Synthesis and characterization of cationic technetium complexes of 1,2-bis(dimethylphosphino)ethane (DMPE): structure determinations of trans-(Tc/sup v/(DMPE)â(OH)(O))(FâCSOâ)â, trans-(Tc/sup III/(DMPE)âClâ)FâCSOâ, and (Tc/sup I/(DMPE)â)/sup +/ using x-ray diffraction, EXAFS, and â¹â¹Tc NMR