Some selected chapters from the (butadiene)zirconocene story

Metallacyclische Fünfring‐Allenoide: Synthese und Struktur stabiler stark verzerrter cyclischer Allen‐Derivate

“…[1,4,5] Wegen der bekannten Tendenz der Gruppe-4-Metallocene, gewinkelte Cumulene 3 [6] und sogar nichtlineare Alkine 4 [7] in metallacyclischen Ringstrukturen erheblich zu stabilisieren, erschien der Versuch naheliegend, auch die entsprechenden metallacyclischen Fünfring-Allene 5 zu synthetisieren (Schema 1 2.340 (3) ). [11] Die C4-C3-Bindung ist kurz (1.276 (4) ). Die C3-C2-Bindung ist länger (1.356 (4) ), und die C1-C2-Bindung ist im Bereich einer C-C-s-Bindung (1.490 (4) ).…”

Five‐Membered Metallacyclic Allenoids: Synthesis and Structure of Remarkably Stable Strongly Distorted Cyclic Allene Derivatives

“…[10] The structure of 5 a ( Figure 1) features a metallacyclic five-membered ring system with all four carbon atoms in bonding distance to hafnium [10] (HfÀC1: 2.494(3) , HfÀC2: 2.513(3) , Hf À C3: 2.314(3) , Hf À C4: 2.340 (3) ). [11] The C4 À C3 bond is short, at 1.276(4) . The C3 À C2 bond is longer (1.356(4) ), and the C1 À C2 bond is in the C À C s-bond range (1.490 (4) ).…”

Di-μ-hydroxo-κ4O:O-bis[aquatris(triphenylsilanolato-κO)zirconium(IV)] toluene solvate

“…The extraordinary potential of metallocene-type group 4 metal catalysts in olefin oligomerization or polymerization has been intensively studied in terms of the promotion of highly active cationic species by methylalumoxan (MAO), the isolation of these cationic species themselves, the development of so-called 'single-site' catalysts and the adjustment of ligands in order to achieve highly selective catalytic reactions (Brintzinger et al, 1995;Britovsek et al, 1999;Mö hring & Coville, 1994;Bochmann, 1996;Kaminsky, 1996;Erker et al, 2004;Cotton, 2000;Kaminsky, 2000;Chirik & Bercaw, 2000;Piers et al, 1999;Chien, 1999;Alt & Samuel, 1998). The chemistry of group 4 metal complexes containing inorganic donor sets, viz.…”