The synthesis of chiral ferrocene ligands and their metal complexes

Starting from the well-known N,N-dimethylaminoethylferrocene (1) {or N,N-dimethyl(1-ferrocenylethyl)amine}, further substitution of the cyclopentadienyl ring in an adjacent position enables formation of -iodo (2), -trimethylsilylethynyl (3) and -ethynyl (4) derivatives in good yields. From 4, fac-[manganese1,2-bis(diphenylphosphinomethane)(tricarbonyl)acetylide] (5), trans-[rutheniumdi(1,2-bis(diphenylphosphinomethane))chloro-acetylide] (6) and trans-[osmiumdi(1,2-bis(diphenylphosphinomethane))chloro-acetylide] (7) have been synthesised and characterised. Electrochemical experiments in solution indicate that there is a decrease in polarisation and a decrease in the degree of metal-to-metal interaction in the chiral ferrocenyl metal-acetylides as opposed to the non-chiral analogues. Second harmonic generation (Kurtz powder) measurements are reported on the chiral metal complexes, but unfortunately negligible second-order non-linear activity was observed.