Electronic fine-tuning of oxygen atom transfer reactivity of cis-dioxomolybdenum(VI) complexes with thiosemicarbazone ligands

Aurélien Ducrot; Bethany Scattergood; Ben Coulson; Robin N. Perutz; Anne K. Duhme-Klair

doi:10.1002/ejic.201500059

Electronic fine-tuning of oxygen atom transfer reactivity of cis-dioxomolybdenum(VI) complexes with thiosemicarbazone ligands

Aurélien Ducrot, Bethany Scattergood, Ben Coulson, Robin N. Perutz, Anne K. Duhme-Klair^*

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

Abstract

A series of six cis-dioxomolybdenum(VI) complexes with thiosemicarbazone ligands was synthesized and characterized. The ligands were obtained by reacting ethyl thiosemicarbazide with salicylaldehydes substituted with a selection of electron-withdrawing and electron-donating groups. The crystal structures, IR, NMR spectroscopic data and oxygen atom transfer activities of the complexes revealed that the electronic effects of the substituents located in the para-position of the phenolate donor are transmitted through to the molybdenum center, as reflected by linear relationships between Hammett constants and key properties of the complexes, including the molybdenum-phenolate bond lengths and the coordination shift of the imine proton resonance. Compared with the unsubstituted catalyst, electron-withdrawing substituents increase the rate of oxygen atom transfer from dimethyl sulfoxide to triphenylphosphine, whereas electron-donating groups have the opposite effect. The highest rate enhancement was achieved through the introduction of a strongly electron-withdrawing NO₂ substituent in the p-position of the phenolate donor.

Original language	English
Pages (from-to)	3562-3571
Number of pages	10
Journal	EUROPEAN JOURNAL OF INORGANIC CHEMISTRY
Early online date	2 Apr 2015
DOIs	https://doi.org/10.1002/ejic.201500059
Publication status	Published - 2015

Keywords

Enzyme models
Ligand effects
Metalloenzymes
Molybdenum
Oxygen atom transfer

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10.1002/ejic.201500059

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title = "Electronic fine-tuning of oxygen atom transfer reactivity of cis-dioxomolybdenum(VI) complexes with thiosemicarbazone ligands",

abstract = "A series of six cis-dioxomolybdenum(VI) complexes with thiosemicarbazone ligands was synthesized and characterized. The ligands were obtained by reacting ethyl thiosemicarbazide with salicylaldehydes substituted with a selection of electron-withdrawing and electron-donating groups. The crystal structures, IR, NMR spectroscopic data and oxygen atom transfer activities of the complexes revealed that the electronic effects of the substituents located in the para-position of the phenolate donor are transmitted through to the molybdenum center, as reflected by linear relationships between Hammett constants and key properties of the complexes, including the molybdenum-phenolate bond lengths and the coordination shift of the imine proton resonance. Compared with the unsubstituted catalyst, electron-withdrawing substituents increase the rate of oxygen atom transfer from dimethyl sulfoxide to triphenylphosphine, whereas electron-donating groups have the opposite effect. The highest rate enhancement was achieved through the introduction of a strongly electron-withdrawing NO2 substituent in the p-position of the phenolate donor.",

keywords = "Enzyme models, Ligand effects, Metalloenzymes, Molybdenum, Oxygen atom transfer",

author = "Aur{\'e}lien Ducrot and Bethany Scattergood and Ben Coulson and Perutz, {Robin N.} and Duhme-Klair, {Anne K.}",

year = "2015",

doi = "10.1002/ejic.201500059",

language = "English",

pages = "3562--3571",

journal = "EUROPEAN JOURNAL OF INORGANIC CHEMISTRY",

issn = "1434-1948",

publisher = "Wiley-Blackwell",

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T1 - Electronic fine-tuning of oxygen atom transfer reactivity of cis-dioxomolybdenum(VI) complexes with thiosemicarbazone ligands

AU - Ducrot, Aurélien

AU - Scattergood, Bethany

AU - Coulson, Ben

AU - Perutz, Robin N.

AU - Duhme-Klair, Anne K.

PY - 2015

Y1 - 2015

N2 - A series of six cis-dioxomolybdenum(VI) complexes with thiosemicarbazone ligands was synthesized and characterized. The ligands were obtained by reacting ethyl thiosemicarbazide with salicylaldehydes substituted with a selection of electron-withdrawing and electron-donating groups. The crystal structures, IR, NMR spectroscopic data and oxygen atom transfer activities of the complexes revealed that the electronic effects of the substituents located in the para-position of the phenolate donor are transmitted through to the molybdenum center, as reflected by linear relationships between Hammett constants and key properties of the complexes, including the molybdenum-phenolate bond lengths and the coordination shift of the imine proton resonance. Compared with the unsubstituted catalyst, electron-withdrawing substituents increase the rate of oxygen atom transfer from dimethyl sulfoxide to triphenylphosphine, whereas electron-donating groups have the opposite effect. The highest rate enhancement was achieved through the introduction of a strongly electron-withdrawing NO2 substituent in the p-position of the phenolate donor.

AB - A series of six cis-dioxomolybdenum(VI) complexes with thiosemicarbazone ligands was synthesized and characterized. The ligands were obtained by reacting ethyl thiosemicarbazide with salicylaldehydes substituted with a selection of electron-withdrawing and electron-donating groups. The crystal structures, IR, NMR spectroscopic data and oxygen atom transfer activities of the complexes revealed that the electronic effects of the substituents located in the para-position of the phenolate donor are transmitted through to the molybdenum center, as reflected by linear relationships between Hammett constants and key properties of the complexes, including the molybdenum-phenolate bond lengths and the coordination shift of the imine proton resonance. Compared with the unsubstituted catalyst, electron-withdrawing substituents increase the rate of oxygen atom transfer from dimethyl sulfoxide to triphenylphosphine, whereas electron-donating groups have the opposite effect. The highest rate enhancement was achieved through the introduction of a strongly electron-withdrawing NO2 substituent in the p-position of the phenolate donor.

KW - Enzyme models

KW - Ligand effects

KW - Metalloenzymes

KW - Molybdenum

KW - Oxygen atom transfer

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U2 - 10.1002/ejic.201500059

DO - 10.1002/ejic.201500059

M3 - Article

SN - 1434-1948

SP - 3562

EP - 3571

JO - EUROPEAN JOURNAL OF INORGANIC CHEMISTRY

JF - EUROPEAN JOURNAL OF INORGANIC CHEMISTRY

ER -

Electronic fine-tuning of oxygen atom transfer reactivity of cis-dioxomolybdenum(VI) complexes with thiosemicarbazone ligands

Abstract

Keywords

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Molybdenum and Tungsten Enzymes Conference

Emerging Areas of Photochemistry: From Fundamentals to Applications

Lecture title: Taking bioinspired catalysis a step further: photoredox activation and the quest for new artificial metalloenzyme scaffolds

Light-driven oxygen atom transfer

Light-induced activation of a molybdenum oxotransferase model within a Ru(II)-Mo(VI) dyad

Cite this

Electronic fine-tuning of oxygen atom transfer reactivity of cis-dioxomolybdenum(VI) complexes with thiosemicarbazone ligands

Abstract

Keywords

Access to Document

Other files and links

Activities

Molybdenum and Tungsten Enzymes Conference

Emerging Areas of Photochemistry: From Fundamentals to Applications

Lecture title: Taking bioinspired catalysis a step further: photoredox activation and the quest for new artificial metalloenzyme scaffolds

Projects

Light-driven oxygen atom transfer

Datasets

Light-induced activation of a molybdenum oxotransferase model within a Ru(II)-Mo(VI) dyad

Cite this