Synthesis and characterization of new copper(I) complexes containing 4-(diphenylphosphane)benzoic acid and "scorpionate" ligands with "in vitro" superoxide scavenging activity

New copper(l) complexes have been synthesised from the reaction of CuCl with 4-(diphenylphosphane)benzoic acid and lithium tris(1H-pyrazol-1-yl)methanesulfonate, Li(SO3)C(pz)(3), sodium hydrotris(3-trifluoromethyl-1H-pyrazol-1-yl)borate, NaHB[3-(CF3)pz](3), potassium dihydrobis(1H-1,2,4-triazol-1-yl)borate, KH2B(tz)(2), hydrotris(1H-1,2,4-triazol-1-yl)borate, KHB(tz)(3), sodium hydrotris(1H-pyrazol-1-yl)borate, NaHB(pz)(3), potassium hydrotris(3,5-dimethyl-1H-pyrazol-1-yl)borate KHB(3,5-Me2pZ)(3) or potassium hydrotris(4-bromo-1H-pyrazol-1-yl)borate KHB(4-BrpZ)(3). The complexes obtained have been characterized by elemental analyses and FT-IR in the solid state, and by NMR (H-1 and P-31{H-1}) spectroscopy and conductivity measurements in solution. The solution data are consistent with partial dissociation of the sterically hindered complexes by way of breaking of Cu-P and Cu-N bonds. Electrospray mass spectrometry has been used to investigate the relative properties of the 4-(diphenylphosphane)benzoic acid and of the "scorpionate" ligands towards copper(I) ions. Chemiluminescence technique was used to evaluate the superoxide scavenging activity of these new copper complexes.