The reaction of [TcNCl4]- with bidentate diphosphines P-P gives the cationic complexes [TcNCl(P-P)2]+[A]- [P-P = Ph2PCH2CH2PPh2 or Me2PCH2CH2PMe2 (dmpe), A = BPh4 or PF6] in good yield. An analogous complex was prepared with Me2PCH2CH2NMe(CH2) 3NMeCH2CH2PMe2 whereas the bulky Pri2PCH2CH2PPRi2 (dippe) gave a binuclear complex [Tc2N2Cl4(dippe)2] which on the basis of 31P NMR spectroscopy has bridging chloride groups. An X-ray crystal structure of [TcNCl(dmpe)2][BPh4] revealed a distorted trans-octahedral geometry about technetium with an exceptionally long Tc=N bond distance of 1.853(6) Å. Reaction of [TcNBr4]- with 2,2′-bipyridyl (bipy) in ethanol gives [TcNBr(bipy)2]2[TcBr4]. An X-ray crystal structure revealed a cis-octahedral structure for the nitrido-cation [Tc=N 1.621(20) Å] with the novel tetrahedral tetrabromotechnetate(II) dianion.
