34629-70-4Relevant academic research and scientific papers
Formation of triniobocene cationic and neutral mononiobocene species as a function of solvent in the reaction of Cp2Nb{(μ-H)2BR2} (R2 = C4H8, C5H10, C8H14) with B(C6F5)3
Liu, Shengming,Liu, Fu-Chen,Renkes, Gordon,Shore, Sheldon G.
, p. 5717 - 5723 (2008/10/08)
Reactions of the niobocene cyclic organohydroborates Cp2Nb{(μ-H)2BR2} (R2 = C4 H8, C5H10, C8H14), with B(C6F5)3 in the poorly coordinating solvent toluene and in the coordinating solvent diethyl ether give different products. In toluene, the salt [Cp2Nb(μ-H)(η5-η1-C5 H4)-Nb (η5-η1-C5H4)2 Nb{(μ-H)(η5-C5H4B (C6F5)2)}]+[HB(C6 F5)3]-1, 1, which contains a triniobocene cation, is formed. On the other hand in diethyl ether, the reaction of Cp2Nb{(μ-H)2BR2} with B(C6F5)3 produces the covalent complex CpNb(C6F5){(μ-H) (η5-C5H4B(C6 F5)2)}, 2. In the formation of these compounds NbIII is oxidized to NbIV. Upon the basis of ESR spectra, 1 and 2 are paramagnetic, each with one unpaired electron. The structures of 1 and 2 were determined by single-crystal X-ray analysis. Complex 2 forms weak adducts in the solvents THF and pyridine. The Nb-H-B bridge is cleaved at the Nb-H site to form CpNb(C6F5)-(L) {η5-C5H4B(H)(C6 F5)2} (L = THF, pyridine). In pyridine, a second adduct in much smaller yield is also formed, CpNb(C6F5)(H){η5-C5H4 B(Py)(C6F5)2}, with the Nb-H-B bridge being cleaved at the H-B site.
Hydride ion abstraction from titanocene cyclic organohydroborates, Cp2Ti{(μ-H)2BR2} (R2 = C4H8, C5H10, C8H14), as a function of solvent
Ple?nik, Christine E.,Liu, Fu-Chen,Liu, Shengming,Liu, Jianping,Meyers, Edward A.,Shore, Sheldon G.
, p. 3599 - 3606 (2008/10/08)
Hydride abstraction reactions of titanocene cyclic organohydroborate complexes Cp2Ti{(μ-H)2BR2} (R2 = C4H8, C5H10, C8H14) with B(C6F5)3 were investigated as a function of solvent. It was determined that the coordinating ability of the solvent directed the course of these abstraction reactions. The reaction in toluene, a noncoordinating solvent, produced a metathesis product, Cp2Ti{(μ-H)2B(C6F5)2} (1), in which the cyclic organohydroborate H2BR2 was substituted by H2B(C6F5)2. In diethyl ether and THF, the salts [Cp2TiL2] [HB(C6F5)3] (2, L = Et2O; 3, L = THF) consisting of titanocene cations with solvent ligands were isolated. Salt 2 is the first structurally characterized [Cp2TiL2]+ cation containing diethyl ether solvent ligands. The diethyl ether molecules of the cation in 2 are weakly coordinated and are labelized in THF and toluene. Dissolution of 2 in THF afforded 3. The complex Cp2Ti{(μ-H)B(C6F5)3} (OEt2) (4) and the proposed 15-electron species Cp2Ti{(μ-H)B(C6F5)3} (5) were generated through the displacement of an ether molecule from 2 by the [HB(C6F5)3]- anion in toluene. Single-crystal X-ray structures of 1, 2, and 3 were determined.
