Homodinuclear [Fe(III)−Fe(III)] and [Zn(II)−Zn(II)] complexes of a binucleating [N4O3] symmetrical ligand with purple acid phosphatase (PAP) and zinc phosphoesterase like activity. (1st May 2018)

• Record Type: Journal Article
• Authors: Pathak, Chandni; Gangwar, Manoj Kumar; Ghosh, Prasenjit
• Is Part Of: Polyhedron. Volume 145(2018)
• Page Start: 88
• Page End: 100
• Publication Date: 2018-05-01
• Subjects: Homodinuclear complexes -- Magnetic properties -- Enzyme models -- Zinc phosphoesterase -- Purple acid phosphatase; Chemistry, Inorganic -- Periodicals; Chimie inorganique -- Périodiques; Organometaalverbindingen; Anorganische chemie; 546.05
• DOI: 10.1016/j.poly.2018.01.029
• Languages: English
• ISSNs: 0277-5387

Abstract

Graphical abstract: Homodinuclear Fe(III)−Fe(III) and Zn(II)−Zn(II) type complexes supported over a symmetrical [N4 O3 ] ligand serve as small molecule functional mimics of the purple acid phosphatases (PAPs) and the zinc phosphodiesterase enzyme. Abstract: The homodinuclear [Fe(III)–Fe(III)] (2 ) and [Zn(II)–Zn(II)] (3 ) complexes of binucleating [N4 O3 ] symmetrical ligand (1 ) of the formulation, H3 L (L = 2, 6- bis {[(2-hydroxybenzyl)(2-pyridylmethyl)amino]methyl}-4- t -butylphenolate), display purple acid phosphatase (PAP) and zinc phosphoesterase like activity. For the two complexes, the spectrophotometric titration and the ESI-MS studies supported the existence of an equilibrium between a triaquated species, {L[(H2 O)Fe III ( μ -H2 O)Fe III (H2 O)]} 3+ (2A ) and {L[(H2 O)Zn II ( μ -H2 O)Zn II (H2 O)]} + (3A ), a diaquated and monohydroxo species, {L[(H2 O)Fe III ( μ -H2 O)Fe III (OH)]} 2+ (2B ) and {L[(H2 O)Zn II ( μ -H2 O)Zn II (OH)]} (3B ), a monoaquated and dihydroxo species, {L[(H2 O)Fe III ( μ -OH)Fe III (OH)]} + (2C ) and {L[(H2 O)Zn II ( μ -OH)Zn II (OH)]} − (3C ), and a trihydroxo species, {L[(HO)Fe III ( μ -OH)Fe III (OH)]} (2D ) and {L[(HO)Zn II ( μ -OH)Zn II (OH)]} 2− (3D ), depending upon the pH of the solution. Of these, the active species namely, a monoaquated and dihydroxo species, {L[(H2 O)Fe III ( μ -OH)Fe III (OH)]} + (2C ) and {L[(H2 O)Zn II ( μ -OH)Zn II (OH)]} − (3C ), hydrolyzed an activated substrate bis (2, 4-dinitrophenyl)phosphate at the pH range of 5.5–10.5, displaying Michealis– Menton kinetics. Significantly enough, the catalyst-substrate adduct of the type {L[Fe III ( μ -OH)( μ -RPO4 )Fe III ]} (2F ) has been detected by ESI-MS for the dinuclear [Fe(III)–Fe(III)] complex (2 ).