Fulvalene cyclopentadienyl titanium and zirconium(III) and -(IV) complexes. X-Ray crystal structure of [{Ti(η5-C5H5) Cl}2 (μ-O)(μ-η5-η5-C10H8)]

Insertion of Terminal and Internal Acetylenes into the Zr−μ-Methylene Bond of the Dinuclear Cationic Zirconium Complex [{Zr(η5-C5H5)}2(μ-CH2)(μ-Cl)(μ-η5-C5H4-η5-C5H4)][BMe(C6F5)3]. Synthetic Aspects, NMR Spectroscopic Study, and Dynamic Behavior in Solution

“…Novel dinuclear cationic zirconium complexes prepared from dialkynyl zirconocene derivatives have been reported as interesting reagents for stoichiometric and catalytic reactions. 1e, The isolation of dinuclear group 4 metal compounds containing a bridging fulvalene ligand has received increasing interest in the past few years . The bridging ligand allows the metal fragments to be disposed either cis or trans with respect to the fulvalene plane, depending on electronic and steric factors.…”

Dinuclear cationic zirconium complexes with the fulvalene ligand. Synthesis and reactivity

“…The deactivation of electrophilic d o catalysts by formation of dinuclear compounds has been proposed as important in alkene polymerization catalysis [3,6]. The fulvalene group is a particularly interesting ligand because it gives dinuclear compounds with short contacts between both metal atoms and even slight metal-metal interactions [4]. The nature of this ligand makes possible the: cis-trans dispositions of the metal fragments with respect to the fulvalene plane, depending on electronic: and steric factors [5].…”

Synthetic and NMR Studies of Neutral and Cationic Dinuclear Fulvalene Zirconium Complexes Containing the “Zr2(μ-CNtBu)” Unit

“…The structure determination for compounds 1 and 2 by X-ray diffraction methods was not possible, because crystals suitable for a structural study were not obtained. However, the structural behavior of these complexes must be analogous to that reported for the starting chloro complex 9c and for its related dimethyl derivative containing the 2,6-dimethylphenyl isocyanide [{Zr(η 5 -C 5 H 5 )(CH 3 )} 2 {μ-CN(2,6-Me 2 C 6 H 3 )}(μ-η 5 -C 5 H 4 -η 5 -C 5 H 4 )],9h for which the X-ray diffraction studies indicate that the chlorine and the methyl groups are located in an anti- position and the angular isocyanide ligand adopts an asymmetrical η 1 −η 2 -bridging disposition with η 2 - side-on complexation to one of the zirconium atoms, with the corresponding Zr−C bond distance longer than that to the other zirconium center. In the arrangement of ligands in the σ-ligand plane of the zirconium atom with the η 2 -coordinated isocyanide ligand, the “N-inside” fashion is observed.…”

“…The bridging fulvalene ligand provides short contacts between two metal centers, and their group 4 electron-deficient metal compounds, greatly developed in the past few years, provide potential models to evaluate the varying reactivity exhibited by dinuclear compounds compared with the corresponding mononuclear compounds. We have recently reported10a the formation of the cationic species [{Zr(η 5 -C 5 H 5 )} 2 (μ-CH 3 ) (μ-CH 2 )(μ-η 5 -C 5 H 4 -η 5 -C 5 H 4 )] + in quantitative yield and its reactions with donor ligands and chlorocarbon solvents 10b to give the μ -chloro cationic compound [{Zr(η 5 -C 5 H 5 )} 2 (μ-CH 2 )(μ-Cl)(μ-η 5 -C 5 H 4 -η 5 -C 5 H 4 )] + .…”