The first rhenium(V)-imido compounds containing two chelating phosphine ligands of the type trans-[Re(NPh)X(L-L)2]2+ (L-L=bidentate phosphine ligand; X=halide or hydroxide). The structure of trans-[Re(NPh) (OH) (dppbe)2] (ClO4)2·2H2O

Article abstract of DOI:10.1016/S0020-1693(96)05117-1

The bidentate phosphine ligands 1,2-bis(diphenylphosphino)ethane (dppe), 1,2-bis(diphenylphosphino)ethene (dppee) or 1,2-bis(diphenylphosphino)benzene (dppbe) undergo reactions with the rhenium(V)-imido complex, trans-Re(NPh)Cl₃(PPh₃)₂, in refluxing alcoholic solvent to give mixtures of fac-Re(NPh)Cl₃(L-L) and trans-[Re(NPh)X(L-L)₂]²⁺. Mild reaction conditions favor the monosubstituted complexes and harsh conditions favor the salts. The electrochemical properties of the salts reveal subtle differences associated with the backbone of the ligands. The structure of the hydroxy-imido salt trans-[Re(NPh) (OH) (dppbe)₂] (ClO₄)₂?2H₂O was determined and shows the rhenium atom displaced 0.536(2) A above the P₄ equatorial plane, the largest displacement observed for rhenium(V) compounds containing π-donor ligands, and the Re-N(imido) distance of 1.757(10) A is the longest observed for rhenium(V)-imido compounds.