SYNTHESIS AND CRYSTAL-STRUCTURES OF (PHOSPHINE)TECHNETIUM(V) COMPLEXES WITH PHENYLIMIDO AND PHENYLDIAZENIDO LIGANDS USING THE PRECURSOR PHNHNHCOCH(3)

The reaction of of NH4[TcO4] with PhNHNHCOCH(3), PMePh(2), and HX in m ethanol gave the compound Tc-(NPh)(PMePh(2))(2)X(3). The crystal struc tures of the compounds with X = Cl (I) and Br (II) were determined by X-ray diffraction methods. The results have shown that the two phosphi ne ligands are in trans position to each other, with Tc-P distances of 2.467(2), 2.473(2) Angstrom for I and 2.481(5), 2.487(5) Angstrom for II. The Tc-N bond distances are 1.695(3) and 1.711(11) Angstrom, with angles Tc-N-C of 175.9(2) and 176.3(11)degrees for I and III respecti vely. A similar reaction with a less bulky phosphine, dimethylphenylph osphine, and HBr produced the compound Tc-(NNPh)(PMe(2)Ph)(3)Br-2. The organodiazenido unit was obtained from the cleavage of the NH-C bond of the hydrazine derivative. No such rearrangement has been reported b efore. The compound was studied by crystallographic methods. The resul ts have shown that the three phosphine ligands are in a mer geometry a nd the -NNPh is in trans position to one of the Br ligands. The trans Tc-P bonds are 2.458(5) Angstrom, while the third bond (trans to Br) i s shorter, 2.409(5) Angstrom. The Tc-Br bond trans to -NNPh is 2.603(3 )Angstrom, while the one trans to a phosphine is 2.635(3) Angstrom. Th e Tc-N bond distance is 1.770(11) Angstrom and the angles Tc-N-N = 171 .9(11)degrees and N-N-Ph = 122.1(12)degrees.