Metallocene complexes of the Group 3 metals and lanthanides have been utilized for cyclization/silylation reactions of polyunsaturated organic substrates. Acyclic dienes, trienes, enynes, and dienynes can be selectively cyclized to provide fiveand six-membered rings in high yields.

Iron metallodrugs comprise mineral supplements, anti-hypertensive agents and, more recently, magnetic nanomaterials, with both therapeutic and diagnostic roles. As biologically-active metal compounds, concern has been raised regarding the impact of these compounds when emitted to the environment and associated ecotoxicological effects for the fauna. In this work we assessed the relative stabili...

We treated silica with tris(pentafluorophenyl)borane, B(C6F5)3, to create borane-functionalized support, SiO2–B(C6F5)3 which was then used as a support and co-catalyst for the in situ activated dichloro-zirconocene (Cp2ZrCl2/TIBA) and dimethyl-zirconocene catalyst systems (Cp2Zr(CH3)2) for ethylene polymerization. The surface modifications of SiO2– B(C6F5)3 was investigated by SEM–EDX, FTIR and...

In this study, a mathematical model for the time evolution of molecular weight distribution (MWD) was developed. This temporal is based on well-known Ziegler–Natta polymerization mechanism and reaction kinetics by parametric solving related differential equations. However, due to generality reactions involved, can be extended other type catalysts, such as metallocenes, Phillips, etc. The superi...

In this study we have tested the ability of a standard DFT computational protocol to reproduce the experimentally obtained stereoselectivity of 26 different C2-symmetric zirconocene catalysts active in propylene polymerization. The catalysts were chosen for their relevance in metallocene catalyzed polymerization of propylene. To this end, primary insertion of both si- and re-propylene enantiofa...

728 Journal of Chemical Education • Vol. 83 No. 5 May 2006 • www.JCE.DivCHED.org The discovery of the anticancer activity of cisplatin {cis[PtCl2(NH3)2]} in the 1960s and its subsequent clinical success generated interest in the use of metal compounds in cancer treatment (1, 2). Thousands of platinum compounds have since been prepared and evaluated as potential chemotherapeutic agents, although...

The gold salt [(tht)AuCl] was reacted with [1-N,N-dimethylaminométhyl-2-diphenylphosphino]ferrocene (1) forming the bimetallic derivative 4. The reaction of methyl iodide and tetramethylammonium bromide on the chloride 4 produced the ammonium salt 5 and the bromide 6 respectively. New aminophosphines 2 and 3, which represent two of the rare phosphorylated metallocenes containing P(III)-N bond h...

The methylated metallocenes (MeCp),M with M = V, Cr, Mn, Co, Ni (1-5) were investigated by 'H and 'H NMR spectroscopy at natural abundance. The 2H NMR signals are narrower by a factor of up to 30 compared with the corresponding 'H NMR signals, thus establishing an inexpensive method and a general improvement of the NMR spectra of paramagnetic x-complexes. This has allowed the resolution of the ...

We have recently reported on several Fe catalysts for N2-to-NH3 conversion that operate at low temperature (-78 °C) and atmospheric pressure while relying on a very strong reductant (KC8) and acid ([H(OEt2)2][BArF4]). Here we show that our original catalyst system, P3BFe, achieves both significantly improved efficiency for NH3 formation (up to 72% for e- delivery) and a comparatively high turno...