Multinuclear olefin polymerization catalysts

Recent abiotic homogeneous catalytic research focusing on the structures and organizational capabilities of enzymes to discover unique/more efficient catalytic processes is compiled. In 2002 Tian et al. reported a series of silane- and siloxane-bridged binuclear zirconocenes and these metallocenes were studied as catalysts for ethylene polymerization in the presence of MAO. Sierra et al. described the synthesis of binuclear titanium and zirconium complexes, prepared by olefin metathesis. The binuclear CGC titanium catalysts are found to be very active when activated with bisborate B₂ or bisborane BN ₂ cocatalysts. Methylene-bridged binuclear bis(imino)pyridyl Fe(II) complexes, activated with Al(iBu)₃, are found to exhibit higher activity than the corresponding mononuclear iron catalysts, along with an enhanced molecular weight of the linear polyethylene produced. Tetra- and octanuclear half-titanocenes, when activated with MAO, display high ethylene polymerization activities.