Hydrosilane-B(C6F5)3 adducts as activators in zirconocene catalyzed ethylene polymerization

Preparation of silyl-terminated branched polyethylenes catalyzed by Brookhart's nickel diimine complex activated with hydrosilane/B(C6F5)3

Brookhart's nickel α-diimine complex [(κ2-N,N-BIAN)NiCl2] (1) (where BIAN = {Ar-NAceN-Ar}, Ace = acenaphthen-1,2-diyl, and Ar = 2,6-(iPr)2-C6H3) activated with a hydrosilane/B(C6F5)3 (SiHB) adduct forms a highly active catalytic system for ethylene polymerization. Under optimal conditions, the activity of the system depends on the nature of hydrosilane and decreases in the order R3SiH > Ph2SiH2 > PhSiH3. The decrease in system activity within the hydrosilane series is correlated with increasing formation of Ni(I) species. In addition to their activation effect, hydrosilanes act as efficient chain termination/chain transfer agents, with the Si/Ni ratio controlling the molecular weight of the resulting polyethylene (PE). The use of Et3SiH generated elastomeric, highly branched polymers with a saturated chain-end, while systems using Ph2SiH2 and PhSiH3 led to branched end-functionalized PEs terminated with the hydrosilyl functionality (i.e. br-PE-SiPh2H or br-PE-SiPhH2).

The coordination chemistry of oxide and nanocarbon materials

Understanding how a ligand affects the steric and electronic properties of a metal is the cornerstone of the inorganic chemistry enterprise. What happens when the ligand is an extended surface? This question is central to the design and implementation of state-of-the-art functional materials containing transition metals. This perspective will describe how these two very different sets of extended surfaces can form well-defined coordination complexes with metals. In the Green formalism, functionalities on oxide surfaces react with inorganics to form species that contain X-type or LX-type interactions between the metal and the oxide. Carbon surfaces are neutral L-type ligands; this perspective focuses on carbons that donate six electrons to a metal. The nature of this interaction depends on the curvature, and thereby orbital overlap, between the metal and the extended π-system from the nanocarbon.

Hydrodehalogenation of organohalides by Et3SiH catalysed by group 4 metal complexes and B(C6F5)3

The use of the Et₃SiH/B(C₆F₅)₃ system for the activation of group 4 metal catalysts allows the efficient and selective catalytic hydrodefluorination of trifluorotoluenes.

Grignard synthesis of fluorinated nanoporous element organic frameworks based on the heteroatoms P, B, Si, Sn and Ge

We present the synthesis and characterization of fluorinated polymers based on P, B, Si, Sn and Ge as heteroatoms via Grignard activation.

An intramolecular ortho-assisted activation of the silicon–hydrogen bond in arylsilanes: an experimental and theoretical study

An intramolecular activation of the Si–H bond in arylsilanes by selected ortho-assisting functional groups based on boron, carbon and phosphorus was investigated experimentally and by means of theoretical calculations.