34778-24-0Relevant academic research and scientific papers
Synthesis and reactivity of the metal-substituted borane (CO)4CoBH2·THF. Preparation of the ambiphilic clusters (CO)9Co3C(CH2)nOH (n = 4, 5)
Basil, John D.,Aradi, Allen A.,Bhattacharyya, Nripendra K.,Rath, Nigam P.,Eigenbrot, Charles,Fehlner, Thomas P.
, p. 1260 - 1270 (2008/10/08)
The reaction Co2(CO)8 + 2BH3·THF → 2(CO)4CoBH2·THF (I) + H2 has been demonstrated to occur cleanly at -15°C in THF. I has been characterized by low-temperature 11B NMR and infrared spectroscopies as well as classical chemical analysis. The formation of I bears a remarkable similarity to that of (CO)4CoSiR3. Displacement of the bound THF of I occurs with Lewis bases, and the Lewis acidity of I relative to that of BH3·THF for SMe2 has been estimated. Displacement of [Co(CO)4]- from I occurs easily; e.g., reaction with PhMgBr yields PhBH2. I readily accepts hydride from [HFe2(CO)8]-, losing [Co(CO)4]- but reduces the CO ligands of hydride-free metal carbonylate anions. I is a very active reducing agent and above 10°C cleaves THF and condenses with hydrocarbyl and metal fragments to yield a mixture of clusters including an unusual tailed cluster (CO)9Co3C(CH2)nOH (n = 4,5) (II). A deuterium labeling experiment showed that four of the n carbons in the hydrocarbyl chain of II arise from THF. The results of an X-ray diffraction study suggest association of II in the solid state. [Crystals of II (the ratio of II with n = 5/n = 4 is 4) form in the space group R3 with unit cell parameters a = 34.409 (15) A?, b = 34.398 (21) A?, c = 8.575 (5) A?; β = γ = 90°, γ = 120°, V = 8789.8 A?3, and Z = 18. Solution was by direct methods, and all atoms were refined to R1 = 0.077 and R2 = 0.096 for 1443 independent reflections (Fo > 3σ(Fo)). Because of the disorder caused by the cocrystallization of species with different chain lengths, the last two atoms at the OH end of the chain could not be fully defined.] Association of II in solution is shown by a 1H NMR study, thereby demonstrating that II behaves as an ambiphilic cluster.
