Compound 1

View in PubChem | IR | 1H NMR | MDL Molfile | ChemDraw

Synthetic procedure: See article for the definitive version of this procedure and for full experimental details.

5-(8-Chloroanthracen-1-yl)pyridin-2-amine (Anth•^NH₂Py•Cl): a mixture of 2-amino-5-bromopyridine (1.39 g, 8.08 mmol), potassium acetate (2.37 g, 24.2 mmol), bis(pinacolato)diboron (2.05g, 8.08 mmol), [Pd(dba)₂] (92 mg, 0.16 mmol) and 2-dicyclohexylphosphino-2′,6′-dimethoxybiphenyl (SPhos) (92 mg, 0.16 mmol) was prepared in 200 mL of dioxane under N₂ atmosphere inside a drybox. The reaction mixture was refluxed for 6 h, and the resulting orange color solution was used in next step without isolation. In a separate vessel, 1,8-dichloroanthracene (2.00 g, 8.08 mmol) was prepared in 50 mL of dioxane, and tribasic potassium phosphate (5.13 g, 24.2 mmol) was dissolved in 50 mL of degassed water. Into the reaction solution was added the anthracene solution and then the potassium phosphate solution. After reflux for 12 h, the reaction solution was cooled to room temperature and filtered over a bed of Celite. Organic products were extracted with ethyl acetate, and the solution was dried over sodium sulfate. The product was purified by silica gel column chromatography (2:1 ethyl acetate/hexane) to afford a yellow solid. Yield: 1.03 g (42%). ¹H NMR (400 MHz, CDCl₃): δ 4.80 (s, 2H), 6.71 (d, 1H), 7.37 (t, 1H), 7.41 (d, 1H), 7.55 (m, 2H), 7.74 (dd, 1H), 7.93 (d, 1H), 8.01 (d, 1H), 8.29 (s, 1H), 8.50 (s, 1H), 8.90 (s, 1H). ¹³C NMR (CDCl₃): δ 123.15, 123.17, 125.43, 125.66, 126.69, 127.00, 127.37, 127.59, 128.20, 128.76, 128.82, 129.22, 130.14, 130.25, 130.87, 131.27, 131.94, 132.14, 136.33, 136.88, 137.35, 139.73, 141.41, 148.85, 150.68 ppm. HRMS (ESI) calcd. for C₁₉H₁₃ClN₂ [M+H]⁺: 305.08400; found: 305.08420.

Synthesis of 5-(8-(3-(Methylthio)phenyl)anthracen-1-yl)pyridin-2-amine (Anth•^NH₂Py•S): a mixture of 5-(8-chloroanthracen-1-yl)pyridin-2-amine (Anth•^NH₂Py•Cl) (1.03 g, 3.37 mmol), 3-(methylthio)phenylboronic acid (0.566 g, 3.37 mmol), sodium carbonate (0.357 g, 3.37 mmol), [Pd(dba)₂] (0.058 g, 0.10 mmol), and XPhos (0.048 g, 0.10 mmol) was prepared in 100 mL of THF under N₂ atmosphere inside a drybox. After adding 20 mL of degassed water, the reaction solution was heated to reflux for 12 h under N₂ atmosphere. After cooling the solution to room temperature, the mixture was quenched with a saturated, aqueous ammonium chloride solution (~5 mL). The organic compounds were extracted with DCM and washed with saturated brine (2 × 100 mL). The solution was dried over sodium sulfate and concentrated under vacuum. The product was isolated by silica gel column chromatography (4:1 EA/hexane), thus affording a yellow solid. Yield: 0.490 g (37%). ¹H NMR (d₈-THF, 400 MHz): δ 2.46 (s, 3H), 5.43 (s, 2H), 6.51 (d, 1H), 7.2-7.6 (m, 9H), 8.0 (d, 1H), 8.04 (d, 1H), 8.07 (d, 1H), 8.57 (s, 1H), 8.74 (s, 1H) ppm. ¹³C NMR (d₈-THF): δ 15.49, 107.47, 124.00, 125.37, 125.72, 126.04, 126.22, 126.45, 126.82, 127.29, 127.58, 127.80, 128.46, 128.48, 129.22, 130.59, 131.18, 132.79, 133.04, 138.87, 138.89, 139.80, 140.90, 142.08, 149.31, 159.98 ppm. HRMS (ESI) calcd. for C₂₆H₂₀N₂S [M+H]⁺: 393.14200; found: 393.14280. Anal. calcd for C₂₆H₂₀N₂S: C 79.56, H 5.14, N 7.14; found: C 78.85, H 5.29, N 7.03.

Synthesis of [(Anth•C^NHNS)Fe(CO)₂(I)] (1): a portion of [Fe(CO)₄I₂] (108 mg, 0.264 mmol) and Anth•^NH₂Py•S ligand (100 mg, 0.264 mmol) was each prepared separately in 4 mL of DCM at -30 °C. (The ligand solution was a suspension due to low solubility.) The two solutions were mixed at room temperature and the [Fe(CO)₄I₂] solution was added to the ligand solution. The solution was stirred at room temperature as warming naturally, and bubbles were observed due to the CO release. Within several minutes, the reaction mixture became a homogeneous dark yellow solution. After filtering the solution through Celite, the solvent was removed under vacuum. The residual solid was washed with acetonitrile (3 × 1 mL) and diethyl ether (3 × 5 mL), and the yellow product was further purified by precipitation in CH₂Cl₂/pentane (1:10) to afford a yellow solid. Yield: 93 mg (55%). ¹H NMR (d₈-THF, 500 MHz): δ 2.80 (s, 3H), 7.01 (s, 2H), 7.10 (s, 1H), 7.25 (s, 2H), 7.48 (s, 2H), 7.49 (s, 2H), 7.58 (s, 3H), 7.62 (s, 1H), 7.91 (d, 1H), 8.32 (s, 1H), 8.59 (s, 1H) ppm. IR (solid state): ν_C≡O 2031, 1981, ν_C=O 1661, ν_C=N 1613 cm^–1. Anal. calcd. for C₂₉H₁₉FeIN₂O₃S: C 52.91, H 2.91, N 4.26; found: C 52.56, H 3.02, N 4.44.