Models for Catechol Dioxygenases. Structure of Bromobis[2-(2′-hydroxyphenyl)benzothiazolato]iron(III) Derived from the Bromoiron(III) Complex of 2,2′-Bis((salicylideneamino)phenyl) Disulfide

The complex bromobis[2-(2-hydroxyphenyl)benzothiazolato]iron(III), [Fe(HBT)₂Br] or [Fe(C₁₃H₈NOS)₂Br], crystallizes in the orthorhombic space group Pbcn (a = 16.30 (1) Å, b = 7.666 (1) Å, c = 22.797 (9) Å, Z = 4). The crystal structure was determined at 24 °C for 2383 out of a total of 4601 reflections with R = 0.051 and R_w = 0.059. The structure reveals a trigonal-bipyramidal complex with the thiazole nitrogens in the axial positions and the phenolate oxygens and the bromide occupying the equatorial sites, structural features that are germane to the active site of the nonheme iron enzyme protocatechuate 3,4-dioxygenase. The title complex derives from an oxidative rearrangement of the bromoiron(III) complex of 2,2′-bis(salicyclideneaminophenyl) disulfide.