ABSTRACT Two tetranuclear Cu(II) complexes Cu 4 L 2 ( μ 3 ˗OCH 3 ) 2 (ClO 4 ) 2 ∙2H 2 O ( 1 ) and Cu 4 L 2 (H 2 O) 2 ( μ 3 ˗OH) 2 (NO 3 ) 2 ∙H 2 O ( 2 ) (H 2 L = 2,6‐diformyl‐4‐methylphenol bis (thiosemicarbazone)) have been synthesized. Two types of sulfur atom‐bearing L 2− scaffolds were obtained through tautomerization of the thiosemicarbazone arms. Geometric arrangements of Cu 2 ( μ 3 ˗OMe) 2 Cu 2 and Cu 2 ( μ 3 ˗OH) 2 Cu 2 are found for tetranuclear complexes. Reactions of Cu(ClO 4 ) 2 ∙6H 2 O and Cu(NO 3 ) 2 ∙3H 2 O with H 2 L were utilized with linkers HO − and MeO − . These synthesized complexes have been characterized by x‐ray crystallography, and their magnetic properties have been examined. Complexes 1 and 2 showed fluorescence quenching behavior with respect to the free H 2 L. Complexes 1 and 2 exhibit catalytic oxidation reactivity for the 2‐aminophenol and 3,5‐ditertbutyl catechol, effectively mimicking the enzymes catechol oxidase and phenoxazinone synthase, respectively. The turnover numbers k cat for 3,5‐DTBCH 2 and AP are 13.32 ( 1 ), 25.56 ( 2 ) and 23.04 ( 1 ), 13.35 ( 2 ). From the variable temperature magnetic susceptibility measurements, the obtained J values ranged between −200 and −500 cm −1 and were found to be highly correlated, which indicates the strong antiferromagnetic interactions between the interlinked copper(II) centers. For complex 1 , the values are g = 2.13, J = −470 cm −1 , ρ = 1.4% and for compound 2 these are g = 2.08, J = −480 cm −1 , ρ = 2.5%.
Manna et al. (Fri,) studied this question.