Compound 2a

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InChIKey OXGUTQMTHIKYBJ-UHFFFAOYSA-N

Compound data: CIF

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

To Na-Hg (0.5 wt%, 47.0 g, 9.34 mmol) were added THF (30 mL) and then 1a (889.5 mg. 1.49 mmol), and the mixture was stirred at room temperature for 12 h under N₂. The resultant dark purple solution was filtered and extracted with THF (10 mL), and then the combined filtrate was concentrated in vacuo. The residue was extracted with benzene (15 mL), and slow addition of hexane (45 mL) to the obtained extract afforded a dark green crystalline solid, which was collected by filtration and washed with hexane (5 mL) and dried in vacuo to afford 2a as a dark green solid (524.2 mg, 0.47 mmol, 63% yield). ¹H NMR (THF-d₈) δ 7.07 (t, J = 7.3 Hz, ArH, 1H), 6.93 (d, J = 7.3 Hz, ArH, 2H), 3.37 (m, CH₂P^tBu₂, 4H), 1.28 (pseudo t, CH₂P^tBu₂, 36H). ³¹P{¹H} NMR (THF-d₈) δ 94.6 (s). IR (KBr, cm⁻¹) 1936 (s, ν_NN). IR (THF, cm⁻¹) 1944 (s, ν_NN). Raman (THF, cm⁻¹; ν_excite = 514.5 nm) 1890 (ν_NN). The elemental analysis acceptable for the above formulation of 2a (Anal Calcd for C₄₆H₈₆Mo₂N₁₂P₄: C, 49.20; H, 7.72; N, 14.97) is not obtained when the sample of 2a is dried in vacuo. We assume that dinitrogen ligands in 2a are quite labile even in a solid state. Analytic sample was prepared by drying a dark green crystalline solid under gentle N₂ stream. This sample included one molar benzene, which is determined by ¹H NMR in THF-d₈, while one of dinitrogen ligands was lost. Anal Calcd for C₅₂H₉₂Mo₂N₁₀P₄: C, 53.24; H, 7.90; N, 11.94. Found: C, 53.60; H, 7.70; N, 12.32. Additionally, ESI TOF MS of 2a in THF shows that 2a retained the dinuclear structure in solution, whereas the elimination of terminal dinitrogen ligands in 2a was observed. ESI TOF MS (in THF) 1070 (M−2N₂), 1042 (M−3N₂).