Accessing sodium ferrate complexes containing neutral and anionic N-heterocyclic carbene ligands: structural, synthetic, and magnetic insights

This study reports the synthesis and single-crystal X-ray crystallographic, NMR spectroscopic, and magnetic characterization of a series of sodium ferrates using bis(amide) Fe(HMDS)2 as a precursor (HMDS = 1,1,1,3,3,3- hexamethyldisilazide). Reaction with sodium reagents NaHMDS and NaCH2SiMe3 in hex...

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Autores: Maddock, L. C. H., Cadenbach, Thomas, Kennedy, Alan R., Borilović, Ivana, Aromí Bedmar, Guillem, Hevia, Eva
Tipo de recurso: artículo
Estado:Versión aceptada para publicación
Fecha de publicación:2015
País:España
Institución:Universidad de Barcelona
Repositorio:Dipòsit Digital de la UB
OAI Identifier:oai:diposit.ub.edu:2445/128919
Acceso en línea:https://hdl.handle.net/2445/128919
Access Level:acceso abierto
Palabra clave:Magnetisme
Lligands
Propietats magnètiques
Magnetism
Ligands
Magnetic properties
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spelling Accessing sodium ferrate complexes containing neutral and anionic N-heterocyclic carbene ligands: structural, synthetic, and magnetic insightsMaddock, L. C. H.Cadenbach, ThomasKennedy, Alan R.Borilović, IvanaAromí Bedmar, GuillemHevia, EvaMagnetismeLligandsPropietats magnètiquesMagnetismLigandsMagnetic propertiesThis study reports the synthesis and single-crystal X-ray crystallographic, NMR spectroscopic, and magnetic characterization of a series of sodium ferrates using bis(amide) Fe(HMDS)2 as a precursor (HMDS = 1,1,1,3,3,3- hexamethyldisilazide). Reaction with sodium reagents NaHMDS and NaCH2SiMe3 in hexane afforded donor-solvent-free sodium ferrates [{NaFe(HMDS)3}∞] (1) and [{NaFe(HMDS)2(CH2SiMe3)}∞] (2), respectively, which exhibit contacted ion pair structures, giving rise to new polymeric chain arrangements made up of a combination of inter- and intramolecular Na··· Me(HMDS) electrostatic interactions. Addition of the unsaturated NHC IPr (IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2- ylidene) to 1 and 2 caused deaggregation of their polymeric structures to form discrete NHC-stabilized solvent-separated ion pairs [Na(IPr)2]+[Fe(HMDS)3]− (3) and [(THF)3·NaIPr]+[Fe(HMDS)2CH2SiMe3]− (4), where in both cases, the NHC ligand coordinates preferentially to Na. In contrast, when IPr is sequentially reacted with the single-metal reagents NaCH2SiMe3 and Fe(HMDS)2, the novel heteroleptic ferrate (THF)3Na[:C{[N(2,6-iPr2C6H3)]2CHCFe(HMDS)2}] (5) is obtained. This contains an anionic NHC ligand acting as an unsymmetrical bridge between the two metals, coordinating through its abnormal C4 position to Fe and its normal C2 position to Na. The formation of 5 can be described as an indirect ferration process where IPr is first metalated at the C4 position by the polar sodium alkyl reagent, which in turn undergoes transmetalation to the more electronegative Fe(HMDS)2 fragment. Treatment of 5 with 1 molar equiv of methyl triflate (MeOTf) led to the isolation and structural elucidation of the neutral abnormal NHC (aNHC) tricoordinate iron complex [CH3C{[N(2,6-iPr2C6H3)]2CHCFe- (HMDS)2}] (6) with the subsequent elimination of NaOTf, disclosing the selectivity of complex 5 to react with this electrophile via its C2 position, leaving its Fe−C4 and Fe−N bonds intact. The magnetic susceptibility properties of compounds 1−6 have been examined. This study revealed a drastic change of magnetic susceptibility in replacing a pure σ donor from an idealized trigonal coordination environment by an NHC π donating character.American Chemical Society2015info:eu-repo/semantics/articleinfo:eu-repo/semantics/acceptedVersionapplication/pdfhttps://hdl.handle.net/2445/128919Articles publicats en revistes (Química Inorgànica i Orgànica)reponame:Dipòsit Digital de la UBinstname:Universidad de BarcelonaInglésVersió postprint del document publicat a: https://doi.org/10.1021/acs.inorgchem.5b01638Inorganic Chemistry, 2015, vol. 54, num. 18, p. 9201-9210https://doi.org/10.1021/acs.inorgchem.5b01638(c) American Chemical Society , 2015info:eu-repo/semantics/openAccessoai:diposit.ub.edu:2445/1289192026-05-27T06:46:51Z
dc.title.none.fl_str_mv Accessing sodium ferrate complexes containing neutral and anionic N-heterocyclic carbene ligands: structural, synthetic, and magnetic insights
title Accessing sodium ferrate complexes containing neutral and anionic N-heterocyclic carbene ligands: structural, synthetic, and magnetic insights
spellingShingle Accessing sodium ferrate complexes containing neutral and anionic N-heterocyclic carbene ligands: structural, synthetic, and magnetic insights
Maddock, L. C. H.
Magnetisme
Lligands
Propietats magnètiques
Magnetism
Ligands
Magnetic properties
title_short Accessing sodium ferrate complexes containing neutral and anionic N-heterocyclic carbene ligands: structural, synthetic, and magnetic insights
title_full Accessing sodium ferrate complexes containing neutral and anionic N-heterocyclic carbene ligands: structural, synthetic, and magnetic insights
title_fullStr Accessing sodium ferrate complexes containing neutral and anionic N-heterocyclic carbene ligands: structural, synthetic, and magnetic insights
title_full_unstemmed Accessing sodium ferrate complexes containing neutral and anionic N-heterocyclic carbene ligands: structural, synthetic, and magnetic insights
title_sort Accessing sodium ferrate complexes containing neutral and anionic N-heterocyclic carbene ligands: structural, synthetic, and magnetic insights
dc.creator.none.fl_str_mv Maddock, L. C. H.
Cadenbach, Thomas
Kennedy, Alan R.
Borilović, Ivana
Aromí Bedmar, Guillem
Hevia, Eva
author Maddock, L. C. H.
author_facet Maddock, L. C. H.
Cadenbach, Thomas
Kennedy, Alan R.
Borilović, Ivana
Aromí Bedmar, Guillem
Hevia, Eva
author_role author
author2 Cadenbach, Thomas
Kennedy, Alan R.
Borilović, Ivana
Aromí Bedmar, Guillem
Hevia, Eva
author2_role author
author
author
author
author
dc.subject.none.fl_str_mv Magnetisme
Lligands
Propietats magnètiques
Magnetism
Ligands
Magnetic properties
topic Magnetisme
Lligands
Propietats magnètiques
Magnetism
Ligands
Magnetic properties
description This study reports the synthesis and single-crystal X-ray crystallographic, NMR spectroscopic, and magnetic characterization of a series of sodium ferrates using bis(amide) Fe(HMDS)2 as a precursor (HMDS = 1,1,1,3,3,3- hexamethyldisilazide). Reaction with sodium reagents NaHMDS and NaCH2SiMe3 in hexane afforded donor-solvent-free sodium ferrates [{NaFe(HMDS)3}∞] (1) and [{NaFe(HMDS)2(CH2SiMe3)}∞] (2), respectively, which exhibit contacted ion pair structures, giving rise to new polymeric chain arrangements made up of a combination of inter- and intramolecular Na··· Me(HMDS) electrostatic interactions. Addition of the unsaturated NHC IPr (IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2- ylidene) to 1 and 2 caused deaggregation of their polymeric structures to form discrete NHC-stabilized solvent-separated ion pairs [Na(IPr)2]+[Fe(HMDS)3]− (3) and [(THF)3·NaIPr]+[Fe(HMDS)2CH2SiMe3]− (4), where in both cases, the NHC ligand coordinates preferentially to Na. In contrast, when IPr is sequentially reacted with the single-metal reagents NaCH2SiMe3 and Fe(HMDS)2, the novel heteroleptic ferrate (THF)3Na[:C{[N(2,6-iPr2C6H3)]2CHCFe(HMDS)2}] (5) is obtained. This contains an anionic NHC ligand acting as an unsymmetrical bridge between the two metals, coordinating through its abnormal C4 position to Fe and its normal C2 position to Na. The formation of 5 can be described as an indirect ferration process where IPr is first metalated at the C4 position by the polar sodium alkyl reagent, which in turn undergoes transmetalation to the more electronegative Fe(HMDS)2 fragment. Treatment of 5 with 1 molar equiv of methyl triflate (MeOTf) led to the isolation and structural elucidation of the neutral abnormal NHC (aNHC) tricoordinate iron complex [CH3C{[N(2,6-iPr2C6H3)]2CHCFe- (HMDS)2}] (6) with the subsequent elimination of NaOTf, disclosing the selectivity of complex 5 to react with this electrophile via its C2 position, leaving its Fe−C4 and Fe−N bonds intact. The magnetic susceptibility properties of compounds 1−6 have been examined. This study revealed a drastic change of magnetic susceptibility in replacing a pure σ donor from an idealized trigonal coordination environment by an NHC π donating character.
publishDate 2015
dc.date.none.fl_str_mv 2015
dc.type.none.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/acceptedVersion
format article
status_str acceptedVersion
dc.identifier.none.fl_str_mv https://hdl.handle.net/2445/128919
url https://hdl.handle.net/2445/128919
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.relation.none.fl_str_mv Versió postprint del document publicat a: https://doi.org/10.1021/acs.inorgchem.5b01638
Inorganic Chemistry, 2015, vol. 54, num. 18, p. 9201-9210
https://doi.org/10.1021/acs.inorgchem.5b01638
dc.rights.none.fl_str_mv (c) American Chemical Society , 2015
info:eu-repo/semantics/openAccess
rights_invalid_str_mv (c) American Chemical Society , 2015
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
dc.publisher.none.fl_str_mv American Chemical Society
publisher.none.fl_str_mv American Chemical Society
dc.source.none.fl_str_mv Articles publicats en revistes (Química Inorgànica i Orgànica)
reponame:Dipòsit Digital de la UB
instname:Universidad de Barcelona
instname_str Universidad de Barcelona
reponame_str Dipòsit Digital de la UB
collection Dipòsit Digital de la UB
repository.name.fl_str_mv
repository.mail.fl_str_mv
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score 15.301603

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