A new di-m-sulfate complex as a model of purple acid phosphatase-sulfate complexes

Abstract

Reportamos neste trabalho, a síntese, a estrutura cristalina e as propriedades espectroscópicas e eletroquímicas do complexo NH4[Fe2

Synthesis, molecular structure and spectroscopic, electrochemical and magnetic properties of a new dinuclear iron complex containing µ-sulfate-di-µ-alkoxo bridges: evaluating the influence of the sulfate bridge on the physicochemical properties of the di-µ-alkoxo-diiron unit

“…Similar behavior has been observed when the acetate bridges in the complex [Fe 2 (BBPMP)(OAc) 2 ] 2+ 8,2006 (λ max = 601 nm) 5 are replaced by sulfate bridges, resulting in the complex [Fe 2 III (BBPMP)(SO 4 ) 2 ] (λ max = 587 nm). 7 Moreover the same tendency has been observed with bsPAP. Addition of acetate resulted in displacement of λ max from 558 nm (pH 5.2) to 550 nm, while addition of sulfate changed λ max to 546 nm.…”

“…Thus, only complex 2, which contains only two alkoxo bridging groups, presents a planar Fe-(μ-alkoxo) 2 (2) and 2.07(2) Å. 7 The packing arrangement of 3 is governed by both Van der Waals forces and hydrogen bonds. Once the H atoms of the methanol and of the disordered water were not found, the geometric parameters for the possible hydrogen bonds could not be determined.…”

“…These compounds have been prepared mainly on the 1,3-diamino-2-hydroxypropane 2,3 or 2,6-bis(aminomethyl)-4-methylphenol skeleton. [4][5][6][7] Purple acid phosphatases (PAPs) are iron-containing non-heme proteins involved in the regulation of phosphate and phosphorylated metabolite levels in a wide range of organisms. They have been isolated from a variety of mammalian (TRAP, ufPAP, bsPAP), plant (kbPAP, spPAP) and bacterial sources (afPAP, ncPAP).…”

“…[2][3][4][5][6][7][16][17][18][19] This is due to the high ε values observed in electronic spectra of PAPs, which are attributed to a tyrosine→Fe III charge transfer transition. Thus, such dinucleating ligands hold the two metal centers in close proximity and provide phenolate coordinating groups, allowing the study of the influence of such groups on the properties exhibited by the metal centers in the complexes as well as in the enzyme.…”

“…In order to understand other factors that can influence the properties of the diiron unit, we describe herein the synthesis and characterization of a new diiron compound containing the ligand H 2 BPClNOL. This new member of the family H 2 BPClNOL, [Fe 2 III (BPClNOL) 2 (SO 4 )] 3, was designed to study the influence of the sulfate anion on the diiron center, since only a low number of diiron compounds containing the μ-sulfate bridge are reported in the literature 7,23 and, to the best of our knowledge, not a single compound containing the alkoxo and sulfate bridge has been described to date. This study is of relevance since it can be used to understand why PAPs are inactivated by some tetroxide anions and also to show a different way to control the physicochemical properties of synthetic compounds.…”