Organo-aluminum, zinc and magnesium derivatives of the imidotris(amido)phosphate Me3SiNP(NHtBu)3

Reactions of (tBuHN)3PNSiMe3 (1) with the alkyl-metal reagents dimethylzinc, trimethylaluminum and di-n-butylmagnesium yield the monodeprotonated complexes [MeZn{(NtBu)(NSiMe3)P(NHtBu)2}] (2), [Me2Al{(NtBu)(NSiMe3)P(NHtBu)2}] (3) and [Mg{(NtBu)(NSiMe3)P(NHtBu)2}2] (4), respectively. Attempts to further deprotonate complex 2 with n-butyllithium or di-n-butylmagnesium result in nucleophilic displacement of the methylzinc fragment by lithium or magnesium. The two remaining amino protons of 3 are removed by reaction with di-n-butylmagnesium to give a heterobimetallic complex in which the coordination sphere of magnesium is completed by two molecules of THF (5 · 2THF) or one molecule of TMEDA (5 · TMEDA). Reaction of complex 3 with 1 equiv. of n-butyllithium followed by treatment of the product with di-n-butylmagnesium yields the complex {Me2Al[(NtBu)(NSiMe3)P(NtBu)2]MgBu} Li · 4THF (6 · 4THF), the first example of a triply deprotonated complex of 1 containing three different metals. Reaction of complex 5 with iodine results in cleavage of an Al–Me group to give {MeIAl[(NtBu)(NSiMe3)P(NtBu)2Mg]} (7). Complexes 5 · 2THF, 5 · TMEDA, 6 · 4THF and 7 have been characterized in solution by multinuclear (1H, 13C, 31P and 7Li) NMR spectroscopy, while the solid-state structures of 2, 4 and 5 · 2THF have been determined by X-ray crystallography.

Graphical abstractDouble deprotonation of Me2Al[(NtBu)(NSiMe3)P(NHtBu)2] with MgBu2 gives the spirocyclic complex Me2Al[(NtBu)(NSiMe3)P(NtBu)2Mg] · 2THF, the first non-lithiated heterobimetallic tetraimidophosphate complex. Monolithiation of Me2Al[(NtBu)(NSiMe3)P(NHtBu)2] followed by reaction with MgBu2 yields Me2Al[(NtBu)(NSiMe3)P(NHtBu)2MgnBu]Li · 4THF, the first hetero-trimetallic complex of the tetraimidophosphate trianion.Figure optionsDownload full-size imageDownload as PowerPoint slide