A pyrazole ligand yielding both chloro-bridged dinuclear and tetranuclear copper(II) compounds. The crystal and molecular structure of bis[μ-chloro-chloro(3,4-dimethyl-5-phenylpyrazole)(4,5-dimethyl-3-phenylpyrazole)copper(II)] and of (μ4-oxo)hexakis(μ-chloro)tetrakis(3,4-dimethyl-5-phenylpyrazole)t