Chemical behavior of ortho-hydroquinone-based bis(pyrazol-1-yl)methane ligands in the presence of palladium(II) chloride

Abstract

The synthesis, structural characterization, and coordination behavior of ditopic ortho-hydroquinone-based bis(pyrazol-1-yl)methane ligands ( ortho-(OH) 2C 6H 3-4-CHpz 2, ortho-(OH) 2C 6H 3-4-CH(3-Phpz) 2, and ortho-(OH) 2C 6H 3-4-CH(3- tBupz) 2) with pyrazole, 3-phenylpyrazole, and 3- tert-butylpyrazole as donors are described. The reaction of a soluble PdCl 2-source with ortho-(OH) 2C 6H 3-4-CHpz 2 in acetonitrile yielded the related square-planar N, N-coordinated Pd(II) dichloride complex, whereas treatment of ortho-(OH) 2C 6H 3-4-CH(3-Phpz) 2 or ortho-(OH) 2C 6H 3-4-CH(3- tBupz) 2 with PdCl 2 in acetonitrile resulted in degradation of these ligands. The Pd(II) complexes trans-(3-PhpzH) 2PdCl 2 and trans-(3- tBupzH) 2PdCl 2 were isolated and fully characterized including X-ray diffraction analyses.