applying Clausius–Clapeyron equation, the isosteric heat of
adsorption of 28.5 kJ molÀ1. The initial steep increase of the
CO2 uptake combined with the relatively high adsorption
energy led to the conclusion that the micropores are very
efficient for the capture of CO2 at low pressures.
EA (C54H40N12): calcd C 75.68, H 4.70, N 19.61; found C
66.66, H 4.94, N 16.46%.
Scale-up reaction procedure. In a 100 mL sealed tube, 1,3,5,7-
tetrakis(4-ethynylphenyl)adamantane (2, 243 mg, 0.45 mmol,
1.00 equiv.) was solved in 35 mL DMSO under an argon
atmosphere at 100 1C. Then, CuSO4Á5H2O (22.6 mg,
90.6 mmol, 0.20 equiv.), sodium ascorbate (35.9 mg,
181.2 mmol, 0.40 equiv.), both dissolved in 1.75 mL H2O
(total), and 1,4-diazidobenzene (3, 435 mg, 2.72 mmol, 6.00
equiv.) were added slowly. The reaction mixture was heated
for 7 days at 80 1C. The precipitate was filtered off and
extensively washed with chloroform and water. Isolation and
purification of the formed HCP was identical to that of the
above mentioned procedure to yield 380 mg (98%) of HCP 5
as a brown powder.
In conclusion, we have reported preliminary results on the
formation of novel hyper cross-linked polymers by exploiting
the unconventional synthetic route based on click chemistry.
As polyfunctional building elements, tetrahedral-core monomers
have been employed, comprising tetrakisphenylmethane and
an alternative node of Td symmetry such as adamantane.
This knot combined with the rigidity of p-phenylene spacers
guarantees the robustness of the network. The adamantane-
based compound shows remarkable efficiency for CO2 capture
under the mild conditions of low pressure or, alternatively, of
room temperature.
Conceivably, the optimization of the process with the new
substrates is expected to provide ameliorated properties and
permits us to envisage the scale-up at least for the adamantane
derivative. Indeed, further studies to implement HCP
production, a better control of particle size formation,
enhanced surface areas and anchorage of functional groups
are under investigation.
Acknowledgements
This work was supported by the DFG-Center for Functional
Nanostructures (CFN, C5.2, E1.2 and E3.4). O.P. is a fellow
of the Konrad-Adenauer-Stiftung. P.S. and A.C. would like to
thank Lombardy Region and Cariplo Foundation for financial
support.
Experimental section
SAFETY STATEMENT: 1,4-diazidobenzene is potentially
explosive. Due to high nitrogen content (ratio of carbon to
nitrogen should be larger than 3 : 1) it should be handled with
extraordinary care. All reactions and handlings were performed
behind a blast shield in a closed fume hood.
Notes and references
1 (a) N. B. McKeown, P. M. Budd, K. J. Msayib, B. S. Ghanem,
H. J. Kingston, C. E. Tattershall, S. Makhseed, K. J. Reynolds and
D. Fritsch, Chem.–Eur. J., 2005, 11, 2610; (b) P. M. Budd,
N. B. McKeown and D. Fritsch, J. Mater. Chem., 2005,
15, 1977; (c) N. B. McKeown and P. M. Budd, Chem. Soc. Rev.,
2006, 35, 675; (d) N. B. McKeown, B. Gahnem, K. J. Msaylib,
P. M. Budd, C. E. Tattershall, K. Mahmood, S. Tan, D. Book,
H. W. Langmi and A. Walton, Angew. Chem., Int. Ed., 2006,
45, 1804; (e) N. B. McKeown and P. M. Budd, Macromolecules,
2010, 43, 5163.
2 T. Tozawa, J. T. A. Jones, S. I. Swamy, S. Jiang, D. J. Adams,
S. Shakespeare, R. Clowes, D. Bradshaw, T. Hasell, S. Y. Chong,
C. Tang, S. Thompson, J. Parker, A. Trewin, J. Bacsa, A. M. Z.
Slawin, A. Steiner and A. I. Cooper, Nat. Mater., 2009, 8, 973.
3 H. M. El-Kaderi, J. R. Hunt, J. L. Mendoza-Cortes, A. P. Cote,
R. E. Taylor, M. O’Keeffe and O. M. Yaghi, Science, 2007,
316, 268.
4 F. J. Uribe-Romo, J. R. Hunt, H. Furukawa, C. Klock,
M. O’Keeffe and O. M. Yaghi, J. Am. Chem. Soc., 2009, 131, 4570.
5 P. Kuhn, M. Antonietti and A. Thomas, Angew. Chem., Int. Ed.,
2008, 47, 3450.
6 B. Zhan and Z. Wang, Chem. Commun., 2009, 5027.
7 Z. Wang, B. Zhan, H. Yu, L. Sun, C. Jiao and W. Liu, Chem.
Commun., 2010, 46, 7730.
1H NMR spectra were recorded on a Bruker AM 400
(400 MHz) spectrometer as solutions in CDCl3. Chemical
shifts are expressed in parts per million (ppm, d) downfield
from tetramethylsilane (TMS, d = 0) and are referenced to
CHCl3 (7.26 ppm), as internal standard. All coupling
constants are absolute values and J values are expressed in
Hertz (Hz). The description of signals include: s = singlet,
bs = broad singlet, d = doublet, m = multiplet, dd = doublet of
doublets. The spectra were analyzed according to first order.
13C NMR spectra were recorded on a Bruker AM 400
(100 MHz) spectrometer as solutions in CDCl3. Chemical
shifts are expressed in parts per million (ppm, d) downfield
from tetramethylsilane (TMS, d = 0) and are referenced to
CDCl3 (77.4 ppm).
Synthesis of hyper cross-linked polymer 5 (HCP 5)
8 W. Lu, D. Yuan, D. Zhao, C. I. Schilling, O. Plietzsch, T. Muller,
S. Brase, J. Guenther, J. Blumel, R. Krishna, Z. Li and
H.-C. Zhou, Chem. Mater., 2010, 22, 5964.
9 (a) T. Ben, H. Ren, S. Ma, D. Cao, J. Lan, X. Jing, W. Wang,
J. Xu, F. Deng, J. M. Simmons, S. Qiu and G. Zhu, Angew. Chem.,
Int. Ed., 2009, 48, 9457; (b) J. R. Holst, E. Stockel, D. J. Adams
and A. I. Cooper, Macromolecules, 2010, 43, 8531.
10 (a) J. Weber, Q. Su, M. Antonietti and A. Thomas, Macromol.
Rapid Commun., 2007, 28, 1871; (b) J. Weber, J. Schmidt,
A. Thomas and W. Bohlmann, Langmuir, 2010, 26, 15650.
11 (a) P. Pierrat, C. Rethore, T. Muller and S. Brase, Chem.–Eur. J.,
2009, 15, 11458; (b) P. Pierrat, S. Vanderheiden, T. Muller and
S. Brase, Chem. Commun., 2009, 1748; (c) O. Plietzsch,
C. I. Schilling, M. Tolev, M. Nieger, C. Richert, T. Muller and
S. Brase, Org. Biomol. Chem., 2009, 7, 4734; (d) O. Plietzsch,
C. I. Schilling, T. Muller and S. Brase, Tetrahedron: Asymmetry,
Typical procedure. In a sealed reaction vessel, 1,3,5,7-
tetrakis(4-ethynylphenyl)adamantane (2, 35 mg, 0.065 mmol,
1.00 equiv.) was solved in 5 mL DMSO under an argon
atmosphere at 100 1C. Then, CuSO4Á5H2O (4.75 mg, 0.019 mmol,
0.20 equiv.), sodium ascorbate (7.50 mg, 0.038 mmol,
0.40 equiv.), both dissolved in 0.25 mL H2O (total), and
1,4-diazidobenzene (3, 21 mg, 0.13 mmol, 2.00 equiv.) were
added slowly. The reaction mixture was heated for 72 h at
80 1C. The precipitate was filtered off and extensively washed
with chloroform and water. After this, the obtained solid was
extensively washed with THF and then dried in vacuo for
72 h to yield 35 mg (499%) of HPC 5 as brown powder.
c
1580 New J. Chem., 2011, 35, 1577–1581
This journal is The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2011