title: Designed topology and site-selective metal composition in tetranuclear [MM'...M'M] linear complexes.
abstract: The ligand 1,3-bis[3-oxo-3-(2-hydroxyphenyl)propionyl]benzene (H(4)L), designed to align transition metals into tetranuclear linear molecules, reacts with M(II) salts (M=Ni, Co, Cu) to yield complexes with the expected [MMMM] topology. The novel complexes [Co(4)L(2)(py)(6)] (2; py=pyridine) and [Na(py)(2)][Cu(4)L(2)(py)(4)](ClO(4)) (3) have been crystallographically characterised. The metal sites in complexes 2 and 3, together with previously characterised [Ni(4)L(2)(py)(6)] (1), favour different coordination geometries. These have been exploited for the deliberate synthesis of the heterometallic complex [Cu(2)Ni(2)L(2)(py)(6)] (4). Complexes 1, 2, 3 and 4 exhibit antiferromagnetic interactions between pairs of metals within each cluster, leading to S=0 spin ground states, except for the latter cluster, which features two quasi-independent S=1/2 moieties within the molecule. Complex 4 gathers the structural and physical conditions, thus allowing it to be considered as prototype of a two-qbit quantum gate.
authors.affiliation: Facultat de Química, Departament de Química Inorgànica, Universitat de Barcelona Diagonal 647, 08028 Barcelona, Spain.
authors.forename: Leoní A
authors.initials: LA
authors.lastname: Barrios
authors.forename: David
authors.initials: D
authors.lastname: Aguilà
authors.forename: Olivier
authors.initials: O
authors.lastname: Roubeau
authors.forename: Patrick
authors.initials: P
authors.lastname: Gamez
authors.forename: Jordi
authors.initials: J
authors.lastname: Ribas-Ariño
authors.forename: Simon J
authors.initials: SJ
authors.lastname: Teat
authors.forename: Guillem
authors.initials: G
authors.lastname: Aromí