Interpenetrated Three-Dimensional Copper-Iodine Cluster-Based Framework with Enantiopure Porphyrin-like Templates

Article abstract of DOI:10.1021/acs.inorgchem.5b02692

Presented here is an interpenetrated three-dimensional copper-iodine cluster-based framework with dia topology based on two different kinds of Cu₄I₄ subunits that is templated by an enantiopure porphyrin-like Cu^I(5-eatz)

Full text of DOI:10.1021/acs.inorgchem.5b02692

Communication
pubs.acs.org/IC
Interpenetrated Three-Dimensional Copper−Iodine Cluster-Based
Framework with Enantiopure Porphyrin-like Templates
Juan Liu,†,‡ Fei Wang,*,† Li-Yang Liu,† and Jian Zhang*,†
†State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences,
Fuzhou, Fujian350002, P. R. China
‡University of Chinese Academy of Sciences, 100049 Beijing, P. R. China
S
* Supporting Information
phase purity and thermal stability were identified by powder
ABSTRACT: Presented here is an interpenetrated three-
dimensional copper−iodine cluster-based framework with
dia topology based on two different kinds of Cu4I4
subunits that is templated by an enantiopure porphyrin-
like CuI(5-eatz)2 unit and shows excellent photocatalytic
activity to degrade methylene blue under visible light.
XRD (PXRD) and thermogravimetric analysis (TGA), respec-
tively (Supporting Information). Single-crystal XRD revealed
that 1 crystallizes in tetragonal symmetry with space group P42
and contains eight copper atoms, six iodine atoms, two 5-eatz
ligands, and [N(CH3)4]+ ions (Figure S3).
The prominent structural feature of 1 is that it has an
interpenetrated 3D copper−iodine cluster based on two types of
Cu4I4 SBUs generated in situ from CuI. The first one is the
common tetrahedral Cu4I4 cubane (Figure 1a). Each Cu4I4
eolites, as an important class of inorganic crystalline
Z
microporous materials containing TO4 (T = Si, Al, P, Ge)
tetrahedral units, are of current interest for their applications in
the petroleum refining and fine chemical industries.1 However,
because of the inherent insulating characteristic of oxide-based
zeolites, their applications in photocatalytic/electric-related
processes were greatly limited. To broaden their performances
in targeted applications and create multifunctional zeolitic
materials, there is a high demand for new multinuclear building
units.
It has been reported that chalcogenide clusters can serve as
pseudotetrahedral units to form zeotype structures.2 In
comparison, metal halide clusters, especially copper iodides,
display polarizabilities comparable to those of chalcogenides,
making them also suitable to serve as tetrahedral units of zeotype
frameworks. However, because of the multiple forms and
structural diversities of metal iodides, it still remains a great
challenge to prepare metal iodide cluster-based zeolitic
materials.3
Herein we report an interpenetrated three-dimensional (3D)
copp er − io dine cluster-based framework, [ N-
(CH3)4)]22+[Cu14I12(5-eatz)4]2− [1; 5-eatz = (1R)-1-(5-
tetrazolyl)ethylamine], based on two kinds of Cu4I4 subunits
(secondary building units, SBUs), a cubane and an eight-
membered ring, which exhibits 2-fold-interpenetrated dia
topology and is templated by an enantiopure porphyrin-like
CuI(5-eatz)2 unit. Furthermore, such a 2-fold-interpenetrated
copper−iodine clusters were linked by the Cu-5-eatz units, giving
rise to a zeolitic framework with 4,4-connected (64.82)2(66)
topology. Furthermore, this copper−iodine cluster-based frame-
work shows excellent photocatalytic activity to degrade
methylene blue (MB) under visible light because of its narrow
band gap of 1.49 eV.
Figure 1. (a) Cu4I4 cubane. (b) Cu4I4 eight-membered ring. (c) dia
topology cage. (d) 3D copper−iodine clusters with 2-fold inter-
penetration. (e) dia topology of the copper(I)−iodine clusters.
cubane in 1 consists of four tetrahedrally coordinated Cu+ ions
bonded by four μ3-I− anions. The relatively short Cu···Cu
distances ranging from 2.549 to 2.825 Å are comparable or even
less than twice the van der Waals radius (1.4 Å) of CuI, implying
strong Cu−Cu interaction. The second one is an unusual Cu4I4
subunit with an eight-membered ring (Figure 1b). Notably, it
shows an interesting configuration: four copper and two iodine
atoms are coplanar, and the other two I− ions locate oppositely
along the plane. The Cu···Cu distances of the eight-membered
ring range from 2.879 to 3.443 Å, which are longer than that of a
Cu4I4 cubane. It should be noted that the coexistence of two such
The orange crystal of 1 was prepared by the reaction of 5-eatz,
N(CH3)4Br, CuI, and KI under hydrothermal conditions. The
structure and composition of 1 were characterized by single-
crystal X-ray diffraction (XRD) and elemental analysis, and its
Received: November 20, 2015
© XXXX American Chemical Society
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DOI: 10.1021/acs.inorgchem.5b02692
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Inorganic Chemistry
Communication
different Cu4I4 SBUs in one compound has never been observed
previously. Each Cu4I4 cubane serves as a tetrahedral node, which
was linked by four Cu4I4 eight-membered rings, while each Cu4I4
eight-membered ring, acting as linkers, uses its two edges to
connect two Cu4I4 cubane tetramers. Both Cu4I4 SBUs link each
other to form 2-fold-interpenetrated 3D clusters (Figure 1d),
which can be simplified into a dia net (Figure 1e).4 A typical dia
cage substructure, including 10 Cu4I4 cubanes and 12 Cu4I4
eight-membered rings, is presented (Figure 1c).
Another extraordinary feature of 1 is the presence of derivation
from 4-connected dia topology to 4,4-connected topology.
Besides the above-mentioned two Cu4I4 clusters, another
interesting unit, denoted by CuI(5-eatz)2, is also observed in 1
(Figure 2a). Such an enantiopure porphyrin-like unit is formed
Figure 3. (a) dia cages interpenetrating each other. (b) CuI(5-eatz)2
units linking adjacent dia cages to form another kind of small cage. (c)
Magnification of the cage and relative tile. (d) 68 topology with the
[N(CH3)4]+ ion located in the center of it. There are no obvious
interactions between the [N(CH3)4]+ ion and the framework.
reason may be that the in situ captured enantiopure porphyrin-
like CuI(5-eatz)2 units act as effective templates. In the synthesis
of inorganic zeolites as well as metal halide clusters, organic
amines are widely applied as structure-directing agents (SDAs).
However, metal−organic templates such as the SDAs reported
here have never been observed before.
The band gap of 1 was investigated by a UV−vis diffuse-
reflectance measurement method at room temperature (Figure
4a). According to the equation αhν2 = K(hν − Eg)1/2 (where α is
Figure 2. (a) Strong hydrogen-bonding interactions between
enantiopure porphyrin-like templates consisting of CuI and 5-eatz.
The hydrogen atoms were omitted for clarity. (b) Whole framework of
1. (c) 2-fold-interpenetrated dia nets of the 3D copper−iodine clusters.
(d) Whole topology of 1.
by two homochiral 5-eatz ligands chelating one CuI. There are
strong hydrogen-bonding interactions between them. Moreover,
CuI(5-eatz)2 only located between two Cu4I4 eight-membered-
ring SBUs, which linked the 2-fold-interpenetrated 3D clusters
(Figure 2c) into one and further stabilized the framework (Figure
2d). The attendance of the CuI(5-eatz)2 unit also brings a new
node, the planar four-connected (Cu4I4 eight-membered ring)
node, for the whole framework topology. The whole framework
of 1 can be topologically represented as a 4,4-connected net with
a point symbol of (64.82)2(66). Interestingly, the introduction of
the planar 4-connected node generates an unusual cage structure,
including six Cu4I4 cubanes, 12 Cu4I4 eight-membered rings, and
eight CuI(5-eatz)2 units (Figure 3c) with the symbol of 68, which
has never been observed in both zeolite and zeolitic imidazolate
frameworks before.5 The [N(CH3)4]+ cations just fill in the
center of the cage.
Figure 4. (a and b) Solid-state UV−vis reflectance spectra of crystal 1.
(c) Temporal UV−vis absorption spectral changes of MB aqueous
solutions with photodegradation catalyzed by 1 in the presence of a
H2O2 additive. (d) Photodegradation rates of 1 (red), H2O2 (black), and
1 in the presence of a H2O2 additive (blue).
the absorption coefficient, hν is the discrete photo energy, K is a
constant, and Eg is the band-gap energy), the extrapolated values
(the straight lines to the x axis) of hν at α = 0 give absorption
edge energies corresponding to Eg = 1.49 eV for 1. It has an
absorption response to visible light due to its narrow-band-gap
size.7 This result is also consistent with the color of their crystals,
with yellow for 1 (Figure 4a).
It should be noted that only a few examples of 3D copper(I)
halide clusters have been reported before.6 Among them, just two
compounds are based on copper−iodine clusters.6a,b The
compound reported here is the first one with 3D copper−iodine
clusters based on two different copper−iodine clusters. The main
B
DOI: 10.1021/acs.inorgchem.5b02692
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Inorganic Chemistry
Communication
(3) (a) Bi, M. H.; Li, G. H.; Hua, J.; Liu, X. M.; Hu, Y. W.; Shi, Z.; Feng,
S. H. CrystEngComm 2007, 9, 984−986. (b) Braga, D.; Maini, L.;
Mazzeo, P. P.; Ventura, B. Chem. - Eur. J. 2010, 16, 1553−1559.
(c) Kang, Y.; Wang, F.; Zhang, J.; Bu, X. J. Am. Chem. Soc. 2012, 134,
17881−17884. (d) Kang, Y.; Fang, W.; Zhang, L.; Zhang, J. Chem.
Commun. 2015, 51, 8994−8997.
The photocatalytic activities of 1 were evaluated for MB
photodegradation under visible-light illumination. The charac-
teristic absorption of MB at about 665 nm was selected for
monitoring the adsorption and photocatalytic degradation
process. The photocatalytic activity of 1 was gradually enhanced
with time increasing from 0 to 25 min, which demonstrated that
1 has a much higher activity (Figure 4). After 25 min, MB in the
solution almost disappeared when using 1 as the photocatalyst.
Moreover, 1 is stable under repeated application with a nearly
constant photocatalytic degradation rate (Figures S4b and S6).
These results show that 1 is an excellent photocatalyst under
visible light.
In summary, we report an interpenetrated 3D copper−iodine
cluster-based framework, based on two kinds of Cu4I4 subunits
(SBUs), a cubane and an eight-membered ring. It exhibits 2-fold-
interpenetrated dia topology and is templated by an enantiopure
porphyrin-like CuI(5-eatz)2 unit. Furthermore, this zeolitic
framework exhibits outstanding photocatalytic activity under
visible light.
(4) Blatov, V. A. Struct. Chem. 2012, 23, 955−963.
(5) See the International Zeolite Association website: http://www.iza-
structure.org/.
(6) (a) Chan, H.; Chen, Y.; Dai, M.; Lu, C.-N.; Wang, H.-F.; Ren, Z.-
̈
G.; Huang, Z.-J.; Ni, C.-Y.; Lang, J.-P. CrystEngComm 2012, 14, 466−
473. (b) Cheng, J.-K.; Chen, Y.-B.; Wu, L.; Zhang, J.; Wen, Y.-H.; Li, Z.-
J.; Yao, Y.-G. Inorg. Chem. 2005, 44, 3386−3388. (c) DeBord, J. R. D.;
Lu, Y.-J.; Warren, C. J.; Haushalter, R. C.; Zubieta, J. Chem. Commun.
1997, 15, 1365−1366. (d) Healy, P. C.; Kildea, J. D.; White, A. H. J.
Chem. Soc., Dalton Trans. 1988, 6, 1637−1639.
(7) Tsunekawa, S.; Fukuda, T.; Kasuya, A. J. Appl. Phys. 2000, 87,
1318−1321.
ASSOCIATED CONTENT
* Supporting Information
■
S
The Supporting Information is available free of charge on the
ACS Publications website at DOI: 10.1021/acs.inorg-
chem.5b02692.
Experimental details, TGA diagram, and PXRD (PDF)
CIF file (CIF)
AUTHOR INFORMATION
Corresponding Authors
*E-mail: wangfei04@fjirsm.ac.cn.
*E-mail: zhj@fjirsm.ac.cn.
■
Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
■
This work is supported by the National Basic Research Program
of China (973 Program 2012CB821705), NSFC (Grants
21573236, 21425102, and 21221001), and Chunmiao Project
of Haixi Institute of Chinese Academy of Sciences (Grant
CMZX-2015-001).
REFERENCES
■
(1) (a) Cejka, J.; Corma, A.; Zones, S. Zeolites and Catalysis: Synthesis
Reactions and Applications; Wiley: Weinheim, Germany, 2010. (b) Li, Y.;
Yu, J. H. Chem. Rev. 2014, 114, 7268−7316. (c) Schmidt, J. E.; Xie, D.;
Rea, T.; Davis, M. E. Chem. Sci. 2015, 6, 1728−1734. (d) Lin, H. Y.;
Chin, C. Y.; Huang, H. L.; Huang, W. Y.; Sie, M. J.; Huang, L. H.; Lee, Y.
H.; Lin, C. H.; Lii, K. H.; Bu, X.; Wang, S. L. Science 2013, 339, 811−813.
(e) Liu, T.-F.; Feng, D.; Chen, Y.-P.; Zou, L.; Bosch, M.; Yuan, S.; Wei,
Z.; Fordham, S.; Wang, K.; Zhou, H.-C. J. Am. Chem. Soc. 2015, 137,
413−419. (f) Feng, D.; Wang, K.; Su, J.; Liu, T.-F.; Park, J.; Wei, Z.;
Bosch, M.; Yakovenko, A.; Zou, X.; Zhou, H.-C. Angew. Chem., Int. Ed.
2015, 54, 149−154.
(2) (a) Sun, J.; Bonneau, C.; Cantin, A.; Corma, A.; Diaz-Cabanas, M.
̃
J.; Moliner, M.; Zhang, D.; Li, M.; Zou, X. Nature 2009, 458, 1154−
1157. (b) Zheng, N.; Bu, X.; Feng, P. Nature 2003, 426, 428−432.
(c) Wu, T.; Wang, X.; Bu, X.; Zhao, X.; Wang, L.; Feng, P. Angew. Chem.,
Int. Ed. 2009, 48, 7204−7207. (d) Xiong, W.-W.; Athresh, E. U.; Ng, Y.
N.; Ding, J.; Wu, T.; Zhang, Q. J. Am. Chem. Soc. 2013, 135, 1256−1259.
(e) Lin, J.; Dong, Y.; Zhang, Q.; Hu, D.; Li, N.; Wang, L.; Liu, Y.; Wu, T.
Angew. Chem., Int. Ed. 2015, 54, 5103−5107. (f) Lin, Q.; Bu, X.; Mao, C.;
Zhao, X.; Sasan, K.; Feng, P. J. Am. Chem. Soc. 2015, 137, 6184−6187.
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DOI: 10.1021/acs.inorgchem.5b02692
Inorg. Chem. XXXX, XXX, XXX−XXX