Synthesis and Characterization of Nitrido Tc(V) and Re(V) Complexes with Ferrocenedithiocarboxylate {FcCS(2) = [Fe(C(5)H(4)CS(2))(C(5)H(5))](-)}
The first mixed technetium-iron complexes [(99g)Tc(N)(FcCS(2))(2)] {FcCS(2) = [Fe(II)(C(5)H(5))(C(5)H(4)CS(2))](-)} (1) and [(99g)Tc(N)(FcCS(2))(FcCS(2)( bigstar))](+) {FcCS(2) = [Fe(II)(C(5)H(5))(C(5)H(4)CS(2))](-); FcCS(2)( bigstar) = Fe(III)(C(5)H(5))(C(5)H(4)CS(2))} (2) have been prepared and characterized. Complex 1 was obtained by reaction of the precursor complex [(99g)Tc(N)Cl(2)(PPh(3))(2)] with the piperidinium salt of the ligand FcCS(2). The resulting biferrocene complex is formed by two FcCS(2) ligands bound to the Tc atom through the four sulfur atoms of the two CS(2)(-) groups and bridged by a Tc&tbd1;N multiple bond. The mixed-valence Fe(2+)-Fe(3+), monocationic complex 2 was isolated as secondary product of the reaction of the precursor complex [(99g)Tc(N)Cl(4)](-) with the ligand FcCS(2). It has the same composition as 1 except for the fact that the Fe(II) center of one FcCS(2) ligand has been oxidized to Fe(III). The electrochemical properties of 1 and 2 are consistent with their formulations. Cyclic voltammetric studies and controlled potential electrolyses showed that complex 1 undergoes a quasi-reversible, two-electron exchange at 0.320 V (vs ferrocene/ferrocenium couple) attributed to the oxidation of the two Fe(II) ions, while complex 2 undergoes a quasi-reversible, one-electron exchange at nearly the same potential (0.344 V) assigned to the oxidation of the residual Fe(II) ion. These results indicate that in complex 1 the two Fe(II) atoms behave as independent redox centers. The synthesis, characterization, and electrochemical behavior of the analogous, six-coordinated rhenium(V) complex [Re(N)(FcCS(2))(2)(PPh(3))] are also reported.
Bolzati
Cristina
C
Dipartimento di Chimica Fisica ed Inorganica, Università di Bologna, Via Risorgimento, 4, 40136 Bologna, Italy, Laboratorio di Medicina Nucleare, Università di Ferrara, Via L. Borsari, 46, 44100 Ferrara, Italy, Laboratoire d'Etudes Dynamiques et Structurales de la Sélectivité, Université de Grenoble, BP 53X, 38041 Grenoble, France, and Istituto di Chimica e Tecnologie Inorganiche e dei Materiali Avanzati, Area della Ricerca CNR, Corso Stati Uniti, 4, 35020 Padova, Italy.
Uccelli
Licia
L
Duatti
Adriano
A
Venturini
Mirko
M
Morin
Christophe
C
Chéradame
Stephane
S
Refosco
Fiorenzo
F
Ossola
Franco
F
Tisato
Francesco
F