The effects of auxiliary ligands on the synthesis,crystal structures and properties of three complexes with a substituted pyridazine ligand

Abstract  Three new complexes, [Co(L)₂(SCN)₂] (1), [Co₂(L)₄(μ-N₃)₂](ClO₄)₂(H₂O)_1.5 (2), and [Ni(L)₃](ClO₄)₂(CH₃OH)₂ (3), have been synthesized and structurally characterized, where L is 3-(3′,5′-dimethyl-pyrazole)-6-Cl-pyridazine. Single crystal X-ray analyses show that all three complexes crystallize in the monoclinic crystal system. In complex (1), the Co(II) atom is in a distorted octahedral environment consisting of four nitrogen atoms from two ligands and two nitrogen atoms of SCN⁻, which is further extended into a 1D chain by intermolecular hydrogen bonds. Two Co(II) atoms in complex (2) are linked by two azide anions in a μ-1,1 mode to make a binuclear structure. Without any auxiliary ligand, the Ni(II) atom in complex (3) adopts a distorted octahedral geometry involving six nitrogen atoms from three ligands. The electronic absorption spectra of the title compounds are discussed as well. The effects of auxiliary ligands on the structures and properties of the title complexes have been studied and discussed. Graphical Abstract  Three new complexes, [Co(L)₂(SCN)₂] (1), [Co₂(L)₄(μ-N₃)₂](ClO₄)(H₂O)_1.5 (2) and [Ni(L)₃](ClO₄)₂(CH₃OH)₂ (3), have been synthesized and structurally characterized, where L is 3-(3′,5′-dimethyl-pyrazole)-6-Cl-pyridazine. Complexes (1) and (3) are mononuclear compounds, which are different from the binuclear complex (2). Auxiliary ligands are the main reasons that results in the different structures of the title complexes and their different fungicidal activities. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.