Supporting Information:
Highly Emissive Iptycene-Fluorene Conjugated Copolymers:
Synthesis and Photophysical Properties
Zhihua Chen, Jean Bouffard, Steven E. Kooi, Timothy M. Swager*
Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
Experimental Section
Materials. Vinylene carbonate, anthracene, glacial acetic acid, trifluoroacetic anhydride, anhydrous
DMSO, metal tin, NBS, 9,9-dioctylfluorene-2,7-bis(trimethyleneborate) (8),
tetrakis(triphenylphosphine)palladium(0) (Pd(PPh3)4), potassium carbonate, and methyltrioctylammonium chloride (aliquat 336) were purchased from Alfa Aesar, TCI America, Strem
Chemical Inc., or Aldrich Chemical Co., and used without further purification. Anhydrous solvents used in the reactions were purchased from Mallinckrodt Baker Inc. Known compounds 9,10-dihydro-
9,10-ethanoanthracene-11,12-dione (3),1 3,6-dibromo-1,2-diaminobenzene,2 3,4-diaminothiophene dihydrochloride (5),3 and 1,4-diiodotriptycene (9)4 were prepared according to literature procedures.
General Methods and Instrumentation. All synthetic manipulations were performed under an argon atmosphere using standard Schlenk techniques unless otherwise noted. Column chromatography was performed using silica gel (40–63 µm) from SiliCycle. NMR spectra were obtained on Bruker
Advance–400 MHz or Varian Inova–500 MHz instruments. The 1H and 13C chemical shifts are given
1 in units of δ (ppm) relative to tetramethylsilane (TMS) where δ (TMS) = 0 and are referenced to residual solvent. High-resolution mass spectra (HRMS) were obtained on a Bruker Daltonics APED II
3T FT-ICR-MS using electron impact ionization (EI) or electrospray ionization (ESI). Melting points were measured on a Mel-Temp II apparatus (Laboratory Devices INC) and were not corrected.
Polymer molecular weights were determined on a HP series 1100 GPC system in THF (1mg/mL sample concentration) at room temperature vs polystyrene standards. TGA was carried out with TA
Instruments Q50 under nitrogen at a scan rate of 10 oC/min. UV–vis spectra were obtained from
Hewlett-Packard 8452A diode array UV–visible spectrophotometer. Fluorescence spectra were measured with a SPEX Fluorolog-τ2 fluorometer (model FL112, 450W xenon lamp). Fluorescence quantum yields in chloroform solutions were determined relative to quinine sulfate solution in 0.1 N
H2SO4 or cresyl violet perchlorate in methanol. The solid state quantum yields were obtained relative
-3 to 9,10-diphenylanthracene in poly(methyl methacrylate) (PMMA) (Φre = 0.83, 10 M) as a reference.
Time-resolved fluorescence measurements were acquired by exciting the samples with 170 femtosecond pulses at 330, 390, or 530 nm from a Coherent RegA Ti:Sapphire amplifier. The resulting fluorescence was spectrally and temporally resolved with a Hamamatsu C4770 Streak Camera system.
Synthesis of monomers
5,12-diaza-6,11-benzeno-1,4-dibromo-6,11-dihydrotetracene (4). A mixture of 9,10-dihydro-9,10- ethanoanthracene-11,12-dione (3) (0.91 g, 3.9 mmol) and 2,3-diamino-1,4-dibromobenzene (1.03 g,
3.9 mmol) in glacial acetic acid (30 mL) and ethanol (30 mL) was heated for 20 h at 125 oC. Solvent was removed in vacuo, and the residue was recrystallized from acentonitrile, affording a white/slightly yellow solid as the product (1.54 g, 85%). Further purification involved column chromatography on
silica gel with CH2Cl2:hexane (2:5, up to 1:1, v/v), affording a white solid as clean product. mp 292–
o 1 294 C (acetonitrile). H NMR (400 MHz, CDCl3) 7.75 (s, 2H), 7.58 (dd, J = 5.6, 3.2 Hz, 2H), 7.15
2 13 (dd, J = 5.6, 3.2 Hz, 2H), 5.85 (s, 2H). C NMR (100 MHz, CDCl3) 159.0, 141.7, 138.4, 132.9, 127.1,
+ 125.5, 123.2, 54.8. HRMS calcd for C20H12N2O4 [M+H] 462.9440, found 462.9426.
1,4-diaza-5,10-benzeno-5,10-dihydroanthra[2,3-c]thiophene (6). A mixture of 9,10-dihydro-9,10- ethanoanthracene-11,12-dione (3) (0.50 g, 2.1 mmol), 3,4-diaminothiophene hydrochloride (0.40 g, 2.1
mmol), and CH3COONa (0.35 g, 4.3 mmol) in glacial acetic acid (20 mL) and ethanol (20 mL) was
o stirred at 125 C for 18 h. Solvent was removed in vacuo, and the residue was taken with CH2Cl2. The mixture was washed with dilute aqueous NaHCO3 and saturated aqueous NaCl, dried over Na2SO4, and concentrated on a rotary evaporator. Purification by column chromatography on silica gel with
CH2Cl2:hexane (2:1, v/v) afforded a white solid as the product (0.57 g, 86%), which is pure enough for next step. A small portion of the product was recrystallized to obtain analytical pure sample for
o 1 melting point measurement. mp > 280 C (acetonitrile) (decomposed). H NMR (400 MHz, CDCl3)
7.68 (s, 2H), 7.53 (dd, J = 5.2, 3.2 Hz, 2H), 7.17 (dd, J = 5.6, 3.2 Hz, 2H), 5.47 (s, 2H). 13C NMR (100
+ MHz, CDCl3) 156.2, 141.3, 140.2, 127.2, 125.2, 116.7, 55.4. HRMS calcd for C20H12N2S [M+1]
313.0794, found 313.0790.
1,4-diaza-5,10-benzeno-5,10-dihydroanthra[2,3-c]-(2’,5’-dibromo)thiophene (7). A solution of
NBS (3.6 g, 20 mmol) in DMF (100 mL) was added drop wise to a solution of 6 (3.0 g, 9.6 mmol) in
DMF (250 mL) that was cooled by an ice-water bath. After addition, the ice-water bath was removed and the mixture was allowed to warm to room temperature and stirred for 24 h. The mixture was
poured into water (400 mL) and the product was extracted with CHCl3. Organic layers were combined, washed with saturated aqueous NaCl, dried over anhydrous Na2SO4, and concentrated by rotary evaporation. The residue was recrystallized from CH2Cl2, leading to yellow crystals (3.08 g). Mother liquor from recrystallization was concentrated and purified by column chromatography on silica gel
3 with CH2Cl2:hexane (1:1, v/v), affording a second crop of product (0.65 g, totally 3.73 g, 83%). mp >
o 1 200 C (CH2Cl2) (decomposed). H NMR (400 MHz, CDCl3) 7.53 (dd, J = 5.2, 3.2 Hz, 2H), 7.19 (dd, J
13 = 5.6, 3.2 Hz, 2H), 5.60 (s, 2H). C NMR (100 MHz, CDCl3) 157.6, 140.7, 138.3, 127.4, 125.3, 103.9,
+ 54.6. HRMS calcd for C20H10Br2N2S [M+1] 468.9004, found 468.8994.
Polymer synthesis
PFQ: Under Ar, an aqueous solution of potassium carbonate (2 M, 7 mL) was added to a mixture of
8 (190 mg, 0.34 mmol), compound 4 (158 mg, 0.34 mmol), Pd(PPh3)4 (7.0 mg, 0.006 mmol), Aliquat
336 (60 mg), and toluene (15 mL) in a 25 mL Schlenk flask, which was equipped with a condenser.
The reaction mixture was stirred for 72 h at 105 oC under Ar, and then it was cooled to room temperature and taken with chloroform. The resulting mixture was washed with water and saturated
aqueous NaCl, dried over anhydrous Na2SO4, and concentrated on a rotary evaporator. The residue was dissolved in a small amount of chloroform and the solution was precipitated in methanol and acetone.
A slightly green solid was collected by centrifugation and dried in a vacuum. (0.23 g, 94% yield). 1H
NMR (400 MHz, CDCl3), (ppm): 7.99 (d, br, 2H), 7.93 (s, br, 2H), 7.83 (s, br, 2H), 7.79 (d, br, 2H),
7.56 (s, br, 4H), 7.18 (s, br, 4H), 5.65 (s, 2H), 2.18 (br, 4H), 1.00-1.50 (m, br, 24H), 0.83 (s, 6H).
PFTP: This was prepared according to the procedure described for the synthesis of PFQ using 7
(88.5 mg, 0.19 mmol), 8 (105 mg, 0.19 mmol), Pd(PPh3)4 (5.0 mg, 0.0043 mmol), Aliquat 336 (40 mg), aqueous potassium carbonate (2 M, 5 mL), and toluene (10 mL) (110 mg, 84%). 1H NMR (400
MHz, CDCl3), (ppm): 8.34 (d, br, 2H), 8.03 (s, br, 2H), 7.90 (d, br, 2H), 7.60 (m, br, 4H), 7.22 (s, br,
4H), 5.58 (s, 2H), 2.17 (br, 4H), 1.00-1.30 (s, br, 20H), 0.94 (s, br, 4H), 0.78 (m, br, 6H).
4 PFP: This was prepared according to the procedure described for the synthesis of PFQ using 9 (46.4
mg, 0.092 mmol), 8 (51.0 mg, 0.092 mmol), Pd(PPh3)4 (3.0 mg, 0.0026 mmol), Aliquat 336 (20 mg), aqueous potassium carbonate (2 M, 2 mL), and toluene (4 mL) (50 mg, 85%). 1H NMR (400 MHz,
CDCl3), (ppm): 8.06 (d, br, 2H), 7.59 (m, br, 4H), 7.39 (s, br, 4H), 7.27 (overlap with CHCl3 peak,
2H), 7.10 (s, br, 4H), 5.90 (s, 2H), 2.29 (s, br, 4H), 1.10-1.40 (m, br, 20H), 1.00 (S, br, 4H), 0.80 (t,
6H).
References
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5 1H NMR spectrum of 4
13C NMR spectrum of 4
6 1H NMR spectrum of 6
13C NMR spectrum of 6
7 1H NMR spectrum of 7
13C NMR spectrum of 7
8 1H NMR spectrum of PFQ
1H NMR spectrum of PFTP
9 1H NMR spectrum of PFP
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