Insights into group 4 and 5 ansa-bis(cyclopentadienyl) complexes with a single-atom bridge

A novel alkenyl-substituted ansa-zirconocene complex with dual application as olefin polymerization catalyst and anticancer drug

“…This bond length is significantly longer than those observed between the zirconium atom and the other b-carbon atom of the monosubstituted cyclopentadienyl ring (Zr(1)-C(9) 2.588(4) Å). However, this Zr(1)-C(8) distance is in the range observed for the b-carbon atoms of the tetramethylcyclopentadienyl moiety (Zr(1)-C(3) 2.611(4) Å and Zr(1)-C(4) 2.607(4) Å) and similar to those found for other ansa-zirconocene complexes [3,26].…”

“…Group 4 metallocene dichloride complexes have been extensively studied due to their excellent behaviour as catalysts for the polymerization of a-olefins [1][2][3]. It is well established that the structural make-up of the catalyst directly influences the physical properties of the polymer [1][2][3].…”

“…It is well established that the structural make-up of the catalyst directly influences the physical properties of the polymer [1][2][3]. In addition, titanocene and zirconocene complexes have been used as catalysts in other processes in organic synthesis such as carbometallation, hydrometallation, carbonylation, acylation, isomerization, hydrogenation, hydroamination, dehydrosilylation and hydrosilylation [4][5][6][7][8].…”

Synthesis and reactivity of asymmetrically substituted ansa-bridged zirconocene complexes: X-ray crystal structures of [Zr{R(H)C(η5-C5Me4)(η5-C5H4)}Cl2] (R=Bun, But) and [Zr{Bun(H)C(η5-C5Me4)(η5-C5H4)}(CH2Ph)2]

“…It is now well established that the structural make up of the catalyst not only plays a part in its activity in polymerization but also in determining the microstructure of the polymer [2]. It is therefore evident the necessity of rational ligand design in order to fulfil differing polymerization goals [3].…”

Substituent effects in reduction-induced synthesis of ansa-titanocenes

“…Ansa-metallocene derivatives of early transition metals [1] attract an unceasing interest for their catalytic properties which can be very finely tuned by modifying their ansa-chain [2][3][4][5]. Their synthesis is based on either ansa-dicyclopentadienyl anions as precursors for synthesis of ansa-metallocene dichlorides [6][7][8][9] or ansa-chain forming reactions of functional groups residing on cyclopentadienyl ligands in metallocene dichlorides [10][11][12][13][14].…”