A novel hexacoordinating non-Schiff base ligand (H 4L) with N 2O 4 donor atoms has been synthesized by simple Mannich reactions. The use of this ligand with Cu(ClO 4) 2* 6H 2O in different molar ratios as well as pH leads to the formation of a mononuclear species and a tetranuclear CuII complex possessing a cubane [Cu 4L 2] core with almost equal Cu...Cu separation. In the presence of an excess amount of copper(II) ions and triethylamine at reflux, the mononuclear [CuH 2L] species can be converted into the tetranuclear one, whereas the reverse process was not observed even after prolonged reaction time. Both the complexes have been characterized by single-crystal X-ray diffraction and magnetic measurements. Magnetic studies reveal that complex 1 displays a paramagnetic Curie-type behavior whereas 2 displays a singletspin ground state induced by strong intramolecular antiferromagnetic interactions.
All Science Journal Classification (ASJC) codes
- Inorganic Chemistry