Synthesis and molecular structure of tricarbonyl(diphenyl ditelluride)diiodoiron (CO)₃FeI₂(Te₂Ph ₂) and tricarbonyldiiodo[iodo(phenyl)tellurido]iron (CO) ₃FeI₂(PhTeI): First example of the coordination of unstable PhTeI to the transition metal atom

A reaction of the tetramer [PhTeI]₄ with Fe(CO)₅ gave the monomeric complex (CO)₃FeI₂(Ph₂Te ₂) (I) containing a diphenyl ditelluride molecule linked with cis-tricarbonyldiiodoiron. According to X-ray diffraction data, the Fe-Te distance in complex I (2.5724(6) Å) is appreciably shorter than the sum of the covalent Fe and Te radii and the Te-Te bond (2.7705(5) Å) is only slightly longer than that in free Ph₂Te₂ (2.705(1) Å). In the reaction of Fe(CO)₅ with PhTeI₃, a complex with PhTeI as a ligand to the transition metal atom was obtained for the first time. Unlike free PhTeI, the resulting complex (CO)₃FeI ₂(PhTeI) (II) is stable in air at room temperature for several days. According to X-ray diffraction data, the ligand PhTeI (Te-C 2.126(4) Å, Te-I(3) 2.7548(5) Å) is stabilized by the coordination of tellurium to both the iron (Te-Fe 2.5451(6) Å) and iodine atoms (Te(1)-I(1) 3.1634(5) Å). The latter coordination probably involves the vacant d orbital of tellurium and the lone electron pair on the iodide ligand.