Chemistry of β-diketiminate Group 14 and Group 2 complexes and macrocyclic amines and amine ethers

• Main Author: Taylor, Morgan James
• Published: University of Sussex 2012
• Subjects: 547.05; QD0241 Organic chemistry
• Online Access: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.554474

Group 14 metal(II) alkyl complexes are very rare, with few examples being studied in great detail. To this end, a series of β-diketiminate lead(II) alkyl and aryl complexes, [{(2,6-iPr2C6H3)NC(CH3)}2CH]PbR (R = Me, iPr, sBu, Np, Bn, tBu and Ph) were synthesised and a number of computational studies were performed on them to increase the understanding of the nature of these compounds. Reactivity studies on both the lead, and the analogous tin systems, showed that they could be used as precursors to generate examples of very rare two-coordinate group 14 metal cation complexes, including the first example of a β-diketiminate two-coordinate lead(II) cation, and an analogous example of a rare low-coordinate tin(II) system. These were studied in detail by computational methods, including the stabilising effects of a coordinated solvent molecule on the metal centre. β-Diketiminate magnesium alkyl complexes were generated to investigate the +2 oxidation state metal environment without the presence of a stereochemically active lone pair, as present in the group 14 metal(II) complexes. A carbodiimide was successfully inserted into the magnesium-carbon bond, and novel magnesium phosphides were generated from the alkyl complexes. Solvent stabilisation effects on these phosphides were also studied by computational methods. A series of macrocyclic amines and amine ethers were synthesised to investigate the hydrolysis of a phosphate diester model RNA system by lead(II) salts, monitored by UV-visible kinetics. The reaction kinetics gave no reproducible results, but the syntheses of the macrocycles are presented in detail for further citation.