A macrocyclic oxamido vanadium(IV)-oxo ligand and its derivative VOIV2MII (M = Cu, Mn) trinuclear complexes: synthesis, structures and magnetic properties

A new oxamido-bridged vanadium(IV)-oxo complex ligand VOL (H2L = 2,3-dioxo-5,6:13,14-dibenzo-7,12-diphenyl-1,4,8,11-tetraazacyclo-tetradeca-7,12-diene) (1) has been synthesized. Based on the mononuclear ligand, two trinuclear complexes [Cu(VOL)2(H2O)2](ClO4)2 · 1.5H2O (2) and [Mn(VOL)2(CH3OH)2](ClO4)2 · 5CH3OH (3) have been prepared and structurally characterized by X-ray crystallography. In complexes 2 and 3, the central ions Cu(II) and Mn(II) are connected to two VOL fragments via an exo-cis oxamido bridge. Magnetic susceptibility studies (2–300 K) indicate the occurrence of ferromagnetic coupling between the paramagnetic metals in complex 2, while a weak antiferromagnetic interaction is detected in complex 3. The experiment data have been fitted according to the Heisenberg Hamiltonian Hˆ=-2JSˆ1Sˆ2, leading to J = 9.09 cm−1, zJ′ = 5.0 × 10−3 cm−1 for complex 2 and J = −0.27 cm−1, θ = −0.03 K for complex 3.

A new oxamido-bridged vanadium(IV)-oxo complex ligand VOL (H2L = 2,3-dioxo-5,6:13,14-dibenzo-7,12-diphenyl-1,4,8,11-tetraazacyclo-tetradeca-7,12-diene) (1) has been synthesized. Based on the mononuclear ligand, two trinuclear complexes [Cu(VOL)2(H2O)2](ClO4)2 · 1.5H2O (2) and [Mn(VOL)2(CH3OH)2](ClO4)2 · 5CH3OH (3) have been prepared and structurally characterized by X-ray crystallography. Their spectroscopic properties and magnetic properties have also been investigated.Figure optionsDownload as PowerPoint slide