Magnesium complexes with isomeric pyrazol-4-ylidene and imidazol-2-ylidene ligands

Stuart Burnett; Matthew de Vere-Tucker; Matthew Davitt; David B. Cordes; Alexandra M. Z. Slawin; Rochelle Ferns; Tanja van Mourik; Andreas Stasch

doi:10.1002/zaac.202200207

Magnesium complexes with isomeric pyrazol-4-ylidene and imidazol-2-ylidene ligands

Stuart Burnett
, Matthew de Vere-Tucker
, Matthew Davitt
, David B. Cordes
, Alexandra M. Z. Slawin
, Rochelle Ferns
, Tanja van Mourik
, Andreas Stasch^*

^*Corresponding author for this work

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

Abstract

Dimagnesium(I) complexes [{(^Arnacnac)Mg}₂], where ^Arnacnac = HC(MeCNAr)₂, Ar = Dip = 2,6-iPr₂-C₆H₃, Ar = Dep = 2,6-Et₂-C₆H₃, Ar = Mes = 2,4,6-Me₃-C₆H₂, react with iodoarenes in oxidative addition reactions. With iodobenzene, magnesium phenyl and magnesium iodide complex fragments were obtained, and from a reaction with 4-iodo-1,2,3,5-tetramethylpyrazolium iodide, [^MePZI]I, the pyrazol-4-ylidene complex [(^Dipnacnac)MgI(^MePZ)] was structurally characterised, alongside other products. The isomeric imidazol-2-ylidene complex [(^Dipnacnac)MgI(^MeNHC)], where ^MeNHC is 1,3,4,5-tetramethylimidazol-2-ylidene, was prepared and characterised. X-ray crystal structure determinations and DFT computational studies have been carried out to compare the related complexes. The results show that the ^MePZ ligand is higher in energy and more nucleophilic than its more common isomeric ^MeNHC carbene.

Original language	English
Article number	e202200207
Number of pages	25
Journal	Zeitschrift für Anorganische und Allgemeine Chemie
Volume	648
Issue number	19
Early online date	4 Aug 2022
DOIs	https://doi.org/10.1002/zaac.202200207
Publication status	Published - 14 Oct 2022

Keywords

Magnesium
Carbenes
Low oxidation states
Bent allenes
Grignard reagents

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Copyright © 2022 The Authors. Zeitschrift für anorganische und allgemeine Chemie published by Wiley-VCH GmbH. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
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@article{1a3939808253498aaeb31661da14c0b6,

title = "Magnesium complexes with isomeric pyrazol-4-ylidene and imidazol-2-ylidene ligands",

abstract = "Dimagnesium(I) complexes [\{(Arnacnac)Mg\}2], where Arnacnac = HC(MeCNAr)2, Ar = Dip = 2,6-iPr2-C6H3, Ar = Dep = 2,6-Et2-C6H3, Ar = Mes = 2,4,6-Me3-C6H2, react with iodoarenes in oxidative addition reactions. With iodobenzene, magnesium phenyl and magnesium iodide complex fragments were obtained, and from a reaction with 4-iodo-1,2,3,5-tetramethylpyrazolium iodide, [MePZI]I, the pyrazol-4-ylidene complex [(Dipnacnac)MgI(MePZ)] was structurally characterised, alongside other products. The isomeric imidazol-2-ylidene complex [(Dipnacnac)MgI(MeNHC)], where MeNHC is 1,3,4,5-tetramethylimidazol-2-ylidene, was prepared and characterised. X-ray crystal structure determinations and DFT computational studies have been carried out to compare the related complexes. The results show that the MePZ ligand is higher in energy and more nucleophilic than its more common isomeric MeNHC carbene.",

keywords = "Magnesium, Carbenes, Low oxidation states, Bent allenes, Grignard reagents",

author = "Stuart Burnett and \{de Vere-Tucker\}, Matthew and Matthew Davitt and Cordes, \{David B.\} and Slawin, \{Alexandra M. Z.\} and Rochelle Ferns and \{van Mourik\}, Tanja and Andreas Stasch",

note = "Authors thank the University of St Andrews, the EPSRC doctoral training grant (EP/N509759/1), and the Centre for Doctoral Training in Critical Resource Catalysis (CRITICAT, EP/ L016419/1) for support. Part of this research was undertaken on the MX1 beamline at the Australian Synchrotron, Victoria, Australia. We gratefully acknowledge computational support via the EaStCHEM Research Computing Facility.",

year = "2022",

month = oct,

day = "14",

doi = "10.1002/zaac.202200207",

language = "English",

volume = "648",

journal = "Zeitschrift f{\"u}r Anorganische und Allgemeine Chemie",

issn = "0044-2313",

publisher = "Wiley-VCH, Weinheim",

number = "19",

}

TY - JOUR

T1 - Magnesium complexes with isomeric pyrazol-4-ylidene and imidazol-2-ylidene ligands

AU - Burnett, Stuart

AU - de Vere-Tucker, Matthew

AU - Davitt, Matthew

AU - Cordes, David B.

AU - Slawin, Alexandra M. Z.

AU - Ferns, Rochelle

AU - van Mourik, Tanja

AU - Stasch, Andreas

N1 - Authors thank the University of St Andrews, the EPSRC doctoral training grant (EP/N509759/1), and the Centre for Doctoral Training in Critical Resource Catalysis (CRITICAT, EP/ L016419/1) for support. Part of this research was undertaken on the MX1 beamline at the Australian Synchrotron, Victoria, Australia. We gratefully acknowledge computational support via the EaStCHEM Research Computing Facility.

PY - 2022/10/14

Y1 - 2022/10/14

N2 - Dimagnesium(I) complexes [{(Arnacnac)Mg}2], where Arnacnac = HC(MeCNAr)2, Ar = Dip = 2,6-iPr2-C6H3, Ar = Dep = 2,6-Et2-C6H3, Ar = Mes = 2,4,6-Me3-C6H2, react with iodoarenes in oxidative addition reactions. With iodobenzene, magnesium phenyl and magnesium iodide complex fragments were obtained, and from a reaction with 4-iodo-1,2,3,5-tetramethylpyrazolium iodide, [MePZI]I, the pyrazol-4-ylidene complex [(Dipnacnac)MgI(MePZ)] was structurally characterised, alongside other products. The isomeric imidazol-2-ylidene complex [(Dipnacnac)MgI(MeNHC)], where MeNHC is 1,3,4,5-tetramethylimidazol-2-ylidene, was prepared and characterised. X-ray crystal structure determinations and DFT computational studies have been carried out to compare the related complexes. The results show that the MePZ ligand is higher in energy and more nucleophilic than its more common isomeric MeNHC carbene.

AB - Dimagnesium(I) complexes [{(Arnacnac)Mg}2], where Arnacnac = HC(MeCNAr)2, Ar = Dip = 2,6-iPr2-C6H3, Ar = Dep = 2,6-Et2-C6H3, Ar = Mes = 2,4,6-Me3-C6H2, react with iodoarenes in oxidative addition reactions. With iodobenzene, magnesium phenyl and magnesium iodide complex fragments were obtained, and from a reaction with 4-iodo-1,2,3,5-tetramethylpyrazolium iodide, [MePZI]I, the pyrazol-4-ylidene complex [(Dipnacnac)MgI(MePZ)] was structurally characterised, alongside other products. The isomeric imidazol-2-ylidene complex [(Dipnacnac)MgI(MeNHC)], where MeNHC is 1,3,4,5-tetramethylimidazol-2-ylidene, was prepared and characterised. X-ray crystal structure determinations and DFT computational studies have been carried out to compare the related complexes. The results show that the MePZ ligand is higher in energy and more nucleophilic than its more common isomeric MeNHC carbene.

KW - Magnesium

KW - Carbenes

KW - Low oxidation states

KW - Bent allenes

KW - Grignard reagents

UR - https://onlinelibrary-wiley-com.ezproxy.st-andrews.ac.uk/toc/15213749/2022/648/19

U2 - 10.1002/zaac.202200207

DO - 10.1002/zaac.202200207

M3 - Article

SN - 0044-2313

VL - 648

JO - Zeitschrift für Anorganische und Allgemeine Chemie

JF - Zeitschrift für Anorganische und Allgemeine Chemie

IS - 19

M1 - e202200207

ER -

Magnesium complexes with isomeric pyrazol-4-ylidene and imidazol-2-ylidene ligands

Abstract

Keywords

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CRITICAT CDT: Critical Resource Catalysis - CRITICAT

Data underpinning Stuart Burnett's thesis