Well-defined styryl and biphenyl calcium complexes from dilithio compounds and calcium iodide: Synthesis, structure and reactivity toward nitrous oxide

Article abstract of DOI:10.1039/c8dt01046c

Efficient synthesis and structure elucidation of carbon-calcium σ-bonded compounds are of remarkable interest and importance in organometallic chemistry of the heavier s-block metals. In this paper, we report that styryl and biphenyl calcium complexes wit

Full text of DOI:10.1039/c8dt01046c

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Well-Defined Styryl and Biphenyl Calcium Complexes from Dilithio
Compounds and Calcium Iodide: Synthesis, Structure and
Reactivity toward Nitrous Oxide
Received 00th January 20xx,
Accepted 00th January 20xx
a
a
a,b
DOI: 10.1039/x0xx00000x
Baosheng Wei, Wen-Xiong Zhang* and Zhenfeng Xi*
www.rsc.org/
Efficient synthesis and structure elucidation of carbon–calcium σ-bonded compounds are of remarkable interest and
importance in organometallic chemistry of the heavier s-block metals. In this paper, we report that styryl and biphenyl
calcium complexes with well-defined structures can be facilely obtained via metathesis reaction between their
corresponding dilithio compound and calcium iodide. Single-crystal X-ray structural analysis of these calcium complexes
revealed their unique iodide-bridged or dicalcium-bridged structures. Their reactivity toward nitrous oxide was disclosed.
Considering the ongoing demand for σꢀbonded calcium
compounds and our continued interest in organocalcium
Introduction
8
b,11
chemistry,
we would further explore the metathesis reaction
in this work by
Calcium, a heavier sꢀblock element with global abundance,
easy availability and low toxicity, has attracted much interest in
both organometallic and synthetic chemistry. However, in
contrast to the prosperity of Grignard reagents in modern
organometallic chemistry, advances in the synthesis and
between dilithio compounds and CaI
2
1
expanding the scope of dilithio compounds. Here we report the
synthesis of two kinds of calcium complexes based on styryl
and biphenyl skeletons, respectively, from the reaction between
2
2
their corresponding dilithio compound and CaI . Singleꢀcrystal
characterization of Caꢀbased organometallic compounds still
3
Xꢀray structural analysis of these complexes revealed their
unique structures. The iodideꢀbridged styryltricalcium complex
should be formed from a styryldicalcium complex via an
observed Schlenk equilibrium with the elimination of calcium
iodide. The dicalciumꢀbridged biphenylcalcium compound was
first generated as a formal dimeric calciafluorene complex en
route to a trimeric analogue after ligand redistribution. Finally,
the reactivity of these calcium complexes toward nitrous oxide
was investigated.
remain
infrequent,
irrespective
of
the
abundant
cyclopentadienyl πꢀbonded calcium complexes. Actually, many
efforts toward C–Ca σꢀbonded compounds have been in vain
because of synthetic setbacks mainly caused by their inherent
4
5
6
instability, although an enumerable set of alkyl, alkynyl,
7
8
aryl and alkenyl calcium compounds were synthesized by
virtue of certain strategies. Among the limited synthetic
pathways, salt metathesis reaction has proven to be a powerful
strategy, which allowed the efficient synthesis of many calcium
compounds
including
the
important
5
c
5d
bis[tris(trimethylsilyl)methyl]calcium, dibenzylcalcium and
bis(allyl)calcium complexes. Recently, Anwander reported the
Results and discussion
9
Westerhausen and coꢀworkers made major contributions to the
synthesis and structure elucidation of aryl and alkenyl calcium
halides. Based on our previous study, we envisaged that the
mixed alkenyl/aryl calcium bonds might be simultaneously
successful isolation of dimethylcalcium species applying the
metathesis reaction between methyllithium and calcium
bis(trimethylsilyl)amide. Very recently, we investigated the
metathesis reaction between 1,4ꢀdilithioꢀ1,3ꢀbutadienes and
3
c
8b
1
0
formed when styryldilithium compound
1 was applied in the
CaI
2
,
leading to the isolation of
heavy
a
series of novel
8
b
metathesis reaction with CaI . At the outset, we commenced the
butadienylcalciumꢀbased
Grignard
reagents.
2
reaction of
1 with 1.0 equiv of CaI in THF, in an attempt to
2
determine the moiety that calcium might take priority to bond
1
8
with. However, H NMR analysis of this reaction in
showed that could not react completely. An orange crystalline
compound was isolated from the reaction as the sole product.
d ꢀTHF
1
2
Further experiments demonstrated that compound
the preferred product in the reaction between
2
1
was always
and CaI2,
regardless of the amount (0.5
–3.0 equiv) of CaI2 used. As
shown in Scheme 1, the reaction of
1
with 2.0 equiv of CaI in
2
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THF at room temperature proceeded smoothly and afforded a
Journal Name
The structure of
2
prompted us to investigate the mechanism
clear orange solution within 10 min. When THF was removed for its formation. As given in Scheme 1, we envisioned that
and Et was added, white precipitate would appear. compound might be generated from putative
Crystallization of the reaction residue in Et O/THF (20:1) styryldicalcium complex via the wellꢀknown Schlenk
in relatively high equilibrium with the elimination of CaI
mechanistic evidence, the THF solution obtained from
2
O
2
a
2
3
o
12
mixed solvent at ꢀ28 C yielded compound
2
2
.
To gain some
and
was monitored by H NMR analysis, which
revealed a clean set of peaks that was different from that of
symmetrical structure of 2. Singleꢀcrystal Xꢀray analysis of 2 When the pure was reacted with 1.0 equiv of CaI in THF, a
yield.
1
8
1
The NMR spectra of 2 in d ꢀTHF showed single set of peaks 2.0 equiv of CaI
assignable to the styryl skeleton, which probably indicated
2
a
2.
2
2
1
revealed an iodideꢀbridged monomeric structure (Fig. 1), in which new compound showing the same set of peaks as above in H
three calcium centers are simultaneously bridged by an iodide and NMR spectrum was observed. These experiments might
two styryl skeletons. One calcium atom lies in between two styryl indicate the involvement of
skeletons and bonds to all alkenyl/aryl carbanions of two skeletons. 1). However, all attempts to isolate
The formed dicalcium bridges in the structure of 2 are analogous to remarkable lability in THF, as evidenced by the unclean NMR
3
in the reaction toward
2 (Scheme
3
failed due to its
o
those in our previous reported 2,3ꢀdimethylꢀ1,4ꢀbis(trimethylsilyl)ꢀ spectrum after a longꢀtime preservation of
3
in THF at ꢀ28 C.
The structure of dilithio compound may have a decisive effect on
alkenyl/aryl C–Ca bonds and Ca–I bonds in the structure of 2 are the product structure. When biphenylꢀ2,2’ꢀdilithium compound 4
8b
substituted butadienyldicalcium complexes.
The lengths of
8
comparable to those in the reported structures.
was treated with CaI2 in THF, regardless of the amount (0.5–2.0
equiv) of CaI used, a yellow crystalline compound 5 was always
2
o
Me
Me Si
thf Ca
Ca (thf)
3
isolated from the THF solution at ꢀ28
reaction of
temperature could afford compound
determined by H NMR analysis and in 88% isolated yield after
crystallization in THF.
C
. As shown in Scheme 2, the
in THF at room
in a quantitative yield as
SiMe
3
1
) CaI
2
(2.0 equiv)
4 with 1.0 equiv of CaI
2
Me
3
Li
Li
THF, rt, 10 min
I
5
2
2) Crystallization in
Me Si
3
1
Et O/THF
2
Me
Ca (thf)
2
1
I
2, 72%
thf
thf
1
) CaI
(1.0 equiv)
(thf)
2
2
Ca
THF, rt, 10 min; then
toluene, rt, 12 h
Me
Me
3
Si
Ca
Li
Li
+ CaI
2
in THF
in Et
+
2 CaI
2
2
2/3
I
Ca
Ca
2
2) Crystallization in
toluene/THF
thf
thf
thf
thf
in THF
- CaI
O
Ca
2
2
I
(thf)
2
4
3, quant. NMR yield
6
, 59%
thf
thf
Scheme 1 Synthesis of styryltricalcium complex 2 and possible mechanism.
1) CaI2 (1.0 equiv)
Ca
THF, rt, 10 min
rt, 12 h
in toluene
2
) Crystallization
in THF
Ca
thf thf thf
, 88%
5
Scheme 2 Synthesis of biphenylcalcium complexes 5 and 6.
Fig. 1 ORTEP drawing of 2 with 20% thermal ellipsoids. Hydrogen atoms are
omitted for clarity. Selected bond length (Å) and bond angle (°): Ca1–C1
2
2
3
.546(7), Ca1–C4 2.552(7), Ca2–C1 2.681(7), Ca2–C4 2.589(7), Ca2–C13
.622(7), Ca2–C16 2.574(7), Ca3–C13 2.559(7), Ca3–C16 2.575(7), Ca1–I1
.1803(14), Ca2–I1 3.3053(14), Ca3–I1 3.1981(14), Ca3–I2 3.0922(15), Ca1---
Fig. 2 ORTEP drawing of 5 with 20% thermal ellipsoids. Hydrogen atoms are
omitted for clarity. Selected bond length (Å) and bond angle (°): Ca1–C2
2
.6698(18), Ca1–C8 2.6502(19), Ca1–C14 2.5072(19), Ca1–C20 2.6494(17),
Ca2 3.4640(18), Ca2---Ca3 3.509(2); C1–Ca1–C4 70.3(2), C1–Ca2–C4 67.6(2),
C13–Ca2–C16 68.0(2), C13–Ca3–C16 68.9(2), Ca1–I1–Ca2 64.53(3), Ca2–I1–
Ca3 65.28(4), Ca1–I1–Ca3 129.77(4), I1–Ca3–I2 92.84(4).
Ca2–C2 2.5845(17), Ca2–C8 2.6593(18), Ca2–C20 2.6036(18), C1–C2
1
.423(2), C1–C7 1.507(2), C7–C8 1.420(3), C13–C14 1.422(3), C13–C19
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ARTICLE
1
.503(3), C19–C20 1.425(3), Ca1---Ca2 3.1355(5); C2–Ca1–C8 65.44(6), C2– with a N
2
O balloon for 0.5 h, the redox reaction should have
occurred but no product was obtained in a preparative yield.
Whereas compound 5 or 6 can react relatively cleanly with N O at
C, providing the benzo[c]cinnoline 8 in moderate yield. This
Ca2–C8 66.50(6), C14–Ca1–C20 70.56(6).
2
Compound
5
was structurally characterized to be
a
o
0
dicalciumꢀbridged biphenylcalcium complex, which can also be
interpreted as a formal dimeric calciafluorene complex. The
short distance between Ca1 and Ca2 (3.1355(5) Å) indicates a
weak CaꢀꢀꢀCa interaction. The lengths of aryl C–Ca bonds are
in the range from 2.5072(19) Å (Ca1–C14) to 2.6698(18) Å
2
reaction should proceed via the double nucleophilic attack of N O by
biphenyl dianion followed by elimination of calcium oxide. The
appropriate reductivity and nucleophilicity of biphenyl dianion
should be beneficial to this reaction. This novel synthetic method
1
3
2
toward benzo[c]cinnoline would expand the utilization of N O in Nꢀ
7
(Ca1–C2), which are close to those of the reported structures.
14c
transfer reactions in synthesis.
In comparison to the structure of
2
, the less steric hindrance
Me
around the biphenyl dianion should favor the formation of the
calciafluorene structure other than an iodideꢀbridged structure.
SiMe
3
N O (1.0 bar)
2
2
or 3
THF, -40 oC to rt, 0.5 h
N
When compound
5
was stirred in toluene at room
N
7
, not observed
temperature for 12 h followed by crystallization in toluene/THF
o
(
10:1) mixed solvent at ꢀ28 C, another yellow crystalline
compound was isolated in 59% yield and characterized by Xꢀ
ray structural analysis. Understandably, can be directly
obtained from via a oneꢀpot procedure as shown in Scheme 2.
The structure of shown in Fig. 3 can be regarded as a trimeric
analogue of complex
have caused the change from
6
N
2
O (1.0 bar)
6
5 or 6
THF, 0 oC, 0.5 h
N
N
4
8
, 55% from 5
8, 51% from 6
6
5
. The loss of a THF molecule in
to . In the structure of
5
6
might
, three
Scheme 3 Reaction of calcium complexes with nitrous oxide.
5
6
Ca centers are nearly located at three vertices of a regular
triangle. Together with three bridging biphenyl dianions, a void
was thus formed in the centroid of the structure, which might
Conclusion
find further application. It should also be noted that other In summary, we have synthesized styryl and biphenyl calcium
analogous compounds with more than three Ca centers were not complexes via metathesis reaction between their corresponding
observed.
2
dilithio compound and CaI . Their wellꢀdefined structures were
demonstrated by singleꢀcrystal Xꢀray analysis, revealing unique
structural characteristics and bonding modes. Schlenk
equilibrium and ligand redistribution were found to be key
processes. The reactivity of these calcium complexes toward
nitrous oxide was investigated.
Experimental section
General experimental details
All reactions were carried out under a slightly positive pressure of
dry and oxygenꢀfree argon atmosphere by using standard Schlenk
line techniques or under an argon atmosphere in a Mikrouna Super
(
1220/750) Glovebox. The argon in the glovebox was constantly
circulated through a copper/molecular sieve catalyst unit. The
oxygen and moisture concentrations in the glovebox atmosphere
Fig. 3 ORTEP drawing of 6 with 20% thermal ellipsoids. Hydrogen atoms are
omitted for clarity. Selected bond length (Å) and bond angle (°): Ca1–C2
were monitored by an O /H O CombiꢀAnalyzer to ensure both were
2
2
2
1
1
1
.586(4), Ca1–C8 2.613(4), Ca1–C14 2.586(4), Ca1–C20 2.581(4), Ca2–C2
.602(4), Ca2–C8 2.609(4), Ca2–C26 2.591(4), Ca2–C32 2.605(4), Ca3–C14
.589(4), Ca3–C20 2.594(4), Ca3–C26 2.593(4), Ca3–C32 2.591(4), C1–C2
.434(6), C1–C7 1.509(6), C7–C8 1.419(6), C13–C14 1.422(6), C13–C19
.519(6), C19–C20 1.427(6), C25–C26 1.429(6), C25–C31 1.515(6), C31–C32
.433(6), Ca1---Ca2 3.4581(11), Ca1---Ca3 3.4644(12), Ca2---Ca3 3.4429(12);
2
2
always below 1 ppm. Unless otherwise noted, all starting materials
were commercially available and were used without further
purification. Solvents were purified by the Mbraun SPSꢀ800 Solvent
Purification System and dried over fresh Na chips in the glovebox.
Organometallic samples for NMR analysis were prepared in the
1
glovebox using J. Young valve NMR tubes (Wilmad 528ꢀJY). H
C2–Ca1–C8 66.95(14), C2–Ca2–C8 66.76(14), C14–Ca1–C20 67.26(14), C14–
Ca3–C20 67.03(14), C26–Ca2–C32 67.06(13), C26–Ca3–C32 67.23(13).
13
and C NMR spectra were recorded on a Bruker 400 MHz
1
13
o
spectrometer (FT, 400 MHz for H; 100 MHz for C) at 30 C.
Chemical shifts were reported in units (ppm) by assigning one
Inspired by the early report that phenylcalcium iodide could react
1
4
8
1
with nitrous oxide to provide azobenzene, we explored the
reactivity of these styryl and biphenyl calcium compounds with
nitrous oxide in search for some Nꢀcontaining compounds. As
indicated in Scheme 3, when 2 or 3 was stirred in THF bubbling
resonance of d ꢀTHF in the H NMR spectrum as 3.58 ppm, in the
C NMR spectrum as 67.57 ppm. Dilithio compounds 1 and 4 were
synthesized by the reported procedures. Calcium complexes 2 and
are too sensitive to be characterized by elemental analysis.
1
3
15
5
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Journal Name
Synthetic procedures
removed under reduced pressure. Toluene (10 mL) was added
and the reaction solution was stirred at room temperature for 12
h. After filtration, the solvent was partly removed and a small
amount of THF was added. The saturated toluene/THF (10:1)
solution was stored at ꢀ28°C with exposure to hexane vapor for
General procedure for synthesis of styryltricalcium complex 2.
In a 50 mL flask, the dilithio compound
was added to the slurry of CaI (294 mg, 1.0 mmol) in THF (5
mL). The solution was stirred at room temperature for about 10
min until a clear orange solution was afforded. The solvent was
removed under reduced pressure. A mixed Et O/THF (20:1)
2
solvent (5 mL) was added and a white turbid solution was
obtained. After filtration, the saturated solution was stored at ꢀ
1 (101 mg, 0.5 mmol)
2
3
days, producing single crystals of
analysis. Compound was isolated in 59% yield as a yellow
solid (0.10 mmol, 99 mg). H NMR (400 MHz,
.76–1.80 (m, 24H, ꢀCH in THF), 3.60–3.63 (m, 24H,
in THF), 6.87 (t, = 6.8 Hz, 6H, CH), 7.12 (t, = 7.2 Hz, 6H,
6 suitable for Xꢀray
6
1
8
d
ꢀTHF)
δ
1
β
2
α
ꢀCH
2
J
J
1
2
8°C with exposure to hexane vapor for 3 days, producing
single crystals of suitable for Xꢀray analysis. Compound
was isolated in 72% yield as an orange solid (0.18 mmol, 212
3
CH), 7.96 (dd,
MHz,
J
δ
= 6.8 Hz, 1.6 Hz, 12H, CH); C NMR (100
26.5, 68.4, 124.2, 127.0, 143.9, 156.6, 176.0.
2
2
8
d ꢀTHF)
1
8
Anal. Calcd for C60
H, 6.98.
3 6
H72Ca O : C, 71.4; H, 7.19; Found: C, 71.0;
mg). H NMR (400 MHz,
d
ꢀTHF)
in THF), 2.38 (s, 6H, Me), 3.60–
in THF), 6.66ꢀ6.69 (m, 2H, CH), 6.80 (td,
= 7.6 Hz, 2.0 Hz, 2H, CH), 7.38 (d, = 8.0 Hz, 2H, CH), 7.91
3
δ 0.08 (s, 18H, SiMe ),
1
3
J
.76–1.79 (m, 24H,
.63 (m, 24H, ꢀCH
βꢀCH
2
Reaction of calcium complexes with nitrous oxide. To the THF
solution (5 mL) of and (0.5 mmol), respectively, in a
50 mL Schlenk tube at ꢀ40 C or 0 C, N
α
2
2,
3,
5
6
J
o
o
1
3
8
2
O was bubbled with a
balloon for 0.5 h, all affording a dark red solution. The reaction
solution was quenched with NaHCO aqueous solution. The
aqueous layer of the solution was extracted with CH Cl for
(dd, J = 6.4 Hz, 1.2 Hz, 2H, CH); C NMR (100 MHz, d ꢀTHF)
δ
1
4.1, 26.5, 27.0, 68.4, 121.9, 122.5, 124.7, 143.1, 156.8, 157.5,
88.8, 202.5.
3
2
2
NMR determination of intermediate 3. In a 50 mL flask, the
three times and the combined organic layer was washed with
brine. Solvent was evaporated and the residue was purified by
dilithio compound
1 (10 mg, 0.05 mmol) was added to the
8
slurry of CaI (30 mg, 0.10 mmol) in
2
d ꢀTHF (0.5 mL). The
column chromatography using CH
2
Cl
2
as eluent to give product
solution was stirred at room temperature for about 10 min until
a clear orange solution was afforded. The solution was quickly
transferred into NMR tubes for NMR analysis. The putative
1
8
8
. H NMR (400 MHz, CDCl
.55 (m, 2H, CH), 8.71ꢀ8.75 (m, 2H, CH); C NMR (100 MHz,
120.8, 121.3, 129.1, 131.2, 131.4, 145.2. The isolated
benzo[c]cinnoline was compared with NMR spectra of an
3
) δ 7.86ꢀ7.90 (m, 4H, CH), 8.51ꢀ
1
3
1
3
CDCl ) δ
intermediate
NMR (400 MHz,
6H, ꢀCH in THF), 2.40 (s, 3H, Me), 3.60–3.63 (m, 16H,
CH in THF), 6.86 (t, = 6.8 Hz, 1H, CH), 7.03 (td, = 7.6 Hz,
.6 Hz, 1H, CH), 7.53 (d, = 8.0 Hz, 1H, CH), 8.00 (dd, = 6.4
4.2, 26.4, Single crystals of
6.7, 68.4, 124.2, 125.1, 127.8, 142.5, 156.2, 164.4, 186.4, 210.0. mixed Et O/THF (20:1) solvent at ꢀ28°C for 3 days. Single
General procedure for synthesis of biphenylcalcium complex crystals of suitable for Xꢀray analysis were grown in THF at ꢀ
In a 50 mL flask, the dilithio compound (85 mg, 0.5 mmol) 28°C with exposure to hexane vapor for 3 days. Single crystals
was added to the slurry of CaI (147 mg, 0.5 mmol) in THF (5 of suitable for Xꢀray analysis were grown in toluene/THF
3
can be detected by the clean set of peaks. H
8
d
3
ꢀTHF) δ 0.31 (s, 9H, SiMe ), 1.75–1.78 (m,
1
6
authentic sample.
1
β
2
αꢀ
2
J
J
X-ray crystallography
suitable for Xꢀray analysis were grown in
1
J
J
1
3
8
Hz, 0.8 Hz, 1H, CH); C NMR (100 MHz,
d
ꢀTHF)
δ
2
2
2
5
5.
4
2
6
mL). The solution was stirred at room temperature for about 10 (10:1) at ꢀ28°C with exposure to hexane vapor for 3 days. Data
min until a clear yellow solution was afforded. The solvent was collections for them were performed at 180 K or 130 K on a
partly removed under reduced pressure. The saturated THF XtaLAB Pro: Kappa single diffractometer using Mo K
α
1
7
solution was stored at ꢀ28°C with exposure to hexane vapor for radiation (
days, producing single crystals of suitable for Xꢀray solved with Superflip solution program using Charge Flipping
analysis. Compound
yellow solid (0.22 mmol, 164 mg). H NMR (400 MHz,
THF) 1.76–1.79 (m, 20H, ꢀCH
ꢀCH in THF), 6.81ꢀ6.85 (m, 4H, CH), 6.94 (td,
.6 Hz, 4H, CH), 7.53 (d, = 7.6 Hz, 4H, CH), 8.08 (dd,
λ = 0.71073 Å). Using Olex2 , the structures were
1
8
3
5
1
9
5
could be isolated in 88% yield as a or ShelXSꢀ97 solution program using Direct Methods and
1
8
20
d
ꢀ
refined with the ShelXL refinement package using Least
2
δ
β
2
in THF), 3.60–3.63 (m, 20H, Squares minimization. Refinement was performed on F
α
2
J = 7.6 Hz, anisotropically for all the nonꢀhydrogen atoms by the fullꢀ
1
J
J
δ
= 6.8 matrix leastꢀsquares method. The hydrogen atoms were placed
26.5, at the calculated positions and were included in the structure
calculation without further refinement of the parameters. A
1
3
8
Hz, 1.6 Hz, 4H, CH); C NMR (100 MHz,
8.4, 123.0, 123.7, 125.4, 142.5, 159.9, 191.3.
The reaction of (8 mg, 0.05 mmol) with 1.0 equiv of CaI
15 mg, 0.05 mmol) in
d ꢀTHF)
6
4
2
very large solvent accessible void in
2
was squeezed by using
ꢀTHF at room temperature was Platon. In all of the structures, the commands DELU, SIMU
monitored by H NMR analysis, which demonstrated that and ISOR were applied to mostly restrain the disorders of
compound was in situ generated in a quantitative yield. coordinated THF molecules. In the structure of , the command
General procedure for synthesis of biphenylylcalcium complex AFIX 66 was applied to constrain one benzene ring.
In a 50 mL flask, the dilithio compound (85 mg, 0.5 mmol) Crystallographic data (excluding structure factors) have been
was added to the slurry of CaI (147 mg, 0.5 mmol) in THF (5 deposited with the Cambridge Crystallographic Data Centre as
mL). The solution was stirred at room temperature for about 10 supplementary publication nos. CCDCꢀ1823281 ( ), CCDCꢀ
). Copies of these data can be
8
21
(
d
1
5
6
6.
4
2
2
min until a clear yellow solution was afforded. The solvent was 1823282 (
5
), CCDCꢀ1823283 (
6
4
| J. Name., 2012, 00, 1-3
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DOI: 10.1039/C8DT01046C
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ARTICLE
obtained free of charge from the Cambridge Crystallographic
Data Centre via www.ccdc.cam.ac.uk/data_request/cif.
8
9
For reports of alkenylcalcium compounds, see: (a) M. Köhler,
H. Görls, J. Langer and M. Westerhausen, Chem. Eur. J.
014, 20, 5237; (b) B. Wei, L. Liu, W.ꢀX. Zhang and Z. Xi,
Angew. Chem., Int. Ed., 2017, 56, 9188.
(a) M. J. Harvey, T. P. Hanusa and V. G. Young, Jr., Angew.
Chem., Int. Ed., 1999, 38, 217; (b) P. Jochmann, T. Dols, L.
Perrin, L. Maron, T. P. Spaniol and J. Okuda, Angew. Chem.,
Int. Ed., 2009, 48, 5715.
,
2
Conflicts of interest
The authors declare no competing financial interest.
1
1
0 B. M. Wolf, C. Stuhl, C. MaichleꢀMössmer and R.
Anwander, J. Am. Chem. Soc., 2018, 140, 2373.
1 (a) H. Li, X.ꢀY. Wang, B. Wei, L. Xu, W.ꢀX. Zhang, J. Pei
and Z. Xi, Nat. Commun., 2014, 5, 4508; (b) B. Wei, H. Li,
W.ꢀX. Zhang and Z. Xi, Organometallics, 2015, 34, 1339; (c)
Acknowledgements
This work was supported by the Natural Science Foundation of
China (nos. 21690061, 21725201).
B. Wei, H. Li, W.ꢀX. Zhang and Z. Xi, Organometallics
016, 35, 1458.
,
2
1
1
2 (a) R. Fischer, M. Gärtner, H. Görls, L. Yu, M. Reiher and M.
Westerhausen, Angew. Chem., Int. Ed., 2007, 46, 1618; (b) J.
Langer, S. Krieck, H. Görls and M. Westerhausen, Angew.
Chem., Int. Ed., 2009, 48, 5741.
3 For calculated values of Ca–Ca bond lengths, see: (a) M.
Westerhausen, M. Gärtner, R. Fischer, J. Langer, L. Yu and
M. Reiher, Chem. Eur. J., 2007, 13, 6292; (b) H. Li, H. Feng,
Y. Xie and H. F. Schaefer III, Chem. Eur. J., 2016, 22, 15019.
4 (a) R. Meier and K. Rappold, Angew. Chem., 1953, 65, 560;
Notes and references
1
2
(a) T. P. Hanusa, Coord. Chem. Rev., 2000, 210, 329; (b) M.
Westerhausen, Z. Anorg. Allg. Chem., 2009, 635, 13; (c) S.
Harder, Chem. Rev., 2010, 110, 3852; (d) S. Harder (Ed.),
AlkalineꢀEarth Metal Compounds, Topics in Organometallic
Chemistry, Springer: Berlin, 2013, Vol. 45; (e) A. S. S.
Wilson, M. S. Hill, M. F. Mahon, C. Dinoi and L. Maron,
Science, 2017, 358, 1168.
1
1
(
b) M. Hays and T. P. Hanusa, Tetrahedron Lett., 1995, 36,
(a) F. Bickelhaupt, J. Organomet. Chem., 1994, 475, 1; (b) H.
G. Richey (Ed.), Grignard Reagents: New Developments
2
435; (c) K. Severin, Chem. Soc. Rev., 2015, 44, 6375.
,
5 (a) L. Liu, W.ꢀX. Zhang, C. Wang, C. Y. Wang and Z. Xi,
Angew. Chem., Int. Ed., 2009, 48, 8111; (b) E. H. Braye, W.
Hübel and I. Caplier, J. Am. Chem. Soc., 1961, 83, 4406; (c)
WileyꢀVCH, Weinheim, 2000; (c) P. Knochel, W. Dohle, N.
Gommermann, F. F. Kneisel, F. Kopp, T. Korn, I. Sapountzis
and V. A. Vu, Angew. Chem., Int. Ed., 2003, 42, 4302; (d) Z.
Rappoport and I. Marek (Eds.), The Chemistry of
Organomagnesium Compounds
Chichester, UK, 2008; (e) R. E. Mulvey and S. D. Robertson,
B. Wei, H. Li, J. Yin, W.ꢀX. Zhang and Z. Xi, J. Org. Chem.
015, 80, 8758.
6 S. Wada, M. Urano and H. Suzuki, J. Org. Chem., 2002, 67,
254.
,
2
,
Patai Series, Wiley,
1
1
8
Top. Organomet. Chem., 2013, 45, 103.
(a) M. Westerhausen, Angew. Chem., Int. Ed., 2001, 40,
7 O. V. Dolomanov, L. J. Bourhis, R. J. Gildea, J. A. K.
Howard and H. Puschmann, OLEX2: a complete structure
3
4
5
2975; (b) J. D. Smith, Angew. Chem., Int. Ed., 2009, 48,
solution, refinement and analysis program., J. Appl. Cryst.
009, 42, 339.
8 (a) L. Palatinus and G. Chapuis, J. Appl. Cryst., 2007, 40,
86; (b) L. Palatinus, S. J. Prathapa and S. van Smaalen, J.
,
6
597; (c) M. Westerhausen, A. Koch, H. Görls and S. Krieck,
2
Chem. Eur. J., 2017, 23, 1456.
1
(a) J. Langer, M. Köhler, R. Fischer, F. Dündar, H. Görls and
7
M. Westerhausen, Organometallics, 2012, 31, 6172; (b) M.
Köhler, J. Langer, H. Görls and M. Westerhausen,
Organometallics, 2014, 33, 6381.
For examples of alkylcalcium compounds, see: (a) F. G. N.
Cloke, P. B. Hitchcock, M. F. Lappert, G. A. Lawless and B.
Royo, J. Chem. Soc., Chem. Commun., 1991, 724; (b) K.
Mashima, H. Sugiyama, N. Kanehisa, Y. Kai, H. Yasuda and
A. Nakamura, J. Am. Chem. Soc., 1994, 116, 6977; (c) C.
Eaborn, S. A. Hawkes, P. B. Hitchcock and J. D. Smith,
Appl. Cryst., 2012, 45, 575.
1
2
2
9 G. M. Sheldrick, Acta Cryst., 2008, A64, 112.
0 G. M. Sheldrick, Acta Cryst., 2015, C71, 3.
1 A. L. Spek, Acta Cryst., 2009, D65, 148.
TOC:
Chem. Commun., 1997, 1961; (d) S. Harder, S. Müller and E.
Hübner, Organometallics, 2004, 23, 178; (e) M. R. Crimmin,
A. G. M. Barrett, M. S. Hill, D. J. MacDougall, M. F. Mahon
and P. A. Procopiou, Chem. Eur. J., 2008, 14, 11292; (f) O.
Michel, H. Kaneko, H. Tsurugi, K. Yamamoto, K. W.
Törnroos, R. Anwander and K. Mashima, Eur. J. Inorg.
Chem., 2012, 998; (g) M. Köhler, A. Koch, H. Görls and M.
Westerhausen, Organometallics, 2016, 35, 242.
For reports of alkynylcalcium compounds, see: (a) D. J.
Burkey and T. P. Hanusa, Organometallics, 1996, 15, 4971;
6
7
(
b) D. C. Green, U. Englich and K. RuhlandtꢀSenge, Angew.
Chem., Int. Ed., 1999, 38, 354; (c) A. G. Avent, M. R.
Crimmin, M. S. Hill and P. B. Hitchcock, Organometallics
005, 24, 1184.
,
2
For examples of arylcalcium compounds, see: (a) S.ꢀO.
Hauber, F. Lissner, G. B. Deacon and M. Niemeyer, Angew.
Chem., Int. Ed., 2005, 44, 5871; (b) M. Westerhausen, M.
Gärtner, R. Fischer and J. Langer, Angew. Chem., Int. Ed.
,
2
007, 46, 1950; (c) M. Westerhausen, J. Langer, S. Kriech, R.
Fischer, H. Görls and M. Köhler, Top. Organomet. Chem.
,
2013, 45, 29.
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