Ferromagnetic coupling in a unique Cu(II) metallacyclophane with functionalized diazamesocyclic ligands formed by Cu(II)-directed self-assembly: magneto-structural correlations for dichloro-bridged Cu(II) dinuclear complexes

摘要

Two new di-#mu#-Cl dinuclear Cu~(II) complexes [Cu(HL~1)Cl_2]_2(ClO_4)_2 (1) and [Cu_2(L~2)_2Cl_2](ClO_4)_2 (2) with the pyridyl-functionalized diazamesocyclic ligands 1,5-bis(pyridin-4-ylmethyl)-1,5-diazacyclooctane (L~1) and 1-(pyridin-2-ylmethyl)-1,4-diazacycloheptane (L~2) have been synthesized and structurally characterized by single crystal X-ray diffraction. Complex 1 is a unique paramagnetic Cu~(II) metallamacrocycle (ca. 14.1 X 3.5 A~2) directly self-assembled by metal ions and the organic spacer under strongly acidic conditions. The magnetic properties of both complexes have been investigated by variable-temperature magnetic susceptibility measurements. Although complexes 1 and 2 have almost the same geometrical parameters for Cu~(II), their magnetic parameters vary from ferromagnetic for 1 to antiferromagnetic for 2. The magneto-sructural correlation of such complexes have been further developed.