Chemistry of the terminal pnictogen complexes of lead, tin and germanium

Harris, Lisa Ann Marie (2013) Chemistry of the terminal pnictogen complexes of lead, tin and germanium. Doctoral thesis (PhD), University of Sussex.

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Abstract

A series of tin(II) and lead(II) β-diketiminate amides [(BDI)MNRR’] (BDI = [CH{(CH3)CN-2,6-iPr2C6H3}2]; M = Sn, Pb; RR’ = iPr2, H(2,6-iPr2-C6H3), H(2-iPr-C6H4), H(C6H5)) were synthesised and characterised. The reactivity of [(BDI)MN(iPr)2] and [(BDI)MNH(2,6-iPr2-C6H3)] towards aliphatic electrophiles, heterocumulenes and acids was investigated. The lead systems were found to be more reactive than the tin systems and the amide ligand was found to be more reactive than the anilide ligand. In general, the [(BDI)MNRR’] systems under investigation displayed the expected nucleophilic and basic behaviour. For instance, treatment of [(BDI)SnNH(2,6-iPr2-C6H3)] with methyl triflate resulted in the formation of [(BDI)SnOSO2CF3]. However, addition of phenyl isocyanate to [(BDI)MNRR’] (M = Sn, Pb; RR’ = iPr2, H(2,6-iPr2-C6H3)) resulted in the formation of a bis-β-diketiminate complex, [(BDI)M(OC{=NPh}C{=C(Me)CN(H)(Ar)}(C{Me}=CN(Ar)})], a net result of nucleophilic addition to the electrophilic carbon in phenyl isocyanate by the γ-carbon in the BDI backbone. DFT studies were undertaken to rationalise the reactivity.
The reactivity of group 14 metal β-diketiminate phosphide complexes [(BDI)MPR2] (BDI = [CH{(CH3)CN-2,6-iPr2C6H3}2]; M = Ge, Sn, Pb; R = C6H11, C6H5) towards selenium and tellurium was examined. For the tin(II) and lead(II) systems, no reactivity was observed upon addition of one or five equivalents of tellurium. In contrast, the germanium(II) systems exhibited unexpected reactivity with selenium and tellurium, where one equivalent of the chalcogen resulted in its insertion into the germanium-phosphorus bond, [(BDI)GeEPR2] (E = Se, Te), and five equivalents of selenium resulted in a further coordination of a selenium to the phosphorus, [(BDI)GeSeP(Se)R2]. DFT studies were undertaken in order to rationalise this behaviour. Lastly, the process of aerosol-assisted chemical vapour deposition (AACVD) was undertaken on some of these group 14 metal chalcogenide complexes in order to probe their suitability as a single source precursor (SSP) for thermo-electric materials.

Item Type: Thesis (Doctoral)
Schools and Departments: School of Life Sciences > Chemistry
Subjects: Q Science > QD Chemistry > QD0146 Inorganic chemistry
Depositing User: Library Cataloguing
Date Deposited: 08 Jan 2014 07:23
Last Modified: 17 Sep 2015 12:30
URI: http://sro.sussex.ac.uk/id/eprint/47053

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