Magnesium compounds dihalide complexes

The second route (Scheme 1) is a redistribution reaction, in fact the Schlenk equilibrium. This route may be used in the reverse direction for the preparation of pure diorganomagnesium compounds from organomagnesium halides. Addition of a ligand, usually dioxane, that forms an insoluble complex with magnesium dihalide, shifts the Schlenk equilibrium completely to the left side and allows isolation of pure diorganomagnesium compounds from the remaining solution. ... 

The synthesis and spectroscopic features of a number of titanocene dicarbonyl derivatives have been reviewed previously.41 Typically, these complexes are prepared via magnesium reduction of the corresponding dihalide derivative under 1 atm of carbon monoxide. New compounds prepared since COMC(1995) are presented in Scheme 10. Mixed cyclopentadienyl phosphinimide dicarbonyl compounds such as (if-CsMcs)-(Buc3PN)Ti(CO)2 61 have also been isolated.46... 

Complexes related to 57 described above were prepared with the diimino pyridine ligands with the benefit that a larger set of R groups could be linked to Co. The compounds 58 were made by reaction between the dihalide or monohalide cobalt complexes with magnesium or lithium reagents (Figure... 

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