title: A new approach to the synthesis of heteronuclear propeller-like single molecule magnets.
abstract: Propeller-like [Fe(4)(L)(2)(dk)(6)] complexes, in which Hdk is a β-diketone and H(3)L is a tripodal alcohol, R-C(CH(2)OH)(3), exhibit tunable magnetic anisotropy barriers and retain their magnetic memory effect when chemically anchored on metal surfaces. Heteronuclear analogues of these M(4) complexes have been sought to afford a library of compounds with different total spin (S) values, but synthetic efforts described so far gave solid solutions containing M(4) in addition to the desired M(3)M' species. We now present a novel synthetic route to M(3)M' complexes featuring a central chromium(III) ion. The three-step preparation goes through coordination of Cr(III) by two equivalents of tripodal alkoxide (R = Et and Ph), followed by reaction of this complex "core" with the peripheral +III metal ions. Products have been characterised by chemical analyses together with (1)H-NMR, FTIR, W-band EPR, DC/AC magnetic susceptibility measurements and single crystal X-ray diffractometry. Due to the chemical inertness of Cr(III), this route yields 100% pure Fe(3)Cr complexes without metal scrambling; what is more, it is suitable for designing novel heteronuclear single molecule magnets (SMMs) with a variety of d- and f-metals and R groups.
authors.affiliation: Dipartimento di Chimica Ugo Schiff and INSTM RU, Università degli Studi di Firenze, Via della Lastruccia 3-13, 50019 Sesto Fiorentino-FI, Italy.
authors.forename: Pasquale
authors.initials: P
authors.lastname: Totaro
authors.forename: Kátia Cristina M
authors.initials: KC
authors.lastname: Westrup
authors.forename: Marie-Emmanuelle
authors.initials: ME
authors.lastname: Boulon
authors.forename: Giovana G
authors.initials: GG
authors.lastname: Nunes
authors.forename: Davi F
authors.initials: DF
authors.lastname: Back
authors.forename: Andersson
authors.initials: A
authors.lastname: Barison
authors.forename: Samuele
authors.initials: S
authors.lastname: Ciattini
authors.forename: Matteo
authors.initials: M
authors.lastname: Mannini
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Sorace
authors.forename: Jaísa F
authors.initials: JF
authors.lastname: Soares
authors.forename: Andrea
authors.initials: A
authors.lastname: Cornia
authors.forename: Roberta
authors.initials: R
authors.lastname: Sessoli