Synthesis, characterization and antifungal activity of copper (II) complexes of sterically hindered o-diphenol derivatives

Abstract Cu (II) complexes with 3,5-di( tert -butyl)-1,2-benzenediol ( I ), 4,6-di( tert -butyl)-1,2,3-benzentriol ( II ) and sulfur-containing sterically hindered o -diphenol derivatives such as 4,6-di( tert -butyl)-3-(2-hydroxyethylsulfanyl)-1,2-benzenediol ( III ) and 2-[4,6-di( tert -butyl)-2,3-dihydroxyphenylsulfanyl]acetic acid ( IV ) have been synthesized and characterized by means of elemental analysis, TG/DTA, FT-IR, ESR, XPS, XPD and conductivity measurements. Antifungal activities of these ligands and their respective Cu (II) complexes have been determined against Aspergillus niger , Fusarium sp. , Penicillium lividum , Mucor sp. and Botrytis cinerea . Most of the compounds (both the free ligands and the complexes) exert pronounced antifungal activities (RI ⩾ 70%), and virtually all of them (apart from the Cu(L II ) 2 complex) have the highest inhibitory properties (RI = 100%) against B. cinerea .