title: Preparative and electrochemical investigations on the electron sponge behavior of cobalt telluride clusters: CO substitution in [Co11Te7(CO)10]n- ions (n=1, 2) by PMe2Ph and crystal structure of [Co11Te7(CO)5(PMe2Ph)5].
abstract: The reaction of the cluster salts [Cp(2*) Nb(CO)(2)](n)[Co(11)Te(7)(CO)(10)] (Cp*=C(5)Me(5); n=1, 2) with excess PMe(2)Ph gave the neutral, dark brown clusters [Co(11)Te(7)(CO)(6)(PMe(2)Ph)(4)] (5) and [Co(11)Te(7)(CO)(5)(PMe(2)Ph)(5)] (6) with 147 metal valence electrons. The new compounds were characterized by IR spectroscopy, elemental analyses, and mass spectrometry. The molecular structure of 6 was determined by X-ray crystallography. Like its precursor anion, it consists of a pentagonal-prismatic [Co(11)Te(7)] core, but with a ligand sphere composed of five CO and five PMe(2)Ph ligands. Detailed electrochemical studies of both reactions reveal that a stepwise substitution of CO ligands in the initial cluster anions takes place leading to intermediate [Co(11)Te(7)(CO)(10-m)(PMe(2)Ph)(m)](n-) ions (m=1-5; n=1, 2). Each of these intermediates is distinguished by at least one oxidation and two reduction waves, giving rise to a total of 21 redox couples and 27 electroactive species. The electron sponge character of the new compounds is particularly pronounced in 5, which exhibits charges n between +1 and -4 corresponding to metal valence electron counts of between 146 and 151.
authors.affiliation: Institut für Anorganische Chemie der Universität Regensburg 93040 Regensburg, Germany.
authors.forename: Henri
authors.initials: H
authors.lastname: Brunner
authors.forename: Hélène
authors.initials: H
authors.lastname: Cattey
authors.forename: Walter
authors.initials: W
authors.lastname: Meier
authors.forename: Yves
authors.initials: Y
authors.lastname: Mugnier
authors.forename: A Claudia
authors.initials: AC
authors.lastname: Stückl
authors.forename: Joachim
authors.initials: J
authors.lastname: Wachter
authors.forename: Robert
authors.initials: R
authors.lastname: Wanninger
authors.forename: Manfred
authors.initials: M
authors.lastname: Zabel