W.-D. Jang et al.
Synthesis of 4: TFA (2.0 mL, 25.96 mmol) was added to a mixture solu-
tion of 3 (4.0 g, 19.77 mmol) and pyrrole (1.31 g, 19.77 mmol) in CH2Cl2
(1.0 L) and stirred for 12 h at 258C. Then, p-chloranil (7.29 g,
29.66 mmol) was added, and the reaction mixture was further stirred for
4 h. The reaction mixture was concentrated to a volume of 200 mL and
then chromatographed in silica gel with CH2Cl2. Without further purifica-
tion, the product was dissolved in 10% MeOH/CH2Cl2 containing Zn-
AHCTUNGRTEG(NNNU OAc)2 (4.34 g, 19.77 mmol) and then stirred for 1 h at 258C. The reac-
tion mixture was purified using column chromatography with 30%
CH2Cl2/hexane to produce a mixture of atropisomers of 4 as a reddish–
purple solid (0.79 g, 15%): MALDI-TOF-MS: m/z calcd for
C64H60N4Si4Zn: 1062.94 [M]+; found: 1063.08.
Synthesis of 5: Tetrabutylammonium fluoride (5.0 mL, 1m in THF) was
added to a solution of 4 (0.79 g, 0.74 mmol) in CH2Cl2 (100 mL) and
stirred for 30 min at 258C, then the solvent was removed under reduced
pressure. The residue was purified using column chromatography with
50% CH2Cl2/hexane as the eluent. Recrystallization from the CH2Cl2/
hexane gave a mixture of the atropisomers of 5 as a purple solid (0.55 g,
95%): MALDI-TOF-MS: m/z calcd for C52H28N4Zn: 774.22 [M]+; found
774.52.
Figure 6. The energy-minimized molecular structure of 1 with ClÀ and
omission of other functionalities except porphyrin and triazoles.
Synthesis of 6: NaN3 (1.14 g, 17.46 mmol) was added to a stirred solution
of methyl 4-(bromomethyl)benzoate (2.0 g, 8.73 mmol) in a 40.0 mL ace-
tone/H2O mixture (3:1). The resulting suspension was stirred for 30 min
at 258C, and the reaction mixture was evaporated. The residue was puri-
fied using column chromatography with 50% CH2Cl2/hexane to produce
6 as a white solid (1.6 g, 99%): 1H NMR (400 MHz, CDCl3, 258C): d=
8.05 (d, J=8 Hz, 2H), 7.49 (d, J=8 Hz, 2H), 4.41 (s, 2H), 3.92 ppm (s,
3H); 13C NMR (100 MHz, CDCl3, 258C): d=166.72, 140.49, 130.21,
128.02, 54.37, 52.30 ppm.
when it forms host–guest complexes with halides. Therefore,
we are going to investigate the control of chiral space using
chiral guest or introduction of chiral substituent in a further
study.
Conclusion
Synthesis of 1: CuSO4·5H2O (0.16 g, 0.65 mmol) and sodium ascorbate
(0.13 g, 0.65 mmol) were added to a mixture of 5 (0.1 g, 0.13 mmol) and 6
(0.13 g, 0.65 mmol) in 20 mL THF/H2O (1:1). The reaction mixture was
stirred for 12 h at 508C, and then the organic layer was separated, dried
over MgSO4, and filtered. After evaporation of the solvent under re-
duced pressure, the residue was purified using column chromatography
with 70% ethyl acetate/CH2Cl2, and the second fraction was collected
and evaporated to dryness. The residue was recrystallized from CH2Cl2/
hexane to produce 1 as a purple solid (0.1 g, 51%): 1H NMR (400 MHz,
[D6]DMSO, 258C): d=8.57 (s, J=8H), 8.37 (d, J=8 Hz, 4H), 7,93–7.86
(m, 8H), 7.78 (t, J=6 Hz, 4H), 6.89 (d, J=8 Hz, 8H), 5.74 (d, J=8 Hz,
8H), 5.62 (s, 4H), 4.36 (s, 8H), 3.72 ppm (s, 12H); 13C NMR (100 MHz,
[D6]DMSO, 258C): d=165.40, 149.30, 146.50, 140.12, 139.97, 134.76,
132.85, 131.40, 128.59, 128.43, 127.24, 126.16, 126.02, 123.03, 118.66, 52.12,
50.92 ppm; MALDI-TOF-MS: m/z calcd for C88H64N16O8Zn: 1538.96
[M]+; found: 1538.04.
We designed a new type of porphyrin-based host compound
containing four triazole groups. While this new host com-
pound does not have a shape-persistent macrocyclic struc-
ture of triazole groups, the cooperative effects of axial coor-
À
dination and quadruple C H···X hydrogen bonds resulted in
extremely high halide binding affinities. Moreover, we were
the first to examine halide ligation to zinc ions with the aid
À
of C H···X hydrogen bonds. Thus, the present work may
allow future investigation of new physicochemical aspects of
metalloporphyrins associated with axial ligation of halides.
In addition, new ideas for receptor design can be proposed
based on a combination of multiple binding motifs.
Synthesis of 2: Trifluoroacetic acid (1 mL) was added to a solution of 1
(50 mg, 0.03 mmol) in CH2Cl2 (10 mL), and stirred for 30 min. The reac-
tion mixture was poured into water, and then extracted with CH2Cl2.
After the evaporation of solvent, compound 2 was obtained as purple
solid with quantitative yield. 1H NMR (400 MHz, CDCl3, 258C): d=8.68
(s, 8H), 8.48 (d, J=8 Hz, 4H), 7.92 (t, J=7 Hz, 8H), 7.75 (d, J=7 Hz,
4H), 7.64 (t, J=8, 4H), 6.21 (d, J=8 Hz, 8H), 5.32 (s, 4H), 5.14 (d, J=8,
4H), 4.13 (s, 8H), 3.63 (s, 12H), À2.60 ppm (s, 2H); MALDI-TOF-MS:
m/z calcd for C88H66N16O8: 1476.58 [M+H]+; found: 1477.08.
Experimental Section
Measurements: Electronic-absorption spectra were recorded on
JASCO V-660 spectrometer. 1H and 13C NMR spectra were recorded on
Bruker Advance DPX 400 spectrometer at 258C in CDCl3 and
[D6]DMSO. MALDI-TOF-MS was performed on an Applied Biosystems
4700 proteomics analyzer with a-cyano-4-hydroxycinnamic acid as the
matrix.
a
a
Synthesis of 3: 2-Bromobenzaldehyde (10.22 g, 55.22 mmol), CuI
(0.526 g, 2.76 mmol), and [PdACHTNUGTRNEGNU(PPh3)2Cl2] (3.88 g, 5.52 mmol) were mixed
Acknowledgements
in a Schlenk flask. The flask was degassed three times under high
vacuum and back-filled with N2. Dried THF (70.0 mL), Et3N (30.0 mL),
and trimethylsilylacetylene (11.47 mL, 82.83 mmol) were added. The re-
action mixture was stirred for 16 h at 508C and then filtered through
Celite. The filtrate was concentrated and then purified using column
chromatography with 2% ethyl acetate/hexane to produce 3 as a color-
less oil (10.0 g, 90%): 1H NMR (400 MHz, CDCl3, 258C): d=10.55 (s,
1H), 7.90 (d, J=8 Hz, 1H), 7.58–7.51 (m, 2H), 7.43 (t, J=6 Hz, 1H),
0.27 ppm (s, 9H); 13C NMR (100 MHz, CDCl3, 258C): d=191.99, 136.30,
133.81, 133.63, 128.96, 127.00, 102.55, 100.19 ppm.
This work was supported by the Natianl Research Foundation of Korea
(NRF) grant funded by the Korea government (MEXT) (No. 2011–
0001126 and 2009-0073885). C.-H. Lee and H. Yoon acknowledge fellow-
ships from the BK21 program form the Ministry of Education, Science
and Technology, Korea.
13902
ꢁ 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2011, 17, 13898 – 13903