Unexpected Macrocyclic Multinuclear Zinc and Nickel Complexes that Function as Multitasking Catalysts for CO2 Fixations

Article abstract of DOI:10.1002/anie.201904224

Unique self-assembled macrocyclic multinuclear Zn^II and Ni^II complexes with binaphthyl-bipyridyl ligands (L) were synthesized. X-ray analysis revealed that these complexes consisted of an outer ring (Zn₃L₃ or Ni₃L₃) and an inner core (Zn₂ or Ni). In the Zn^II complex, the inner Zn₂ part rotated rapidly inside the outer ring in solution on an NMR timescale. These complexes exhibited dual catalytic activities for CO₂ fixations: synthesis of cyclic carbonates from epoxides and CO₂ and temperature-switched N-formylation/N-methylation of amines with CO₂ and hydrosilane.

Full text of DOI:10.1002/anie.201904224

A Journal of the Gesellschaft Deutscher Chemiker
Angewandte
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Accepted Article
Title: Unexpected Macrocyclic Multinuclear Zinc and Nickel Complexes
Function as Multitask Catalysts for CO₂ Fixations
Authors: Kazuto Takaishi, Bikash Dev Nath, Yuya Yamada, Hiroyasu
Kosugi, and Tadashi Ema
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To be cited as: Angew. Chem. Int. Ed. 10.1002/anie.201904224
Angew. Chem. 10.1002/ange.201904224
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10.1002/anie.201904224
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Unexpected Macrocyclic Multinuclear Zinc and Nickel Complexes
Function as Multitask Catalysts for CO2 Fixations
Kazuto Takaishi,* Bikash Dev Nath, Yuya Yamada, Hiroyasu Kosugi, and Tadashi Ema*
Abstract: Unique self-assembled macrocyclic multinuclear Zn(II)
and Ni(II) complexes with binaphthyl–bipyridyl ligands (L) were
synthesized. X-ray analysis revealed that these complexes consisted
of an outer ring (Zn3L3 or Ni3L3) and an inner core (Zn2 or Ni). In
the Zn(II) complex, the inner Zn2 part rotated rapidly inside the outer
ring in solution on an NMR time scale. These complexes exhibited
dual catalytic activities for CO2 fixations: synthesis of cyclic
carbonates from epoxides and CO2 and temperature-switched N-
formylation/N-methylation of amines with CO2 and hydrosilane.
Artificial metallosupramolecular architectures have been actively
investigated, and various macrocycles,[1] cages,[2] and helicates[3]
have been synthesized from simple ligands and metal ion sources.
Large but ordered multinuclear metal complexes can be constructed
by self-assembly. Recently, several metallosupramolecules with
catalytic activities have been reported.[4]
CO2 is a promising C1-building block as an alternative to
petroleum-based chemicals, and catalysts for CO2 fixations have
been developed extensively.[5] For example, synthesis of cyclic
[6]
carbonates from epoxides and CO2 and N-functionalization of
amines with CO2 and hydrosilane[7,8] have been actively studied.
Cyclic carbonates are raw materials of polycarbonates and
polyurethanes, and N-functionalized amines are intermediates of
Scheme 1. Synthesis of multinuclear Zn(II) and Ni(II) complexes.
various chemicals such as drugs. A multitask catalyst for these CO2
fixations have not been reported, and its development presents a
significant challenge.
We synthesized (R)-1 via the Suzuki–Miyaura reaction of 3,3’-
B(pin)-substituted (R)-1,1’-binaphthyl[10] with 6-bromo-2,2’-
bipyridyl (Scheme S1). (R)-1 and each metal acetate hydrates were
self-assembled to give the Zn(II) or Ni(II) complexes in 80–82%
yields (Scheme 1).
Here, we report a new type of macrocyclic multinuclear Zn(II)
and Ni(II) complexes 2 and 3, respectively, prepared by self-
assembly of a binaphthyl–bipyridyl ligand (H2L; (R)-1) and metal
acetate hydrates (Scheme 1). These structures were surprising
because we originally expected the formation of simple acyclic
dinuclear complexes such as M2L(OAc)2. The complexes 2 and 3
comprise an outer ring (M3L3) and an inner core (M2 or M). In other
words, they are “complex@complex” structures. This type of
structure is unprecedented, although many multinuclear metal
complexes with binaphthyl-based ligands have been reported.[9]
Furthermore, the complexes exhibited high catalytic activities for
distinct CO2 fixations: (1) synthesis of cyclic carbonates from
epoxides and CO2 and (2) N-formylation/N-methylation of amines
with CO2 and hydrosilane. This is the first example of multitask
catalysts for the CO2 fixations.
The crystal structures of the Zn(II) and Ni(II) complexes were
determined by X-ray analyses. The Zn(II) complex was found to
have
a
unique
macrocyclic
pentanuclear
structure,
[Zn5L3(OAc)(O)]OH (2) (Figure 1a). Complex 2 contained a
trinuclear macrocyclic part, a dinuclear inner part, and a hydroxide
as
a
counter anion, which can be represented by
[Zn2(OAc)(O)]@[Zn3L3]OH. MALDI-TOF-MS analysis also
clearly demonstrated the formation of 2 (Figure S8). The peripheral
macrocyclic part consisted of three hexacoordinate octahedral Zn
ions (Zn1–3) and three ligands (L), which were connected via two
sets of NNO coordinations of the adjacent ligands. All three Zn1–3
centers had -chirality induced by the (R)-binaphthyl moieties. The
inner part consisted of two distorted square pyramidal
pentacoordinate Zn ions (Zn4 and Zn5) and bridging AcO– and O2–,
forming a six-membered ring (Zn4–O–C–O–Zn5–O) to fill the cavity.
This inner core is similar to the active site of a peptidase[11] and a
phosphotriesterase[12]. The Zn1–3 ions were arranged to form a nearly
isosceles triangle, and the dihedral angles of the naphthalene rings
of each binaphthyl differed: 68°, 72°, and 88°, because the inner part
was horizontally long.
Dr. K. Takaishi, B. D. Nath, Y. Yamada, H. Kosugi, Prof. Dr. T. Ema
Division of Applied Chemistry, Graduate School of Natural Science
and Technology, Okayama University, Tsushima, Okayama 700-
8530 (Japan)
E-mail: takaishi@okayama-u.ac.jp
ema@cc.okayama-u.ac.jp
Supporting information for this article is given via a link at the end of
the document.
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10.1002/anie.201904224
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We next analyzed the conformations of Zn(II) complex 2 in
solution. 1H NMR, 13C NMR, COSY, and NOESY spectra suggested
an averaged C3-symmetrical structure with the inner core rotating
around the z-axis like a molecular motor as shown in Figure 2 (see
the Supporting Information for details). The OH– proton appeared at
a high magnetic field (–0.38 ppm in CDCl3), suggesting that the OH–
of 2 was incorporated into the inner part in equilibrium to form 2OH
with a hydrogen-bonded OH ligand surrounded by aromatic rings
(Figures 2 and S4). The Ni(II) complexes were NMR-inactive due
to paramagnetism, and hence, UV-Vis and CD spectra were
analyzed instead. The solution of the cocrystal of 3 and 4 exhibited
the same spectra as that of 5 (Figure S10), which suggests a rapid
equilibrium between complexes 3–5 in solution (Scheme S2).
In view of the quite unique static and dynamic structures of the
Zn(II) and Ni(II) complexes 2 and 3, we decided to investigate the
latent catalytic activity of 2 and 3. In the context of our ongoing
research for CO2 fixations,[13] we tested these metal complexes for
the synthesis of cyclic carbonate 7a from CO2 and epoxide 6a (Table
1).[14] We screened combinations of 2 or 3 (2 mol%) and
tetrabutylammonium halide (TBAX) at 50 °C under solvent-free
conditions (entries 1–6), expecting that the metal ions and halide
anions act as a Lewis acid and a nucleophile, respectively. The
simultaneous use of complex 2 or 3 and TBAI yielded 7a in high
yield (73–95%, entries 3 and 6). The reaction did not proceed
significantly in the presence of either metal complex alone or TBAI
alone (entries 7 and 8). The substrate scope of 3 and TBAI was
broad; styrene oxides, glycidyl ethers, and hexene oxide 6b−i were
efficiently converted into the corresponding cyclic carbonates
(Scheme S3).
Figure 1. X-ray crystal structures of 2 and 3. Solvent molecules are
omitted for clarity.
On the other hand, the Ni(II) complexes exhibited polymorphism
(Schemes 1 and S2), and two types of single crystals of macrocyclic
complexes were obtained (Figures 1b and S3). One of them was a
cocrystal of tetranuclear complexes Ni4L3(OH)2(H2O)2 (3) and
Ni4L3(OH)2 (4), and the other was a dinuclear complex Ni2L2 (5).
Complex 3 consisted of a macrocyclic part (Ni3L3) and an inner part
(Ni(OH)2(H2O)2). The macrocyclic part was very similar to that of
Zn(II) complex 2. In contrast, the inner part of 3 consisted of a
hexacoordinate octahedral Ni4 ion, two OH–, and two H2O. The Ni1–
3 ions of the macrocyclic part have -chirality again. The difference
between 3 and 4 was the presence or absence of two H2O molecules
coordinating the inner Ni ion. Complex 5 has two hexacoordinate Ni
ions without a cavity. The average Ni–Ni distances in the
macrocyclic parts were 7.86 Å for 3 and 6.95 Å for 4, indicating that
the cavity size is somewhat variable.
Table 1: Synthesis of cyclic carbonate 7a from styrene oxide (6a)
and CO2
[a]
Entry
Cat.
X
co-cat.[b]
Temp
[°C]
Time
[h]
Yield
[%][c]
[mol%]
1
2
2
2
TBAC
TBAB
TBAI
TBAC
TBAB
TBAI
–
50
50
12
12
12
12
12
12
12
12
24
24
24
24
24
24
15
59
73
31
68
95
16
11
70
97
0
2
2
3
2
2
50
4
3[d]
2
50
5
3[d]
2
50
6
3[d]
2
50
7
3[d]
2
50
8
–
2
TBAI
–
50
9
2
0.1
0.1
2
120
120
120
120
120
120
10
11
12
13[e]
14[f]
3[d]
–
Zn(OAc)2·2H2O
–
Ni(OAc)2·4H2O
2
–
0
2
2
–
99
97
3[d]
1
–
Figure 2. Equilibrium mixture of 2 and 2OH in solution.
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10.1002/anie.201904224
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COMMUNICATION
amounts (mol%) are based on 3. [d] Zn(OAc)2·2H2O (2.5 mol%). [e] 9a was
used as a substrate.
[a] Conditions: 6a (2.0 mmol), CO2 (1.7 MPa), cat. (amount indicated above),
co-cat. (3 mol%). [b] Tetrabutylammonium chloride (TBAC), bromide
(TBAB), and iodide (TBAI). [c] Isolated yield. [d] Equilibrium mixture of 3–5.
The amounts (mol%) are based on 3. [e] After four-time recycling of the
catalyst. [f] After nine-time recycling of the catalyst.
In contrast, N,N-dimethylaniline (10a) was obtained preferentially
at 100 °C (60%, entry 3). The selectivity for 9a or 10a was
independent of the amount of phenylsilane (entry 2) and controlled
by temperature. Catalyst 2 was applicable to other aromatic and
aliphatic amines 8b–e (Scheme S5). Although several examples of
chemoselective N-formylation/N-methylation were reported,[8] the
method using 2 has the following advantages: (1) catalyst loading is
low (0.5 mol%), (2) the reaction proceeds in no solvent under the
CO2 pressure of 1 atm, and (3) chemoselectivity is controlled by
only temperature.
Ni(II) complex 3 showed much lower catalytic activity than 2
(entries 4 and 5), probably because the Ni(II) ions were reduced to
Ni(0) during the reaction. Zn(OAc)2·2H2O was a poor catalyst
(entries 6 and 7). When 9a was used as a substrate at 100 °C, 10a
was not obtained, but 9a was recovered (entry 8). This result
indicates that 9a is not an intermediate leading to 10a.
Interestingly, 2 and 3 with only 0.1 mol% loading worked well
without a co-catalyst at 120 °C to produce 7a in high yields (70–
97%, entries 9 and 10). By contrast, Zn(OAc)2 and Ni(OAc)2
hydrates showed no catalytic activity (entries 11 and 12). In addition,
ZnCl2, ZnBr2, ZnI2, and Zn(OCOCF3)2·H2O also showed no activity
(not shown). These results suggest a catalytic mechanism specific to
2 and 3. The counter anion or ligand such as OH– and AcO–, or
HCO3– generated by the reaction of OH– with CO2,[15] might act as
a nucleophile, and the inner metal ion in 2 and 3 might act as a Lewis
acid; the inner Zn ions of 2 are likely to provide a vacant site by the
partial dissociation of the AcO bridge, while the inner Ni ion of 3
seems to act as a Lewis acid after loss of a H2O molecule. In addition,
the catalysts were recyclable without lowering catalytic activity at
least over five cycles (entries 13 and 14 and Figure S1).
Epoxide 6a was kinetically resolved in the presence of 3 and
TBAI (Scheme S4). The reaction proceeded to give (S)-7a with 21%
ee and (R)-6a with 16% ee at a 44% conversion (kS/kR = s value =
1.8).[16] This result suggests that the macrocyclic structure was
retained to some degree during the reactions. We suppose that the
low stereoselectivity was due to the active center remote from the
chiral axes. We expected that 2 and 3 might show catalytic activities
for other CO2 fixations as well.
The reaction pathway for the 2-catalyzed N-functionalization is
tentatively proposed in Scheme 2. Initially, the inner Zn2 moiety of
2 is reduced to give hydride complex 2H.[17] Insertion of a CO2
molecule gives formate 2OCHO
. Subsequent reaction with
phenylsilane gives silylformate at 30 °C, and further successive
reactions with phenylsilane take place at 100 °C to give
methoxysilane species. Silylformate and methoxysilane react with
8a to afford 9a and 10a, respectively. DFT calculations support 2H
and 2OCHO as plausible intermediates (Figure S11).[18]
We next investigated N-formylation and N-methylation of amines
with CO2 and hydrosilane (Table 2).[7,8] First, Zn(II) complex 2 (0.5
mol%) was used as a catalyst for the N-functionalization of N-
methylaniline (8a) in the presence of CO2 (1 atm) and phenylsilane
under solvent-free conditions. To our delight, N-methylformanilide
(9a) was obtained with complete selectivity at 30 °C (99%, entry 1).
Table 2: N-Formylation and N-methylation of N-methylaniline
(8a)[a]
Scheme 2. Proposed pathway for N-functionalization of 8a. Ecalcd
values are relative energies based on 2OH + CO2 + PhSiH3.
Yield [%][b]
Entry
Cat.
Temp
[°C]
X
[equiv]
9a
99
97
9
10a
0
In summary, we demonstrated that binaphthyl–bipyridyl ligands
and metal acetates self-assembled to form novel multinuclear Zn(II)
and Ni(II) complexes. These complexes acted as multitask catalysts
for CO2 fixations, the synthesis of cyclic carbonates from epoxides
and the temperature-switched N-formylation/N-methylation of
amines, under solvent-free conditions. The macrocyclic complexes
presented here have great potential in catalysis and other functions,
and a further study is underway in our laboratory.
1
2
30
30
2
6
6
2
6
2
6
6
2
2
0
3
2
100
30
60
0
4
3[c]
15
0
5
3[c]
100
30
21
0
6
Zn(OAc)2·2H2O[d]
Zn(OAc)2·2H2O[d]
2
0
7
100
100
0
10
0
8[e]
–
Acknowledgements
[a] Conditions: 8a (0.25 mmol), CO2 (1 atm, balloon), cat. (0.5 mol% of 8a),
PhSiH3 (amount indicated above), 24 h. [b] Determined by 1H NMR using
mesitylene as an internal standard. [c] Equilibrium mixture of 3–5. The
This work was supported by the JSPS KAKENHI Grant No.
JP16H01030 for Precisely Designed Catalysts with Customized
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10.1002/anie.201904224
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COMMUNICATION
Scaffolding and a Grant for Promotion of Science and Technology
in Okayama Prefecture by MEXT. We thank Dr. Shigeki Mori
(Ehime University) and Dr. Hiromi Ota (Okayama University) for
X-ray analyses.
C. Detrembler, Catal. Sci. Technol. 2017, 7, 2651; d) R. R. Shaikh, S.
Pornpraprom, V. D’Elia, ACS Catal. 2018, 8, 419.
[7] a) C. Das Neves Gomes, O. Jacquet, C. Villiers, P. Thuéry, M.
Ephritikhine, T. Cantat, Angew. Chem. Int. Ed. 2012, 51, 187; Angew.
Chem. 2012, 124, 191; b) O. Jacquet, C. Das Neves Gomes, M.
Ephritikhine, T. Cantat, J. Am. Chem. Soc. 2012, 134, 2934; c) O.
Jacquet, X. Frogneux, C. Das Neves Gomes, T. Cantat, Chem. Sci.
2013, 4, 2127; d) Y. Li, X. Fang, K. Junge, M. Beller, Angew. Chem.
Int. Ed. 2013, 52, 9568; Angew. Chem. 2013, 125, 9747; e) S. Itagaki,
K. Yamaguchi, N. Mizuno, J. Mol. Catal. A: Chem. 2013, 366, 347;
f) K. Motokura, M. Naijo, S. Yamaguchi, A. Miyaji, T. Baba, Chem.
Lett. 2015, 44, 1217.
Conflict of interest
The authors declare no conflict interest.
Keywords: multinuclear complexes • self-assembly • carbon
dioxide fixation • cyclic carbonates • N-functionalization
[8] a) X. Frogneux, O. Jacquet, T. Cantat, Catal. Sci. Technol. 2014, 4,
1529; b) S. Das, F. D. Bobbink, S. Bulut, M. Soudani, P. J. Dyson,
Chem. Commun. 2016, 52, 2497; c) C. Fang, C. Lu, M. Liu, Y. Zhu,
Y. Fu, B.-L. Lin, ACS Catal. 2016, 6, 7876; d) X.-F. Liu, R. Ma, C.
Qiao, H. Cao, L.-N. He, Chem. Eur. J. 2016, 22, 16489; e) M.-Y.
Wang, N. Wang, X.-F. Liu, C. Qiao, L.-N. He, Green Chem. 2018, 20,
1564; f) R. H. Lam, C. M. A. McQueen, I. Pernik, R. T. McBurney,
A. F. Hill, B. A. Messerle, Green Chem. 2019, 21, 538.
[9] a) E. C. Escudero-Adán, M. M. Belmonte, J. Benet-Buchholz, A. W.
Kleij, Org. Lett. 2010, 12, 4592; b) K. Endo, M. Ogawa, T. Shibata,
Angew. Chem. Int. Ed. 2010, 49, 2410; Angew. Chem. 2010, 122,
2460; c) S. Akine, T. Shimada, H. Nagumo, T. Nabeshima, Dalton
Trans. 2011, 40, 8507; d) L. Ma, R. Jin, Z. Bian, C. Kang, Y. Chen, J.
Xu, L. Gao, Chem. Eur. J. 2012, 18, 13168; e) B. Wu, J. C. Gallucci,
J. R. Parquette, T. V. RajanBabu, Chem. Sci. 2014, 5, 1102; f) Y. Deng,
C. V. Karunaratne, E. Csatary, D. L. Tienrney, K. Wheeler, H. Wang,
J. Org. Chem. 2015, 80, 7984; g) N. Kumagai, M. Kanai, H. Sasai,
ACS Catal. 2016, 6, 4699. h) J. T. Fleming, P. G. Waddell, M. R.
Probert, W. Clegg, L. J. Higham, Eur. J. Inorg. Chem. 2017, 2837; i)
K.-Y. Cheng, S.-C. Wang, Y.-S. Chen, Y.-T. Chan, Inorg. Chem. 2018,
57, 3559; j) T. Arai, K. Sato, A. Nakamura, H. Makino, H. Masu, Sci.
Rep. 2018, 8, 837.
[1] For recent reviews, see: a) J. Dong, C. Tan, K. Zhang, Y. Liu, P. J.
Low, J. Jiang, Y. Cui, J. Am. Chem. Soc. 2017, 139, 1554; b) L.-J.
Chen, H.-B. Yang, M. Shionoya, Chem. Soc. Rev. 2017, 46, 2555; c)
D. A. Roberts, B. S. Pilgrim, J. R. Nitschke, Chem. Soc. Rev. 2018, 47,
626; d) S. Chakraborty, G. R. Newkome, Chem. Soc. Rev. 2018, 47,
3991.
[2] For recent examples, see: a) D. Fujita, Y. Ueda, S. Sato, N. Mizuno,
T. Kumasaka, M. Fujita, Nature 2016, 540, 563; b) W. M. Bloch, Y.
Abe, J. J. Holstein, C. M. Wandtke, B. Dittrich, G. H. Clever, J. Am.
Chem. Soc. 2016, 138, 13750; c) S. H. A. M. Leenders, R. Becker, T.
Kumpulainen, B. de Bruin, T. Sawada, T. Kato, M. Fujita, J. N. H.
Reek, Chem. Eur. J. 2016, 22, 15468; d) A. J. Musser, P. P.
Neelakanden, J. M. Richter, H. Mori, R. H. Friend, J. R. Nitschke, J.
Am. Chem. Soc. 2017, 139, 12050; e) D. Peterson, J. E. M. Lewis, J.
D. Crowley, J. Am. Chem. Soc. 2017, 139, 2379; f) X.-Z. Li, L.-P.
Zhau, L. L. Yan, Y.-M. Dong, Z.-L. Bai, X.-Q. Sun, J. Diwu, S. Wang,
J.-C. Bünzil, Q.-F. Sun, Nat. Commun. 2018, 9, 547; g) L. Zhang, D.
P. August, J. Zhong, G. F. S. Whitehead, I. Victoria-Yrezabal, D. A.
Leigh, J. Am. Chem. Soc. 2018, 140, 4982; h) D. Samanta, D.
Galaktionova, J. Gemen, L. J. W. Shimon, Y. Diskin-Posner, L.
Avram, P. Král, R. Klajn, Nat. Commun. 2018, 9, 641.
[3] For recent examples, see: a) O. Gidron, M. O. Ebert, N. Trapp, F.
Diederich, Angew. Chem. Int. Ed. 2014, 53, 13614; Angew. Chem.
2014, 126, 13833; b) O. Gidron, M. Jirásek, N. Trapp, M.-O. Ebert, X.
Zhang, F. Diederich, J. Am. Chem. Soc. 2015, 137, 12502; c) M. H.-
Y. Chan, M. Ng, S. Y.-L. Leung, W. H. Lam, V. W.-W. Yam, J. Am.
Chem. Soc. 2017, 139, 8639; d) P. Mateus, B. Wicher, Y. Ferrand, I.
Huc, Chem. Commun. 2018, 54, 5078.
[4] For reviews, see: a) C. J. Brown, F. D. Toste, R. G. Bergman, K. N.
Raymond, Chem. Rev. 2015, 115, 3012; b) C. Tan, D. Chu, X. Tang,
Y. Liu, W. Xuan, Y. Cui, Chem. Eur. J. 2019, 25, 662; For recent
examples, see: c) C. García-Simón, R. Gramage-Doria, S.
Raoufmoghaddam, T. Parella, M. Costas, X. Ribas, J. H. N. Reek, J.
Am. Chem. Soc. 2015, 137, 2680; d) D. M. Kaphen, M. D. Levin, R.
G. Bergman, K. N. Raymond, F. D. Toste, Science 2015, 350, 1235;
e) W. Cullen, M. C. Misuraca, C. A. Hunter, N. H. Williams, M. D.
Ward, Nat. Chem. 2016, 8, 231; f) P. Howlader, P. Das, E. Zangrando,
P. S. Mukherjee, J. Am. Chem. Soc. 2016, 138, 1668; g) Y. Ueda, H.
Ito, D. Fujita, M. Fujita, J. Am. Chem. Soc. 2017, 139, 6090; h) L.
Zhao, J. Wang, P. Wu, C. He, X. Guo, C. Duan, Sci. Rep. 2017, 7,
14347; i) J. Jiao, C. Tan, Z. Li, Y. Liu, X. Han, Y. Cui, J. Am. Chem.
Soc. 2018, 140, 2251; j) L. R. Holloway, P. M. Bogie, Y. Lyon, C.
Ngai, T. F. Miller, R. R. Julian, R. J. Hooley, J. Am. Chem. Soc. 2018,
140, 8078.
[10] a) H.-B. Yu, Q.-S. Hu, L. Pu, J. Am. Chem. Soc. 2000, 122, 6500; b)
L. Ma, R.-Z. Jin, G.-H. Lü, Z. Bian, M.-X. Ding, L.-X. Gao, Synthesis
2007, 2461.
[11] D. Jozic, G. Bourenkow, H. Bartunik, H. Scholze, V. Dive, B. Henrich,
R. Huber, W. Bode, K. Maskos, Structure 2002, 10, 1097.
[12] G. Gotthard, J. Hiblot, D. Gonzalez, M. Elias, E. Chabriere, PLoS One
2013, 8, e77995.
[13] For selected papers, see: a) T. Ema, Y. Miyazaki, J. Shimonishi, C.
Maeda, J. Hasegawa, J. Am. Chen. Soc. 2014, 136, 15270; b) C. Maeda,
T. Taniguchi, K. Ogawa, T. Ema, Angew. Chem. Int. Ed. 2015, 54,
134; Angew. Chem. 2015, 127, 136; c) C. Maeda, J. Shimonishi, R.
Miyazaki, J. Hasegawa, T. Ema, Chem. Eur. J. 2016, 22, 6556; d) T.
Ema, M. Yokoyama, S. Watanabe, S. Sasaki, H. Ota, K. Takaishi, Org.
Lett. 2017, 19, 4070; e) K. Takaishi, T. Okuyama, S. Kadosaki, M.
Uchiyama, T. Ema, Org. Lett. 2019, 21, 1397.
[14] For macrocyclic multinuclear Zn complexes as epoxide/CO2
copolymerization catalysts, see: a) H. Nagae, R. Aoki, S. Akutagawa,
J. Kleemann, R. Tagawa, T. Schindler, G. Choi, T. P. Spaniol, H.
Tsurugi, J. Okuda, K. Mashima, Angew. Chem. Int. Ed. 2018, 57,
2492; Angew. Chem. 2018, 130, 2518; b) J. A. Garden, P. K. Saini, C.
K. Williams, J. Am. Chem. Soc. 2015, 137, 15078.
[15] T. Ema, K. Fukuhara, T. Sakai, M. Ohbo, F.-Q. Bai, J. Hasegawa,
Catal. Sci. Technol. 2015, 5, 2314.
[16] Zn complex 2 did not promote the kinetic resolution (s value = 1.0).
[17] For the hydrosilylation of CO2 with zinc hydride complexes, see: a) A.
Rit, A. Zanardi, T. P. Spaniol, L. Maron, J. Okuda, Angew. Chem. Int.
Ed. 2014, 53, 13273; Angew. Chem. 2014, 126, 13489; b) M. Rauch,
G. Parkin, J. Am. Chem. Soc. 2017, 139, 18162; c) M. Tüchler, L.
Gärtner, S. Fischer, A. D. Boese, F. Belaj, N. C. Mösch-Zanetti,
Angew. Chem. Int. Ed. 2018, 57, 6906; Angew. Chem. 2018, 130, 7022.
[18] DFT calculations were performed using Gaussian16, revision A.03.
Frisch, M. J. et al., Gaussian, Inc., Wallingford, CT, 2016.
[5] For recent reviews, see: a) C. Maeda, Y. Miyazaki, T. Ema, Catal. Sci.
Technol. 2014, 4, 1482; b) Q.-W. Song, Z.-H. Zhou, L.-N. He, Green
Chem. 2017, 19, 3707; c) Y.-Y. Gui, W.-J. Zhou, J.-H. Ye, D.-G. Yu,
ChemSusChem 2017, 10, 1337; d) T. Janes, Y. Yang, D. Song, Chem.
Commun. 2017, 53, 11390.
[6] For recent reviews, see: a) C. Martín, G. Fiorani, A. W. Kleij, ACS
Catal. 2015, 5, 1353; b) X.-D. Lang, L.-N. He, Chem. Rec. 2016, 16,
1337; c) M. Alves, B. Grignard, R. Mereau, C. Jerome, T. Tassaing,
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10.1002/anie.201904224
Angewandte Chemie International Edition
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Multi-task catalysts: Unique self-
assembled macrocyclic multinuclear
Zn(II) and Ni(II) complexes with
binaphthyl–bipyridyl ligands (L) were
synthesized. These complexes
consisted of an outer ring (Zn3L3 or
Ni3L3) and an inner core (Zn2 or Ni).
These complexes acted as multitask
catalysts for CO2 fixations.
Kazuto Takaishi,* Bikash Dev Nath,
Yuya Yamada, Hiroyasu Kosugi, and
Tadashi Ema*
Page No. – Page No.
Unexpected Macrocyclic Multinuclear
Zinc and Nickel Complexes Function
as Multitask Catalysts for CO2
Fixations
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