Unprecedented quadruple Me2biim-bridged di- and tetranuclear complexes: Syntheses, structures and magnetic properties

Quadruple Me2biim-bridged di- and tetranuclear complexes[Cu2(H2O)2(Me2biim)4](SO4)2 (1) and [Cr4(μ-Cl)(μ-Me2biim)8(H2O)1.67(OH)0.33](ClO4)6.67 (2) have been prepared and characterized. The repulsion between the methyl groups forces the two imidazole rings out of coplanarity, responsible for the much weaker magnetic exchange coupling between the Cu2+ ions in 1.