Synthesis, Characterization, and CO Elimination of Ferrio-Substituted Two-Coordinate Germylenes and Stannylenes

The reactions of [ArE­(Cl)]2 (E = Ge, Sn; Ar = −C6H3-2,6-(C6H3-2,6-iPr2)2 (ArPri4), −C6H3-2,6-(C6H2-2,4,6-iPr3)2 (ArPri6)) with K­[(η5-C5H5)­Fe­(CO)2] afforded the deep green ferriogermylenes ArGeFe­(η5-C5H5)­(CO)2 (Ar = ArPri4 (1), ArPri6 (2)) and the ferriostannylenes ArSnFe­(η5-C5H5)­(CO)2 (Ar = ArPri4 (3), ArPri6 (4)), respectively. Complexes 1–4 were characterized by NMR, UV–vis, and IR spectroscopy, as well as by X-ray crystallography. The solid-state structures of 1–4 feature two-coordinate Ge or Sn atoms with bent C–E–Fe (E = Ge, Sn) geometries. Although germylenes 1 and 2 remain intact upon heating or UV irradiation, stannylenes 3 and 4 were shown to eliminate one carbonyl group upon exposure to UV light, affording the brown dimeric species {ArSnFe­(η5-C5H5)­(CO)}2 (Ar = ArPri4 (5), ArPri6 (6)), respectively.