| Summary: | Diiron μ-aminocarbyne complexes [Fe<sub>2</sub>Cp<sub>2</sub>(NCMe)(CO)(μ-CO){μ-CN(Me)(R)}]CF<sub>3</sub>SO<sub>3</sub> (R = Xyl, <b>[1a<sup>NCMe</sup>]CF<sub>3</sub>SO<sub>3</sub></b>; R = Me, <b>[1b<sup>NCMe</sup>]CF<sub>3</sub>SO<sub>3</sub></b>; R = Cy, <b>[1c<sup>NCMe</sup>]CF<sub>3</sub>SO<sub>3</sub></b>; R = CH<sub>2</sub>Ph, <b>[1d<sup>NCMe</sup>]CF<sub>3</sub>SO<sub>3</sub></b>), freshly prepared from tricarbonyl precursors <b>[1a–d]CF<sub>3</sub>SO<sub>3</sub></b>, reacted with NaOCN (in acetone) and NBu<sub>4</sub>SCN (in dichloromethane) to give [Fe<sub>2</sub>Cp<sub>2</sub>(k<i>N</i>-NCO)(CO)(μ-CO){μ-CN(Me)(R)}] (R = Xyl, <b>2a</b>; Me, <b>2b</b>; Cy, <b>2c</b>) and [Fe<sub>2</sub>Cp<sub>2</sub>(k<i>N</i>-NCS)(CO)(μ-CO){μ-CN(Me)(CH<sub>2</sub>Ph)}], <b>3</b> in 67–81% yields via substitution of the acetonitrile ligand. The reaction of <b>[1a<sup>NCMe</sup>–1c<sup>NCMe</sup>]CF<sub>3</sub>SO<sub>3</sub></b> with KSeCN in THF at reflux temperature led to the cyanide complexes [Fe<sub>2</sub>Cp<sub>2</sub>(CN)(CO)(μ-CO){μ-CNMe(R)}], <b>6a</b>–<b>c</b> (45–67%). When the reaction of <b>[1a<sup>NCMe</sup>]CF<sub>3</sub>SO<sub>3</sub></b> with KSeCN was performed in acetone at room temperature, subsequent careful chromatography allowed the separation of moderate amounts of [Fe<sub>2</sub>Cp<sub>2</sub>(k<i>Se</i>-SeCN)(CO)(μ-CO){μ-CN(Me)(Xyl)}], <b>4a</b>, and [Fe<sub>2</sub>Cp<sub>2</sub>(k<i>N</i>-NCSe)(CO)(μ-CO){μ-CN(Me)(Xyl)}], <b>5a</b>. All products were fully characterized by elemental analysis, IR, and multinuclear NMR spectroscopy; moreover, the molecular structure of <b><i>trans</i>-6b</b> was ascertained by single crystal X-ray diffraction. DFT calculations were carried out to shed light on the coordination mode and stability of the {NC<i>Se</i>-} fragment.
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