The Synthesis of Tetrakis(N,N-dimethylaminomethyl)ferrocene and Its Bimetallic Nickel(II) Dichloride Complex: The Search for Precursors for Methoxycarbonylation Ligands

The family of N,N-dimethylaminomethylferrocene compounds is one of the most important in ferrocene chemistry. They serve as precursors for a range of anti-malarial and anti-tumour medicinal compounds, in addition to being key precursors for ferrocene ligands in the Lucite alpha process. A brief discussion on the importance and synthesis of N,N-dimethylaminomethyl-substituted ferrocenes preludes the synthesis of the new ligand, 1,1′,2,2′-tetrakis-(N,N-dimethylaminomethyl)ferrocene. The crystal structure of this compound is reported, and a comparison is made with its disubstituted analogue, 1,2-bis-(N,N-dimethylaminomethyl)ferrocene. The tetrahedral nickel dichloride complexes of both these ligands have been crystallographically characterised. Finally, a pointer to future research in the area is given, which includes a discussion of a new method to extract ferrocenylmethylamines from mixtures using additives and a new synthetic avenue from substituted cyclopentadiene itself.