Synthesis, characterization, and crystal structure of (PPN)(Re7C CO 21 P OPh 3). Illustration of a polar intermediate stage in cluster decapping

The addition of (Cp2Fe)(PF6) to a dichloromethane solution of (PPN)3(Re7C CO 21) yielded the compound (PPN)(Re7C CO21 P OPh 3). The structure of the compound is a monocapped octahedron, where Re7, the capping rhenium center of (Re7C CO 21 P OPh 3)1-, is coordinated to the phosphite and the three carbonyl ligands. The variable-temperature 13C NMR spectra of the anion at room temperature exhibited only one broad signal at delta 192.7 which is assigned to the single carbonyl ligand trans to the phosphite ligand.