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.
Original language | English |
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Pages (from-to) | 6238-6246 |
Number of pages | 8 |
Journal | Inorganic Chemistry |
Volume | 36 |
Issue number | 27 |
DOIs | |
Publication status | Published - 1997 |
Keywords
- Bu2Mg
- magnesium
- crystalline
- monodentate donor solvents
- di-
- tri-
- tetracoordination
- metal