title: Electron deficiency in tetrahedral transition-metal clusters: electronic structure and magnetic properties of [Ru4(eta6-C6H6)4(mu3-H)4](2+).
abstract: Analysis of the electronic structure of the electron-deficient cluster cation [Ru4(eta6-C6H6)4H4](2+) (1(2+)) by density functional theory calculations shows a very small energy gap (0.06 eV) between the diamagnetic singlet state and the paramagnetic triplet state, as a consequence of the absence of a significant Jahn-Teller distortion in the molecular structure of 1(2+). Magnetic measurements of [1]Cl2, [1][BF4]2, and [1][PF6]2 show 1(2+) to be diamagnetic in the fundamental state, with some weak temperature-independent paramagnetism, depending upon the nature of the counterion.
authors.affiliation: Département de Physicochimie, UPRES-1795, Ecole Nationale Supérieure de Chimie de Rennes, Institut de Chimie de Rennes, F-35700 Rennes, France.
authors.forename: Régis
authors.initials: R
authors.lastname: Gautier
authors.forename: Frédéric
authors.initials: F
authors.lastname: Chérioux
authors.forename: Georg
authors.initials: G
authors.lastname: Süss-Fink
authors.forename: Jean-Yves
authors.initials: JY
authors.lastname: Saillard