Synthesis and Structural Characterization of Some New Magnesium Formamidinates

Article abstract of DOI:10.1002/zaac.201500659

[Mg(Form)₂(THF)] [Form = bis(2,6-dimethylphenyl)formamidinate (XylForm) (1), bis(2,6-diethylphenyl)formamidinate, (EtForm) (2), bis(2,6-diisopropylphenyl)formamidinate (DippForm) (3)] are conveniently synthesized by treating bis(2,6-dimethylphe

Full text of DOI:10.1002/zaac.201500659

Journal of Inorganic and General Chemistry
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ARTICLE
Zeitschrift für anorganische und allgemeine Chemie
DOI: 10.1002/zaac.201500659
Synthesis and Structural Characterization of Some New Magnesium
Formamidinates
Marcus L. Cole[a] and Peter C. Junk*[b]
Keywords: Formamidinates; Magnesium; Organomagnesium compounds
Abstract. [Mg(Form)2(THF)] [Form
=
bis(2,6-dimethylphenyl)-
ylmagnesium in THF. Compounds 1–3 are mononuclear species in the
formamidinate (XylForm) (1), bis(2,6-diethylphenyl)formamidinate, solid state with five coordinate central metal atoms. The 1H NMR
(EtForm) (2), bis(2,6-diisopropylphenyl)formamidinate (DippForm) chemical shift of the formamidinate formyl proton exhibits a corre-
(3)] are conveniently synthesized by treating bis(2,6-dimethylphenyl)- lation with ligand sterics wherein increasing bulk leads to a shift to
formamidine, bis(2,6-diethylphenyl)formamidine, or bis(2,6-diisoprop-
ylphenyl)formamidine, respectively, with half an equivalent of dibut-
higher field.
of alkali metal reagents in metathesis reactions can sometimes
be beneficial, especially if the alkali metal reagents are too
strongly reducing. Synthetic approaches to magnesium amidin-
ates and guanidinates have been by a wide range of routes and
all are generally high yielding, for example (i) protolysis of
an amidine with a Grignard reagent;[8a] (ii) redistribution of a
CpMg(amidinate) to MgCp2 and Mg(amidinate)2 (Cp =
C5H5);[13] (iii) treatment of [Bi(DippForm)Cl2] [DippForm =
bis(2,6-diisopropylphenyl)formamidinate] with Mg metal;[8c]
(iv) treatment of [Mg(N(SiMe3)2)2] with nitriles;[6c] (v) treat-
ment of an amidine with dibutylmagnesium;[6d,8b] (vi) treat-
ment of a lithium amidinate with iPrMgCl;[5b] and (vii) treat-
ment of MgR2 with a carbodiimide.[5a,5c] We have shown that
a very high yielding approach to low steric demand bis(p-tolyl-
formamidinate)magnesiums (Figure 1, left, R1 = p-tolyl, R2 =
H; p-TolForm) is through treatment of the p-TolFormH with
half an equivalent of dibutylmagnesium [route (v) above],[8b]
and this is the approach we have used to extend the family of
magnesium formamidinates to those with much higher steric
demands herein. The only magnesium complexes involving
formamidinate ligands are the amido Grignard reagent, [Mg(μ-
Cl)(DippForm)(thf)]2[8c] and those with very limited steric hin-
drance,viz.[Mg2Cl2(PhForm)(THF)3](PhForm=bis(phenyl)form-
amidinate),[8a] [Mg(p-TolForm)2(solvent)n] (solvent = THF,
n = 2; solvent = dme, n = 1; solvent = tmeda, n = 1) and
[Mg(o-TolForm)2(solvent)n] [o-TolForm = bis(o-tolyl)formam-
idinate; solvent = THF, n = 2].[8b]
Introduction
Organomagnesium compounds have enjoyed a rich success
over the last 100 years or so, mainly due to the ubiquitous
nature of Grignard reagents and their utility in organic synthe-
sis.[1] Organoamidomagnesium compounds have been less
studied.[2] Recently, there have been a number of structural
studies,[3] and the reactivity of these compounds have also
been investigated.[4] Magnesium amidinates (Figure 1) are a
subclass of these organoamidomagnesium compounds and
whileanumberofexampleshavebeenstudiedwithR2 =Me(acet-
amidinates),[5a,5b] Ph (benzamidinates),[3a,5a,6] or NRЈЈ2
(guanidinates),[4a,7] there have been relatively few formamidin-
ates (R2 = H) in the literature.[8]
Figure 1. A general amidinate ligand (left) and the ligands used in this
paper [right: R = Me (XylForm), Et (EtForm), iPr (DippForm)].
Indeed, we have extensively studied the structural chemistry
of the alkali metal formamidinates as precursors to lanthanoid
and other main group formamidinate complexes and while we
have shown that magnesium mono- and bis(formamidinates)
can be prepared,[8b,8c] we have not studied these as extensively
as alkali metal,[9] heavier alkaline earth,[10] p-block[11] or f-
block counterparts.[12] The use of magnesium reagents instead
As part of a systematic study of the organoamido chemistry
of the formamidinates we now report three magnesium com-
plexes involving bis(2,6-dialkylphenyl)formamidinate ligands:
[Mg(Form)2(THF)] [Form = bis(2,6-dimethylphenyl)formam-
idinate (XylForm) (1); bis(2,6-diethylphenyl)formamidinate,
* Dr. P. C. Junk
E-Mail: peter.junk@jcu.edu.au
[a] School of Chemistry
University of New South Wales
Sydney, NSW 2052, Australia
[b] College of Science
(EtForm)
(2);
bis(2,6-diisopropylphenyl)formamidinate,
Technology & Engineering
James Cook University
Townsville, Qld. 4811, Australia
(DippForm) (3)] where the alkyl groups on the 2,6-positions
of the ligand N-aryl can potentially influence the coordination
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number and arrangement of the central metal atom as we have pound 2 decomposing soon thereafter (213 °C), compound 1
observed in lanthanoid chemistry[12] and the closely related decomposing at 286 °C, and compound 3 decomposing at
chemistries of the heavy alkaline earth formamidinates.[10] The 314 °C. All compounds retain a metal-bound THF upon stand-
data presented confirms the expected decline in coordination ing and their C,H,N analyses reflect the composition deter-
number for magnesium upon transitioning to N-2,6-dialk- mined by X-ray diffraction methods vide infra.
ylphenyl substituents vis-à-vis smaller N-phenyl, N-p-tolyl, or
N-o-tolyl formamidinates, and a shift to higher field in
NC(H)N 1H NMR resonance with increasing N-2,6-dialk-
ylphenyl bulk. A similar spectroscopic trend is observed when
transitioning from higher to lower coordination numbers or
upon moving from the heavier alkaline earth formamidinates,
e.g. Sr and Ba, to their calcium or magnesium counterparts.
Results and Discussion
Scheme 1. Synthesis of compounds 1–3 [R = Me (1), Et (2), isopropyl
(3)].
Syntheses and Spectroscopic Characterization
1
[Mg(Form)2(THF)] [Form = bis(2,6-dimethylphenyl)form-
Resonance signal integrals in the H NMR spectra of 1–3
amidinate (XylForm) (1); bis(2,6-diethylphenyl)formamidin- also indicate the robust coordination of THF at magnesium.
ate, (EtForm) (2); bis(2,6-diisopropylphenyl)formamidinate, The infrared spectra of all three complexes exhibit no absorp-
(DippForm) (3)] were conveniently synthesized by treating tions for an N–H stretch indicating complete deprotonation of
two equivalents of bis(2,6-dimethylphenyl)formamidine, the respective formamidines and exhibit moderate to strong C–
bis(2,6-diethylphenyl)formamidine, or bis(2,6-diisopropyl- N stretches for the chelated formamidinate ligands between
phenyl)formamidine, respectively, with dibutylmagnesium in 1661 and 1538 cm–1 and C–O stretches for coordinated THF
THF (Scheme 1). The isolated yields of each reaction were at approximately 1025 cm–1 (asymmetric) and 805 cm–1 (sym-
moderately good, except 3, where the enhanced solubility of metric). By comparing the 1H NMR chemical shift of the
the compound made its complete isolation in high purity more NC(H)N function for compounds 1–3 and those of related al-
difficult. The thermal stability of each compound is excellent kaline earth compounds previously prepared by us,[8b,8c,10]
with no discernible decomposition up to 200 °C, with com- there is a clear trend between the frequency of the NC(H)N
1
Table 1. H NMR spectroscopic data in C6D6 for the formamidinate NC(H)N resonances of the compounds presented in this work and some
data for selected alkaline earth formamidinate compounds reported by us. All structures are mononuclear and all formamidinate ligands are N,NЈ
chelating.
Metal
Mg
Ligand
Donor
THF2
1H NC(H)N /ppm
IR /cm–1
13C NCN /ppm
Reference
[8b]
pTolForm
8.61
1670s
161.1
1503m
1674 s
1501 m
1651 m
1590 m
1538 m
1645 m
1600 m
1567 m
1661 m
1589 m
1539s
1651 m
1595 m
1531 m
1668 m
1588 m
1664 m
1592 m
1520 m
1666 m
1593 m
1528 s
1666m
1593 w
1530 s
Mg
Mg
oTolForm
XylForm
THF2
THF1
8.58
8.08
163.9
165.6
[8b]
this work
Mg
Mg
Ca
DiepForm
DippForm
XylForm
THF1
THF1
THF2
7.86
7.82
7.75
162.4
162.0
174.7
this work
this work
[10b]
Ca
Ca
oTolForm
DippForm
THF2
THF1
8.39
8.16
162.1
169.4
[10b]
[10a]
Ba
Sr
DippForm
DippForm
THF2
THF2
8.17
8.12
166.9
168.5
[10a]
[10a]
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resonance (Table 1) and the steric congestion about the central bound by two N,NЈ-chelating formamidinate ligands and one
metal atom. The NC(H)N resonance is shifted to higher field terminal THF ligand (see Figure 2 for 1 and Table 2).
as the steric bulk of the ligand (leading to congestion about
the metal centre along with coordinated THF) increases. For
example, in moving from compounds 1 to 2 to 3 we see an
NC(H)N 1H NMR resonance shift from 8.08 to 7.86 to
7.82 ppm, respectively, as the steric bulk of the ligand is in-
creased. When comparing these chemical shifts with those of
the magnesium complexes with much less sterically de-
manding ligands, e.g. the aforementioned o-TolForm and p-
TolForm [MgL2(THF)2] complexes (cf. increased coordination
number), there is a marked downfield shift of the same reso-
nance to 8.58 and 8.61 ppm, respectively.[8b]
This trend is also evident for calcium, strontium, and barium
complexes involving these ligands where, for example, argu-
ably the most sterically crowded calcium complex; [Ca(Xyl-
Form)2(THF)2] has a 1H NMR NC(H)N resonance at δ =
7.75 ppm vs. 8.39 ppm for the related bis-formamidinate bis-
Figure 2. X-ray crystal structure of [Mg(XylForm)2(THF)] (1) dis-
played close to the O–Mg vector and showing the triangular arrange-
THF o-TolForm complex.[10] The former represents the lowest
1
formyl proton H NMR chemical shift reported by us amongst
all bis(formamidinate)alkaline earth compounds.[8b,8c,10] It is
feasible that the observed shift to higher field results from
steric crowding, which leads to a decline in formamidinate to
metal donation and therefore increased magnetic shielding of
the formyl proton. Thus, a decline in formamidinate bulk and/
ment of O(1), C(17), and C(34) about Mg(1). Compounds 2 and 3 are
isostructural with 1. Thermal ellipsoids are shown at the 50% level.
The THF ligand is depicted as a wire-frame and hydrogen atoms are
omitted for clarity. See Table 2 for selected bond lengths and angles
for compounds 1–3.
The arrangement about the central magnesium atoms of 1–
or a reduction in coordination number, as per the transition 3 is severely distorted for regular five coordinate polyhedra
from 3 to 1 or from [Mg(o-TolForm)2(THF)2] to 1 (Table 1) (e.g. trigonal bipyramidal or square pyramidal) due to the tight
1
effects a downfield shift in the H NMR NC(H)N resonance. bite size of the N,NЈ-formamidinate chelate [N–Mg–N angles
A less striking but similar trend is observed for the 13C NMR for the bidentate ligands range from 63.58(9) to 64.42(8)°]. If
NCN carbon resonances of 1–3, with signals at 165.6, 162.4, the carbon atom on the backbone of the formamidinate ligands
and 162.0 ppm, respectively.
is considered as a point donor, the magnesium atoms of 1–3
may be considered as three coordinate with the sum of the C–
Mg–CЈ, C–Mg–O, and CЈ–Mg–O angles being 359.98° in each
case giving almost perfect trigonal planar arrangements. The
X-ray Crystal Structures
Compounds 1–3 are isostructural, with compounds 1 and 2 Mg–N bond lengths for 1–3 range from 2.0876(19) to
crystallizing in the monoclinic space group P21/n and com- 2.169(2) Å (av. = 2.125 Å), from 2.105(2) to 2.1462(19) Å (av.
¯
pound 3 crystallizing in the triclinic space group P1 (for se- = 2.125 Å) and from 2.087(2) to 2.192(2) Å (av. = 2.143 Å),
lected bond lengths and angles see Table 2). In all compounds respectively. The averages of these suggest similar steric con-
one whole mononuclear unit comprises the asymmetric unit of gestion for the ligands about 1 and 2, while the DippForm
the structure in which the magnesium is five coordinate, being ligands of complex 3 exhibit greater disparities and are longer
Table 2. Selected bond lengths /Å and angles /° for compounds 1–3.
[Mg(XylForm)
2(THF)]
[Mg(EtForm)2(THF)]
[Mg(DippForm)2(THF)]
Mg1–O1
Mg1–N1
Mg1–N2
Mg1–N3
Mg1–N4
Av. Mg–N = 2.125
N1–C17
N2–C17
N3–C34
N4–C34
2.0576(17)
2.0904(19)
2.155(2)
2.169(2)
2.0876(19)
Mg1–O1
Mg1–N1
Mg1–N2
Mg1–N3
Mg1–N4
Av. Mg–N = 2.125
N1–C21
N2–C21
N3–C42
N4–C42
2.040(2)
2.1361(19)
2.112(2)
2.1462(19)
2.105(2)
Mg1–O1
Mg1–N1
Mg1–N2
Mg1–N3
Mg1–N4
Av. Mg–N = 2.143
N1–C25
N2–C25
N3–C50
N4–C50
2.055(3)
2.191(2)
2.087(2)
2.101(2)
2.192(2)
1.325(3)
1.317(3)
1.321(3)
1.322(3)
1.314(3)
1.328(3)
1.314(3)
1.327(3)
1.317(3)
1.318(3)
1.316(3)
1.314(4)
C17–Mg1–C34
C17–Mg1–O1
C34–Mg1–O1
Σ = 359.98(24)
150.27(8)
105.06(8)
104.65(8)
C21–Mg1–C42
C21–Mg1–O1
C42–Mg1–O1
Σ = 359.98(27)
150.38(9)
105.68(9)
103.92(9)
C25–Mg1–C50
C25–Mg1–O1
C50–Mg1–O1
Σ = 359.98(30)
150.76(10)
104.76(10)
104.46(10)
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resonances of the [D6]benzene solvent. C, H and N elemental analyses
on average. Closer inspection of the Mg–N bond lengths in
were conducted by the Campbell Microanalytical Laboratory, Depart-
ment of Chemistry, University of Otago, Dunedin, New Zealand. Melt-
ing points were determined in sealed glass capillaries in a nitrogen
atmosphere and are uncorrected.
each compound indicates a degree of asymmetry, with one
shorter and one longer Mg–N internuclear distance per for-
mamidinate. While this may be suggestive of some Mg–N(am-
ido) vs. Mg–N(amino) type binding, this is not reflected in the
N–C bond lengths of the formamidinates, where the N–C bond
lengths are essentially the same within three e.s.ds in each li-
General Preparation of [Mg(Form)2(THF)] [Form = Bis(2,6-di-
methylphenyl)formamidinate (XylForm) (1), Bis(2,6-dieth-
gand in each compound. The average Mg–N bond lengths are ylphenyl)formamidinate (EtForm) (2), Bis(2,6-diisopropylphenyl)-
formamidinate (DippForm) (3): Dibutylmagnesium (0.50 cm3,
0.50 mmol) was added dropwise to a stirred colorless solution of
bis(aryl)formamidine (1.00 mmol) in THF (25 mL) at –30 °C. Gradual
warming of the solution to ambient temperature over a period of 1 h
afforded a yellow solution that was filtered, concentrated in vacuo to
incipient crystallization (Ͻ 5 cm), and left at room temperature to af-
ford colorless prisms (1), hexagonal rods (2), or blocks (3) suitable
for single-crystal X-ray diffraction structure determination. These were
isolated by filtration and, in the specific cases of 1 and 2, further crops
were obtained by placement of the supernatant at –10 °C overnight.
shorter than those in the six coordinate but less sterically de-
manding complexes [Mg(p-TolForm)2(THF)2] (av. = 2.157 Å)
and [Mg(o-TolForm)2(THF)2] (av. = 2.165 Å)[8b] as might be
expected. The Mg–O(THF) bond lengths in 1 to 3 [2.0576(17),
2.040(2) and 2.055(3) Å, respectively] are much shorter
than
those
in
the
six
coordinate
analogues;
[Mg(p-TolForm)2(THF)2] (av. 2.150 Å) and [Mg(o-
TolForm)2(THF)2] (av. = 2.134(2) Å].[8b] These data imply
that, as expected, the XylForm, EtForm, and DippForm ligands
are more sterically demanding than the p-TolForm and o-Tol- Relevant details for each compound are listed below.
Form ligands leading to diminishing space in the metal coordi-
nation spheres of 1–3 for the coordination of a second THF
ligand. Despite the substantial steric bulk of the DippForm li-
gand, it is not sufficient to invoke a solvent free composition.
Indeed, as evidenced by the thermal stability of 3 vide supra,
THF coordination is robust about this compound.
Compound 1 (R = Me): Yield 0.14 + 0.04 g (60%), m.p. 286 °C.
C38H46MgN4O: calcd. C 76.18, H 7.74, N 9.35%; found: C 75.42, H
1
7.15, N 8.99%. H NMR: δ = 8.08 [s, 2 H, NC(H)N], 7.06 (d, 8 H,
3
3JHH 7.4 Hz, m-ArH), 6.98 (t, 4 H, JHH 7.4 Hz, p-ArH), 3.57 (m, 4
H, OCH2), 2.29 (s, 24 H, CH3), 1.34 (m, 4 H, CH2). 13C NMR: δ =
165.6 (NCN), 147.8, 134.5, 126.3, 124.1 (s, ArCH), 67.6 (s, OCH2),
25.5 (s, CH2), 19.4 (s, CH3). IR (Nujol): ν˜ = 1651 (m), 1590 (m), 1538
(m) (C–N str), 1019 (s), 803 (sh s) (C–O, asym and symm str) cm–1.
Conclusions
Compound 2 (R = Et): Yield 0.15 + 0.08 g (65%), m.p. 213 °C (dec).
We have shown that clean deprotonation of the formamidine
ligands XylFormH, EtFormH, and DippFormH occurs upon
treatment with half an equivalent of dibutylmagnesium in THF
and that all three formamidinates generate mononuclear five
coordinate species. In view of the observed correlation be-
C46H62MgN4O: calcd. C 77.67, H 8.79, N 7.88%; found: C 76.98, H
8.67, N 7.50%. H NMR: δ = 7.86 [br. s, 2 H, NC(H)N], 7.08 (m, 8
1
H, m-ArH), 6.99 (m, 4 H, p-ArH), 3.58 (m, 4 H, OCH2), 2.83 (br. q,
16 H, CH2CH3), 1.50 (m, 4 H, CH2), 1.18 (br. t, 24 H, CH2CH3). 13C
NMR: δ = 162.4 (NCN), 149.5, 137.9 (s, ArC), 127.3, 122.8, 66.8 (s,
OCH2), 25.8 (s, CH2), 18.6 (s, CH3). IR (Nujol): ν˜ = 1645 cm–1 (m),
1600 (m), 1567 (m) (C-N str), 1027 (s), 807 (m) (C-O, asym and symm
str) cm–1.
1
tween the H NMR chemical shift of the formyl NC(H)N pro-
ton and the steric bulk / coordination number of the observed
[MgL2(THF)n] complexes (L = formamidinate, n = 1 or 2) it
is likely that the five coordination of 1–3 is retained in C6D6
solution and that, likewise, the solid state compositions of the
complexes listed in Table 2 are also maintained in deutero-
benzene solution.
Compound 3 (R = iPr): Yield 0.11 g (27%), m.p. 314 °C (dec).
C54H78MgN4O: calcd. C 78.76, H 9.55, N 6.80%; found: C 78.98, H
1
9.34, N 6.82%. H NMR: δ = 7.82 [s, 2 H, NC(H)N], 7.20–7.10 (m,
3
12 H, ArH), 3.61 [sep, 8 H, JHH 6.8 Hz, CH(CH3)2], 3.56 (obscured
m, 4 H, OCH2), 1.57 (m, 4 H, CH2), 1.29 (d, 48 H, 3JHH 6.8 Hz, CH3).
13C NMR: δ = 162.0 (NCN), 149.7, 141.5, 124.7, 123.6 (ArC), 68.9
(OCH2), 32.9 [CH(CH3)2], 25.7, 25.5 [CH(CH3)2 and CH2]. IR (Nu-
jol): ν˜ = 1661 cm–1 (m), 1589 (m) 1539 (s) (C-N str), 1031 (s), 804
(m) (C-O, asym and symm str) cm–1.
Experimental Section
General: The bis(aryl)formamidinate precursors HXylForm, HEt-
Form, and HDippForm were synthesized according to the procedure
of Roberts through the condensation of two equivalents of 2,6-dialk-
ylaniline with triethylorthoformate in the absence of solvent with one
drop of glacial acetic acid as catalyst.[14]
X-ray Diffraction Structure Determinations: Crystalline samples of
compounds 1–3 were mounted in viscous hydrocarbon oil on glass
fibres at –150 °C (123 K). Crystal data were obtained with an Enraf-
Nonius Kappa CCD diffractometer. X-ray data were processed using
Dibutylmagnesium (1.0 m in heptane) was purchased from Aldrich. the DENZO program.[15] Structural solution and refinement was car-
Tetrahydrofuran (THF) was dried with sodium, freshly distilled from
sodium benzophenone ketyl and freeze-thaw degassed prior to use. All
manipulations were performed using conventional Schlenk or
glovebox techniques in an atmosphere of purified nitrogen in flame-
dried glassware. Infrared spectra (4000–500 cm–1) were recorded as
Nujol mulls with a PerkinElmer 1600 Fourier transform infrared spec-
ried out using the SHELX suite of programs[16] with the graphical
interface X-Seed.[17] All hydrogen atoms were placed in calculated
positions using the riding model. Crystal data and refinement param-
eters are compiled below with selected bond lengths and angles pro-
vided in Table 2. In compounds 2 and 3 there are atoms with high
thermal envelopes and these are those that are involved in disorder.
trometer. 1H NMR spectra were recorded at 300.13 MHz and 13C NMR Compound 3 has severely prolate carbon atoms on the methyls of the
spectra were recorded at 75.46 MHz with a Bruker AC 300 spectrome- isopropyl groups as well as the THF molecule suffering from disorder.
ter at 300K, with chemical shifts referenced to the residual H or 13C This disorder has been modelled for all atoms. Percentage occupancies
1
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[4] a) S. P. Green, C. Jones, A. Stasch, Science 2007, 318, 1754; b)
and numbering of methyls (of iPr) concerned, as well as a disorder of
S. J. Bonyhady, C. Jones, S. Nambenna, A. Stasch, A. J. Edwards,
G. J. McIntyre, Chem. Eur. J. 2010, 16, 938.
the THF over two sites are compiled in the cif. Compound 2 similarly
has disorder problems (methyls of ethyl groups). This disorder was
modelled (see cif).
[5] a) A. R. Sadique, M. J. Heeg, C. H. Winter, Inorg. Chem. 2001,
40, 6349; b) N. Nimitsiriwat, V. C. Gibson, E. L. Marshall, P.
Takolpuckdee, A. K. Tomov, A. J. P. White, D. J. Williams,
M. R. J. Elsegood, S. H. Dale, Inorg. Chem. 2007, 46, 9988; c)
S. Anga, J. Bhattacharjee, A. Harinath, T. K. Panda, Dalton Trans.
2015, 44, 955.
[6] a) J. A. R. Schmidt, J. Arnold, J. Chem. Soc., Dalton Trans. 2002,
2890; b) B. M. Day, W. Knowelden, M. P. Coles, Dalton Trans.
2012, 41, 10930; c) G. J. Moxey, F. Ortu, L. G. Sidley, H. N.
Strandberg, A. J. Blake, W. Lewis, D. L. Kays, Dalton Trans.
2014, 43, 4838; d) R. Forret, A. R. Kennedy, J. Klett, R. E. Mul-
vey, S. D. Robertson, Organometallics 2010, 29, 1436.
[7] a) O. Ciobanu, A. Fuchs, M. Reinmuth, A. Lebkucher, E. Kaifer,
H. Wadepohl, H.-J. Himmel, Z. Anorg. Allg. Chem. 2010, 636,
543; b) B. M. Day, N. E. Mansfield, M. P. Coles, P. B. Hitchcock,
Chem. Commun. 2011, 47, 4995; c) M. K. Barman, A. Baishya,
S. Nembenna, J. Organomet. Chem. 2015, 785, 52.
[8] a) F. A. Cotton, S. C. Haefner, J. H. Matonic, X. Wang, C. A.
Murillo, Polyhedron 1997, 16, 541; b) M. L. Cole, D. J. Evans,
P. C. Junk, L. M. Louis, New J. Chem. 2002, 26, 1015; c) P. C.
Andrews, M. Brym, C. Jones, P. C. Junk, M. Kloth, Inorg. Chim.
Acta 2006, 359, 355.
Crystallographic data (excluding structure factors) for the structures in
this paper have been deposited with the Cambridge Crystallographic
Data Centre, CCDC, 12 Union Road, Cambridge CB21EZ, UK. Copies
of the data can be obtained free of charge on quoting the depository
numbers CCDC-1420278 for compound 2, CCDC-1420279 for com-
pound 3, and CCDC-1420280 for compound 1 (Fax: +44-1223-336-
033; E-Mail: deposit@ccdc.cam.ac.uk, http://www.ccdc.cam.ac.uk).
Crystal Data for Compound 1: C38H46MgN4O, M = 599.10, color-
less prism, 0.30ϫ0.20ϫ0.20 mm3, monoclinic, space group P21/n
(no. 14), a = 12.465(3), b = 15.016(3), c = 19.071(4) Å, β = 108.53(3)°,
V = 3384.5(12) Å3, Z = 4, Dc = 1.176 g·cm–3, F(000) = 1288, Nonius
Kappa CCD, Mo-Kα radiation, λ = 0.71073 Å, T = 123(2) K, 2θmax
=
56.6°, 23261 reflections collected, 8264 unique (Rint = 0.0990). Final
GooF = 0.914, R1 = 0.0560, wR2 = 0.1139, R indices based on 3537
reflections with I Ͼ 2σ(I) (refinement on F2), 405 parameters, 0 re-
straints. Lp and absorption corrections applied, μ = 0.088 mm–1.
Crystal Data for Compound 2: C46H62MgN4O, M = 711.31, colorless
hexagonal rods, 0.40ϫ0.20ϫ0.20 mm3, monoclinic, space group
P21/n (no. 14), a = 14.208(3), b = 15.970(3), c = 18.637(4) Å, β =
100.86(3)°, V = 4153.4(14) Å3, Z = 4, Dc = 1.138 g·cm–3, F(000) =
1544, Nonius Kappa CCD, Mo-Kα radiation, λ = 0.71073 Å, T =
123(2) K, 2θmax = 56.6°, 38693 reflections collected, 9846 unique (Rint
= 0.1370). Final GooF = 0.895, R1 = 0.0626, wR2 = 0.1364, R indices
based on 3696 reflections with I Ͼ 2σ(I) (refinement on F2), 509
parameters, 0 restraints. Lp and absorption corrections applied, μ =
0.081 mm–1.
[9] a) M. L. Cole, P. C. Junk, L. M. Louis, J. Chem. Soc., Dalton
Trans. 2002, 3906; b) J. Baldamus, C. Berghof, M. L. Cole, D. J.
Evans, E. Hey-Hawkins, P. C. Junk, J. Chem. Soc., Dalton Trans.
2002, 2802; c) J. Baldamus, C. Berghof, M. L. Cole, D. J. Evans,
E. Hey-Hawkins, P. C. Junk, J. Chem. Soc., Dalton Trans. 2002,
4185; d) J. Baldamus, C. Berghof, M. L. Cole, E. Hey-Hawkins,
P. C. Junk, L. M. Louis, Eur. J. Inorg. Chem. 2002, 2878; e) M. L.
Cole, D. J. Evans, P. C. Junk, M. K. Smith, Chem. Eur. J. 2003,
9, 415; f) M. L. Cole, P. C. Junk, J. Organomet. Chem. 2003, 666,
55; g) M. L. Cole, A. J. Davies, C. Jones, P. C. Junk, J. Or-
ganomet. Chem. 2004, 689, 3093; h) M. L. Cole, A. J. Davies, C.
Jones, P. C. Junk, New J. Chem. 2005, 29, 1404; i) M. L. Cole,
A. J. Davies, C. Jones, P. C. Junk, J. Organomet. Chem. 2007,
692, 2508; j) M. L. Cole, A. J. Davies, C. Jones, P. C. Junk, Z.
Anorg. Allg. Chem. 2011, 637, 50.
Crystal Data for Compound 3: C54H78MgN4O, M = 823.51, block,
3
¯
0.20ϫ0.10ϫ0.10 mm , triclinic, space group P1 (no. 2), a = 11.
128(2), b = 13.661(3), c = 17.599(4) Å, α = 90.29(3), β = 98.30(3),
γ = 69.36(3)°, V = 2474.5(8) Å3, Z = 2, Dc = 1.105 g·cm–3, F(000) =
900, Nonius Kappa CCD, Mo-Kα radiation, λ = 0.71073 Å, T = 123(2)
[10] a) M. L. Cole, P. C. Junk, New J. Chem. 2005, 29, 135; b) M. L.
Cole, G. B. Deacon, C. M. Forsyth, K. Konstas, P. C. Junk, Dal-
ton Trans. 2006, 3360.
K, 2θmax = 56.6°, 26630 reflections collected, 11871 unique (Rint
=
[11] a) S. P. Green, C. Jones, P. C. Junk, K.-A. Lippert, A. Stasch,
Chem. Commun. 2006, 3978; b) M. Brym, C. M. Forsyth, C.
Jones, P. C. Junk, R. P. Rose, A. Stasch, D. R. Turner, Dalton
Trans. 2007, 3282; c) A. Stasch, C. M. Forsyth, C. Jones, P. C.
Junk, New J. Chem. 2008, 32, 829; d) G. Jin, C. Jones, P. C. Junk,
K.-A. Lippert, R. P. Rose, A. Stasch, New J. Chem. 2009, 33,
64; e) S. Hamidi, H. Martin Dietrich, D. Werner, L. N. Jende, C.
Maichle-Mossmer, K. W. Tornroos, G. B. Deacon, P. C. Junk, R.
Anwander, Eur. J. Inorg. Chem. 2013, 2460; f) M. L. Cole, A. J.
Davies, C. Jones, P. C. Junk, A. I. McKay, A. Stasch, Z. Anorg.
Allg. Chem. 2015, 641, 2233–2244.
0.0943). Final GooF = 0.871, R1 = 0.0804, wR2 = 0.1701, R indices
based on 4714 reflections with I Ͼ 2σ(I) (refinement on F2), 638
parameters, 0 restraints. Lp and absorption corrections applied, μ =
0.076 mm–1.
Acknowledgements
We gratefully acknowledge the Australian Research Council
(DP0211090 and DP130100152) for support of this work.
[12] a) M. L. Cole, G. B. Deacon, P. C. Junk, K. Konstas, Chem. Com-
mun. 2005, 1581; b) M. L. Cole, P. C. Junk, Chem. Commun.
2005, 2695; c) M. L. Cole, G. B. Deacon, C. M. Forsyth, P. C.
Junk, K. Konstas, J. Wang, Chem. Eur. J. 2007, 13, 8092; d) G. B.
Deacon, C. M. Forsyth, P. C. Junk, J. Wang, Inorg. Chem. 2007,
46, 10022; e) M. L. Cole, G. B. Deacon, C. M. Forsyth, P. C.
Junk, D. P. Ceron, J. Wang, Dalton Trans. 2010, 39, 6732; f)
M. L. Cole, G. B. Deacon, C. M. Forsyth, P. C. Junk, K. Konstas,
J. Wang, H. Bittig, D. Werner, Chem. Eur. J. 2013, 19, 1410; g)
S. Hamidi, L. N. Jende, H. Martin Dietrich, C. Maichle-Mossmer,
K. W. Tornroos, G. B. Deacon, P. C. Junk, R. Anwander, Organo-
metallics 2013, 32, 1209; h) M. L. Cole, G. B. Deacon, P. C. Junk,
J. Wang, Organometallics 2013, 32, 1370; i) G. B. Deacon, C. M.
Forsyth, D. Freckmann, P. C. Junk, K. Konstas, J. Luu, G. Meyer,
D. Werner, Aust. J. Chem. 2014, 67, 1860; j) G. B. Deacon, P. C.
Junk, J. Wang, D. Werner, Inorg. Chem. 2014, 53, 12553; k) G. B.
References
[1] a) D. M. Huryn, in: Comprehensive Organic Synthesis 1, (Eds.:
P. Knochel, G. A. Molander), 2nd ed., Elsevier, Amsterdam, 2014,
pp. 1–26; b) P. Knochel, in: Organometallics in Synthesis (Ed.:
M. Schlosser), John Wiley & Sons, Hoboken, 2013, pp. 223–372,
; c) C. E. I. Knappke, A. J. v. Wangelin, Chem. Soc. Rev. 2011,
40, 4948.
[2] a) C.-C. Chang, M. S. Ameerunisha, Coord. Chem. Rev. 1999,
189, 199; b) G. B. Deacon, P. C. Junk, R. P. Kelly, Aust. J. Chem.
2013, 66, 1288.
[3] a) R. T. Boere, M. L. Cole, P. C. Junk, New J. Chem. 2005, 29,
128; b) D. Kalden, S. Krieck, H. Gorls, M. Westerhausen, Dalton
Trans. 2015, 44, 8089.
Z. Anorg. Allg. Chem. 2015, 2624–2629
2628
© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Journal of Inorganic and General Chemistry
www.zaac.wiley-vch.de
ARTICLE
Zeitschrift für anorganische und allgemeine Chemie
Deacon, P. C. Junk, L. K. MacReadie, D. Werner, Eur. J. Inorg. [15] Z. Otwinowski, W. Minor, in: Macromolecular Crystallography
Part A, 307 (Eds.: C. W. Cater, R. M. Sweet), Elsevier, Amster-
dam, 1997.
[16] G. M. Sheldrick, Acta Crystallogr., Sect. A 2008, 64, 112.
[17] L. J. Barbour, J. Supramol. Chem. 2001, 1, 189.
Chem. 2014, 5240; l) D. Werner, G. B. Deacon, P. C. Junk, D.
Werner, Chem. Eur. J. 2014, 20, 4426; m) G. B. Deacon, P. C.
Junk, D. Werner, Eur. J. Inorg. Chem. 2015, 1484.
[13] A. Xia, H. M. El-Kaderi, M. J. Heeg, C. H. Winter, J. Organomet.
Chem. 2003, 682, 224.
Received: August 26, 2015
Published Online: October 14, 2015
[14] R. M. Roberts, J. Org. Chem. 1949, 14, 277.
Z. Anorg. Allg. Chem. 2015, 2624–2629
2629
© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim