Structural and catalytic characterization of a heterovalent Mn(II)Mn(III) complex that mimics purple acid phosphatases

Sarah J. Smith; Mark J. Riley; Christopher J. Noble; Graeme R. Hanson; Robert Stranger; Vidura Jayaratne; Cavigliasso Germán; Gerhard Schenk; Lawrence R. Gahan

doi:10.1021/ic9005086

Structural and catalytic characterization of a heterovalent Mn(II)Mn(III) complex that mimics purple acid phosphatases

Sarah J. Smith, Mark J. Riley, Christopher J. Noble, Graeme R. Hanson, Robert Stranger, Vidura Jayaratne, Cavigliasso Germán, Gerhard Schenk, Lawrence R. Gahan

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Abstract

The binuclear heterovalent manganese model complex [Mn(II)Mn(III)(L1 )(OAc)₂] CIO₄-H₂O (H₂L1 = 2-(((3-((bis(pyrldin-2-ylmethyl)amino)methyl)-2-hydroxy-5-methylbenzyl) (pyridin-2-ylmethyl)amino)-methyl)phenol) has been prepared and studied structurally, spectroscopically, and computationally. The magnetic and electronic properties of the complex have been related to its structure. The complex is weakly antiferromagnetically coupled (J ∼ -5 cm^-1, H = -2J S₁ • S₂) and the electron paramagnetic resonance (EPR) and magnetic circular dichroism (MCD) spectra identify the Jahn-Teller distortion of the Mn(III) center as predominantly a tetragonal compression, with a significant rhombic component. Electronic structure calculations using density functional theory have confirmed the conclusions derived from the experimental Investigations. In contrast to isostructural M(II)Fe(III) complexes (M = Fe, Mn, Zn, Ni), the Mn(II)Mn(III) system is afunctional possessing both catalase and hydrolase activities, and only one catalytically relevant pK _a (= 8.2) is detected. Mechanistic Implications are discussed.

Original language	English
Pages (from-to)	10036-10048
Number of pages	13
Journal	Inorganic Chemistry
Volume	48
Issue number	21
DOIs	https://doi.org/10.1021/ic9005086
Publication status	Published - 2 Nov 2009

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@article{dbc33de9c1594ab29aea37cc2a3da17c,

title = "Structural and catalytic characterization of a heterovalent Mn(II)Mn(III) complex that mimics purple acid phosphatases",

abstract = "The binuclear heterovalent manganese model complex [Mn(II)Mn(III)(L1 )(OAc)2] CIO4-H2O (H2L1 = 2-(((3-((bis(pyrldin-2-ylmethyl)amino)methyl)-2-hydroxy-5-methylbenzyl) (pyridin-2-ylmethyl)amino)-methyl)phenol) has been prepared and studied structurally, spectroscopically, and computationally. The magnetic and electronic properties of the complex have been related to its structure. The complex is weakly antiferromagnetically coupled (J ∼ -5 cm-1, H = -2J S1 • S2) and the electron paramagnetic resonance (EPR) and magnetic circular dichroism (MCD) spectra identify the Jahn-Teller distortion of the Mn(III) center as predominantly a tetragonal compression, with a significant rhombic component. Electronic structure calculations using density functional theory have confirmed the conclusions derived from the experimental Investigations. In contrast to isostructural M(II)Fe(III) complexes (M = Fe, Mn, Zn, Ni), the Mn(II)Mn(III) system is afunctional possessing both catalase and hydrolase activities, and only one catalytically relevant pK a (= 8.2) is detected. Mechanistic Implications are discussed.",

author = "Smith, {Sarah J.} and Riley, {Mark J.} and Noble, {Christopher J.} and Hanson, {Graeme R.} and Robert Stranger and Vidura Jayaratne and Cavigliasso Germ{\'a}n and Gerhard Schenk and Gahan, {Lawrence R.}",

year = "2009",

month = nov,

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doi = "10.1021/ic9005086",

language = "English",

volume = "48",

pages = "10036--10048",

journal = "Inorganic Chemistry",

issn = "0020-1669",

publisher = "American Chemical Society",

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TY - JOUR

T1 - Structural and catalytic characterization of a heterovalent Mn(II)Mn(III) complex that mimics purple acid phosphatases

AU - Smith, Sarah J.

AU - Riley, Mark J.

AU - Noble, Christopher J.

AU - Hanson, Graeme R.

AU - Stranger, Robert

AU - Jayaratne, Vidura

AU - Germán, Cavigliasso

AU - Schenk, Gerhard

AU - Gahan, Lawrence R.

PY - 2009/11/2

Y1 - 2009/11/2

N2 - The binuclear heterovalent manganese model complex [Mn(II)Mn(III)(L1 )(OAc)2] CIO4-H2O (H2L1 = 2-(((3-((bis(pyrldin-2-ylmethyl)amino)methyl)-2-hydroxy-5-methylbenzyl) (pyridin-2-ylmethyl)amino)-methyl)phenol) has been prepared and studied structurally, spectroscopically, and computationally. The magnetic and electronic properties of the complex have been related to its structure. The complex is weakly antiferromagnetically coupled (J ∼ -5 cm-1, H = -2J S1 • S2) and the electron paramagnetic resonance (EPR) and magnetic circular dichroism (MCD) spectra identify the Jahn-Teller distortion of the Mn(III) center as predominantly a tetragonal compression, with a significant rhombic component. Electronic structure calculations using density functional theory have confirmed the conclusions derived from the experimental Investigations. In contrast to isostructural M(II)Fe(III) complexes (M = Fe, Mn, Zn, Ni), the Mn(II)Mn(III) system is afunctional possessing both catalase and hydrolase activities, and only one catalytically relevant pK a (= 8.2) is detected. Mechanistic Implications are discussed.

AB - The binuclear heterovalent manganese model complex [Mn(II)Mn(III)(L1 )(OAc)2] CIO4-H2O (H2L1 = 2-(((3-((bis(pyrldin-2-ylmethyl)amino)methyl)-2-hydroxy-5-methylbenzyl) (pyridin-2-ylmethyl)amino)-methyl)phenol) has been prepared and studied structurally, spectroscopically, and computationally. The magnetic and electronic properties of the complex have been related to its structure. The complex is weakly antiferromagnetically coupled (J ∼ -5 cm-1, H = -2J S1 • S2) and the electron paramagnetic resonance (EPR) and magnetic circular dichroism (MCD) spectra identify the Jahn-Teller distortion of the Mn(III) center as predominantly a tetragonal compression, with a significant rhombic component. Electronic structure calculations using density functional theory have confirmed the conclusions derived from the experimental Investigations. In contrast to isostructural M(II)Fe(III) complexes (M = Fe, Mn, Zn, Ni), the Mn(II)Mn(III) system is afunctional possessing both catalase and hydrolase activities, and only one catalytically relevant pK a (= 8.2) is detected. Mechanistic Implications are discussed.

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U2 - 10.1021/ic9005086

DO - 10.1021/ic9005086

M3 - Article

SN - 0020-1669

VL - 48

SP - 10036

EP - 10048

JO - Inorganic Chemistry

JF - Inorganic Chemistry

IS - 21

ER -

Structural and catalytic characterization of a heterovalent Mn(II)Mn(III) complex that mimics purple acid phosphatases

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