[TcII(NO)(trifluoroacetate)4F]2− – synthesis and reactions

Abstract

Fluoridotetrakis(trifluoroacetato)nitrosyltechnetate(II) was prepared by the dissolution of Cs₂[Tc(NO)F₅] in trifluoroacetic acid and addition of (NBu₄)F·3H₂O. The compound crystallizes as a mixed Cs⁺/NBu₄⁺ salt in the form of green crystals. Unlike the [Tc(NO)F₅]²⁻ 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 (PPh₃), 1,2-bis(diphenylphosphino)ethane (DPPE) or pyridyldiphenylphosphine (pyPPh₂) give technetium(I) complexes of the compositions Cs[Tc(NO)(PPh₃)₂(CF₃COO)₂F], [Tc(NO)(DPPE)₂(OOCCF₃)](PF₆) and [Tc(NO)(κN,P-pyPPh₂)(κP-pyPPh₂)(CF₃COO)₂]. The products were studied spectroscopically and by X-ray diffraction. The ⁹⁹Tc 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.