Me2Si(C5Me4)2Cr:  Synthesis and Crystal Structure of a Ligand-Free ansa-Chromocene

Me2Si(C5Me4)2Cr, the first example of an ansa-chromocene containing no additional ligands at chromium, was synthesized from Me2Si(C5Me4)2Li2 and CrCl2(THF)x in the presence of 2,6-xylyl isocyanide. The crystal structure of the complex was determined. The complex is paramagnetic and does not coordinate phosphines, phosphites, nitriles, amines, or acetylenes, but it reacts readily with 2,6-xylyl isocyanide to give mono- and diisocyanide complexes.