Compound 5

potassium (µ-cyanimido)bis(µ-oxo)bis[(tris-tert-butoxysiloxouranium(V)]

From: The role of bridging ligands in dinitrogen reduction and functionalization by uranium multimetallic complexes

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Synonyms:
  • [K2{[U(OSi(OtBu)3)3]2(μ-O)2(μ-NCN)}]

Compound data: 1H NMR

Compound data: IR

Compound data: Crystallographic data

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

A dark brown solution of complex 4 (81.0 mg, 0.037 mmol) in toluene (1 mL) prepared in a glove box under argon was transferred to a Schlenk line, was degassed by freeze-pump-thawing and 3 equivalents of CO were added. The color of the solution turned immediately purple. The solution was concentrated to 0.2 mL and left standing at -40 °C for 24 h, affording XRD suitable crystals of complex [K2{[U(OSi(OtBu)3)3]2(μ-O)2(μ-NCN)}], 5 (55.4 mg, 67.8 % yield). 1H NMR of 5 (400 MHz, tol-d8, 298 K): δ(ppm) = 1.15 (s, CH3 terminal siloxide), 1.32 (s, CH3 terminal siloxide), 1.55 (s, CH3 terminal siloxide). The 13C labelled analogue 13C-5 was prepared with the same procedure using 13CO. 13C NMR of 13C-5 (400 MHz, tol-d8, 298 K): δ(ppm) = 261.63 (N13CN), 73.16 (C(CH3)3), 32.06 (C(CH3)3). IR of 5: 2008 cm-1; IR of 13C-5: 1942 cm-1. Anal. Calcd for 5 C73H162N2O26K2Si6U2: C, 39.73; H, 7.40; N, 1.27; Found: C, 40.12; H, 7.49; N, 1.02. The reaction of 4 with CO to afford 5 is immediate. The addition of larger amounts of CO (10-100 equivalents) to complex 5 slowly (the reaction time depends on the CO amount) affords new products as shown by 1H NMR.

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