New bonding modes in complexes that display interesting magnetic properties develop our understanding of molecular magnetism. Complexes of selenites and tellurites have displayed useful properties such as second-order nonlinear behavior, ferroelectricity, and piezoelectricity. In addition, when bridging two metal cations, these ligands permit magnetic exchange between paramagnetic centers.

A group of scientists led by Massimiliano Delferro, Northwestern University, USA, and Giovanni Predieri, University of Parma, Italy, report a new and unusual coordination mode (µ₂-κ⁴O,O’:O’,O”) of the selenite group in the heteroleptic complex [{Ni(TMEDA)SeO₃}₂] (see picture). The two nickel ions are antiferromagnetically coupled with J = –25.7 ± 0.1 cm^–1, in good agreement with DFT calculations.

• Synthesis, Structural Characterization, and Magnetic Properties of the Heteroleptic Dinuclear Nickel Selenite Complex [{Ni(TMEDA)SeO₃}₂],
  Massimiliano Delferro, Claudia Graiff, Luciano Marchiò, Lisa Elviri, Marcello Mazzani, Mauro Riccò, Giovanni Predieri,
  Eur. J. Inorg. Chem. 2011.
  DOI: 10.1002/ejic.201100385