A Distorted Cubic Tetranuclear Copper(II) Phosphonate Cage with a Double-Four-Ring-Type Core

Vadapalli Chandrasekhar (1) , Loganathan Nagarajan (1) , Rodolphe Clérac (2) , Surajit Ghosh (1) , Sandeep Verma (1)

1 Department of Chemistry, Indian Institute of Technology
2 CRPP - Centre de recherches Paul Pascal

The reaction of Cu2(O2CMe)4â2H2O 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 øT 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.

Mots clés: Inorganic chemistry

Domaines: Matériaux

Vadapalli Chandrasekhar, Loganathan Nagarajan, Rodolphe Clérac, Surajit Ghosh, Sandeep Verma. A Distorted Cubic Tetranuclear Copper(II) Phosphonate Cage with a Double-Four-Ring-Type Core. Inorganic Chemistry, 2008, 47 (3), pp. 1067-1073. ⟨10.1021/ic701948g⟩. ⟨hal-00222936⟩