Synthesis, crystal structures and properties of the novel mononuclear copper(II) and tetranuclear cobalt(II) complexes with 3,6-bis-(3,5-dimethylpyrazolyl)-pyridazine

A novel monomer copper(II) complex [Cu(L)(2)(SCN)] center dot ClO4 (1) and a tetranuclear cobalt(II) complex [CO4(L)(4)(N-3)(4)](OH)(4) center dot 2H(2)O (2)(L = 3,6-bis-(3,5-dimethylpyrazolyl)-pyridazine) have been synthesized and structurally characterized. Single crystal X-ray analyses show that the Cu(II) atom is in a distorted trigonal bipyramidal coordinated environment consisting of four N atoms of L and one N atom of SCN- in complex (1), and the monomer is extended to a 1D chain by the weak intermolecular pi...pi stacking interactions. In the complex (2), four Co(II) atoms are linked by four bridging azido groups in mu-l,l-N-3 (end-on) coordination mode to form a tetranuclear configuration. The fungicidal activity of the title compounds have been studied, and the results show that there are certain activities against several bacteria for the complexes and the ligand. Furthermore, two complexes exhibit blue emission fluoresce in the solid state at room temperature.