title: A distorted cubic tetranuclear copper(II) phosphonate cage with a double-four-ring-type core.
abstract: The reaction of Cu2(O2CMe)(4).2H2O with tert-butylphosphonic acid and 3,5-di-tert-butylpyrazole in the presence of triethylamine leads to a high-yield synthesis of the tetranuclear compound [Cu2(3,5-t-Bu2PzH)2(t-BuPO3)2]2 (1). The latter has a distorted cubic cage structure and its core resembles the D4R (double-four-ring) motif found in zeolites. The phosphonate, [t-BuPO3]2-, functions as a dianionic tridentate ligand, while the pyrazole ligands are neutral and are monodentate. The coordination geometry at each copper atom is distorted square planar with a 3O,1N coordination environment. Magnetic measurements on 1 reveal that the chiT product continuously decreases to reach a value very close to zero at 1.8 K, indicating dominant antiferromagnetic interactions between Cu(II) ions that leads to an S=0 ground state. The tetranuclear cage 1 functions as a very effective artificial nuclease in the presence of an external oxidant, magnesium monoperoxyphthalate.
authors.affiliation: Department of Chemistry, Indian Institute of Technology-Kanpur, Kanpur-208 016, India. vc@iitk.ac.in
authors.forename: Vadapalli
authors.initials: V
authors.lastname: Chandrasekhar
authors.forename: Loganathan
authors.initials: L
authors.lastname: Nagarajan
authors.forename: Rodolphe
authors.initials: R
authors.lastname: Clérac
authors.forename: Surajit
authors.initials: S
authors.lastname: Ghosh
authors.forename: Sandeep
authors.initials: S
authors.lastname: Verma