N 1.96; Found: C 80.68, H 7.24, N 1.92. UV-VIS (toluene,
1589 m, 1522 s, 1495 m, 1473 m, 1443 s, 1432 s, 1362 w, 1346 293 K): 305 (sh), 319, 340, 370 nm.
w, 1331 s, 1300 m, 1241 m, 1218 w, 1210 w, 1180 m, 1124 m,
dpp-mian(PhCvCH2)H (8). A mixture of complex 4 (pre-
1105 m, 1068 m, 1034 w, 1016 m, 1003 w, 957 w, 932 m, pared from 0.34 g dpp-mian) and phenylacetylene (0.51 g,
913 m, 865 w, 813 m, 769 m, 744 w, 730 m, 695 m, 671 w, 5.0 mmol) was heated in thf (35 mL) at 80 °C for 8 h in a
626 m, 612 w, 597 m, 571 w, 544 w, 525 m, 499 m, 483 w, 464 sealed ampule. After addition of H2O (0.1 mL) to the obtained
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Table 1 Crystal data and structure refinement details for 3, 5, 7·C7H8, 7·C4H8O, 8 and 9
3
5
7·C7H8
7·C4H8O
8
9
Formula
Mr
C
24H23NO
C140H156Mg4N4O8 C102H102Mg2N2O4 C96H102Mg2N2O6
C32H31NO
445.58
100(2)
C74H74Mg2N2O6
1135.97
100(2)
341.43
100(2)
0.14 × 0.10 ×
0.08
2119.93
100(2)
1468.48
100(2)
1428.41
100(2)
T/K
Crystal size/mm3
0.50 × 0.45 × 0.40 0.60 × 0.50 × 0.40 0.36 × 0.32 × 0.30 0.50 × 0.20 × 0.10
0.65 × 0.46 × 0.15
Crystal system
Space group
Monoclinic
P2(1)/c
Triclinic
P1
Triclinic
P1
Triclinic
P1
Monoclinic
P2(1)/n
Monoclinic
P2(1)/n
ˉ
ˉ
ˉ
a/Å
b/Å
c/Å
α/°
15.2395(11)
14.3009(11)
17.4321(12)
90
96.931(2)
90
3771.4(5)
8
1.203
0.073
1456
−18 ≤ h ≤ 18
−17 ≤ k ≤ 17
−21 ≤ l ≤ 21
2.20 to 26.00
15.3860(4)
18.9900(5)
20.3370(4)
85.228(2)
84.9367(18)
81.210(2)
5834.7(2)
2
1.207
0.093
2272
−18 ≤ h ≤ 18
−22 ≤ k ≤ 22
−24 ≤ l ≤ 24
2.94 to 25.00
10.83521(13)
13.2253(2)
15.70481(19)
97.5746(12)
99.7585(10)
110.4065(14)
2033.83(5)
1
1.199
0.085
784
−15 ≤ h ≤ 15
−18 ≤ k ≤ 18
−22 ≤ l ≤ 22
3.05 to 30.00
10.5447(12)
12.8512(15)
15.2786(17)
98.9945(19)
94.5901(18)
109.5268(17)
1907.8(4)
1
1.243
0.091
764
−13 ≤ h ≤ 13
−15 ≤ k ≤ 15
−18 ≤ l ≤ 18
2.587 to 25.997
9.1993(2)
18.5141(4)
14.7826(4)
90
102.905(3)
90
2454.15(11)
4
1.206
0.072
952
−12 ≤ h ≤ 12
−24 ≤ k ≤ 24
−19 ≤ l ≤ 19
2.931 to 28.000
11.2637(7)
18.6717(11)
15.0467(9)
90
92.6400(10)
90
3161.1(3)
2
1.193
0.092
1208
−14 ≤ h ≤ 14
−23 ≤ k ≤ 23
−19 ≤ l ≤ 19
2.465 to 27.000
β/°
γ/°
V/Å3
Z
Dcalcd/g cm−3
μ/mm−1
F(000)/e
hkl range
θ Range for data
collection/°
Max. and min.
transmission
Refl. measured
Refl. unique
0.9942 and
0.9899
32 162
0.9638 and
0.9551
82 508
0.9667 and
0.9506
41 431
0.7457 and
0.6654
17 520
1.00000 and
0.68031
43 719
0.9697 and
0.8761
34 803
7403
20 491
11 810
7424
5906
6884
Rint.
0.0910
477
0.0585/0.1106
0.1147/0.1263
0.962
0.0778
1410
0.0828/0.1943
0.1281/0.2216
1.080
0.0232
509
0.0381/0.1039
0.0440/0.1079
1.051
0.0224
498
0.0554/0.1467
0.0665/0.1535
1.045
0.0720
314
0.0458/0.0961
0.0732/0.1038
1.032
0.0316
385
0.0437/0.1132
0.0536/0.1180
1.055
Parameters refined
R(F2)/wR(F2) [I > 2s(I)]
R(F2)/wR(F2) [all data]
GoF (F2)
Δρfin (max/min)/e Å−3
0.240/−0.172
0.778/−0.453
0.430/−0.316
0.764/−0.439
0.260/−0.204
0.360/−0.193
mixture at ambient temperature the colour of the solution 650 m, 598 m, 545 w, 535 m, 503 w, 484 w, 472 w, 461
turned brown. After evaporation of the volatiles under vacuum w. UV-VIS (toluene, 293 K): 305 (sh), 315, 345, 390 (sh) nm.
the residue was dissolved in hexane (20 mL). The solution was
filtered off. From the concentrated solution compound 8 was complex 4 (prepared from 0.34 g dpp-mian) and phenyl-
isolated as light yellow crystals. Yield 0.10 (22%). acetylene (0.51 g, 5.0 mmol) was heated in thf (30 mL) at 80 °C
[{dpp-mian(PhCvCH2)}Mg(acac)]2
(9). A
mixture
of
g
M.p. 104 °C. Anal. calcd for C32H31NO: C 86.25, H 7.01; Found: for 8 h in a sealed ampule. After removal of all volatiles in a
C 85.45, H 7.34. 1H NMR (400 MHz, CDCl3, ppm): 7.92–7.88 vacuum the residual solid was treated with a solution of
(m, 2H, arom), 7.73(d, 1H, arom, 2.0 Hz), 7.71(s, 1H), 7.28 0.098 g (0.98 mmol) of acetylacetone in toluene (20 mL). The
(pst, 1H, arom, 7.3 Hz), 7.17–7.06 (m, 4H, arom), 7.03–6.95 (m, obtained solution was heated for 1 h at 100 °C. Concentration
2H, arom), 6.78 (m, 2H, arom), 6.43 (d, 1H, arom, 7.0 Hz), 6.20 of the resulting solution gave the product 9 as colourless crys-
(d, 1H, PhCvCH
(s, 1H, OH), 2.81 (sept, 1H, CH
6.8 Hz), 1.12 (d, 3H, CH(CH3)2, 7.0 Hz), 0.90 (d, CH(CH3 2
Hz), 0.78 (d, 3H, CH(CH3)2, 7.0 Hz), 0.52 (d, 3H, CH(CH3)2, 7.0 Hz), 7.37–6.47 (m, 19H, arom), 5.49 (d, 1H, PhCvCH
Hz). 13C NMR (50.32 MHz, CDCl3, ppm): 174.55, 150.92, 5.15 (s, 1H, CH acac), 3.58–3.54 (m, 4H, thf), 3.38 (sept, 1H,
146.00, 141.74, 140.32, 139.90, 137.10, 135.66, 131.22, 130.89, CH(CH3)2, 6.8 Hz), 3.09 (sept, 1H, CH(CH3)2, 6.8 Hz), 2.10 (s,
128.99, 128.80, 128.03, 127.49, 125.76, 124.38, 123.89, 123.58, 3H, C6H5CH3), 1.77 (d, 3H, CH(CH3)2, 6.8 Hz), 1.53 (s, 6H, CH3
123.30, 121.09, 116.49, 83.12, 28.70, 27.80, 27.64, 23.80, 23.72, acac), 1.42–1.38 (m, 4H, thf), 1.35 (d, 3H, CH(CH3)2, 6.8 Hz),
23.36, 23.09. IR (Nujol, cm−1): ν = 3216 m, 3095 w, 3060 m, 1.02 (d, 3H, CH(CH
3)2, 6.8 Hz), 0.61 (d, 3H, CH(CH3)2, 6.8 Hz).
̲
2, 1 Hz), 5.66 (d, 1H, PhCvCH2
(CH3)2, 7.0 Hz), 2.00 (sept, 1H, C74H74Mg2N2O6: C 78.24, H 6.57; Found: C 79.01, H 6.69. H
) , 6.8 NMR (400 MHz, C6D6, ppm): 7.93 (dd, 1H, arom, 6.5 and 1.0
2, 1.8 Hz),
̲ , 1 Hz), 3.42 tals. Yield 0.22 g (39%). M.p. 210–220 °C (dec.). Anal. calcd for
1
̲
̲
̲
̲
̲
̲
̲
̲
̲
̲
̲
̲
̲
3023 m, 1983 w, 1954 w, 1895 w, 1883 w, 1856 w, 1823 w, 1797 IR (Nujol, cm−1): ν = 3112 w, 3083 w, 3056 m, 3024 w, 3010 w,
w, 1754 w, 1657 s, 1635 m, 1623 m, 1590 m, 1554 w, 1493 m, 2363 w, 2341 w, 2274 w, 1934 w, 1865 w, 1826 w, 1803 w, 1745
1443 m, 1399 m, 1365 m, 1349 m, 1325 m, 1290 m, 1255 m, w, 1661 s, 1599 s, 1542 w, 1516 s, 1490 w, 1456 w, 1440 w, 1429
1231 w, 1217 w, 1192 m, 1165 m, 1146 m, 1113 m, 1104 m, w, 1407 s, 1361 m, 1348 w, 1326 m, 1263 m, 1247 w, 1236 w,
1075 m, 1058 m, 1050 w, 1029 w, 997 m, 962 w, 940 m, 919 w, 1220 w, 1198 m, 1188 m, 1168 m, 1144 m, 1107 w, 1099 m,
904 w, 892 m, 836 m, 793 m, 776 w, 766 w, 731 m, 704 w, 1080 m, 1055 w, 1033 m, 1014 m, 994 w, 964 w, 929 w, 912 m,
Dalton Trans.
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Table 2 Selected bond lengths (Å) for 3, 5, 7·C7H8, 7·C4H8O, 8 and 9
Compound
3a
5b
7·C7H8
7·C4H8O
8
9
O(1)–C(1)
C(1)–C(2)
C(2)–N(1)
N(1)–Ar
Mg–N(1)
Mg–O(1)
Mg–O(1′)
Mg–O(thf)
Mg–O(2)
Mg–O(3)
Mg–C
1.215(2)
1.552(3)
1.273(3)
1.431(3)
—
—
—
—
—
1.389(3)–1.409(3)
1.375(3)–1.388(4)
1.351(4)–1.382(3)
1.429(3)–1.445(4)
2.031(2)–2.065(2)
2.022(2)–2.389(2)
2.022(2)–2.389(2)
2.073(2)–2.116(2)
—
1.3924(8)
1.5626(9)
1.2788(9)
1.4421(8)
2.3083(6)
2.0492(5)
2.0035(5)
2.0740(5)
—
1.384(2)
1.548(2)
1.268(2)
1.436(2)
2.283(2)
2.035(1)
2.000(1)
2.058(1)
—
1.4420(15)
1.5569(17)
1.2730(16)
1.4290(16)
—
—
—
—
—
—
—
1.382(1)
1.548(2)
1.272(2)
1.440(2)
2.255(1)
2.025(1)
1.960(1)
—
1.957(1)
1.987(1
—
—
—
—
—
—
—
2.138(2)
2.1511(8)
a The numbering scheme is that presented in the literature.12b b The range of bond lengths in four chemically equivalent units in tetramers.
894 w, 834 m, 815 w, 802 m, 797 w, 781 s, 774 w, 758 m, 709 w,
697 m, 669 m, 647 m, 612 m, 600 w, 586 w, 572 w, 558 m, 531
References
w, 521 m, 505 m, 481 m, 465 w.
1 R. Siebenlist, H.-W. Frühauf, K. Vrieze, W. J. J. Smeets and
A. L. Spek, Organometallics, 2002, 21, 5628 and references
therein.
2 (a) J. Scholz and H. Görls, Inorg. Chem., 1996, 35, 4378;
(b) J. Scholz, H. Görls, H. Schumann and R. Weimann,
Organometallics, 2001, 20, 4394.
3 (a) C. A. Stewart, R. L. Harlow and A. J. Arduengo III, J. Am.
Chem. Soc., 1985, 107, 5544; (b) C. Jones, D. P. Mills,
R. P. Rosea and A. Stasch, Dalton Trans., 2008, 4395.
4 (a) I. L. Fedushkin, A. S. Nikipelov and K. A. Lyssenko,
J. Am. Chem. Soc., 2010, 132, 7874; (b) I. L. Fedushkin,
A. S. Nikipelov, A. G. Morozov, A. A. Skatova,
A. V. Cherkasov and G. A. Abakumov, Chem. – Eur. J., 2012,
18, 255.
5 (a) I. L. Fedushkin, M. V. Moskalev, A. N. Lukoyanov,
A. N. Tishkina, E. V. Baranov and G. A. Abakumov, Chem. –
Eur. J., 2012, 18, 11264; (b) Y. Zhao, Y. Liu, Y. Lei, B. Wu
and X.-J. Yang, Chem. Commun., 2013, 49, 4546.
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G. A. Abakumov, J. Organomet. Chem., 2013, 747, 235;
(b) I. L. Fedushkin, O. V. Kazarina, A. N. Lukoyanov,
A. A. Skatova, N. L. Bazyakina, A. V. Cherkasov and
E. Palamidis, Organometallics, 2015, 34, 1498.
7 For a frustrated Lewis pair see: (a) D. W. Stephan and
G. Erker, Angew. Chem., Int. Ed., 2010, 49, 46;
(b) D. W. Stephan, Acc. Chem. Res., 2015, 48, 306; (c) Special
issue Dalton Trans., 2012, 41, 8999.
8 I. L. Fedushkin, N. M. Khvoinova, A. A. Skatova and
G. K. Fukin, Angew. Chem., Int. Ed., 2003, 42, 5223.
9 O. V. Kazarina, M. V. Moskalev and I. L. Fedushkin, Russ.
Chem. Bull., 2015, 64, 32 [O. V. Kazarina, M. V. Moskalev
and I. L. Fedushkin, Izv. Akad. Nauk. Ser. Khim., 2015, 32].
10 I. L. Fedushkin, A. G. Morozov, V. A. Chudakova,
G. K. Fukin and V. K. Cherkasov, Eur. J. Inorg. Chem., 2009,
4995.
Single-crystal X-ray structure determination
The data were collected on Bruker SMART APEX (for 3), Agilent
Xcalibur E (for 5, 7·C4H8O and 8) and Bruker D8 Quest (for
7·C7H8 and 9) diffractometers using monochromated MoKα
radiation (ω-scan technique, λ = 0.71073 Å). The intensity data
18
were integrated by using SAINT for 3,17 7·C7H8 and 918 and
by using CrysAlisPro for 5,19 7·C4H8O19 and 8.19 The structures
were solved by direct20 (3, 5, 7·C7H8 and 7·C4H8O) and dual-
space21 (8 and 9) methods and were refined on F2 using the
SHELXTL package.22 SADABS (for 3, 7·C7H8 and 6)23 and
SCALE3 ABSPACK (for 5, 7·C4H8O and 8)24 were used to
perform area-detector scaling and absorption corrections. All
non-hydrogen atoms were refined anisotropically. Hydrogen
atoms were placed in the calculated positions and refined in
the “riding-model” (Uiso(H) = 1.5Ueq(C) in CH3-groups and
Uiso(H) = 1.2Ueq(C) in other ligands), except for those of CH2
and OH groups in 7·C4H8O and 8 respectively, which were
obtained from differential Fourier-synthesis and refined iso-
tropically. In 5 and 7·C7H8 solvate molecules of toluene were
found in a common position. In the same position a dis-
ordered THF solvate molecule was located in the crystal of
7·C4H8O. A part of the toluene molecules in 5 are also dis-
ordered. The crystal data and structure refinement details are
collected in Table 1. Selected bond distances and angles are
presented in Table 2. CCDC 1419025 (for 3), 1419026 (for 5),
1419027 (for 7·C7H8), 1419028 (for 7·C4H8O), 1419029 (for 8)
and 1419030 (for 9) contain the supplementary crystallo-
graphic data for this paper.
Acknowledgements
11 M. V. Moskalev, A. M. Yakub, N. L. Bazyakina, P. Roesky
and I. L. Fedushkin, unpublished.
This work was supported by the Russian Science Foundation
(project no. 14-13-01063).
This journal is © The Royal Society of Chemistry 2015
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