[Tc(NO)Cl(Cp)(PPh3)] – A Technetium(I) Compound with an Unexpected Synthetic Potential

Reactions of the chiral organometallic technetium(I) compound [Tc(NO)Cl(Cp)(PPh3)] (1 a) with phosphines and alkynes give unexpected products such as the dimeric cation [{Tc(NO)(Cp)(PPh3)}2Cl]+ (4) or the Fischer‐type carbene [Tc(NO)(Cp)(PPh3){C(OR)C2H4PPh3}]2+ (5). Both products could be isolated as PF6− salts and studied by spectroscopic methods and X‐ray diffraction. While [Tc(NO)(Cp)(PMe3)(PPh3)](PF6) (2PF6) can be obtained from 1 a, PMe3 and Ag(PF6) under ambient conditions, the synthesis of the corresponding bis‐triphenylphosphine complex [Tc(NO)(Cp)(PPh3)2](PF6) (3PF6) requires high temperatures and long reaction times. The products are stable in air. Stable technetium(I) complex cations with Fischer‐type carbene ligands are formed during reactions of [Tc(NO)(Cp)Cl(PPh3)] with trimetylsilyl propyne and Ag(PF6) in CH2Cl2/‐alcohol mixtures, while the dimeric compound [{Tc(NO)(Cp)(PPh3)}2Cl]+ is formed, when no other ligand is provided.