title: Heptanuclear heterometallic [Cu6Ln] clusters: trapping lanthanides into copper cages with artificial amino acids.
abstract: Employment of the artificial amino acid 2-amino-isobutyric acid, aibH, in Cu(II) and Cu(II)/Ln(III) chemistry led to the isolation and characterization of 12 new heterometallic heptanuclear [Cu(6)Ln(aib)(6)(OH)(3)(OAc)(3)(NO(3))(3)] complexes consisting of trivalent lanthanide centers within a hexanuclear copper trigonal prism (aibH = 2-amino-butyric acid; Ln = Ce (1), Pr (2), Nd (3), Sm (4), Eu (5), Gd (6), Tb (7), Dy (8), Ho (9), Er (10), Tm (11), and Yb (12)). Direct curent magnetic susceptibility studies have been carried out in the 5-300 K range for all complexes, revealing the different nature of the magnetic interactions between the 3d-4f metallic pairs: dominant antiferromagnetic interactions for the majority of the pairs and dominant ferromagnetic interactions for when the lanthanide center is Gd(III) and Dy(III). Furthermore, alternating current magnetic susceptibility studies reveal the possibility of single-molecule magnetism behavior for complexes 7 and 8. Finally, complexes 2, 5-8, 10, and 12 were analyzed using positive ion electrospray mass spectrometry (ES-MS), establishing the structural integrity of the heterometallic heptanuclear cage structure in acetonitrile.
authors.affiliation: Department of Chemistry, The University of Crete, Voutes, 71003, Herakleion, Greece.
authors.forename: George J
authors.initials: GJ
authors.lastname: Sopasis
authors.forename: Angelos B
authors.initials: AB
authors.lastname: Canaj
authors.forename: Aggelos
authors.initials: A
authors.lastname: Philippidis
authors.forename: Milosz
authors.initials: M
authors.lastname: Siczek
authors.forename: Tadeusz
authors.initials: T
authors.lastname: Lis
authors.forename: James R
authors.initials: JR
authors.lastname: O'Brien
authors.forename: Manolis M
authors.initials: MM
authors.lastname: Antonakis
authors.forename: Spiros A
authors.initials: SA
authors.lastname: Pergantis
authors.forename: Constantinos J
authors.initials: CJ
authors.lastname: Milios
mesh_terms: D000621:Aminoisobutyric Acids / Q000737:chemistry*; D056831:Coordination Complexes / Q000737:chemistry*; D003300:Copper / Q000737:chemistry*; D018360:Crystallography, X-Ray; D028581:Lanthanoid Series Elements / Q000737:chemistry*; D013058:Mass Spectrometry; D008958:Models, Molecular
chemical_list: D000621:Aminoisobutyric Acids; D056831:Coordination Complexes; D028581:Lanthanoid Series Elements; C100049:2-aminoisobutyric acid; D003300:Copper