Octanuclear Cadmium Cages
FULL PAPER
ꢁ42% based on H4LCl2. Selected IR peaks (cmꢀ1): 3368 (m), 2917 (w),
1651 (s), 1590 (s), 1539 (m), 1443 (m), 1387 (m), 1336 (m), 1249 (m), 864
(s), 629 (m), 636 (m).
ent study highlights the significance of double-anion templa-
tion in synthetic chemistry of cage compounds. Further
work on spherical, tetrahedral, and octahedral anion templa-
tion in this system is underway.
Synthesis of MOCC-6: MOCC-6 was prepared by a route similar to that
of MOCC-4 but by using dilute nitrate acid (1m) instead. Yield: ꢁ39%
based on H4LCl2. Selected IR peaks (cmꢀ1): 3441 (w), 2919 (w), 1651 (s),
1595 (s), 1529 (s), 1443 (w), 1386 (m), 1335 (m), 1254 (m), 864 (s),
807(m), 622 (m).
Experimental Section
Synthesis of MOCC-7: MOCC-7 was prepared by a route similar to that
of MOCC-4 but by using dilute fluoroboric acid (2.5m) instead. Yield:
ꢁ51% based on H4LCl2. Selected IR peaks (cmꢀ1): 3441 (w), 2919 (w),
1651 (s), 1595 (s), 1523 (s), 1434 (w), 1386 (s), 1333 (m), 1259 (s), 866
(m), 807(m), 629 (m).
All reagents and solvents were commercially available and used as re-
ceived without further purification. 1H NMR spectra were recorded on a
Bruker AVANCE-400 NMR spectrometer. Elemental analysis was car-
ried out on a CE instruments EA 1110 elemental analyzer. The FTIR
spectra were recorded from KBr pellets in the range 4000–400 cmꢀ1 with
a Nicolet AVATAR FT-IR360 spectrometer. X-ray powder diffraction
was performed on a Bruker AXS D8 Advance with CuKa radiation (l=
1.5418 ꢂ, 40.0 kV, 30.0 mA). Photoluminescence spectra were measured
on a Hitachi F-4500 fluorescence spectrophotometer (slit width: 5 nm;
sensitivity: high). TG curves were measured on a SDT Q600 instrument
at a heating rate of 108Cminꢀ1 under N2 atmosphere (100 mLminꢀ1).
Synthesis of MOCC-8: MOCC-8 was prepared by a route similar to that
of MOCC-4 but using dilute perchloric acid (1m) instead. Yield: ꢁ55%
based on H4LCl2. Selected IR peaks (cmꢀ1): 2919 (w), 1651 (s), 1588 (s),
1522 (s), 1484 (w), 1386 (s), 1335 (s), 1257 (s), 866 (m), 807(m), 626 (m).
Synthesis of MOCC-9: H4LCl2 (2.5 mg, 0.005 mmol) and CdACHTNUGTRNEUNG(OAc)2·2H2O
(5 mg, 0.018 mmol) were dissolved in DMF/1,4-dioxane/H2O (1/1/1, v/v/v,
1 mL), and one drop (0.05 mL) of dilute sulfuric acid (1m) was added.
The solution was sealed in a glass tube, slowly heated to 1208C from
room temperature in 300 min, kept at 1208C for 4000 min, and then
slowly cooled to 308C in 1000 min. The colorless crystalline block that
formed was collected, washed with DMF, and dried in air. Yield: ꢁ53%
based on H4LCl2. Selected IR peaks (cmꢀ1): 3443 (s), 2920 (m), 1651 (s),
1599 (s), 1534 (m), 1487 (w), 1441 (w), 1385 (m), 1335 (m), 1259 (m),
1140 (m), 866 (m), 809 (m), 628 (w).
Single-crystal X-ray diffraction was performed on a Bruker Apex II CCD
diffractometer equipped with
a fine-focus sealed-tube X-ray source
(MoKa radiation, graphite-monochromated). All absorption corrections
were performed with the SADABS program.[18] All structures were
solved by direct methods by using SHELXS-97[19] and refined by full-
matrix least-squares techniques with SHELXL-97.[20] Non-hydrogen
atoms were refined with anisotropic displacement parameters during the
final cycles. Hydrogen atoms were placed in calculated positions geomet-
ꢀ
rically (C H 0.96 ꢂ) with isotropic displacement parameters set to
1.2Ueq of the attached atom. The crystallographic details of MOCC-4–9
are summarized in Supporting Information Table S1. The guest molecules
in MOCC-9 were treated with the SQUEEZE program of PLATON.[21]
CCDC 866039 (MOCC-4), 866040 (MOCC-5) and 866041 (MOCC-6),
866042 (MOCC-7), 866043 (MOCC-8) and 866044 (MOCC-9) contain
the supplementary crystallographic data for this paper. These data can be
obtained free of charge from The Cambridge Crystallographic Data
Acknowledgements
This work was supported by the NSFC (Grant No. 90922014), the Shan-
dong Natural Science Fund for Distinguished Young Scholars
(JQ201003), and Independent Innovation Foundation of Shandong Uni-
versity (2010JQ011 and 2011GN030), the Special Fund for Postdoctoral
Innovation Program of Shandong Province (201101007) and the China
Postdoctoral Science Foundation (2012M511010).
Synthesis of 1,3-Bis(bromomethyl)-2,4,6-trimethylbenzene: HBr/acetic
acid solution (40 mL, 31 wt%) was added rapidly to a mixture of mesity-
lene (12.0 g, 0.10 mol), paraformaldehyde (6.15 g; 0.20 mol), and glacial
acetic acid (50 mL). The mixture was kept for 8 h at 808C and then
poured into 100 mL of water. The product was filtered off on a G3 glass
frit and dried in vacuum. The yield was 29.1 g (95%) of white powder.
1H NMR (300 MHz, CDCl3): d=6.89 (s, 1H), 4.57 (s, 4H), 2.44 (s, 3H),
2.38 (s, 6H).
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Synthesis of H4LCl2:
A mixture of 4-hydroxy-6-methylnicotinic acid
(3.06 g, 20 mmol), 1,3,5-trimethyl-2,4-bromomethylbenzene (2.73 g,
9 mmol), and K2CO3 (2.76 g, 20 mmol) in acetone (80 mL) was heated to
reflux for 12 h. This resulting solution was filtered while hot and then
cooled to room temperature, and a white precipitate formed. The white
precipitate and aqueous NaOH solution (24 mL, 3m) were mixed with
60 mL of methanol and heated to reflux for 8 h. After cooling to room
temperature, the solution was acidified to pH 2 with dilute hydrochloric
acid, and a white precipitate formed. Yield: 28%. 1H NMR (400 MHz,
[D6]DMSO): d=16.46 (s, 2H, OH) 7.74 (s, 2H), 7.30 (s,1H), 6.82 (s, 2H),
5.40 (s, 4H), 2.64 (s, 6H, CH3), 2.30 (s, 6H, CH3), 2.08 (s, 3H, CH3).
Synthesis of MOCC-4: H4LCl2 (2.5 mg, 0.005 mmol) and CdACHTNUTRGNEUNG(NO3)2·2H2O
(4.9 mg, 0.018 mmol) were dissolved in DMF/1,4-dioxane/H2O (1/1/1, v/v/
v, 1 mL), and one drop (0.05 mL) of dilute hydrochloric acid (1m) was
added. Then the solution was sealed in a glass tube, slowly heated to
1208C from room temperature in 300 min, kept at 1208C for 4000 min,
and then slowly cooled to 308C in 1000 min. The colorless block crystals
that formed were collected, washed with DMF, and dried in air. Yield:
ꢁ46% based on H4LCl2. Selected IR peaks (cmꢀ1): 3450 (w), 1647 (s),
1571 (s), 1404 (s), 1254 (w), 1140 (w), 860 (s), 628 (w).
Synthesis of MOCC-5: MOCC-5 was prepared by a route similar to that
of MOCC-4 but by using dilute hydrobromic acid (1m) instead. Yield:
Chem. Eur. J. 2012, 18, 16525 – 16530
ꢀ 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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