Ligand exchange in zirconocene dichloride–diethylzinc bimetallic systems

The reaction between zirconocene dichloride and excess diethylzinc in d-6-benzene solution was studied. It was found that the exchange reaction between Cp2ZrCl2 and Et2Zn is accompanied by the formation of such complexes as bis-(cyclopentadienyl)ethylzirconium chloride (EtZrCp2Cl), a zirconium-organozinc complex, and bis-(cyclopentadienyl)diethylzirconium (Et2ZrCp2). It was also found that as a result of ligand exchange in zirconocene dichloride–diethylzinc bimetallic systems, the zirconium-organozinc complex is formed in minor amounts. An assessment of the thermodynamic stability of the obtained products is given based on the results of DFT analysis. The description of the NMR spectral data of the obtained organozirconium complexes is carried out.

Ligand exchange in zirconocene dichloride–diethylzinc bimetallic systems

The reaction between zirconocene dichloride and excess diethylzinc in d-6-benzene solution was studied. It was found that the exchange reaction between Cp2ZrCl2 and Et2Zn is accompanied by the formation of such complexes as bis-(cyclopentadienyl)ethylzirconium chloride (EtZrCp2Cl), a zirconium-organozinc complex, and bis-(cyclopentadienyl)diethylzirconium (Et2ZrCp2). It was also found that as a result of ligand exchange in zirconocene dichloride–diethylzinc bimetallic systems, the zirconium-organozinc complex is formed in minor amounts. An assessment of the thermodynamic stability of the obtained products is given based on the results of DFT analysis. The description of the NMR spectral data of the obtained organozirconium complexes is carried out.

Ligand exchange processes in zirconocene dichloride–trimethylaluminum bimetallic systems and their catalytic properties in reaction with alkenes

The exchange processes in the system L2ZrCl2–(AlMe3)2 and its reactivity towards the alkene were studied.

Crystal structure of the formal 20 electron zirconocene pentafulvene complex Cp2Zr(η5,η1-adamantylidenepentafulvene):toluene:n-hexane = 1:0.125:0.125

The crystal structure of a solvated zirconocene pentafulvene complex with a bulky adamantylidene substitution pattern, namely (η5,η1-adamantylidenepentafulvene)bis(η5-cyclopentadienyl)zirconium(IV)–toluene–n-hexane (8/1/1), [Zr(C15H18)(C5H5)2]·0.125C7H8·0.125C6H14, is reported. Reducing zirconocene dichloride with magnesium results in the formation of a low-valent zirconocene reagent that reacts readily with adamantylidenepentafulvene to give the aforementioned complex. Single crystal X-ray diffraction proves the dianion-like η5:η1binding mode of the fulvene ligand to the central ZrIVatom. The asymmetric unit contains four independent molecules of [η5:η1-adamantylidenepentafulvene]bis[(η5)-cyclopentadienyl]zirconium(IV), together with half a molecule of toluene disordered with half a molecule ofn-hexane (the solvent molecules have no direct influence on the complex). In each of the four complex molecules, the central ZrIVatom has a distorted tetrahedral coordination environment. The measured crystal consisted of two domains with a refined ratio of 0.77:0.23.

Insertion and isomerisation of internal olefins at alkylaluminium hydride: catalysis with zirconocene dichloride

The insertion of internal olefins and chain walking isomerisation at di-n-octylaluminium hydride [Al(Oct)2H], promoted by zirconocene dichloride [Cp2ZrCl2] has been studied.