four copper complexes (with copper in the oxidation states I and II) with the bis(pyrazolyl)methane ligands HC(3-tBuPz)2(Py) and HC(3-tBuPz)2(Qu). With the quinolinyl ligand (2-quinolinyl)bis(3-tert-butylpyrazolyl)methane [HC(3-tBuPz)2(Qu)] we obtained the tetrahedral monofacial complex [CuClHC(3-tBuPz)2(Qu)}] (C1) and with the pyridinyl ligand (2-pyridinyl)bis(3-tert-butylpyrazolyl)methane [HC(3-tBuPz)2(Py)]
Additionally, the steric hindrance is easily defined in the ligands by the substitution of the pyrazole rings. By combination of the versatility in donor function and steric demand, a systematic tuning of the properties of the bis(pyrazolyl)methaneligands is possible. The synthesis and full characterization of 11 bis(pyrazolyl)methaneligands are reported. Two of these were structurally characterized