A comparative study of the behaviour of N-trimethylsilyl and N-neopentyl-anilines and 1,2-diaminobenzenes towards trimethylalane; X-ray structures of nine Al–N compounds

Dalton Transactions Pub Date: 2003-04-02 DOI: 10.1039/B300957M

Abstract

The reactions of a pair each of monosubstituted anilines PhNHR1 and disubstituted 1,2-diaminobenzenes C6H4(NHR1)2-1,2 (R1 = SiMe3 = R, or R1 = CH2But = R′) with 1 or 2 equivalents of trimethylalane have been investigated. The trimethylsilyl derivatives were more reactive than the neopentyl analogues. The following crystalline compounds were obtained at ambient temperature or (1) gentle heating: trans-[AlMe2(μ-NRPh)]21, [AlMe3{NH(R′)Ph}] 2, [(AlMe2)2{μ-(NR)2C6H4-1,2}] 4, [(AlMe2){μ-(NR′)2C6H4-1,2}] 5, [([upper bond 1 start]AlMe){N(R)C6H4N[upper bond 1 end]R-μ-1,2}]26 and [[upper bond 1 start]AlMe2{N(R′(C6H4N[upper bond 1 end](H)R′}] 7, while prolonged heating was required in order to obtain [AlMe2(μ-NR′Ph)]23 and [([upper bond 1 start]AlMe{N(R′)C6H4N[upper bond 1 end]R′-μ-1,2}]28. The amine adducts 2 and 7, were identified as intermediates to 3 and 8, respectively. Treatment of C6H4(NHR′)2-1,2 with successively 2 LiBun and 2 AlCl3 afforded [[upper bond 1 start]AlCl{N(R′)C6H4N[upper bond 1 end]R′-μ-1,2}]29. The diamine adduct [C6H4{N(H)R′(AlMe3)}2-1,3] 10 was obtained from C6H4(NHR′)2-1,3 and 2 AlMe3; while the same diamine with successively 2 LiBun, 2 AlClMe2 and 2 tmen yielded a compound tentatively formulated as [C6H4{N(R′)AlMe2(tmen)}2-1,3] 11. The X-ray structures of 1–7, 9 and 10 are presented.

Graphical abstract: A comparative study of the behaviour of N-trimethylsilyl and N-neopentyl-anilines and 1,2-diaminobenzenes towards trimethylalane; X-ray structures of nine Al–N compounds
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