[Tc(NO)(trifluoroacetate)F] - synthesis and reactions.

Fluoridotetrakis(trifluoroacetato)nitrosyltechnetate(ii) was prepared by the dissolution of Cs[Tc(NO)F] in trifluoroacetic acid and addition of (NBu)F·3HO. The compound crystallizes as a mixed Cs/NBu salt in the form of green crystals. Unlike the [Tc(NO)F] salts, the product is soluble in organic solvents and can be used as a precursor for ongoing ligand exchange procedures with organic ligands. The corresponding reactions with triphenylphosphine (PPh), 1,2-bis(diphenylphosphino)ethane (DPPE) or pyridyldiphenylphosphine (pyPPh) give technetium(i) complexes of the compositions Cs[Tc(NO)(PPh)(CFCOO)F], Tc(NO)(DPPE)(OOCCF) and [Tc(NO)(κN,P-pyPPh)(κP-pyPPh)(CFCOO)]. The products were studied spectroscopically and by X-ray diffraction. The Tc NMR resonances of the novel Tc(i) nitrosyls appear between -627 and +952 ppm, which is at a remarkably high field and in the range where normally the signals of Tc(iii) compounds are observed.