Supporting information. Gram scale synthesis of benzophenanthroline and its blue phosphorescent platinum

Transcription

1 Supporting information Gram scale synthesis of benzophenanthroline and its blue phosphorescent platinum complex Patrick J. G. Saris and Mark E. Thompson* Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States S1

2 Supporting Information Table of Contents 1. General methods S3 2. DFT calculated spin densities of 5Pt(dpm) and iso-5pt(dpm) S5 3. Absorption and emission spectrum of 10 and iso-10 S6 4. Experimental procedures S H and 13 C NMR spectra S17 S2

3 Methods All reagents were purchased from commercial sources and used without purification. Benzo[h]quinoline was purchased from TCI. Palladium acetate was purchased from Strem. Iodine pentoxide was purchased from Alpha Asar. 2,6- dimethylphenylboronic acid was purchased from Ark Pharm. All other reagents were purchased from Sigma Aldrich. Equipment UV-visible spectra were recorded on a Hewlett-Packard 4853 diode array spectrometer. Photoluminescence spectra were measured using a QuantaMaster Photon Technology International phosphorescence/fluorescence spectrofluorometer. Quantum yield measurements were carried out using a Hamamatsu C9920 system equipped with a xenon lamp, calibrated integrating sphere and model C10027 photonic multi-channel analyzer (PMA). Photoluminescence lifetimes were measured by time-correlated single-photon counting using an IBH Fluorocube instrument equipped with an LED excitation source. All room temperature photophysical measurements were recorded in methylcyclohexane (MeCy) and all cryogenic photophysical measurements were carried out in 2-methyltetrahydrofuran (2-MeTHF). All samples were deaerated by bubbling N2 in a quartz cuvette fitted with a Teflon stopcock. NMR spectra were recorded on a Varian 400 NMR spectrometer and referenced to the residual proton resonance of chloroform (CDCl3) solvent at 7.26 ppm. S3

4 DFT calculations All calculations were performed using Jaguar 8.4 (release 12) software package on the Schrodinger Material Science Suite (v2016-1). Gas phase geometry optimizations were calculated using B3LYP functional with the LACV3P** basis set as implemented in Jaguar. The HOMO and LUMO energies were determined using minimized singlet geometries to approximate the ground state, whereas the geometry optimized triplet geometries were used to approximate the triplet excited state. S4

5 DFT calculated triplet energies and spin densities of 5Pt(dpm) and iso-5pt(dpm) Structure 5Pt(dpm) iso-5pt(dpm) Triplet energy 2.75 ev 2.48 ev S5

6 Absorption and emission spectrum of 10 and iso-10 in methylcyclohexane 1.0 normallized intensity (arb. units) wavelength (nm) iso-10 abs. iso-10 em. 77 K 10 abs. 10 em. 77K S6

7 Experimental Procedures 10-chlorobenzo[h]quinoline (6): A 250 ml round bottom flask was charged with benzo[h]quinoline (10.0 g, 55.8 mmol, 1.0 eq.), N-chlorosuccinimide (7.82g, 58.6 mmol, 1.05 eq.), palladium (II) acetate (1.25 g, 5.58 mmol, 0.10 eq.), and 150 ml acetonitrile. The flask was fitted with a reflux condenser and placed in an oil bath at 100 C. The reaction was allowed to reflux under ambient atmosphere with magnetic stirring for 16 h, at which point the reaction mixture was allowed to cool to room temperature and passed through a short plug of silica with the aid of 150 ml ethyl acetate. The filtrate was evaporated to dryness in vacuuo and the resulting pale yellow solid was recrystallized by slow cooling of a hot hexanes solution to yield 6 as colorless plates (8.65 g, 73%); mp = C. 1H NMR (400 MHz, Chloroform-d) δ 9.12 (dd, J = 4.3, 1.9 Hz, 1H), 8.16 (dd, J = 8.0, 1.9 Hz, 1H), 7.83 (d, J = 7.6, 3H), 7.77 (d, J = 8.8, 2H), 7.68 (d, J = 8.8, 1H), (m, 3H). 13C NMR (101 MHz, cdcl3) δ , , , , , , , , , , , CHNS: calculated [C, 73.08; H, 3.77; N, 6.56], found [C, 73.24; H, 3.76; N, 6.56] S7

8 10-chlorobenzo[h]quinoline 5,6-dione (7): A 250 ml round bottom flask was charged with 10-chlorobenzo[h]quinoline (8.0 g, 37.4 mmol, 1.0 eq.), I 2 O 5 (15.0 g, 44.9 mmol, 1.2 eq), and 100 ml acetic acid. The flask was fitted with a reflux condenser and placed in an oil bath at 150 C. The reaction was allowed to reflux under ambient atmosphere with magnetic stirring for 3.5 h, at which point the flask was placed in a room temperature water bath to cool the reaction to room temperature. The solvent was removed by vacuum distillation (5 torr, 35 C), chased with 100 ml toluene to remove excess iodine. The resulting red-orange solid was then chromatographed on silica (hexanes/ ethyl acetate 0:1 to 1:1), eluting first a purple fraction (I 2 ), then a colorless fraction (starting material), followed by a minor yellow fraction (not characterized), and finally a major yellow fraction (product). This product fraction was evaporated to dryness, re-dissolved in 100 ml dichloromethane, washed with 100 ml brine, and then dried in vacuuo to yield 7 as an orange-yellow powder (3.73 g, 41%). 1H NMR (400 MHz, Chloroform-d) δ 9.00 (dd, J = 4.7, 2.0 Hz, 1H), 8.42 (dd, J = 7.9, 2.0 Hz, 1H), 8.18 (dd, J = 7.7, 1.5 Hz, 1H), 7.85 (dd, J = 8.0, 1.5 Hz, 1H), (m, 2H). 13C NMR (101 MHz, cdcl3) δ , , , , , , , , , , , , CHNS: calculated [C, 64.09; H, 2.48; N, 5.75], found [C, 63.04; H, 2.37; N, 5.67] S8

9 9-chlorobenzo[h][1,2,4]triazino[5,6-f]quinoline (8) and 8- chlorobenzo[h][1,2,4]triazino[6,5-f]quinoline (iso-8): In a 200 ml round bottom flask, 10-chlorobenzo[h]quinoline 5,6-dione (3.60 g, mmol, 1 eq.) was suspended in 100 ml absolute methanol by vigorous magnetic stirring under ambient atmosphere. Separately, a 100 ml Erlenmeyer flask was charged with formamidinium acetate (1.85 g, mmol, 1.2 eq.), hydrazine hydrate (0.87 ml, 88mg, mmol, 1.2 eq.) and 50 ml absolute methanol. This formamidhydrazone solution was stirred magnetically at ambient conditions for 10 minutes, and then introduced to in one portion to the 10- chlorobenzo[h]quinoline 5,6-dione suspension, causing rapid dissolution of the solids and darkening of the solution to deep red. The flask was stoppered and stirred at room temperature for 16 h, after which a brick red precipitate was observed. The precipitate was recovered by filtration, washed with 10 ml methanol, air dried, and finally dried in vacuuo to yield a mixture of 9-chlorobenzo[h][1,2,4]triazino[5,6-f]quinoline and 8- chlorobenzo[h][1,2,4]triazino[6,5-f]quinoline as a fine rust-brown powder (2.1 g, 53%). This mixture was used without further purification. 1H NMR (400 MHz, Chloroform-d) δ 10.00(s, 0.6H), 9.99 (s, 1H), 9.69 (dd, J = 8.2, 1.9 Hz, 0.6H), 9.51 (dd, J = 8.1, 1.3 Hz, 1H), 9.45 (dd, J = 8.1, 2.0 Hz, 1H), 9.27 (dd, J = 8.0, 1.3 Hz, 0.6H), 9.21 (dd, J = 4.4, 2.0 Hz, 1H), 9.19 (dd, J = 4.4, 1.9 Hz, 0.6H), 8.02 (dd, J = 7.8, 1.4 Hz, 0.6H), 7.98 (dd, J = 7.8, 1.4 Hz, 1H), (m, 3.2H). 13C NMR (101 MHz, cdcl3) δ , , , , , , , , , , , , , S9

10 133.39, , , , , , , , , , , , , , CHNS: calculated [C, 63.05; H, 2.65; N, 21.01], found [C, 60.76; H, 2.51; N, 19.40] 12-chlorobenzo[f][1,7]phenanthroline (9) and 9-chlorobenzo[f][4,7]phenanthroline (iso-9): A 150 ml round bottom flask was charged with the previously synthesized mixture of 9-chlorobenzo[h][1,2,4]triazino[5,6-f]quinoline and 8- chlorobenzo[h][1,2,4]triazino[6,5-f]quinoline (2.10 g, 7.87 mmol, 1 eq.), norbornadiene (8.06 ml, 7.26 g, 78.7 mmol, 10 eq.), and 75 ml o-dichlorobenzene. The flask was fitted with a reflux condenser and placed in an oil bath at 180 C. The reaction was allowed to reflux with magnetic stirring under ambient atmosphere for 24 h, then cooled to room temperature, and the solvent was removed under vacuum. The resulting black residue was chromatographed on silica (ethyl acetate / hexanes 1 : 2) and dried to yield a mixture of 12-chlorobenzo[f][1,7]phenanthroline (9) and 9- chlorobenzo[f][4,7]phenanthroline (iso-9) as a beige solid (1.95 g, 94%). 1H NMR (400 MHz, Chloroform-d) δ 9.60 (dd, J = 8.2, 1.9, 1H), 9.41 (dd, J = 8.2, 1.4 Hz, 0.6H), 9.13 (d, J = 4.2 Hz, 1H), 9.11 (d, J = 4.3 Hz, 0.6H), (m, 1.6H), 8.88 (d, J = 8.4, 1H), 8.84 (d, J = 8.2 Hz, 0.6H), 8.81 (d, J = 8.4 Hz, 0.6H), 8.56 (d, J = 8.1, 1H), 7.92 (d, J = 7.8 Hz, 0.6H), 7.88 (d, J = 7.8 Hz, 1H), (m, 4.8H). 13C NMR (101 MHz, cdcl3) δ , , , , , , , , , , S10

11 133.48, , , , , , , , , , , , , , , , , , , , , CHNS: calculated [C, 72.60; H, 3.43; N, 10.58], found [C, 72.25; H, 3.55; N, 10.46] 12-phenylbenzo[f][1,7]phenanthroline (5): A 200 ml round bottom flask was charged with the previously synthesized mixture of 12-chlorobenzo[f][1,7]phenanthroline and 9- chlorobenzo[f][4,7]phenanthroline (1.90 g, 7.18 mmol, 1 eq.), phenylboronic acid (1.31 g, mmol, 1.5 eq.), cesium fluoride (3.27 g, 21.5 mmol, 3 eq.), triphenylphosphine oxide (400 mg, 1.44 mmol, 0.2 eq.), palladium (II) acetate (161 mg, 0.72 mmol, 0.1 eq.), and 100 ml tetrahydrofuran. The flask was stoppered under ambient atmosphere and placed in an oil bath at 50 C with magnetic stirring for 16 h. The reaction was cooled to room temperature, the solvent removed in vacuuo, and the residue chromatographed on silica (ethyl acetate / hexanes 1 : 4) to yield 12-phenylbenzo[f][1,7]phenanthroline as the first major fraction, a colorless solid (696 mg, 32%); mp = C. 1H NMR (400 MHz, Chloroform-d) δ 9.45 (dd, J = 8.1, 1.9 Hz, 1H), 8.98 (dd, J = 4.4, 1.6 Hz, 1H), 8.95 (dd, J = 8.3, 1.6 Hz, 1H), 8.61 (dd, J = 8.1, 1.3 Hz, 1H), 8.42 (dd, J = 4.3, 1.9 Hz, 1H), 7.75 (dd, J = 8.1, 7.3 Hz, 1H), (m, 2H), (m, 6H). 13C NMR (101 MHz, cdcl3) δ , , , , , , , , , S11

12 131.36, , , , , , , , , , , CHNS: calculated [C, 86.25; H, 4.61; N, 9.14], found [C, 86.17; H, 4.62; N, 9.12] The second fraction from chromatography yielded 460 mg of 90 % pure 9- phenylbenzo[f][4,7]phenanthroline, a colorless solid. 1H NMR (400 MHz, Chloroform-d) δ 9.42 (dd, J = 8.1, 1.5 Hz, 1H), 9.03 (dd, J = 4.4, 1.7 Hz, 1H), 8.78 (dd, J = 8.2, 1.7, Hz, 1H), 8.72 (dd, J = 8.2, 1.8, 1H), 8.39 (dd, J = 4.3, 1.7 Hz, 1H), 7.82 (dd, J = 8.1, 7.3 Hz, 1H), 7.66 (dd, J = 7.3, 1.4 Hz, 1H), 7.61 (dd, J = 8.2, 4.4 Hz, 1H), (m, 6H). (12-phenylbenzo[f][1,7]phenanthrolinato-N 5,C 4 )(2,2,6,6-tetramethyl-3,5- heptanedionato-o,o) platinum (II) (5Pt(dpm)): A 50 ml round bottom flask was charged with potassium tetrachloroplatinate (100 mg, 0.24 mmol, 1 eq.), 12- phenylbenzo[f][1,7]phenanthroline (184 mg, 0.60 mmol, 2.5 eq.), 6 ml 2-ethoxyethanol, and 2 ml H 2 O. The flask was fitted with a reflux condenser, thoroughly sparged with nitrogen, and heated to 80 C with magnetic stirring under nitrogen atmosphere. After 16 h the mixture was cooled to room temperature, diluted with 10 ml H 2 O, and the resulting precipitate was collected by filtration and washed successively with 10 ml each isopropanol, diethyl ether, and hexanes. The approximately 120 mg of olive green precipitate was returned to the flask along with dipivaloylmethane (145 ml, 130 mg, 0.71 mmol, ~5 eq.), potassium carbonate (197 mg, 1.42 mmol, ~10 eq.), and 10 ml 2- ethoxyethanol. The flask was fitted with a reflux condenser, thoroughly sparged with S12

13 nitrogen, and heated to 100 C with magnetic stirring under nitrogen atmosphere. After 16 h the mixture was cooled to room temperature, diluted with 30 ml H 2 O, and extracted with 30 ml dichloromethane. The organic layer was dried over sodium sulfate, evaporated to dryness, and the yellow residue titurated with methanol (5 x 2 ml) by suspension and centrifugation to yield 5Pt(dpm) as a bright yellow powder which was recrystallized by slow diffusion of methanol into a dichloromethane solution. (31 mg, 19%); mp = C. 1H NMR (400 MHz, Chloroform-d) δ 9.17 (dd, J = 5.5, 1.1 Hz, J PtH = 35 Hz, 1H), 8.99 (dd, J = 8.4, 1.2 Hz, 1H), 8.59 (dd, J = 8.2, 1.3 Hz, 1H), 8.08 (d, J = 4.7 Hz, 1H), 7.75 (t, J = 7.7 Hz, 1H), 7.62 (dd, J = 7.4, 1.3 Hz, 1H), 7.58 (dd, J = 8.3, 5.4 Hz, 1H), 7.52 (d, J = 4.7 Hz, 1H), (m, 4H), 5.90 (s, 1H), 1.33 (s, 9H), 1.31 (s, 9H). 13C NMR (101 MHz, cdcl3) δ , , , , , , , , , , , , , , , , , , , 93.45, 41.57, 41.18, 28.63, CHNS: calculated [C, 57.97; H, 4.72; N, 4.10], found [C, 58.33; H, 4.73; N, 3.94] 12-(2,6-dimethylphenyl)benzo[f][1,7]phenanthroline (10): A 200 ml round bottom flask was charged with the previously synthesized mixture of 12- chlorobenzo[f][1,7]phenanthroline and 9-chlorobenzo[f][4,7]phenanthroline (2.0 g, 7.56 mmol, 1 eq.), 2,6-dimethylphenylboronic acid (1.70 g, mmol, 1.5 eq.), cesium S13

14 fluoride (3.44 g, mmol, 3 eq.), triphenylphosphine oxide (420 mg, 1.51 mmol, 0.2 eq.), palladium (II) acetate (170 mg, 0.76 mmol, 0.1 eq.), and 100 ml tetrahydrofuran. The flask was stoppered under ambient atmosphere and placed in an oil bath at 50 C with magnetic stirring for 16 h. The reaction was cooled to room temperature, the solvent removed in vacuuo, and the residue chromatographed on silica (ethyl acetate / hexanes 1 : 7) to yield 12-(2,6-dimethylphenyl)benzo[f][1,7]phenanthroline as the first major fraction, a colorless solid (660 mg, 26%). 1H NMR (400 MHz, Chloroform-d) δ 9.45 (dd, J = 8.2, 1.9 Hz, 1H), (m, 2H), 8.66 (dd, J = 8.4, 1.3 Hz, 1H), 8.41 (dd, J = 4.3, 1.9 Hz, 1H), 7.81 (dd, J = 8.2, 7.3 Hz, 1H), (m, 1H), (m, 2H), 7.19 (dd, J = 8.4, 6.5 Hz, 1H), (m, 2H), 1.83 (s, 6H). 13C NMR (101 MHz, cdcl3) δ , , , , , , , , , , , , , , , , , , , , CHNS: calculated [C, 86.20; H, 5.43; N, 8.38], found [C, 86.15; H, 5.49; N, 8.26] The second fraction from chromatography yielded 440 mg of 90 % pure 9-(2,6- dimethylphenyl)benzo[f][4,7]phenanthroline, a colorless solid. 1H NMR (400 MHz, Chloroform-d) δ 9.48 (dd, J = 8.2, 1.5 Hz, 1H), 9.03 (dd, J = 4.4, 1.6 Hz, 1H), 8.76 (dd, J = 8.3, 1.7 Hz, 1H), 8.70 (dd, J = 8.3, 1.8 Hz, 1H), 8.38 (dd, J = 4.3, 1.7 Hz, 1H), 7.88 (dd, J = 8.2, 7.3 Hz, 1H), 7.59 (dd, J = 8.2, 4.4 Hz, 1H), 7.49 (dd, J = 7.3, 1.5 Hz, 1H), 7.36 (dd, J = 8.2, 4.3 Hz, 1H), 7.21 (dd, J = 8.4, 6.5 Hz, 1H), 7.13 (d, J = 7.4 Hz, 2H), 1.86 (s, 6H). S14

15 (12-(2,6-dimethylphenyl)benzo[f][1,7]phenanthrolinato-N 5,C 4 )(2,2,6,6-tetramethyl- 3,5-heptanedionato-O,O) platinum (II) (10Pt(dpm)): A 50 ml round bottom flask was charged with potassium tetrachloroplatinate (117 mg, 0.28 mmol, 1 eq.), 12-(2,6- dimethylphenyl)benzo[f][1,7]phenanthroline (188 mg, 0.56 mmol, 2.0 eq.), 6 ml 2- ethoxyethanol, and 2 ml H 2 O. The flask was fitted with a reflux condenser, thoroughly sparged with nitrogen, and heated to 80 C with magnetic stirring under nitrogen atmosphere. After 16 h the mixture was cooled to room temperature, diluted with 10 ml H 2 O, and the resulting precipitate was collected by filtration and washed successively with 10 ml each isopropanol, diethyl ether, and hexanes. The approximately 94 mg of olive green precipitate was returned to the flask along with dipivaloylmethane (108 ml, 96 mg, 0.52 mmol, ~5 eq.), potassium carbonate (145 mg, 1.05 mmol, ~10 eq.), and 10 ml 2-ethoxyethanol. The flask was fitted with a reflux condenser, thoroughly sparged with nitrogen, and heated to 100 C with magnetic stirring under nitrogen atmosphere. After 16 h the mixture was cooled to room temperature, diluted with 30 ml H 2 O, and extracted with 30 ml dichloromethane. The organic layer was dried over sodium sulfate, evaporated to dryness, and the yellow residue titurated with methanol (5 x 2 ml) by suspension and centrifugation to yield 10Pt(dpm) as a bright yellow powder (36 mg, 21%). 1H NMR (400 MHz, Chloroform-d) δ 9.17 (dd, J = 5.5, 1.1 Hz, J PtH = 35 Hz, 1H), 9.00 (dd, J = 8.6, 1.2 Hz, 1H), 8.62 (dd, J = 8.3, 1.3 Hz, 1H), 8.06 (d, J = 4.7 Hz, 1H), S15

16 7.79 (dd, J = 8.1, 7.3 Hz, 1H), 7.56 (dd, J = 8.3, 5.4 Hz, 1H), 7.51 (d, J = 4.7 Hz, 1H), 7.45 (dd, J = 7.3, 1.2 Hz, 1H), 7.22 (dd, J = 8.3, 6.7 Hz, 1H), 7.13 (d, J = 7.4 Hz, 2H), 5.90 (s, 1H), 1.85 (s, 6H), 1.34 (s, 9H), 1.31 (s, 9H). 13C NMR (101 MHz, cdcl3) δ , , , , , , , , , , , , , , , , , , , , , , 93.43, 41.58, 41.18, 28.64, 28.44, CHNS: calculated [C, 59.06; H, 5.10; N, 3.94], found [C, 59.15; H, 5.19; N, 3.93] S16

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