Synthesis and biological evaluation of copper (II) complexes of sterically hindered o-aminophenol derivatives as antimicrobial agents

Abstract Cu(II) complexes with 4,6-di( tert -butyl)-2-aminophenol ( I ) and 2-anilino-4,6-di( tert -butyl)phenol ( II ) have been synthesized and characterized by means of elemental analysis, TG/DTA, FT-IR, UV–vis, ESR, and conductance measurements. The compounds I and II can coordinate in their singly deprotonated forms and behave as bidentate O,N-coordinated ligands; their CuL 2 complexes are characterized by CuN 2 O 2 coordination modes and square planar geometry. In vitro antimicrobial screening against Gram-positive and Gram-negative bacteria, yeasts, and moulds indicated that the compound I and its Cu(II) complex were more active than Questiomycin B, the compound II , and its Cu(II) complex.