title: Nonemployed Simple Carboxylate Ions in Well-Investigated Areas of Heterometallic Carboxylate Cluster Chemistry: A New Family of {Cu(II)4Ln(III)8} Complexes Bearing tert-Butylacetate Bridging Ligands.
abstract: The first use of tert-butylacetate as bridging ligand in 3d/4f-metal cluster chemistry, in conjunction with the versatile chelate ligand pyridine-2,6-dimethanol, has afforded a new family of [Cu4Ln8(OH)6(NO3)2(O2CCH2Bu(t))16(pdm)4] clusters with unprecedented structures and slow magnetization relaxation for the {Cu(II)4Dy(III)8} member. The molecular structure of representative complex 1 consists of a {Cu(II)4Gd(III)8} cage-like cluster built from two {CuGd3} cubanes which are linked to each other and to two {CuGd} subunits on opposite sides through two η(2):η(2):η(2):μ5 NO3(-) ions. The metal ions are additionally bridged by μ3-OH(-), μ3-OR(-), and μ-OR(-) groups to give an overall [Cu4Gd8(μ5-NO3)2(μ3-OH)6(μ3-OR)2(μ-OR)8](14+) core. Peripheral ligation about the core is provided by the N,O,O-chelating part of the pdm(2-) groups and, more impressively, by the oxygen atoms of 16 bridging Bu(t)CH2CO2(-) ligands; the latter are arranged into five classes, adopting a total of six different binding modes with the metal centers. The combined work demonstrates the ligating flexibility of tert-butylacetate ion and its usefulness in the synthesis of new 3d/4f-metal cluster compounds.
authors.affiliation: †Department of Chemistry, University of Patras, 265 04 Patras, Greece.
authors.forename: Despina
authors.initials: D
authors.lastname: Dermitzaki
authors.affiliation: ‡Institute of Nanoscience and Nanotechnology, NCSR "Demokritos", 15310 Aghia Paraskevi, Attikis, Greece.
authors.forename: Catherine P
authors.initials: CP
authors.lastname: Raptopoulou
authors.affiliation: ‡Institute of Nanoscience and Nanotechnology, NCSR "Demokritos", 15310 Aghia Paraskevi, Attikis, Greece.
authors.forename: Vassilis
authors.initials: V
authors.lastname: Psycharis
authors.affiliation: §Departament de Quimica Inorganica, Universitat de Barcelona, Diagonal 645, 08028 Barcelona, Spain.
authors.forename: Albert
authors.initials: A
authors.lastname: Escuer
authors.affiliation: †Department of Chemistry, University of Patras, 265 04 Patras, Greece.
authors.forename: Spyros P
authors.initials: SP
authors.lastname: Perlepes
authors.affiliation: ∥Department of Chemistry, Brock University, L2S 3A1 St. Catharines, Ontario, Canada.
authors.forename: Theocharis C
authors.initials: TC
authors.lastname: Stamatatos