title: Hexacyanometalate molecular chemistry: di-, tri-, tetra-, hexa- and heptanuclear heterobimetallic complexes; control of nuclearity and structural anisotropy.
abstract: Following a bottom-up approach to nanomaterials, we present a rational synthetic route to high-spin and anisotropic molecules based on hexacyanometalate [M(CN)(6)](3-) cores. Part 1 of this series was devoted to isotropic heptanuclear clusters; herein, we discuss the nuclearity and the structural anisotropy of nickel(II) derivatives. By changing either the stoichiometry, the nature of the terminal ligand, or the counterion, it is possible to tune the nuclearity of the polynuclear compounds and therefore to control the structural anisotropy. We present the synthesis and the characterisation by mass spectrometry, X-ray crystallography and magnetic susceptibility of bi-, tri-, tetra-, hexa- and heptanuclear species [M(CN)(n)(CN-M'L)(6-n)](m+) (with n=0-5; M=Cr(III), Co(III), M'=Ni(II); L=pentadentate ligand). Thus, with M=Cr(III), d(3), S=3/2, a dinuclear complex [Cr(III)(CN)(5)(CN-NiL(n))](9+), (L(n)=polydentate ligand) was built and characterised, showing a spin ground state, S(G)=5/2, with a ferromagnetic interaction J(Cr,Cu)=+18.5 cm(-1). With M=Co(III) (d(6), S=0) were built di-, tri-, tetra-, hexa and hepanuclear CoNi species: CoNi, CoNi(2), CoNi(3), CoNi(5) and CoNi(6). By a first approximation, they behave as one, two, three, five and six isolated nickel(II) complexes, respectively, but more accurate studies allow us to evaluate the weak antiferromagnetic coupling constant between two next-nearest neighbours M'-Co-M'.
authors.affiliation: Laboratoire de Chimie Inorganique et Matériaux Moléculaires, CNRS, UMR 7071 Université Pierre et Marie Curie, 75252 Paris Cedex 05, France. marvaud@ccr.jussieu.fr
authors.forename: Valérie
authors.initials: V
authors.lastname: Marvaud
authors.forename: Caroline
authors.initials: C
authors.lastname: Decroix
authors.forename: Ariane
authors.initials: A
authors.lastname: Scuiller
authors.forename: Fabien
authors.initials: F
authors.lastname: Tuyèras
authors.forename: Carine
authors.initials: C
authors.lastname: Guyard-Duhayon
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Vaissermann
authors.forename: Jérome
authors.initials: J
authors.lastname: Marrot
authors.forename: Florence
authors.initials: F
authors.lastname: Gonnet
authors.forename: Michel
authors.initials: M
authors.lastname: Verdaguer