Transition Metal Catalysts

Dissymmetric dinuclear transition metal complexes as dual site catalysts for the polymerization of ethylene

A series of dissymmetric dinuclear complexes were synthesized, as dual site catalysts in ethylene polymerization, by coupling the allylated a-diimine complexes of the metals Ti, Zr, V, Ni and Pd with the ansa-zirconocene complex [C5H4-SiH(Me)-C5H4]ZrCl2 possessing a hydride silane moiety. The different stages of syntheses included the formation of bis(cyclopentadienide)methyl silane which was u...

New catalysts for the transition-metal-catalyzed synthesis of aziridines.

Aziridines are especially in demand because of their natural occurrence in diverse biologically active compounds and their manifold transformations in chemical reactions. The ring constraint renders them very reactive substances. In the presence of nucleophiles (N, O, S, C nucleophiles, and halides) they undergo ring-opening, they are used for [3+2] cycloadditions and [3+3] annulations, and the...

Supported Homogeneous Catalysts TRANSITION METAL COMPLEXES WITH POLYMERIC LIGANDS

Almost all industrial catalysts are heterogeneous, the reaction taking place on a solid surface. During the past decade homogeneous catalysts, soluble in the liquidphase reactant, have received a great deal of attention, although they have so far found only limited industrial use, chiefly because of the di$culty of their separation from the reaction products. More recently an intermediate type,...

Transition Metal Sulfide Catalysts for Petroleum Upgrading – Hydrodesulfurization Reactions

Redispersion of transition metal nanoparticle catalysts in tetraalkylphosphonium ionic liquids.

Despite the fact that particle sintering is one of the most common events leading to the deactivation of metal nanoparticle (NP) catalysts, there is a paucity of studies investigating potential routes for the regeneration of smaller, catalytically active nanoparticles from larger particles formed after repeated catalytic cycles. Here, we reveal a simple yet elegant technique for the 'redispersi...