Alkylidenverbrückte, symmetrische, zweikernige Metallocenkomplexe als Katalysatoren für die Propylenpolymerisation

A Chloro-Bridged Dimanganese Complex and an Oxo-Bridged Dititanium Complex of a Ditopic Bis(pyrazol-1-yl)borate Ligand

“…[24][25][26][27] In the context of this paper, two recent developments are particularly important: (i) Titanium poly(pyrazol-1-yl)borates have been employed in the homopolymerization of ethylene and styrene as well as in their copolymerization with 1-hexene. [28][29][30][31][32][33] (ii) Dinuclear Ti IV and Zr IV complexes and the role of cooperative effects on the performance of these catalysts have been outlined in several papers [34][35][36][37][38][39][40][41][42][43][44][45] and patents. [46][47][48][49][50][51] The purpose of this paper is to describe dinuclear Mn II and Ti IV complexes of the p-phenylene-bridged bis(pyrazol-1-yl)borate ligand C. Special emphasis is put on the question of whether the ligand is well enough designed to allow simultaneous binding of both metal centers to the same substrate molecule (cf.…”

“…We now extend our study to middle and early first-row transition metals, as they play an important role in many industrial catalysts and metal-containing enzymes. The bacterial enzyme manganese catalase, for example, which is involved in the disproportionation of hydrogen peroxide to dioxygen and water and thus in the protection of the cells from hydroxyl radicals, possesses an active site containing two manganese centers (Mn II /Mn II ; Mn III /Mn III ) bridged by small molecules (H 2 O, OH - , RCOO - ). , With respect to industrial catalysis, titanium complexes are of ample interest in olefin polymerization reactions. − In the context of this paper, two recent developments are particularly important: (i) Titanium poly(pyrazol-1-yl)borates have been employed in the homopolymerization of ethylene and styrene as well as in their copolymerization with 1-hexene. − (ii) Dinuclear Ti IV and Zr IV complexes and the role of cooperative effects on the performance of these catalysts have been outlined in several papers − and patents. − …”