Solid-state and dynamic solution equilibria of bis(dibenzylamido) magnesium complexes: aggregation dependence on stoichiometry and denticity of donor solvent

W. Clegg, F.J. Craig, K.W. Henderson, A.R. Kennedy, R.E. Mulvey, P.A. O'Neil, D. Reed

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Abstract

Reaction of commercial Bu2Mg with 2 molar equiv of dibenzylamine gives the bis(amido)magnesium complex [{{(PhCH2)2N}2Mg}2], 1. Compound 1 is dimeric with three-coordinate magnesium in the crystalline state. Addition of 2 molar equiv of the monodentate donor solvents THF and HMPA to solutions of 1 affords the complexes [{{(PhCH2)2N}2MgâTHF}2], 2, and [{{(PhCH2)2N}2MgâHMPA}2], 4 respectively, which maintain the dimeric framework but increase the metal's coordination number to 4. Addition of 4 molar equiv of HMPA, or a 20-fold excess, of THF to 1 causes deaggregation of the dimer to the monomeric bis-solvates [{(PhCH2)2N}2- Mgâ2THF], 3, and [{(PhCH2)2N}2Mgâ2HMPA], 5. The chelating ligand TMEDA gives the monomer [{(PhCH2)2N}2MgâTMEDA], 6, on mixing with 1. 1H and 13C NMR spectroscopic studies reveal that dimer 1 is partially retained in arene solution but is in equilibrium with the unsolvated monomer [{(PhCH2)2N}2Mg], 7. Concentration studies on solutions of monosolvated dimer 4 show it to be in equilibrium with both the bissolvated monomer 5 and the unsolvated monomer 7. X-ray crystallographic determinations have been carried out on complexes 1, 2, and 4-6, and a comparative analysis of their structures is detailed. The bis(dibenzylamido)- magnesium system has shown remarkable structural flexibility with di-, tri-, and tetracoordination at the metal.
LanguageEnglish
Pages6238-6246
Number of pages8
JournalInorganic Chemistry
Volume36
Issue number27
DOIs
Publication statusPublished - 1997

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Hempa
Stoichiometry
Dimers
Magnesium
magnesium
stoichiometry
Agglomeration
monomers
Monomers
dimers
solid state
Metals
Chelation
coordination number
metals
flexibility
Nuclear magnetic resonance
Crystalline materials
Ligands
X rays

Keywords

  • Bu2Mg
  • magnesium
  • crystalline
  • monodentate donor solvents
  • di-
  • tri-
  • tetracoordination
  • metal

Cite this

@article{230be5460eca4017ab6a6d5523993a80,
title = "Solid-state and dynamic solution equilibria of bis(dibenzylamido) magnesium complexes: aggregation dependence on stoichiometry and denticity of donor solvent",
abstract = "Reaction of commercial Bu2Mg with 2 molar equiv of dibenzylamine gives the bis(amido)magnesium complex [{{(PhCH2)2N}2Mg}2], 1. Compound 1 is dimeric with three-coordinate magnesium in the crystalline state. Addition of 2 molar equiv of the monodentate donor solvents THF and HMPA to solutions of 1 affords the complexes [{{(PhCH2)2N}2Mg{\^a}THF}2], 2, and [{{(PhCH2)2N}2Mg{\^a}HMPA}2], 4 respectively, which maintain the dimeric framework but increase the metal's coordination number to 4. Addition of 4 molar equiv of HMPA, or a 20-fold excess, of THF to 1 causes deaggregation of the dimer to the monomeric bis-solvates [{(PhCH2)2N}2- Mg{\^a}2THF], 3, and [{(PhCH2)2N}2Mg{\^a}2HMPA], 5. The chelating ligand TMEDA gives the monomer [{(PhCH2)2N}2Mg{\^a}TMEDA], 6, on mixing with 1. 1H and 13C NMR spectroscopic studies reveal that dimer 1 is partially retained in arene solution but is in equilibrium with the unsolvated monomer [{(PhCH2)2N}2Mg], 7. Concentration studies on solutions of monosolvated dimer 4 show it to be in equilibrium with both the bissolvated monomer 5 and the unsolvated monomer 7. X-ray crystallographic determinations have been carried out on complexes 1, 2, and 4-6, and a comparative analysis of their structures is detailed. The bis(dibenzylamido)- magnesium system has shown remarkable structural flexibility with di-, tri-, and tetracoordination at the metal.",
keywords = "Bu2Mg, magnesium, crystalline, monodentate donor solvents, di-, tri-, tetracoordination, metal",
author = "W. Clegg and F.J. Craig and K.W. Henderson and A.R. Kennedy and R.E. Mulvey and P.A. O'Neil and D. Reed",
year = "1997",
doi = "10.1021/ic970912a",
language = "English",
volume = "36",
pages = "6238--6246",
journal = "Inorganic Chemistry",
issn = "0020-1669",
publisher = "American Chemical Society",
number = "27",

}

Solid-state and dynamic solution equilibria of bis(dibenzylamido) magnesium complexes: aggregation dependence on stoichiometry and denticity of donor solvent. / Clegg, W.; Craig, F.J.; Henderson, K.W.; Kennedy, A.R.; Mulvey, R.E.; O'Neil, P.A.; Reed, D.

In: Inorganic Chemistry, Vol. 36, No. 27, 1997, p. 6238-6246.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Solid-state and dynamic solution equilibria of bis(dibenzylamido) magnesium complexes: aggregation dependence on stoichiometry and denticity of donor solvent

AU - Clegg, W.

AU - Craig, F.J.

AU - Henderson, K.W.

AU - Kennedy, A.R.

AU - Mulvey, R.E.

AU - O'Neil, P.A.

AU - Reed, D.

PY - 1997

Y1 - 1997

N2 - Reaction of commercial Bu2Mg with 2 molar equiv of dibenzylamine gives the bis(amido)magnesium complex [{{(PhCH2)2N}2Mg}2], 1. Compound 1 is dimeric with three-coordinate magnesium in the crystalline state. Addition of 2 molar equiv of the monodentate donor solvents THF and HMPA to solutions of 1 affords the complexes [{{(PhCH2)2N}2MgâTHF}2], 2, and [{{(PhCH2)2N}2MgâHMPA}2], 4 respectively, which maintain the dimeric framework but increase the metal's coordination number to 4. Addition of 4 molar equiv of HMPA, or a 20-fold excess, of THF to 1 causes deaggregation of the dimer to the monomeric bis-solvates [{(PhCH2)2N}2- Mgâ2THF], 3, and [{(PhCH2)2N}2Mgâ2HMPA], 5. The chelating ligand TMEDA gives the monomer [{(PhCH2)2N}2MgâTMEDA], 6, on mixing with 1. 1H and 13C NMR spectroscopic studies reveal that dimer 1 is partially retained in arene solution but is in equilibrium with the unsolvated monomer [{(PhCH2)2N}2Mg], 7. Concentration studies on solutions of monosolvated dimer 4 show it to be in equilibrium with both the bissolvated monomer 5 and the unsolvated monomer 7. X-ray crystallographic determinations have been carried out on complexes 1, 2, and 4-6, and a comparative analysis of their structures is detailed. The bis(dibenzylamido)- magnesium system has shown remarkable structural flexibility with di-, tri-, and tetracoordination at the metal.

AB - Reaction of commercial Bu2Mg with 2 molar equiv of dibenzylamine gives the bis(amido)magnesium complex [{{(PhCH2)2N}2Mg}2], 1. Compound 1 is dimeric with three-coordinate magnesium in the crystalline state. Addition of 2 molar equiv of the monodentate donor solvents THF and HMPA to solutions of 1 affords the complexes [{{(PhCH2)2N}2MgâTHF}2], 2, and [{{(PhCH2)2N}2MgâHMPA}2], 4 respectively, which maintain the dimeric framework but increase the metal's coordination number to 4. Addition of 4 molar equiv of HMPA, or a 20-fold excess, of THF to 1 causes deaggregation of the dimer to the monomeric bis-solvates [{(PhCH2)2N}2- Mgâ2THF], 3, and [{(PhCH2)2N}2Mgâ2HMPA], 5. The chelating ligand TMEDA gives the monomer [{(PhCH2)2N}2MgâTMEDA], 6, on mixing with 1. 1H and 13C NMR spectroscopic studies reveal that dimer 1 is partially retained in arene solution but is in equilibrium with the unsolvated monomer [{(PhCH2)2N}2Mg], 7. Concentration studies on solutions of monosolvated dimer 4 show it to be in equilibrium with both the bissolvated monomer 5 and the unsolvated monomer 7. X-ray crystallographic determinations have been carried out on complexes 1, 2, and 4-6, and a comparative analysis of their structures is detailed. The bis(dibenzylamido)- magnesium system has shown remarkable structural flexibility with di-, tri-, and tetracoordination at the metal.

KW - Bu2Mg

KW - magnesium

KW - crystalline

KW - monodentate donor solvents

KW - di-

KW - tri-

KW - tetracoordination

KW - metal

UR - http://dx.doi.org/10.1021/ic970912a

U2 - 10.1021/ic970912a

DO - 10.1021/ic970912a

M3 - Article

VL - 36

SP - 6238

EP - 6246

JO - Inorganic Chemistry

T2 - Inorganic Chemistry

JF - Inorganic Chemistry

SN - 0020-1669

IS - 27

ER -