Me<sub>2</sub>Si(C<sub>5</sub>Me<sub>4</sub>)<sub>2</sub>Cr:  Synthesis and Crystal Structure of a Ligand-Free <i>a</i><i>nsa</i>-Chromocene

Me<sub>2</sub>Si(C<sub>5</sub>Me<sub>4</sub>)<sub>2</sub>Cr, the first example of an <i>ansa</i>-chromocene containing no additional ligands at chromium, was synthesized from Me<sub>2</sub>Si(C<sub>5</sub>Me<sub>4</sub>)<sub>2</sub>Li<sub>2</sub> and CrCl<sub>2</sub>(THF)<i><sub>x</sub></i> 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.