Synthesis, characterisation and properties of bis(permethylindenyl) iron and tin complexes

Neutral iron complex, (EBI*)Fe (EBI* = ethylenebis(1-hexamethylindenyl)), and its cationic analogue, [(EBI*)Fe](BF4), have been synthesised. Both rac- and meso-(EBI*)Fe can be isolated but the isomeric distribution of the reaction products was found to be highly sensitive to the reaction conditions employed. The redox behaviour of rac-(EBI*)Fe in solution has been studied by cyclic voltammetry, it shows a one-electron reversible oxidation at −0.7 V vs. (Cp)2Fe/(Cp)2Fe+. Chemical oxidation of (EBI*)Fe with AgBF4 gives [(EBI*)Fe](BF4). The molecular structures of rac-(EBI*)Fe and meso-[(EBI*)Fe](BF4) have been determined by single crystal X-ray structure analysis. (EBI*)(SnMe3)2 was synthesised by the reaction of [(EBI*)]Na2 with ClSnMe3 in THF. In solution, only two of the many possible isomers are observed by 1H NMR spectroscopy. Single crystals of (EBI*)(SnMe3)2 were grown as pale, plates by the slow cooling to −78 °C of a saturated hexane solution of a mixture of the isomers. 1H NMR analysis of the crystals showed them to be the isomer with C–SnMe3 peaks at a chemical shift of – 0.27 ppm.

New permethylindenyl tin and iron complexes were synthesised and characterised by NMR spectroscopy, X-ray crystallography and the electrochemical behaviour of rac-(EBI*)Fe was studied.Figure optionsDownload as PowerPoint slide