Full Papers
is 6.30 kJmolÀ1 (Figure S7 in the Supporting Information). This
value is in close agreement with that of most MOFs having ex-
posed metal sites.[1e] The powder X-ray diffraction pattern of
a bulk crystalline sample of 1 after the gas adsorption experi-
ments was identical to the simulated pattern and the diffrac-
tion pattern of pristine 1 (Figure S8 in the Supporting Informa-
tion), further supporting the high stability and permanent po-
rosity of the network.
to afford 3,5-diiodobenzoic acid (A) as a yellowish white solid
1
(yield 60%). H NMR (300 MHz, [D6]DMSO): d=13.49 (s, 1H, COOH),
8.35 (s, 1H, 2,6-H), 8.21 ppm (s, 2H, 4-H); 13C NMR ([D6]DMSO,
75 MHz): d=165.12, 148.66, 137.45, 134.78, 96.60 ppm; HRMS (ESI-
TOF) m/z calcd for C7H4I2O2 [M+H]+: 374.8379, found 374.8376.
Synthesis of B: A suspension of 3,5-diiodobenzoic acid (A) (1.00 g,
2.67 mmol), K2CO3 (437 mg), and dimethyl sulfate (0.27 mL) in an-
hydrous acetone (25 mL) was refluxed at 568C for 12 h. After the
reaction mixture had cooled down to room temperature, water
(5 mL) was added. The mixture was stirred under ambient condi-
tions for 12 h. The solvent was removed by evaporation. The resi-
due was dissolved in CH2Cl2 and the organic layer was washed
with water three times. Finally, the organic layer was dried over an-
hydrous Na2SO4, and the volatiles were removed by evaportation
leaving a crude solid. The solid was then purified on silica gel
using hexane as the eluent to afford compound B as a white solid
(yield 95%). 1H NMR (300 MHz, [D6]DMSO): d=8.38 (s, 1H, 4-H),
8.20 (s, 2H, 2,6-H), 3.86 ppm(s, 3H, OCH3); 13C NMR ([D6]DMSO,
100 MHz): d=164.11, 149.10, 137.07, 133.42, 96.76, 53.19 ppm;
HRMS (ESI-TOF) m/z calcd for C8H7I2O2 [M+H]+: 388.8536, found
388.8554.
Conclusion
In summary, we have rationally designed and synthesized an
asymmetrical tricarboxylate organic linker with elongated arms
for the construction of a new twofold interpenetrated micro-
porous MOF with a Pt3O4 topology. Upon activation, 1 shows
the highest BET surface area (2297 m2 gÀ1) among all the re-
ported interpenetrated MOFs. Interestingly, the value is compa-
rable and even higher than that of some well-known highly
porous non-interpenetrated MOFs. Despite its interpenetrated
framework, the activated 1 presents high CO2 and H2 uptake
capability, providing high CO2/N2 and CO2/CH4 selectivity at
ambient conditions. Thus, the high selectivity of 1 for CO2 over
N2 and CH4 makes it promising for potential gas-separation
and -storage applications.
Synthesis of C: A mixture of compound B (2.00 g, 5.17 mmol), tri-
methylsilylacetylene (2.19 mL, 15.51 mmol), [Pd(PPh3)2Cl2] (181 mg,
0.25 mmol), and CuI (99 mg, 0.50 mmol) in diisopropylethyl amine
(DIPEA, 30 mL) and THF (30 mL) was heated at 608C under nitro-
gen for 12 h and then cooled to room temperature. The mixture
was filtered and the solvent was removed by evaporation. The
crude product was deprotected without further purification.
Experimental Section
In a 100 mL round-bottom flask, the trimethylsilylated compound
(1 g) was dissolved in a mixture of THF (20 mL) and methanol
(10 mL). To this reaction mixture, tetrabutylammonium fluoride
(TBAF) solution (1m in THF, 2 mL) was added. The mixture was
stirred undert ambient conditions for 2 h. The solvent was re-
moved by evaporation, and the desilylated crude product was pu-
rified by column chromatography (silica gel, ethyl acetate/hexane
10–30% v/v). The pure product was obtained as brownish white
Materials and methods: Copper nitrate trihydrate, 3,5-diamino-
benzoic acid, dimethyl sulfate, potassium iodide, sodium nitrite,
and trimethylsilylacetylene were purchased from Sigma–Aldrich
and were used as received. Methyl 4-iodobenzoate was purchased
from TCI chemicals. Dichloromethane (DCM) was freshly distilled
from calcium hydride. NMR spectra were recorded on either
a Bruker AV 300 or a Bruker AV400 at room temperature. Electro-
spray ionization mass spectrometry (ESI-MS) experiments were car-
ried out on a ThermoFinnigan LCQ Fleet MS. Thermogravimetric
analysis (TGA) was carried out on a TGA-Q500 thermoanalyzer with
a heating rate of 58CminÀ1 under nitrogen atmosphere. Powder X-
ray diffraction measurements were performed on a Bruker D8 dif-
fractometer using Cu-Ka radiation (l=1.5418 ) at room tempera-
ture.
1
solid (yield 72%). H NMR (300 MHz, CDCl3): d=8.10 (s, 2H, 2,6-H),
7.75 (s, 1H, 4-H), 3.92 (s, 3H, OCH3), 3.13 ppm (s, 2H, ethynyl-H);
13C NMR (CDCl3, 100 MHz): d=165.47, 139.32, 133.26, 130.84,
123.03, 81.59, 78.90, 52.51 ppm; HRMS (ESI-TOF) m/z calcd for
C12H9O2 [M+H]+: 185.0603, found 185.0582.
Synthesis of D: A mixture of compound C (0.58 g, 3.15 mmol),
methyl 4-iodobenzoate (1.78 g, 6.78 mmol), [Pd(PPh3)2Cl2] (166 mg,
0.24 mmol), and CuI (92 mg, 0.48 mmol) in DIPEA (15 mL) and THF
(15 mL) was stirred at room temperature under nitrogen atmos-
phere for 24 h. The mixture was filtered and the filtrate was evapo-
rated to dryness. The residue was purified by column chromatogra-
phy on silica gel using CH2Cl2 as the eluent. The pure compound D
was isolated as a yellowish white solid (yield 70%). 1H NMR
(300 MHz, CDCl3): d=8.19 (s, 2H), 8.05 (d, 4H, J=8.2 Hz), 7.89 (s,
1H), 7.60 (d, 4H, J=8.3 Hz), 3.97 (s, 3H, OCH3), 3.94 ppm (s, 6H,
OCH3); 13C NMR (CDCl3, 100 MHz): d=166.44, 165.58, 138.35,
132.67, 131.65, 131.04, 130.01, 129.61, 127.20, 123.76, 90.20, 90.18,
52.55, 52.29 pm; HRMS (ESI) m/z: [M+H]+ calcd for C28H21O6,
453.1338; found, 453.1326.
Synthesis of A: Compound A was synthesized by a modified litera-
ture procedure.[49] A 1 L three-neck round-bottom flask equipped
with a mechanical stirrer and a thermometer was charged with 3,5-
diaminobenzoic acid (6.00 g, 39.40 mmol) and 25% H2SO4 solution
(70 mL). The reaction mixture was cooled to À58C with an ice-salt
bath. Then, the temperature of the reaction mixture was carefully
monitored. To this cooled reaction mixture, an ice-cooled solution
of NaNO2 (6.53 g, 394 mmol, 10 mL) was added dropwise. After the
solution had been stirred at À58C for 1 h, urea (497 mg,
8.30 mmol) was added to get rid of excess NaNO2. Then, an aque-
ous solution of potassium iodide (65.50 g, 394 mmol) was added
dropwise, and the reaction mixture was stirred at À58C for an ad-
ditional 2.5 h. It was heated to 608C for 30 min. After cooling
down to room temperature, the reaction mixture was filtered. The
precipitate was dissolved in diethyl ether and the organic layer
was washed with Na2S2O3 (3) to remove iodine. The organic layer
was dried over anhydrous Na2SO4 and the solvent was removed by
evaporation. The crude product was purified by chromatography
on silica gel using EtOAc/CH2Cl2 (5:95 to 20:80, v/v) as the eluent
Synthesis of H3L: A mixture of compound D (400 mg, 0.88 mmol),
NaOH (500 mg, 12.50 mmol), THF (20 mL), and water (5 mL) was
stirred at ambient temperature for 12 h. The mixture was then con-
centrated under reduced pressure. The concentrated reaction mix-
ture was acidified with cold 3m HCl in an ice bath. The white pre-
cipitate that appeared was filtered and washed with plenty of dis-
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