Sodium congener of the classical lithium methylchromate dimer: synthetic, x-ray crystallographic, and magnetic studies of Me8Cr2[Na(OEt2)](4)

Ross Campbell, Luca M. Carrella, William Clegg, Robert E. Mulvey, Eva Rentschler, Stuart D. Robertson, Luca Russo

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

One of the milestone structures in the development of transition-metal complexes with metal metal bonds of multiple bond order was the lithium methylchromate dimer Me8Cr2[Li(donor)](4) (donor = THF or Et2O). Using a simple salt metathesis reaction mixing this compound with sodium tert-butoxide, the sodium congener Me8Cr2-[Na(OEt2)]4 has been synthesized as a green crystalline compound and isolated in 51% yield. Its solid-state structure was determined by single-crystal X-ray diffraction. Exhibiting exact crystallographic C-4h symmetry, this heavier alkali-metal chromate structure is also dimeric, formally comprising a (Me8Cr4)(4-) tetranionic core with four peripheral Na+ cations carrying supporting ether ligands. Its salient feature is the long Cr center dot center dot center dot Cr distance of 3.263(2) angstrom, which is remarkably elongated compared to that in the lithium THF-solvated congener [1.968(2) angstrom]. With respect to the methyl C atoms, the Cr coordination is distorted-square-planar. Each Na interacts with four methyl C atoms, and there are also some short Na center dot center dot center dot H(C) contacts. Unlike for lithium chromate, no NMR spectroscopic data could be obtained for sodium chromate. The paramagnetic character of sodium chromate was confirmed by variable-temperature magnetization measurements, which indicated antiferromagnetic behavior.

LanguageEnglish
Pages4656-4659
Number of pages4
JournalInorganic Chemistry
Volume50
Issue number10
DOIs
Publication statusPublished - 16 May 2011

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congeners
Lithium
Dimers
Chromates
chromates
lithium
Sodium
dimers
sodium
X rays
Metals
Alkali Metals
Atoms
x rays
Coordination Complexes
Ether
Heavy metals
Transition metals
Cations
Magnetization

Keywords

  • metal-metal bond
  • li agostic interaction
  • ordered assemblies
  • crystal structures
  • multiple bonds
  • chromium
  • alkali

Cite this

@article{235500dceb5842ea865b191900b5bb47,
title = "Sodium congener of the classical lithium methylchromate dimer: synthetic, x-ray crystallographic, and magnetic studies of Me8Cr2[Na(OEt2)](4)",
abstract = "One of the milestone structures in the development of transition-metal complexes with metal metal bonds of multiple bond order was the lithium methylchromate dimer Me8Cr2[Li(donor)](4) (donor = THF or Et2O). Using a simple salt metathesis reaction mixing this compound with sodium tert-butoxide, the sodium congener Me8Cr2-[Na(OEt2)]4 has been synthesized as a green crystalline compound and isolated in 51{\%} yield. Its solid-state structure was determined by single-crystal X-ray diffraction. Exhibiting exact crystallographic C-4h symmetry, this heavier alkali-metal chromate structure is also dimeric, formally comprising a (Me8Cr4)(4-) tetranionic core with four peripheral Na+ cations carrying supporting ether ligands. Its salient feature is the long Cr center dot center dot center dot Cr distance of 3.263(2) angstrom, which is remarkably elongated compared to that in the lithium THF-solvated congener [1.968(2) angstrom]. With respect to the methyl C atoms, the Cr coordination is distorted-square-planar. Each Na interacts with four methyl C atoms, and there are also some short Na center dot center dot center dot H(C) contacts. Unlike for lithium chromate, no NMR spectroscopic data could be obtained for sodium chromate. The paramagnetic character of sodium chromate was confirmed by variable-temperature magnetization measurements, which indicated antiferromagnetic behavior.",
keywords = "metal-metal bond, li agostic interaction, ordered assemblies, crystal structures, multiple bonds, chromium , alkali",
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doi = "10.1021/ic200471b",
language = "English",
volume = "50",
pages = "4656--4659",
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Sodium congener of the classical lithium methylchromate dimer: synthetic, x-ray crystallographic, and magnetic studies of Me8Cr2[Na(OEt2)](4). / Campbell, Ross; Carrella, Luca M.; Clegg, William; Mulvey, Robert E.; Rentschler, Eva; Robertson, Stuart D.; Russo, Luca.

In: Inorganic Chemistry, Vol. 50, No. 10, 16.05.2011, p. 4656-4659.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Sodium congener of the classical lithium methylchromate dimer: synthetic, x-ray crystallographic, and magnetic studies of Me8Cr2[Na(OEt2)](4)

AU - Campbell, Ross

AU - Carrella, Luca M.

AU - Clegg, William

AU - Mulvey, Robert E.

AU - Rentschler, Eva

AU - Robertson, Stuart D.

AU - Russo, Luca

PY - 2011/5/16

Y1 - 2011/5/16

N2 - One of the milestone structures in the development of transition-metal complexes with metal metal bonds of multiple bond order was the lithium methylchromate dimer Me8Cr2[Li(donor)](4) (donor = THF or Et2O). Using a simple salt metathesis reaction mixing this compound with sodium tert-butoxide, the sodium congener Me8Cr2-[Na(OEt2)]4 has been synthesized as a green crystalline compound and isolated in 51% yield. Its solid-state structure was determined by single-crystal X-ray diffraction. Exhibiting exact crystallographic C-4h symmetry, this heavier alkali-metal chromate structure is also dimeric, formally comprising a (Me8Cr4)(4-) tetranionic core with four peripheral Na+ cations carrying supporting ether ligands. Its salient feature is the long Cr center dot center dot center dot Cr distance of 3.263(2) angstrom, which is remarkably elongated compared to that in the lithium THF-solvated congener [1.968(2) angstrom]. With respect to the methyl C atoms, the Cr coordination is distorted-square-planar. Each Na interacts with four methyl C atoms, and there are also some short Na center dot center dot center dot H(C) contacts. Unlike for lithium chromate, no NMR spectroscopic data could be obtained for sodium chromate. The paramagnetic character of sodium chromate was confirmed by variable-temperature magnetization measurements, which indicated antiferromagnetic behavior.

AB - One of the milestone structures in the development of transition-metal complexes with metal metal bonds of multiple bond order was the lithium methylchromate dimer Me8Cr2[Li(donor)](4) (donor = THF or Et2O). Using a simple salt metathesis reaction mixing this compound with sodium tert-butoxide, the sodium congener Me8Cr2-[Na(OEt2)]4 has been synthesized as a green crystalline compound and isolated in 51% yield. Its solid-state structure was determined by single-crystal X-ray diffraction. Exhibiting exact crystallographic C-4h symmetry, this heavier alkali-metal chromate structure is also dimeric, formally comprising a (Me8Cr4)(4-) tetranionic core with four peripheral Na+ cations carrying supporting ether ligands. Its salient feature is the long Cr center dot center dot center dot Cr distance of 3.263(2) angstrom, which is remarkably elongated compared to that in the lithium THF-solvated congener [1.968(2) angstrom]. With respect to the methyl C atoms, the Cr coordination is distorted-square-planar. Each Na interacts with four methyl C atoms, and there are also some short Na center dot center dot center dot H(C) contacts. Unlike for lithium chromate, no NMR spectroscopic data could be obtained for sodium chromate. The paramagnetic character of sodium chromate was confirmed by variable-temperature magnetization measurements, which indicated antiferromagnetic behavior.

KW - metal-metal bond

KW - li agostic interaction

KW - ordered assemblies

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KW - multiple bonds

KW - chromium

KW - alkali

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SN - 0020-1669

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