title: Six-fold oxygen-coordinated triplet (S = 1) palladium(II) moieties templated by tris(bipyridine)ruthenium(II) ions.
abstract: Tris(bipyridine)ruthenium(II) is used as a templating agent to insert palladium(II) into three-dimensional oxalate-based networks. The templated-assembly of [Ru(bpy)(3)][Pd(2)(ox)(3)] (Pd(2)) and [Ru(bpy)(3)][PdMn(ox)(3)] (PdMn) is described. The latter compound is structurally characterized by powder X-ray diffraction and X-ray absorption spectroscopy. These techniques reveal an unusual 6-fold oxygen environment around the Pd(II) atoms with two short (2.02 Angstrom) and four long (2.17 Angstrom) Pd-O distances. As stated by magnetometry, this environment is associated with a triplet ground state (S = 1) of the palladium(II) ion: when the temperature is decreased, the chiMT product shows a monotonous decrease from 5.54 cm(3) K mol(-1) at 300 K, a value which is slightly lower than the one expected for independent paramagnetic Pd(II) (S = 1, g = 2) and Mn(II) (S = 5/2, g = 2) ions. This thermal variation is due to antiferromagnetic exchange interactions between the two spin bearers. Nevertheless, no long-range magnetic order is detected down to 2 K. These results are confirmed by an analysis of the [MII(C(2)O(4))(3)](4-) (M = Ni, Pd, Pt) complex and of a [Pd(II){mu-(C(2)O(4))Mn(II)(OH(2))(4)}(3)](2+) tetranuclear model using density functional theory.
authors.affiliation: Laboratoire de Chimie Inorganique et Matériaux Moléculaires, UMR CNRS 7071, Université Pierre et Marie Curie-Paris 6, 4 place Jussieu, Case 42, 75252 Paris Cedex 05, France.
authors.forename: Fabrice
authors.initials: F
authors.lastname: Pointillart
authors.forename: Cyrille
authors.initials: C
authors.lastname: Train
authors.forename: Françoise
authors.initials: F
authors.lastname: Villain
authors.forename: Christophe Cartier Dit
authors.initials: CC
authors.lastname: Moulin
authors.forename: Patrick
authors.initials: P
authors.lastname: Gredin
authors.forename: Lise-Marie
authors.initials: LM
authors.lastname: Chamoreau
authors.forename: Michel
authors.initials: M
authors.lastname: Gruselle
authors.forename: Gabriel
authors.initials: G
authors.lastname: Aullon
authors.forename: Santiago
authors.initials: S
authors.lastname: Alvarez
authors.forename: Michel
authors.initials: M
authors.lastname: Verdaguer