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Title: The reactivity of p-block dimethylamide reagents and beyond
Author: Allan, R. L.
Awarding Body: University of Cambridge
Current Institution: University of Cambridge
Date of Award: 1997
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The initial aim of this project was to investigate the reactivity of p-block dimethylamide complexes. Metallation of primary amines (RNH2) with [Sn(NMe2)2] provides a facile synthesis of the imidotin(II) cubanes [SnNR]4. This is illustrated by the X-ray structures of [SnNCy]4 201 (Cy - cyclohexyl), [SnNtBu]4.0.5THF 202 and [Sn(2-NCH2C5H4N)]4 203. It is also possible to synthesise the cubane [PbNCy]4 204 via the reaction of [CyNHLi] with [Cp2Pb]. The ease of preparation of the cubanes led to a study of the reactivity of these species. [SnNtBu]4 was reacted with Ph3CSH, this fracturing the cubane to yield the dimer [(Ph3CS)Sn(μ-NHtBu)2 301. An attempt to generate an analogous molecule using the thiol MitH (MitH = 2-mercapto-1-methylimidazole) and to react it as a ligand with CuCl led to the isolation of the cage [Sn(Mit)6Cu4].4THF 304. Further reactions of [SnNtBu]4 with [C10H7NHLi] (C10H7 = 1-naphthyl) and [CyPHLi] produce [Li(THF)4]+ [tBuN(C10H7N)3Sn3Li.THF]- 302 and [{(Sn[μ-PCy])2(μ-PCy)}2Li4.4THF] 303 respectively. A similar synthetic strategy using group 13 cubanes was also successful. The reaction of [MeAlNMes]4 (Mes = 2, 4, 6-Me3C6H2) with [CyPHLi] yields the fourteen-membered cage complex [{(MeAl[μ-PCy])2(μ-PCy)}2Li4.4THF] 501, containing the first example of an Al(II) phosphinidine anion. By reacting [Sn(NMe2)2] with sterically bulky aromatic amines, intermediates to cubane synthesis are prepared. The reactions are halted at the heteroleptic imido/amido tin(II) complexes [Sn{NR}2{Sn(μ-NMe2)}2] (R = 2, 6.iPr2C6H3 401 or Mes 402). [Sn{NMes}2{Sn(μ-NMe2)}2] reacts with two equivalents of [MaNHLi] (Ma = 2-MeOC6H4) forming the heterobimetallic species [{(MesNH)Sn(μ-NMa)}2(Li.2THF)2] 403. This ladder-shaped structure contains the first example of a binuclear tin(II) imido dianion.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available