An orthogonal ferromagnetically coupled tetracopper(II) [2×2] homoleptic grid supported by four μ-alkoxido bridges

Abstract: A pyrimidyl-pyrazole based ditopic ligand N-[amino(pyridin-2-yl)methylidene]-1-(4,6-dimethylpyrimidin-2-yl)-5-methyl-1H-pyrazole-3-carbohydrazonic acid, PymPzOAP prepared by the reaction between pyrimidyl pyrazole 3-carbohydrazide and methyl ester of iminopicolinic acid, reacts with Cu(NO3)2·6H2O to form a self-assembled, ferromagnetically coupled alkoxide bridged tetranuclear homoleptic Cu(II)4 [2×2] grid complex [Cu4(PymPzOAP)4](NO3)4 (1). The complex has a central Cu4(μ-OR)4 core involving four ligand molecules. All the Cu(II) centers have N4O2 coordination environment with distorted octahedral geometry. Intramolecular ferromagnetic interaction between Cu(II) centers (J =4.94, S =4/2) is the signature of the molecule. [Copyright &y& Elsevier]