THE FIRST RHENIUM(V)-IMIDO COMPOUNDS CONTAINING 2 CHELATING PHOSPHINE-LIGANDS OF THE TYPE TRANS-[RE(NPH)X(L-L)(2)](2-L EQUALS BIDENTATE PHOSPHINE LIGAND, X EQUALS HALIDE OR HYDROXIDE) - THE STRUCTURE OF TRANS-[RE(NPH)(OH)(DPPBE)(2)] (CLO4)(2)CENTER-DOT-2H(2)O() (L)

The bidentate phosphine ligands 1,2-bis(diphenylphosphino)ethane (dppe ), 1,2-bis(diphenylphosphino)ethene (dppee) or 1,2-bis(diphenylphosphi no)benzene (dppbe) undergo reactions with the rhenium(V)-imido complex , trans-Re(NPh)Cl-3(PPh(3))(2), in refluxing alcoholic solvent to give mixtures of fac-Re(NPh)Cl-3(L-L) and trans-[Re(NPh)X(L-L)(2)](2+). Mi ld reaction conditions favor the monosubstituted complexes and harsh c onditions 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) . 2H(2)O was determined and shows the rhenium atom displace d 0.536(2) Angstrom above the P-4 equatorial plane, the largest displa cement observed for rhenium(V) compounds containing pi-donor ligands, and the Re-N(imido) distance of 1.757(10) Angstrom is the longest obse rved for rhenium(V)-imido compounds.