Highly Efficient Dimerization of Ethylene by (Imido)vanadium Complexes Containing (2-Anilidomethyl)pyridine Ligands: Notable Ligand Effect toward Activity and Selectivity
摘要:
(Imido)vanadium(V) complexes containing the (2-anilidomethyl)pyridine ligand, V(NR)Cl(2)[2-ArNCH(2)(C(5)H(4)N)] (R = 1-adamantyl (Ad), cyclohexyl (Cy), phenyl), exhibit remarkably high catalytic activities (e.g. TOF = 2 730 000 h(-1) (758 s(-1)) by V(NAd)Cl(2)[2-(2,6-Me(2)C(6)H(3))NCH(2)(C(5)H(4)N)) for ethylene dimerization in the presence of MAO, affording 1-butane exclusively (selectivity 90.4 to >99%). The steric bulk of the imido ligand plays an important role in the selectivity (polymerization vs dimerization), and the electronic nature directly affects the catalytic activity (activity: R = Ad > Cy > Ph).
Highly Efficient Dimerization of Ethylene by (Imido)vanadium Complexes Containing (2-Anilidomethyl)pyridine Ligands: Notable Ligand Effect toward Activity and Selectivity
摘要:
(Imido)vanadium(V) complexes containing the (2-anilidomethyl)pyridine ligand, V(NR)Cl(2)[2-ArNCH(2)(C(5)H(4)N)] (R = 1-adamantyl (Ad), cyclohexyl (Cy), phenyl), exhibit remarkably high catalytic activities (e.g. TOF = 2 730 000 h(-1) (758 s(-1)) by V(NAd)Cl(2)[2-(2,6-Me(2)C(6)H(3))NCH(2)(C(5)H(4)N)) for ethylene dimerization in the presence of MAO, affording 1-butane exclusively (selectivity 90.4 to >99%). The steric bulk of the imido ligand plays an important role in the selectivity (polymerization vs dimerization), and the electronic nature directly affects the catalytic activity (activity: R = Ad > Cy > Ph).
Reaktionen von Vanadium(V)- und Tantal(V)-Komplexen Mit Kinetisch Stabilisierten Phosphaalkinen. Einfache Synthese von 1,3,4-Thia- und 1,3,4-Selenadiphospholen / Reactions of Vanadium(V) and Tantalum(V)-Complexes with Kinetically Stabilized Phosphaalkynes. A Simple Synthesis of 1,3,4-Thia and 1,3,4-Selenadiphospholes
azaphosphavanada(V)- cyclobutenes 2, generated in situ from the imidovanadium(V) complex tBuN = VCl3 and the phosphaalkynes 1a - d, with an excess of elemental sulfur or grey selenium, respectively. The reactions of the phosphaalkynes 1a,b with TaOCl3 or VOCl3 · DME furnish the 1,2-dichloro-phosphaalkenes 5a,b and 1,2,3,4-tetrachloro-3,4-di-tert-butyl-1,1-diphosphethane 7a. The metallacyclic species 2e - h with
Abstract Imidovanadium(V) Trichlorides The reactions of Me3SiN=VCl3 (1) with MeOH, PhOH, HCl, PyH+Cl- or LiOtBu have been studied. The reductive decomposition of 1 by hydrogen chloride in toluene yields HN=VCl3 as a labile intermediate which could be isolated only in a small amount. The syntheses of RN=VCl3 (R = neopent, nPr, cyclohex, CPh3, 1-Ad) and [(tBuN)2V2Cl4(μ-OC13H9)2] (15) are also described