Compound Ru3

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Compound data: NMR

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

A modification of the Dixneuf and Jutand method was used (Ferrer Flegeau, E., Bruneau, C., Dixneuf, P. H. & Jutand, A. Autocatalysis for C–H bond activation by ruthenium(II) complexes in catalytic arylation of functional arenes. J. Am. Chem. Soc. 133, 10161−10170 (2011)). All liquid reagents and solvents were dried over 4 Å molecular sieves and degassed with 3 freeze-pump-thaw cycles prior to use. KOAc was dried at 140 °C in a vacuum oven for 48 h prior to use. An oven dried 100 mL Ace pressure tube equipped with a stirring bar was transferred to a glove box, then [RuCl₂(p-cymene)]₂ (489.9 mg, 0.8 mmol, 0.5 equiv), KOAc (235.6 mg, 2.4 mmol, 1.5 equiv), KPF₆ (589.0 mg, 3.2 mmol, 2 equiv), 2-(2,5-difluoro-3,4-dimethylphenyl)-4,5-dimethylpyridine 5 (395.7 mg, 1.6 mmol, 1 equiv) and MeCN (10 mL, 0.16 M) were added. The tube was sealed, transferred out of the box, placed in an oil bath at 100 °C and stirred for 24 h. Upon completion, the reaction crude was loaded in an aluminium oxide (Al₂O₃, neutral) column conditioned with CH₂Cl₂, and quickly eluted with MeCN/CH₂Cl₂ (1:1) using N₂ in replacement of compressed air collecting the yellow/orange band. The solution was concentrated under reduced pressure and then quickly precipitated with Et₂O affording the Ru3 as a yellow solid (924.4 mg, 88%). The complex has to be promptly transferred to a glove box as it decomposes turning green if exposed to air. ¹H-NMR (500 MHz, MeCN-d₃) δ 1.96 (s, 3 H), 2.05 (s, 6 H), 2.20 (d, J = 2.5 Hz, 3 H), 2.22 (d, J = 2.5 Hz, 3 H), 2.31 (s, 3 H), 2.39 (s, 3 H), 2.43 (s, 3 H), 8.01 (d, J = 1.5 Hz, 1 H), 8.65 (s, 1 H) ppm (exchange with MeCN-d₃ shows a lower integration than expected for the MeCN ligand at 2.43 ppm); ¹³C-NMR (125 MHz, MeCN-d₃) δ 3.9, 4.0, 11.0 (dd, J = 7.3, 2.1 Hz), 11.9 (dd, J = 4.9, 1.9 Hz), 16.5, 19.7, 121.9, 122.5, 123.8, 124.0, 124.1, 124.8 (dd, J = 25.9, 4.9 Hz), 131.6 (d, J = 1.4 Hz), 133.7 (dd, J = 19.4, 6.1 Hz), 148.0, 152.6, 156.0 (dd, J = 247.8, 1.4 Hz), 160.4 (dd, J = 50.9, 2.3 Hz), 164.4 (d, J = 7.5 Hz), 167.6 (d, J = 223.8 Hz) ppm (signals for both carbons of one of the MeCN ligands were not observed); ¹⁹F-NMR (470 MHz, MeCN-d₃) δ −124.4 (d, J = 22.9 Hz), −106.7 (d, J = 22.9 Hz), −72.9 (d, J = 705.8 Hz) ppm; IR ν_max (neat/cm⁻¹): 3006, 2927, 2272, 1605, 1484, 1403, 1287, 832; HRMS calcd for C₂₁H₂₃F₂N₄Ru⁺ [M–MeCN–PF₆]⁺: 471.0929, found 471.0925.