Abstract
Reaction of R(2-pyr)NH (where R = Me, Ph or 2-pyr) with 'Bu(2)Mg' in an ether-free environment yields the corresponding alkyl(amido)magnesium derivative [{R(2-pyr)NMgBu}(n)]. When polar solvent is added to these species only bis(amido)magnesium compounds separate from solution and not the expected solvated alkyl(amido) derivatives. Isolation of one such alkyl(amido) compound prior to reaction with donor solvent proves that the mixed anion species do indeed exist, However, when polar molecules are introduced a disproportionation reaction ensues, yielding the homoleptic compounds [{R(2)Mg .(S)(x)}(n)] and [{(R(2)N)(2)Mg .(S)(x)}(n)], where S is THF, TMEDA or PMDETA. Theoretical calculations likewise show that the disproportionation reaction of model compounds closely related to our systems is strongly exothermic. A H-1/C-13 NMR spectroscopic study was used to assign the nature of the bis(amido) species in solution. From these analyses it was possible to propose that the solvated bis(amido) derivatives assume a common structural motif, that of a monomer (n = 1) with a pseudo-octahedral magnesium center.
Original language | English |
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Pages (from-to) | 139-146 |
Number of pages | 8 |
Journal | Journal of Organometallic Chemistry |
Volume | 518 |
Issue number | 1-2 |
DOIs | |
Publication status | Published - 12 Jul 1996 |
Keywords
- magnesium
- amido
- ab initio MO calculations
- disproportionation
- ray crystal structures
- aryl compounds
- metal alkyl
- colligative measurements
- solid state
- lithium
- tetrahydrofuran
- amides
- complexes
- reagent