The tungsten nitrido species, [W(μ-N)(CH2-t-Bu)(OAr)2]2 (Ar ) 2,6-diisopropylphenyl), has been prepared in a reaction between the alkylidyne species, W(C-t-Bu)(CH2-t-Bu)(OAr)2, and organonitriles. The dimeric nature of the nitride was established in the solid state through an X-ray study and in solution through a combination of 15N NMR spectroscopy and vibrational spectroscopy. Reaction of the ...

The first 4d/4f polyphosphides were obtained by reaction of the divalent metallocenes [Cp*2Ln(thf)2] (Ln = Sm, Yb) with [{CpMo(CO)2}2(μ,η2:2-P2)] or [Cp*Mo(CO)2(η3-P3)]. Treatment of [Cp*2Ln(thf)2] (Ln = Sm, Yb) with [{CpMo(CO)2}2(μ,η2:2-P2)] gave the 16-membered bicyclic compounds [(Cp2*Ln)2P2(CpMo(CO)2)4] (Ln = Sm, Yb) as the major products. From the reaction involving samarocene, the cyclic ...

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...

Spray dry granulation of clay minerals was studied to obtain clay mineral base support material for metallocene supported olefin polymerization catalysts. The morphology of the granules was strongly influenced by the nature of the clay mineral itself. Because of swelling characteristics of montmorillonite, its water dispersion was highly viscous even in the low slurry concentration (< 4 wt %). ...

Beside Ziegler-Natta and Phillips catalysts the development of methylaluminoxane (MAO) as cocatalyst in combination with metallocenes or other transition metal complexes for the polymerization of olefins has widely increased the possibilities in controlling the polymer composition, polymer structure, tacticity and special properties with high precision. These catalysts allow the synthesis of is...

Polysilane high polymers have been attracting increasing interest owing to their potential applications as photoresists, photoinitiators, thermochromic materials, and precursors to silicon carbide.1 In 1985, Harrod and co-workers discovered that group 4 metallocenes such as Cp2TiMe2 could catalyze the dehydrogenative coupling of primary organosilanes to linear poly(hydrosilanes), H-(SiHR)n-H wi...

In this work, we report the first computational study on the assembly and stabilization of a novel kind of radical, i.e., the planar tetracoordinate carbon radical CAl(4)(-). Based on the 6-31+G(d)-UB3LYP, UMP2 and UCCSD(T) calculations on charged [D(CAl(4))M](q-), saturated [D(CAl(4))M(n)] and extended (CpM)(p)(CAl(4))(q) sandwich-like compounds (D = CAl(4)(-), Cp(-); M = Li, Na, K, Be, Mg, Ca...