805241-07-0Relevant academic research and scientific papers
Reaction scope and mechanism of sterically induced ruthenium-mediated intramolecular coupling of o-carboranyl with cyclopentadienyl. Synthesis and structure of ruthenium complexes incorporating doubly linked cyclopentadienyl-carboranyl ligands
Sun, Yi,Chan, Hoi-Shan,Xie, Zuowei
, p. 4188 - 4195 (2008/10/09)
Reactions of [Me(R1)A(C5H3R 2)(C2B10H10)]Li2 (A = C, Si; R1 = H, Me; R2 = H, Me) with 1 equiv of RuCl 2(PPh3)3 in THF afforded the corresponding doubly linked cyclopentadienyl-carboranyl ruthenium-(II) hydride complexes [η-Me2C(C5H3)(C2B 10H10)]RuH(PPh3)2 (6), [η 5-MeHC(C5H3)(C2B10H 10)]RuH-(PPh3)2 (7), [η5-Me 2C(5-Me-C5H2)(C2B10H 10)]RuH(PPh3)2 (8), [η5-Me 2C(3/4-Me-C5H2)(C2B 10H10)]RuH-(PPh3)2 (9a/9b), and [η5-Me2Si(C5H3)(C 2B10H10)]RuH(PPh3)2 (10) in 72-85% isolated yields. On the other hand, interaction of [Me 2C(C5H4)(C2B10H 10)]Li2 with 1 equiv of RuCl2[PPh 2(OEt)]3 produced only [η5:σ-Me 2C(C5H4)((C2B10H 10)]Ru[PPh2(OEt)]2 (14). An equimolar reaction of [Me2C(C5H4)(C2B 10H10)]-Li2 with RuCl2(PPh 3)3 in the presence of dppe (dppe = 1,2-bis(diphenylphosphino)ethane) generated [η5:σ-Me 2C(C5H4)(C2B10H 10)]Ru(dppe) (15). No ruthenium hydride complexes were detected in the latter two cases. Treatment of [η5-Me2C(C 5H3)(C2B10H 10)]RuH(PPh3)2 (6) with excess HBF 4·OEt2 in toluene gave the neutral ligand Me 2C(C5H4)(C2B10H 10) (12). This work showed that such intramolecular coupling reactions were driven by steric factors. A possible reaction mechanism was proposed to account for these ruthenium-mediated coupling reactions. All new complexes were fully characterized by multinuclear NMR techniques and elemental analyses. Molecular structures of 6, 7, and 8 were further confirmed by single-crystal X-ray analyses.
Synthesis, structural characterization, ligand displacement reaction, and electrochemical property of ruthenium complexes incorporating linked cyclopentadienyl-carboranyl ligands
Sun, Yi,Chan, Hoi-Shan,Dixneuf, Pierre H.,Xie, Zuowei
, p. 5864 - 5872 (2008/10/09)
Reactions of the dilithium salts of carbon-bridged cyclopentadienyl- carboranyl ligands with 1 equiv of [RuCl2(COD)]x in THF afforded the organoruthenium(II) complexes [η6:σ-Me 2C-(C5H4)(C2B10H 10)]Ru(COD) (1a), [η5:σ-Me2C(C 9H6)(C2B10H10)]Ru(COD) (2a), and [η5:σ-H2C-(C13H 8)(C2B10H10)]Ru(COD) (3a), respectively. Treatment of 1a with bidentate tertiary phosphines in THF gave the corresponding COD displacement complexes [η5:σ-Me 2C(C5H4)-(C2B10H 10)]Ru(dppe) (1b, dppe = 1,2-bis(diphenylphosphino)ethane), [η5:σ-Me2C(C5H4)(C 2B10-H10)]Ru(dppm) (1c, dppm = bis(diphenylphosphino)methane), [η5:σ-Me 2C(C5H4)(C2B10H 10)]-Ru(dppf) (1d, dppf = 1,1′-bis(diphenylphosphino)ferrocene) , and [η5:σ-Me2C(C5H 4)(C2B10H10)]-Ru(dppc) (1e, dppc = 1,2-(Ph2P)2-1,2-C2B10H 10). 1a also reacted with 2,2′-bipyridine (bipy) to offer [η5:σ-Me2C(C5H4)(C 2B10H10)]Ru(bipy) (1f). However, 1a did not react with monodentate tertiary phosphines such as PPh3 and PCy 3, tertiary amines, and bidentate ligands with no π-acidity such as dimethoxyethane and tetramethylethylenediamine. These results imply that a bidentate ligand with π-acidity is critical to displace the COD in 1a. The electrochemical studies showed that the electron-donating power of various ligands increases in the following order: cyclopentadienyl indenyl fluorenyl, and COD dppc dppm ≈ dppe bipy. All of these new complexes were fully characterized by various spectroscopic techniques and elemental analyses. Their molecular structures (except for 1d) were further confirmed by single-crystal X-ray analyses.
