Chiral Covalent Organic Frameworks with High Chemical Stability for Heterogeneous Asymmetric Catalysis

Article abstract of DOI:10.1021/jacs.7b04008

Covalent organic frameworks (COFs) featuring chirality, stability, and function are of both fundamental and practical interest, but are yet challenging to achieve. Here we reported the metal-directed synthesis of two chiral COFs (CCOFs) by imine-condensat

Full text of DOI:10.1021/jacs.7b04008

Subscriber access provided by Binghamton University | Libraries
Article
Chiral Covalent Organic Frameworks with High Chemical
Stability for Heterogeneous Asymmetric Catalysis
Xing Han, Qingchun Xia, jinjing huang, Yan Liu, Chunxia Tan, and Yong Cui
J. Am. Chem. Soc., Just Accepted Manuscript • Publication Date (Web): 08 Jun 2017
Downloaded from http://pubs.acs.org on June 8, 2017
Just Accepted
“Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted
online prior to technical editing, formatting for publication and author proofing. The American Chemical
Society provides “Just Accepted” as a free service to the research community to expedite the
dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts
appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been
fully peer reviewed, but should not be considered the official version of record. They are accessible to all
readers and citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered
to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published
in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just
Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor
changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers
and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors
or consequences arising from the use of information contained in these “Just Accepted” manuscripts.
Journal of the American Chemical Society is published by the American Chemical
Society. 1155 Sixteenth Street N.W., Washington, DC 20036
Published by American Chemical Society. Copyright © American Chemical Society.
However, no copyright claim is made to original U.S. Government works, or works
produced by employees of any Commonwealth realm Crown government in the course
of their duties.

Page 1 of 6
Journal of the American Chemical Society
1
2
3
4
5
6
7
8
9
Chiral Covalent Organic Frameworks with High Chemical Stability
for Heterogeneous Asymmetric Catalysis
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
Xing Han,† Qingchun Xia,† Jinjing Huang,† Yan Liu,*,† Chunxia Tan, and Yong Cui*,†,‡
†School of Chemistry and Chemical Engineering and State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University,
Shanghai 200240, China
‡Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300072, China
Supporting Information
ABSTRACT: Covalent organic frameworks (COFs) featuring chirality, stability and function are of both fundamental and practical
interest, but are yet challenging to achieve. Here we reported the metalꢀdirected synthesis of two chiral COFs (CCOFs) by
imineꢀcondensations of enantiopure 1,2ꢀdiaminocyclohexane with C3ꢀsymmetric triꢀsalicylaldehydes having one or zero 3ꢀtertꢀbutyl group.
Powder Xꢀray diffraction and modeling studies, together with pore size distribution analysis demonstrate that the Zn(salen)ꢀbased CCOFs
possess a twoꢀdimensional hexagonal grid network with AA stacking. Dramatic enhancement in the chemical stability toward acidic (1 M
HCl) and basic (9 M NaOH) conditions was observed for the COF incorporated with tertꢀbutyl groups on the pore walls compared to the
nonꢀalkylated analog. The Zn(salen) modules in the CCOFs allow for installing multivariate metals into the frameworks by postꢀsynthetic
metal exchange. The exchanged CCOFs maintain high crystallinity and porosity and can serve as efficient and recyclable heterogeneous
catalysts for asymmetric cyanation of aldehydes, DielsꢀAlder reaction, alkene epoxidation, epoxide ringꢀopening and related sequential
reactions with up to 97% ee.
triꢀsalicylaldehydes. By introducing bulky hydrophobic groups
INTRODUCTION
into the pore walls to protect hydrolytically susceptible backbones
through kinetic blocking, drastic boost of chemical stability for the
CCOF in acidic and alkaline solutions has been achieved. After
exchanging Zn2+ ions for other metal ions, the CCOFs are shown
to be efficient and recyclable heterogeneous catalysts for the
archetypical M(salen)ꢀcatalyzed asymmetric reactions and related
sequential reactions, with stereoselectivities comparable to the
homogeneous analogs.
C
ovalent–organic frameworks (COFs), covalently formed from
organic building units,1-3 are a structurally and compositionally
varied class of crystalline porous materials of which the host–guest
behavior has been explored for diverse applications that include
gas storage,4 separations,5 catalysis,6,7 sensors,8 optoelectronics9
and energy storage.10 In particular, COFs hold great potential as
heterogeneous catalysts because of the large channels that make
the catalytic sites readily accessible to substrates, and the
capability of precisely controlling the environment around these
sites. Although many COFs have been examined as solid
catalysts,6,7 examples of stereoselective COF catalysts are very
scarce.7 In fact, it is still challenging to construct chiral COFs
(CCOFs) because of the discrepancy between asymmetry and
crystallinity. Another challenge facing COFs is their generally low
stability under harsh conditions, thus limiting their use in practical
processes.7c,11 In this work, we demonstrated how to address such
issue by using chiral metallosalen catalysts with bulky
hydrophobic groups as building blocks for CCOF construction.
RESULTS AND DISCUSSION
Synthesis and characterization. CCOFs
3 and 4 were
synthesized by solvothermal reactions of THB or TTHB (0.067
mmol) and Zn(OAc)2⋅2H2O (0.15 mmol) and chiral
1,2ꢀdiaminocyclohexane (0.1 mmol) in 1.5 mL of
mesitylene/EtOH (1:1 v/v) or DMF/EtOH (2:1 v/v) at 120 oC for
three days, which afforded yellow crystalline solids in ~70% yields
(Scheme 1). Both CCOFs are stable in common organic solvents.
In the FTꢀIR spectra of 3 and 4, the characteristic C=O stretching
bands (1658 and 1648 cmꢀ1, respectively) disappeared, indicative
of the consumption of the aldehydes (Figure S1). Strong stretching
vibration bands attributed to the new generation of C=N linkages
were observed at 1624 and 1612 cmꢀ1, respectively. In the 13C
CPꢀMAS NMR spectra of 3 and 4, the characteristic signals due to
C=N bonds were observed at 167 and 170 ppm, respectively
(Figure S2). The aldehyde carbon peaks were no longer present.
The chemical shifts of other fragments are consistent with those of
the monomers. Circular dichroism (CD) spectra of 3 and 4 made
from the opposite enantiomers of 1, 2ꢀdiaminocyclohexane were
mirror images of each other, suggesting their enantiomeric nature
(Figure S3). The CD spectra were consistent with their
corresponding UVꢀvis spectra (Figure S4). Thermal gravimetric
analysis (TGA) showed that both CCOFs were stable up to around
350 °C (Figure S5).
Chiral salen ligands such as (R,R)ꢀ1,2ꢀcyclohexanediamino
ꢀN,N′ꢀbis(3ꢀtertꢀbutylꢀsalicylidene) are wellꢀknown privileged
ligands for asymmetric catalysis.12 Some examples of salenꢀbased
asymmetric catalysis include epoxidation of olefins catalyzed by
Mn(salen) and Fe(salen) complexes,13a,13b ringꢀopening of
epoxides catalyzed by Co(salen) and Cr(salen) complexes,13c,13d
and cyanation of aldehydes by VO(salen) complexes.13e To allow
their recyclable uses, M(salen) catalysts have been immobilized on
diverse porous solid supports such as silica and metalꢀorganic
frameworks (MOFs).14,15 Very recently, one report has used
salenꢀtype linkers to build achiral COFs.16 Nonetheless, the
synthesis of CCOFs from M(salen) complexes has not yet been
explored. Here we report the synthesis of two Zn(salen)ꢀbased 2D
CCOFs by coꢀcondensation of chiral 1,2ꢀdiaminocyclohexane and
ACS Paragon Plus Environment

Journal of the American Chemical Society
Page 2 of 6
Scheme 1. Synthesis of the CCOFs
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
1
Å, c = 4.05 Å, α = β = 90°, γ = 120° for 4). CCOF 3 exhibited
strong PXRD peaks at at 3.51°, 7.02°, 9.29°, 12.18°, 15.34° and
22.72°, which were assigned to the (100), (200), (210), (220), (320)
and (001) facets of P321 space group, respectively (Figure 1a,
black curve). This PXRD pattern agreed well with the simulated
pattern generated from the AA stacking of the 2D layers. Lattice
modeling and Pawley refinement (Materials Studio, version 7.0)
gave optimized parameters of a = b = 29.05 Å, c = 3.91 Å, α= β =
90°, γ = 120°) for the unit cell with space group P321, which
provided good agreement factors (Rp = 2.96% and Rwp = 3.75%).
CCOF 4 (Figure 1b, black curve) gave strong PXRD peaks at
3.63°, 7.26°, 9.61°, 14.55°, and 22.48°, corresponding to the (100),
(200), (210), (400) and (001) facets of space group P321,
respectively (Figure 1b, black curve). This experimental pattern
matched well with the simulated pattern based on the AA stacking
structure. The refinement results yielded unit cell parameters
nearly equivalent to the predictions (a = b = 28.09 Å, c = 3.95 Å, α
= β = 90°, γ = 120° for the unit cell with the space group of P321)
with acceptably low residuals (Rp = 3.14% and Rwp = 4.12%).
PXRD patterns were also calculated for the two CCOFs on the
other structures, but the calculated patterns did not match the
experimental patterns well (Figure S12). In the PXRD patterns,
peaks at 22.72° for 3 and 22.48° for 4 correlating to the values of
the interlayer distances were observed; the d spacing for them was
calculated to be 3.91 Å and 3.95 Å, respectively.
a)
b)
Figure 1. PXRD patterns of CCOFs 3 (a) and 4 (b) with the experimental
profiles in black, Pawleyꢀrefined profiles in red, calculated profiles in blue,
and the differences between the experimental and refined PXRD patterns in
dark cyan (Insert: Views of spaceꢀfilling models along the cꢀaxis with the
layer distances).
Figure 2. N2 adsorptionꢀdesorption isotherms (77 K) and pore size
distribution profiles (insert) of CCOFs 3 (red) and 4 (blue), as well as 4
after 7 days treatment in 1 M HCl (green) and 9 M NaOH (black).
The crystalline structures of the CCOFs were determined by
powder Xꢀray diffraction (PXRD) analysis with Cu Kα radiation
(Figure 2). Two types of possible 2D structures were generated for
them, that is, eclipsed stacking (AA) and staggered stacking (AB).
After a geometrical energy minimization based on the AA stacking
mode for CCOFs 3 and 4, the unit cell parameters were obtained (a
= b = 27.47 Å, c = 3.97 Å, α = β = 90°, γ = 120° for 3; a = b = 27.21
The porosity of the CCOFs was examined by measuring N2
sorption isotherms at 77 K on the activated samples. The adsorption
curves of the CCOFs exhibited the typeꢀI isotherm (Figure 2), a
characteristic of microporous materials. The Brunauer–Emmett–
Teller (BET) surface areas of 3 and 4 were estimated to be 826 and
683 m2gꢀ1, respectively. Their total pore volumes were calculated to
be 0.61 and 0.45 cm3gꢀ1 at P/P0 = 0.99, respectively. The nonlocal
2
ACS Paragon Plus Environment
b)

Page 3 of 6
Journal of the American Chemical Society
density functional theory (NLDFT) gave rise to a narrow pore size
the third metal ions did not substitute Cr3+ ions can be ascribed to
1
2
3
4
5
6
7
8
distribution with an average pore width 1.84 nm for 3, and 1.65 nm
for 4, in good agreement with the related simulated values (2.0 nm
and 1.6 nm, respectively).
the kinetic inertness of their coordination bonds. Scanning electron
microscopeꢀenergyꢀdispersive Xꢀray spectra (SEMꢀEDS) analysis
demonstrated the homogeneous distribution of metal ions in the
crystal structures (Figures S6 and S7). PXRD showed that the
exchanged CCOFs 4-M and 4-Cr-M׳ retained high crystallinity
and the original crystal structure (Figure 3b). The porosity (BET
surface area = 547ꢀ628 m2gꢀ1) of them is close to that of CCOF 4
(Figure S11).
a)
b)
9
Heterogeneous Asymmetric catalysis. 4-M demonstrated
excellent activity and selectivity for several catalytic reactions.
We first studied the catalytic activity of 4-V. After oxidation of
V(IV) to V(V) with mꢀCPBA, 5 mol% loading of 4-V catalyzed
cyanation of aldehydes with TMSCN in the presence of Ph3PO in
THF at 0 °C, which gave 89ꢀ94% ee of cyanohydrin silyl ethers
(Figure 4a), which are versatile synthetic intermediates for
pharmaceuticals.18a 4-Co can catalyze asymmetric DielsꢀAlder
(DA) reaction of 1ꢀaminosubstituted butadienes and αꢀsubstituted
acroleins, which provides one of the most powerful methods for the
preparation of cyclic molecules.18b The DA reactions was
performed in CHCl3 at r.t in the presence of AgNO3, 4 Å molecular
sieves and 5.0 mol% 4-Co, providing the cycloadducts with
86ꢀ96% ee (Figure 4b). Both 4-Mn and 4-Fe are active in the
synthetically important reactions of epoxidation of alkenes. At 1.0
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
Figure 3. (a) PXRD patterns of CCOFs 3 and 4 after 7 days treatment in
boiling water, 1M HCl (aq.) and 9 M NaOH (aq.). (b) PXRD patterns of 4
after postꢀsynthetic metal exchange.
mol%
loading,
4-Mn
catalyzed
and its
oxidation
substrates
of
with
2,2ꢀdimethylꢀ2Hꢀchromene
2ꢀ(tertbutylsulfonyl)iodosylbenzene (sPhIO) as oxidant in CHCl3
at 0 oC, affording 77ꢀ97% ee of the targeted epoxides (Figure 4c).
However, when the NaClO was used as oxidant, no product were
detected. (Table S6). In the presence of iodosylbenzene (PhIO),
4-Fe promoted the above oxidation reactions to yield the products
with up to 92% ee. 4-Cr could serve as a catalyst for the
aminolysis of transꢀstilbene oxide with different anilines, which
constitutes a useful method to synthesize biologically important
enantioenriched antiꢀβꢀamino alcohols.18c 5 mol% loading of 4-Cr
promoted the aminolysis reactions in CHCl3 at r.t, affording
82ꢀ96% ee of the amino alcohols (Figure 4d).
The chemical stability of the materials was examined by
PXRD and N2 sorption after 7 days treatment in boiling water, 1
M HCl (aq) and 9 M NaOH (aq) (Figure 3a). Both CCOFs are
stable in boiling water, but CCOF 3 gave a decreased crystallinity.
The difference between the stabilities of 3 and 4 is most striking
under acidic and alkaline conditions. At 1 M HCl (aq) and 9 M
NaOH, the alkyated CCOF 4 retained good crystallinity whereas
the nonalkylated CCOF 3 was nearly or completely dissolved and
the remaining material was rendered amorphous. The asꢀtreated
samples of 4 have a BET surface area of 373 and 569 m2gꢀ1,
respectively (Figure 2). A small decrease in signalꢀtoꢀnoise ratio
and an obvious decrease in the surface area of 4 (683 m2g–1)
indicate just partial structural collapse upon treatment. It is worth
noting that 3 can retained its crystalline structure after 7 days
treatment in 3 M NaOH, as indicated by PXRD (Figure S10). In 4,
the bulky tertꢀbutyl groups were positioned near phenoxo oxygens
that can protect hydrolytically susceptible Zn(salen) cores through
kinetic blocking, which led to high chemical stability.17
a)
OSiMe3
O
5 mol% 4-V
TMSCN
+
CN
H
Ph3PO
THF, 0 oC, 36 h
R
R
77-79% conv.; 89 % ee (R = Me)
94% ee (R = OMe), 89% ee (R = Br)
b)
MeO2C Bn
N
CHO
R2
5.0 mol% 4-Co
R2
+
CO2Me
O
AgNO3, 4Å MS
CHCl3, r.t, 48 h
R1
N
The relative liability of ZnꢀO/N bonds and the readily
R1
Bn
accessible channels of
4
prompted us to explore the
83-88% conv.; 86% ee (R1/R2 = H/Me)
89% ee (R1/R2 = H/Et), 96% ee (R1/R2 = Me/Et)
metalꢀexchange capacity of the framework. Indeed, when crystals
of 4 were immersed in saturated solutions containing Mn+ salts
(Mn+ = Cr2+, Co2+, Mn2+, Fe2+, V4+) at r.t. for 1ꢀ2 days with
refreshment of the solutions three times, they were transformed
into new CCOFs 4-M. While 4-Cr-M׳ were obtained through a
dual strategy, involving sequential exchanges of Zn2+ ions in 4
with Cr2+ ions and M'2+ ions (M' = Mn, Fe and Co) in
solutions. The ion exchanges were clearly indicated by dramatic
changes in the color of the crystals that were consistent with the
colors reported for the molecular metallosalen analogs. ICPꢀOES
(inductively coupled plasma optical emission spectrometry)
indicated molar ratios of Zn/M ranging from 1:12 to 1:54 (Zn/Mn
= 1:17, Zn/Fe = 1:29, Zn/V = 1:12, Zn/Cr = 1:54 and Zn/Co =
1:15) and Zn/Cr/M׳ ranging from 1:16:10 to 1:46:45 (Zn/Cr/Mn =
1:16:10, Zn/Cr/Fe = 1:46:45, and Zn/Cr/Co = 1:36:20). Xꢀray
photoelectron spectroscopy (XPS) spectra suggested Fe, Cr, Mn
and Co in the +3 oxidation state and V in the +4 oxidation state
(Figures S9). In the bimetallic substituted samples, the reason for
c)
O
O
1.0 mol% 4-Mn
sPhIO
1.0 mol% 4-Fe
PhIO
CHCl3
O
CHCl3
O
O
R
R
R
-20 oC, 48 h
0 oC, 10 h
76-84% conv.; 88% ee (R = H)
79-85% conv.; 77% ee (R = H)
84% ee (R = Me), 92% ee (R = NO2) 86% ee (R = Me), 97% ee (R = NO2)
d)
Ar
NH
O
5 mol % 4-Cr
Ph
Ar-NH2
+
Ph
Ph
Ph
CHCl3, r.t., 24h
OH
72-81% conv.; 82% ee (Ar = Ph),
86% ee (Ar = 3-MePh), 96% ee (Ar = 4-IPh)
e)
NHAr
1.0 mol% 4-Cr-Mn
sPhIO
OH
ArNH2
+
CHCl3, 0 oC, 48 h
71-80% conv.; 84% ee (Ar = Ph)
86% ee (Ar = 3-MePh), 91% ee (Ar = 4-MePh)
O
O
Figure 4. Asymmetric reactions catalyzed by the CCOFs.
3
ACS Paragon Plus Environment

Journal of the American Chemical Society
Page 4 of 6
R.; Furukawa, H.; Klöck, C.; O’Keeffe, M.; Yaghi, O. M. J. Am. Chem. Soc.
2009, 131, 4570.
Given that that 4-Mn can promote epoxidation of alkenes and
1
2
3
4
5
6
7
8
4-Cr promote ring opening of epoxides, we studied the catalytic
performance of 4-Cr-Mn bearing two different active metal
centers in the sequential reactions initiated by epoxidation of
alkene followed by ring opening of epoxide to afford the amino
alcohol. In the presence of 1.0 mol% 4-Cr-Mn, epoxidation of 2,
2ꢀdimethyl benzopyran with PhIO as oxidant and subsequent
ringꢀopening reactions with different anilines were performed in
CHCl3 at r.t.. The reactions proceeded smoothly to give the amino
alcohols with up to 91% ee (Figure 4e). COFꢀmediated sequential
reactions should prove highly valuable for the synthesis of
complex molecules with excellent stereoꢀcontrols.
The present CCOF catalysts displayed enantioselectivities
comparable to those of the corresponding homogeneous controls
and other M(salen)ꢀbased hybrid solid catalysts for the examined
reactions and substrates (Tables S11ꢀ14).14,15 All CCOF catalysts
can be readily recycled and reused for at least five times without
obvious loss of activity and enantioselectivity (Tables S15ꢀS19).
For instance, the conversions/ee’s for 4-Vꢀcatalyzed cynation of
4ꢀmethoxybenzaldehyde are 77/94%, 77/94%, 76/93%, 76/93%
and 75/92% for 1ꢀ5 runs, respectively. ICPꢀOES analysis of the
filtrate after the reaction revealed almost no leaching of Zn and V
ions. PXRD showed that the recovered solid after five recycles
remained crystalline and structurally intact (Figure S13)
(2) (a) Kandambeth, S.; Mallick, A.; Lukose, B.; Mane, M. V.; Heine, T.;
Banerjee, R. J. Am. Chem. Soc. 2012, 134, 19524. (b) Bunck, D. N.; Dichtel,
W. R. J. Am. Chem. Soc. 2013, 135, 14952. (d) Dalapati, S.; Jin, S.; Gao, J.;
Xu, Y.; Nagai, A.; Jiang, D. J. Am. Chem. Soc. 2013, 135, 17310.
(3) (a) Fang, Q.; Zhuang, Z.; Gu, S.; Kaspar, R. B.; Zheng, J.; Wang, J.;
Qiu, S.; Yan, Y. Nat. Commun. 2014, 5, 4503. (b) Calik, M.; Sick, T.;
Dogru, M.; Döblinger, M.; Datz, S.; Budde, H.; Hartschuh, A.; Auras, F.;
Bein, T. J. Am. Chem. Soc. 2016, 138, 1234. (c) Beaudoin, D.; Maris, T.;
Wuest, J. D. Nat. Chem. 2013, 5, 830. (d) Pang, Z.; Xu, S.; Zhou, T.; Liang,
R.; Zhan, T.; Zhao, X. J. Am. Chem. Soc. 2016, 138, 4710.
(4) (a) Doonan, C. J.; Tranchemontagne, D. J.; Glover, T. G.; Hunt, J. R.;
Yaghi, O. M. Nat. Chem. 2010, 2, 235. (b) Baldwin, L. A.; Crowe, J. W.;
Pyles, D. A.; McGrier, P. L. J. Am. Chem. Soc. 2016, 138, 15134. (c)
Huang, N.; Chen, X.; Krishna, R.; Jiang, D. Angew. Chem., Int. Ed. 2015,
54, 2986.
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
(5) (a) Sun, Q.; Aguila, B.; Perman, J.; Earl, L. D.; Abney, C. W.; Cheng,
Y.; Wei, H.; Nguyen, N.; Wojtas, L.; Ma, S. J. Am. Chem. Soc. 2017, 139,
2786. (b) Qian, H.; Yang, C.; Yan, X.. Nat. Commun. 2016, 7, 12104. (c)
Ma, H.; Ren, H.; Meng, S.; Yan, Z.; Zhao, H.; Sun, F.; Zhu, G. Chem.
Commun. 2013, 49, 9773.
(6) (a) Sun, Q.; Aguila, B.; Perman, J.; Nguyen, N.; Ma, S. J. Am. Chem.
Soc. 2016, 138, 15790. (b) Ding, S.ꢀY.; Gao, J.; Wang, Q.; Zhang, Y.; Song,
W.; Su, C.; Wang, W. J. Am. Chem. Soc. 2011, 133, 19816. (c) Fang, Q.;
Gu, S.; Zheng, J.; Zhuang, Z.; Qiu, S.; Yan, Y. Angew. Chem., Int. Ed. 2014,
53, 2878. (d) Lin, S.; Diercks, C. S.; Zhang, Y.ꢀB.; Kornienko, N.; Nichols,
E. M.; Zhao, Y.; Paris, A. R.; Kim, D.; Yang, P.; Yaghi, O. M.; Chang, C. J.
Science 2015, 349, 1208. (e) Vyas, V. S.; Haase, F.; Stegbauer, L.; Savasci,
G.; Podjaski, F.; Ochsenfeld, C.; Lotsch, B. V. Nat. Commun. 2015, 6,
8508. (f) Peng, Y.; Hu, Z.; Gao, Y.; Yuan, D.; Kang, Z.; Qian, Y.; Yan, N.;
Zhao, D. ChemSusChem 2015, 8, 3208.
(7) (a) Wang, X.; Han, X.; Zhang, J.; Wu, X.; Liu, Y.; Cui, Y. J. Am.
Chem. Soc. 2016, 138, 12332. (b) Xu, H.; Chen, X.; Gao, J.; Lin, J.;
Addicoat, M.; Irle, S.; Jiang, D. Chem. Commun. 2014, 50, 1292ꢀ1294. (c)
Xu, H.; Gao, J.; Jiang, D. Nat. Chem. 2015, 7, 905. (d) Xu, H.ꢀS.; Ding,
S.ꢀY.; An, W.ꢀK.; Wu, H.; Wang, W. J. Am. Chem. Soc. 2016, 138, 11489.
(8) (a) Das, G.; Biswal, B. P.; Kandambeth, S.; Venkatesh, V.; Kaur, G.;
Addicoat, M.; Heine, T.; Verma, S.; Banerjee, R. Chem. Sci. 2015, 6, 3931.
(c) Lin, G.; Ding, H.; Yuan, D.; Wang, B.; Wang, C. J. Am. Chem. Soc.
2016, 138, 3302. (d) Rao, M. R.; Fang, Y.; De Feyter, S.; Perepichka, D. F.
J. Am. Chem. Soc. 2017, 139, 2421.
(9) (a) Bertrand, G. H. V.; Michaelis, V. K.; Ong, T.ꢀC.; Griffin, R. G.;
Dincă, M. Proc. Natl. Acad. Sci. U.S.A. 2013, 110, 4923. (b) Calik, M.;
Auras, F.; Salonen, L. M.; Bader, K.; Grill, I.; Handloser, M.; Medina, D.
D.; Dogru, M.; Löbermann, F.; Trauner, D.; Hartschuh, A.; Bein, T. J. Am.
Chem. Soc. 2014, 136, 17802. (c) Du, Y.; Yang, H.; Whiteley, J. M.; Wan,
S.; Jin, Y.; Lee, S.ꢀH.; Zhang, W. Angew. Chem., Int. Ed. 2016, 55, 1737.
(10) (a) DeBlase, C. R.; Silberstein, K. E.; Truong, T.ꢀT.; Abruña, H. D.;
Dichtel, W. R. J. Am. Chem. Soc. 2013, 135, 16821. (b) Wang, S.; Wang,
Q.; Shao, P.; Gan, Y.; Gao, X.; Ma, L., Yuan, S., Ma, X., Zhou, J., Feng,
X.; Wang, B. J. Am. Chem. Soc., 2017, 139, 4258.
CONCLUSIONS
We have synthesized two isostructral 2D metallosalenꢀbased
CCOFs and demonstrated that the chemical stability of the
framework can be improved by incorporating bulky alkyl groups.
The structure assignment is supported by PXRD analysis,
modeling studies, and the pore size distribution experimental data.
The framework constituting Zn(II) ions can undergo exchange with
a variety of metal ions in solutions without alternation of structural
integrity and loss in crystallinity. The exchanged materials can
serve as efficient and recyclable heterogeneous catalysts for
several asymmetric transformations. This work provides a new
approach to achieve high chemical stability, catalytic activity and
enantioselectivity in COFs and will promote the design of CCOFs
from privileged chiral ligands/catalysts that will display interesting
chirality properties.
ASSOCIATED CONTENT
Supporting Information.
Experimental procedures and characterization data. This material
is available free of charge via the Internet at http://pubs.acs.org.
(11) Segura, J. L.; Mancheno, M. J.; Zamora, F. Chem. Soc. Rev. 2016,
45, 5635.
(12) Cozzi, P. G. Chem. Soc. Rev. 2004, 33, 410.
(13) (a) Palucki, M.; Finney, N. S.; Pospisil, P. J.; Guler, M. L.; Ishida,
T.; Jacobsen, E. N. J. Am. Chem. Soc. 1998, 120, 948. (b) O’Connor,
K.J.; Wey, S. J.; Burrows. C. J. Tetrahedron Lett. 1992, 33, 1001ꢀ1004. (c)
Nielsen, L. P. C.; Stevenson, C. P.; Blackmond, D. G.; Jacobsen, E. N. J.
Am. Chem. Soc. 2004, 126, 1360. (d) Hansen, K. B.; Leighton, J. L.;
Jacobsen, E. N. J. Am. Chem. Soc. 1996, 118, 10924. (e) Belokon’, Y. N.;
North, M.; Parsons, T. Org. Lett. 2000, 2, 1617.
AUTHOR INFORMATION
Corresponding Author
*yongcui@sjtu.edu.cn
*liuy@sjtu.edu.cn
Notes
The authors declare no competing financial interest.
(14) Baleizão, C.; Garcia, H. Chem. Rev. 2006, 106, 3987.
ACKNOWLEDGMENTS
(15) (a) Cho, S. H.; Ma, B. Q.; Nguyen, S. T.; Hupp, J. T.;
AlbrechtꢀSchmitt, T. E. Chem. Commun. 2006, 2563. (b) Song, F.; Wang,
C.; Falkowski, J. M.; Ma, L.; Lin, W. J. Am. Chem. Soc. 2010, 132, 15390.
(c) Zhu, C.; Yuan, G.; Chen, X.; Yang, Z.; Cui, Y. J. Am. Chem. Soc. 2012,
134, 8058. (d) Zhu, C.; Xia, Q.; Chen, X.; Du, X.; Liu, Y.; Cui, Y. ACS
Catal. 2016, 6, 7590. (e) Xia, Q.; Liu, Y.; Li, Z.;Gong, W.; Cui, Y. Chem.
Commun. 2016, 52, 13167. (f) Xi, W.; Liu, Y.; Xia, Q.; Li, Z.; Cui, Y.
Chem. Eur. J. 2015, 21, 12581. (g) Xiang, S.; Zhang, Z.; Zhao, C.; Hong, K.;
Zhao, X.; Ding, D.; Xie, M.; Wu, C.; Das, M. C.; Gill, R.; Thomas, K. M.;
Chen, B. Nat. Commun. 2011, 2: 204.
This work was financially supported by the National Science
Foundation of China (Grants 21371119, 21431004, 21401128,
21522104 and 21620102001), the National Key Basic Research
Program of China (Grants 2014CB932102 and 2016YFA
0203400), and the Shanghai “Eastern Scholar” Program.
REFERENCES
(1) Côté, A. P.; Benin, A. I.; Ockwig, N. W.; O'Keeffe, M.; Matzger, A.
J.; Yaghi, O. M. Science 2005, 310, 1166. (b) UribeꢀRomo, F. J.; Hunt, J.
(16) Li, L.; Feng, X.; Cui, X.; Ma, Y.; Ding, S.;Wang, W. J. Am. Chem.
Soc. 2017, 139, 6042.
4
ACS Paragon Plus Environment

Page 5 of 6
Journal of the American Chemical Society
(17) Yang, C.; Kaipa, U.; Mather, Q. Z.; Wang, X.; Nesterov, V.;
Venero, A. F.; Omary, M. A. J. Am. Chem. Soc. 2011, 133, 18094.
(18) ( ) Kurono, N.; Ohkuma, T. ACS Catal. 2016, 6, 989. (b) Ahrendt,
K. A.; Borths, C. J.; MacMillan, D. W. C. J. Am. Chem. Soc. 2000, 122,
4243. (c) Jacobsen, E. N. Acc. Chem. Res. 2000, 33, 421.
1
2
3
4
a
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
5
ACS Paragon Plus Environment

Journal of the American Chemical Society
Page 6 of 6
Graphic Content
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
6
ACS Paragon Plus Environment