Reaction of a Potassium Aluminyl with Sn[N(SiMe3)2]2 - Isolation of a Stable, Trimetallic Sn(I) Radical Anion

Andrea O'Reilly; Andrew M.S. Booth; George W.A. Smith; Matthew J. Evans; Li Feng Lim; Dimitrios A. Pantazis; Nicholas Cox; Claire L. McMullin; J. Robin Fulton; Martyn P. Coles

doi:10.1002/chem.202500358

Reaction of a Potassium Aluminyl with Sn[N(SiMe₃)₂]₂ - Isolation of a Stable, Trimetallic Sn(I) Radical Anion

Andrea O'Reilly, Andrew M.S. Booth, George W.A. Smith, Matthew J. Evans, Li Feng Lim, Dimitrios A. Pantazis, Nicholas Cox^*, Claire L. McMullin^*, J. Robin Fulton^*, Martyn P. Coles^*

^*Corresponding author for this work

Research School of Chemistry

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

Abstract

The reaction of the potassium aluminyl K[Al(NON)] ([NON]^2–=[O(SiMe₂NDipp)₂]^2–, Dipp=2,6-iPr₂C₆H₃) with the stannylene Sn[N(SiMe₃)₂]₂ in benzene afforded K₃[(Sn₄){Al(NON)}₂{N(SiMe₃)₂}], containing a distorted tetrahedral Sn₄-cluster. Computational analysis indicates that four of the edges in this unit are composed of Sn–Sn bonds, with the remaining two that are spanned by aluminium involved in three centre two electron (3c2e) Sn–Al–Sn bonds. The formation of Al(II) species during this reaction is indicated by the isolation of the dialuminated cyclohexadiene 1,4-[Al(NON)]₂(μ-C₆H₆). Repeating the reaction in methylcyclohexane generated a thermally stable, trimetallic Sn(I) radical anion in K[Sn{Al(NON)}₂]. Compared to all other reported Sn(I) radicals, its EPR spectrum is unique; the main turning points of its spectrum appear at g values above 2 and the Sn hyperfine coupling is substantially smaller in magnitude. These data, together with ENDOR measurements and DFT calculations show that the SOMO is entirely localised in an unhybridised 5p orbital, such that spin-orbit contributions to the g and Sn hyperfine tensors are quenched.

Original language	English
Article number	e202500358
Journal	Chemistry - A European Journal
Volume	31
Issue number	20
DOIs	https://doi.org/10.1002/chem.202500358
Publication status	Published - 4 Apr 2025

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@article{188f5b7a9519482ba3ce57bc052ef68f,

title = "Reaction of a Potassium Aluminyl with Sn[N(SiMe3)2]2 - Isolation of a Stable, Trimetallic Sn(I) Radical Anion",

abstract = "The reaction of the potassium aluminyl K[Al(NON)] ([NON]2–=[O(SiMe2NDipp)2]2–, Dipp=2,6-iPr2C6H3) with the stannylene Sn[N(SiMe3)2]2 in benzene afforded K3[(Sn4){Al(NON)}2{N(SiMe3)2}], containing a distorted tetrahedral Sn4-cluster. Computational analysis indicates that four of the edges in this unit are composed of Sn–Sn bonds, with the remaining two that are spanned by aluminium involved in three centre two electron (3c2e) Sn–Al–Sn bonds. The formation of Al(II) species during this reaction is indicated by the isolation of the dialuminated cyclohexadiene 1,4-[Al(NON)]2(μ-C6H6). Repeating the reaction in methylcyclohexane generated a thermally stable, trimetallic Sn(I) radical anion in K[Sn{Al(NON)}2]. Compared to all other reported Sn(I) radicals, its EPR spectrum is unique; the main turning points of its spectrum appear at g values above 2 and the Sn hyperfine coupling is substantially smaller in magnitude. These data, together with ENDOR measurements and DFT calculations show that the SOMO is entirely localised in an unhybridised 5p orbital, such that spin-orbit contributions to the g and Sn hyperfine tensors are quenched.",

keywords = "aluminyl, Birch reduction, EPR spectroscopy, main group radical, Sn-cluster",

author = "Andrea O'Reilly and Booth, {Andrew M.S.} and Smith, {George W.A.} and Evans, {Matthew J.} and {Feng Lim}, Li and Pantazis, {Dimitrios A.} and Nicholas Cox and McMullin, {Claire L.} and Fulton, {J. Robin} and Coles, {Martyn P.}",

note = "Publisher Copyright: {\textcopyright} 2025 The Author(s). Chemistry - A European Journal published by Wiley-VCH GmbH.",

year = "2025",

month = apr,

day = "4",

doi = "10.1002/chem.202500358",

language = "English",

volume = "31",

journal = "Chemistry - A European Journal",

issn = "0947-6539",

publisher = "Wiley-VCH Verlag GmbH",

number = "20",

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TY - JOUR

T1 - Reaction of a Potassium Aluminyl with Sn[N(SiMe3)2]2 - Isolation of a Stable, Trimetallic Sn(I) Radical Anion

AU - O'Reilly, Andrea

AU - Booth, Andrew M.S.

AU - Smith, George W.A.

AU - Evans, Matthew J.

AU - Feng Lim, Li

AU - Pantazis, Dimitrios A.

AU - Cox, Nicholas

AU - McMullin, Claire L.

AU - Fulton, J. Robin

AU - Coles, Martyn P.

PY - 2025/4/4

Y1 - 2025/4/4

N2 - The reaction of the potassium aluminyl K[Al(NON)] ([NON]2–=[O(SiMe2NDipp)2]2–, Dipp=2,6-iPr2C6H3) with the stannylene Sn[N(SiMe3)2]2 in benzene afforded K3[(Sn4){Al(NON)}2{N(SiMe3)2}], containing a distorted tetrahedral Sn4-cluster. Computational analysis indicates that four of the edges in this unit are composed of Sn–Sn bonds, with the remaining two that are spanned by aluminium involved in three centre two electron (3c2e) Sn–Al–Sn bonds. The formation of Al(II) species during this reaction is indicated by the isolation of the dialuminated cyclohexadiene 1,4-[Al(NON)]2(μ-C6H6). Repeating the reaction in methylcyclohexane generated a thermally stable, trimetallic Sn(I) radical anion in K[Sn{Al(NON)}2]. Compared to all other reported Sn(I) radicals, its EPR spectrum is unique; the main turning points of its spectrum appear at g values above 2 and the Sn hyperfine coupling is substantially smaller in magnitude. These data, together with ENDOR measurements and DFT calculations show that the SOMO is entirely localised in an unhybridised 5p orbital, such that spin-orbit contributions to the g and Sn hyperfine tensors are quenched.

AB - The reaction of the potassium aluminyl K[Al(NON)] ([NON]2–=[O(SiMe2NDipp)2]2–, Dipp=2,6-iPr2C6H3) with the stannylene Sn[N(SiMe3)2]2 in benzene afforded K3[(Sn4){Al(NON)}2{N(SiMe3)2}], containing a distorted tetrahedral Sn4-cluster. Computational analysis indicates that four of the edges in this unit are composed of Sn–Sn bonds, with the remaining two that are spanned by aluminium involved in three centre two electron (3c2e) Sn–Al–Sn bonds. The formation of Al(II) species during this reaction is indicated by the isolation of the dialuminated cyclohexadiene 1,4-[Al(NON)]2(μ-C6H6). Repeating the reaction in methylcyclohexane generated a thermally stable, trimetallic Sn(I) radical anion in K[Sn{Al(NON)}2]. Compared to all other reported Sn(I) radicals, its EPR spectrum is unique; the main turning points of its spectrum appear at g values above 2 and the Sn hyperfine coupling is substantially smaller in magnitude. These data, together with ENDOR measurements and DFT calculations show that the SOMO is entirely localised in an unhybridised 5p orbital, such that spin-orbit contributions to the g and Sn hyperfine tensors are quenched.

KW - aluminyl

KW - Birch reduction

KW - EPR spectroscopy

KW - main group radical

KW - Sn-cluster

UR - http://www.scopus.com/inward/record.url?scp=105002184753&partnerID=8YFLogxK

U2 - 10.1002/chem.202500358

DO - 10.1002/chem.202500358

M3 - Article

AN - SCOPUS:105002184753

SN - 0947-6539

VL - 31

JO - Chemistry - A European Journal

JF - Chemistry - A European Journal

IS - 20

M1 - e202500358

ER -

Reaction of a Potassium Aluminyl with Sn[N(SiMe₃)₂]₂ - Isolation of a Stable, Trimetallic Sn(I) Radical Anion

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