Reactions of cis‐2,3‐Dimethylaziridine, 3‐Pyrroline and Pyrrolidine with Me₃Al and Me₃Ga: Adducts and Dimeric Amides

Abstract

The reactions of Me3Al and Me3Ga with cis‐2,3‐dimethylaziridine (1‐H), 3‐pyrroline (2‐H) and pyrrolidine (3‐H) have been investigated. At room temperature, monomeric adducts [Me3M·LH] are obtained (M = Al, Ga; L = 1−3). [Me3Al·1‐H] is the first example of a structurally characterized adduct of an aziridine and a group 13 metal. On heating in mesitylene, all adducts except [Me3Ga·2‐H] evolve methane to form the corresponding amides; the Ga complexes require somewhat higher temperatures for this reaction. In contrast to the unsubstituted aziridine derivatives (which are trimers), dimethylaziridine amides Me2M‐1 are dimers, as shown by X‐ray crystallography. NMR spectroscopic data suggest the occurrence of a cis‐trans equilibrium for these dimers in solution. For the pyrroline and pyrrolidine derivatives, the X‐ray structures suggested large changes in the C−C and C−N bond lengths on formation of the adducts and amides. However, DFT calculations reveal that these changes are artefacts, and that the real bond length changes are fairly modest. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)

The synthesis and deep purification of GaEt3. Reversible complexation of adducts MAlk3 (M = Al, Ga, In; Alk = Me, Et) with phenylphosphines

“…However, the donoreacceptor interaction strength of nitrogen compounds with GaR 3 described in literature is characterized by high values of formation enthalpy; therefore it is almost impracticable to destruct such complexes into constituent compounds under reasonable conditions. Any attempt of their thermal destruction leads as a rule to the formation of a covalent GaeN bond and the elimination of unsaturated hydrocarbons [18,22,23]. Similar results have been obtained when we have attempted to purify triethylgallium by way of its complexation with N,N-dimethyldodecilamine.…”

Trimethylaluminum and Borane Complexes of Primary Amines

“…Both spectra of compounds show that the vaporization of the complexes during their purification provides only 1:1 adduct. Although the first mole of methane elimination of 1:1 amine–TMA complexes is calculated to be exothermic, and methane elimination was observed in the case of several secondary amine–TMA complexes upon heating, this decomposition has been avoided in our procedure.…”

5 Aluminium, gallium, indium and thallium

“…The former is interesting in that methane elimination is comparatively reluctant, a fact which prompted the characterisation of [Me 3 Al{cyclo-NH(CH 2 ) 4 }], its corresponding elimination product, and its Ga analogue [Me 2 Ga{m-N(CH 2 ) 4 }] 2 . 70 Complex formation between AlMe 3 and the iminophosphoran(8-quinolyl)methane 1-N-C 9 H 6 -8-CH 2 PPh 2 LNBu t , is rich being complicated by the possibility of ligand methylation. Among the products are some containing {AlMe 2 } groups bound to the same C atom.…”