Efficient Greenish Blue Electrochemiluminescence from Fluorene and Spirobifluorene Derivatives Federico Polo, *,, Fabio Rizzo, *, Manoel Veiga Gutierrez, Luisa De Cola, Silvio Quici Physikalisches Institut, Westfälische Wilhelms-Universität, Heisenbergstrasse 11, D-48149 Münster, Germany; Istituto di Scienze e Tecnologie Molecolari (ISTM) CR, Via Golgi 19, I-20133 Milano, Italy; Polo Scientifico Tecnologico (PST) CR, Via Fantoli 16/15, I-20138 Milano, Italy. Current Address: Dipartimento di Scienze Chimiche, Università degli Studi di Padova, Via Marzolo 1, I-35131 Padova, Italy Supporting Information S1
General Experiments. All solvents and reagents used are commercially available and were employed as received without further purifications. TLC was carried out on silica gel Si 60-F254. Column chromatography was carried out on silica gel Si 60, mesh size 0.040-0.063 mm (Merck, Darmstadt, Germany). Flash chromatography was carried out on J. T. Baker silica gel mesh size 230-400. 1 H MR (400 MHz) and 13 C MR (101 MHz) spectra were recorded in CDCl 3 with a Bruker Avance 400 spectrometer. The assignment of protons and carbon atoms was carried out by bidimensional MR experiments (COSY, heterocorrelate 1 H- 13 C). The coupling constants J are given in Hz. Mass analyses were performed by Fourier Transform Ion Cyclotron Resonance (FT-ICR) Mass Spectrometer APEX II and Xmass Software (Bruker Daltonics) at the Centro Interdipartimentale Grandi Apparecchiature (Università di Milano). Melting points (uncorrected) were determined with a Buchi Melting Point B- 540 capillary melting point apparatus. Compounds 2,2 -dibromo-9,9 -dimethyl-fluorene (4), 1 2,2 - dibromo-9,9 -spirobifluorene (5), 2 2,2,7,7 -tetrabromo-9,9 -spirobifluorene (6) 3 were synthesized according to the respective literature procedures. All coupling reactions are been performed under nitrogen using Schlenk technique. 2,7-bis-(4-(,-diphenylamino)phen-1-yl)-9,9 -dimethyl-fluorene (1). In a Schlenk tube a stirred mixture of 2,7-dibromo-9,9 -dimethyl-fluorene (4) (204.8 mg, 0.5818 mmol), 4-(,diphenylamino)phenylboronic acid (310.2 mg, 1.073 mmol), aqueous a 2 CO 3 2M (3 ml), Pd(PPh 3 ) 4 (65.1 mg, 0.056 mmol) in dry THF (8 ml) was refluxed overnight under inert atmosphere. After cooling at room temperature, the organic solvent was removed under vacuum and the solid dissolved in CH 2 Cl 2. The aqueous phase was extracted with CH 2 Cl 2 (2 x 10 ml) and the collected organic phases were washed with water (1 x 30 ml), and dried over a 2 SO 4. After removing the solvent under vacuum, the product was purified by column chromatography over silica using the mixture hexane/ch 2 Cl 2 (4:1) as eluent to give the product as white solid (234.3 mg, 60 %). 1 H MR (400 MHz, CDCl 3, 25 C): δ = 7.77 (d, J H-H = 7.89 Hz, 2 H, 4-H, 5-H), 7.64 (d, J H-H = 1.42 Hz, 2 H, 1-H, 8-H), 7.58 7.55 (m, 6 H, 3- H, 6-H, 2-H phenyl, 6-H phenyl), 7.30 7.26 (m, 8 H, H phenyl), 7.18 7.15 (m, 12 H, 3-H phenyl, 5- H phenyl, H phenyl), 7.05 (t br, J H-H = 7.30 Hz, 4 H, H phenyl), 1.58 (s, 6 H, CH 3 ) ppm. 13 C MR (101 MHz, CDCl 3, 25 C): δ = 154.51 (q), 147.73 (q), 147.10 (q), 139.78 (q), 137.80 (q), 135.62 (q), 129.29 S2
(phenyl), 127.83 (2-C phenyl, 6-C phenyl), 125.77 (3-C, 6-C), 124.39 (phenyl), 124.06 (phenyl), 122.92 (phenyl), 120.91 (1-C, 8-C), 120.26 (4-C, 5-C), 47.02 (9-C), 27.38 (CH 3 ) ppm. M.p.: 253 255 C. m/z (HRMS ESI + ): 680.3190 (M +. C 51 H 40 2 requires 680.3186), 340.1592 (M 2+. C 51 H 40 2 requires 340.1590). UV/Vis (CHCl 3 ): λ max (ε) = 369 (65370), 305 nm (31130 mol -1 dm 3 cm -1 ). 2,7-bis-(4-(,-diphenylamino)phen-1-yl)-9,9 -spirobifluorene (2). In a Schlenk tube a stirred mixture of 2,7-dibromo-9,9 -spirobifluorene (5) (230.1 mg, 0.4856 mmol), 4-(,diphenylamino)phenylboronic acid (310.2 mg, 1.073 mmol), aqueous a 2 CO 3 2M (3 ml), Pd(PPh 3 ) 4 (65.1 mg, 0.056 mmol) in dry THF (8 ml) was refluxed overnight under inert atmosphere. After cooling at room temperature, the organic solvent was removed under vacuum and the solid dissolved in CH 2 Cl 2. The aqueous phase was extracted with CH 2 Cl 2 (2 x 10 ml) and the collected organic phases were washed with water (1 x 30 ml), and dried over a 2 SO 4. After removing the solvent under vacuum, the product was purified by column chromatography over silica using the mixture hexane/ch 2 Cl 2 (4:1) as eluent to give the product as white solid (234.3 mg, 60 %). 1 H MR (400 MHz, CDCl 3, 25 C): δ = 7.89 (d, J H-H = 7.96 Hz, 2 H, 4-H, 5-H), 7.86 (d, J H-H = 7.62 Hz, 2 H, 4 -H, 5 -H), 7.60 (dd, J H-H = 7.96 Hz, J H-H = 1.68 Hz, 2 H, 3-H, 6-H), 7.37 (dt, J H-H = 7.51 Hz, J H-H = 0.84 Hz, 2 H, 3 -H, 6 -H), 7.30 (d, J H-H = 8.66 Hz, 4 H, 2-H aminophenyl, 6-H aminophenyl), 7.24-7.20 (m, 8 H, H phenyl), 7.12 (dt, J H- H = 7.56 Hz, J H-H = 1.00 Hz, 2 H, 2 -H, 7 -H), 7.07-6.98 (m, 16 H, 3-H aminophenyl, 5-H aminophenyl, H phenyl), 6.91 (d, J H-H =1.60 Hz, 2 H, 1-H, 8-H), 6.82 (d, J H-H = 7.59 Hz, 2 H, 1 -H, 8 - H) ppm. 13 C MR (101 MHz, CDCl 3, 25 C): δ = 149.80 (q), 148.82 (q), 147.60 (q), 147.05 (q), 141.82 (q), 140.32 (q), 140.28 (q), 134.97 (q), 129.22 (phenyl), 127.89 (2 -C, 7 -C), 127.74 (3 -C, 6 - C), 127.70 (2-C aminophenyl, 6-C aminophenyl), 126.39 (3-C, 6-C), 124.28 (phenyl, 1 -C), 123.86 (phenyl), 122.85 (phenyl), 122.19 (1-C, 8-C), 120.23 (4 -C, 5 -C), 120.04 (4-C, 5-C), 66.10 (C spiro) ppm. m/z (HRMS ESI + ): 802.3341 (M +. C 61 H 42 2 requires 802.3342), 401.1670 (M 2+. C 61 H 42 2 requires 401.1668). UV/Vis (CHCl 3 ): λ max (ε) = 372 nm (73020 mol -1 dm 3 cm -1 ). S3
2,2,7,7 -tetrakis-(4-(,-diphenylamino)phen-1-yl)-9,9 -spirobifluorene (3). In a Schlenk tube a stirred mixture of 2,2,7,7 -tetrabromo-9,9 -spirobifluorene (6) (153.1 mg, 0.2424 mmol), 4-(,diphenylamino)phenylboronic acid (315.5 mg, 1.091 mmol), aqueous a 2 CO 3 2M (3 ml), Pd(PPh 3 ) 4 (60.9 mg, 0.053 mmol) in dry THF (7 ml) was refluxed overnight under inert atmosphere. The grey precipitate formed was filtered over glass filter and washed with pentane (2 x 5 ml) to give the product (194.4 mg, 62%). 1 H MR (400 MHz, CDCl 3, 25 C): δ = 7.88 (d, J H-H = 7.95 Hz, 4 H, 4-H, 5-H, 4 - H, 5 -H), 7.59 (dd, J H-H = 7.99 Hz, J H-H = 1.68 Hz, 4 H, 3-H, 6-H, 3 -H, 6 -H), 7.32 (d, J H-H = 8.73 Hz, 8 H, 2-H phenyl, 6-H phenyl), 7.22-7.18 (m, 16 H, H phenyl), 7.06-6.95 (m, 36 H, 1-H, 8-H, 1 - H, 8 -H, 3-H phenyl, 5-H phenyl, H phenyl) ppm. 13 C MR (101 MHz, CDCl 3, 25 C): δ = 149.81 (q), 147.59 (q), 147.02 (q), 140.33 (q), 140.26 (q), 134.93 (q), 129.19 (phenyl), 127.70 (2-C phenyl, 6-C phenyl), 126.40 (3-C, 6-C, 3 -C, 6 -C), 124.25 (phenyl), 123.89 (phenyl), 122.82 (phenyl), 122.31 (1- C, 8-C, 1 -C, 8 -C), 120.28 (4-C, 5-C, 4 -C, 5 -C), 66.23 (C spiro) ppm. m/z (HRMS ESI + ): 1311.5353 (Ma +. C 97 H 68 4 a requires 1311.5336). UV/Vis (CHCl 3 ): λ max (ε) = 373 (98400), 305 nm (48550 mol -1 dm 3 cm -1 ). (1) Saroja, G.; Pingzhu, Z.; Ernsting,. P.; Liebscher, J. J. Org. Chem., 2004, 69, 987-990. (2) Yu, W.-L.; Pei, J.; Huang, W.; Heeger, A. J. Adv. Mater., 2000, 12, 828-831. (3) Pei, J.; i, J.; Zhou, X.-H.; Cao, X.-Y.; Lai, Y.-H. J. Org. Chem., 2002, 67, 4924-4938. S4
Figure S1. Current (black line) and ECL (red line) of 2. Pulse width: 0.3 s. S5
Figure S2. Coreactant ECL emission spectrum of 3 in DMF/0.1 M TBAH using 20 eq BPO. S6
Figure S3. PL emission spectra of 2 in 10-3 M DMF/0.1 M TBAH solution exciting at 370 nm (a) and 430 nm (b). S7
Figure S4. PL emission spectra of 1 (a) and 2 (b) in solid state. S8