I. Group 14 metal alkoxides: synthesis and reactivity studiesudII. Synthesis of novel planar chiral complexes based on 2.2paracyclophane

摘要

I. A series of group 14 β-­diketiminate alkoxides (BDI)EOR (BDI = [CH{(CH3)CN-­‐2,6-­‐iPr2C6H3}2; E = Ge, Sn, Pb; R = iPr, sBu, tBu) was synthesised and characterised. The reactivity towards aliphatic and unsaturated electrophiles was investigated. For the tin and lead systems, an unexpected trend was observed. For instance, they do not or very sluggishly react with aliphatic electrophiles, but readily activate carbon dioxide. The slower tin system was used to investigate the mechanism of carbon dioxide insertion through detailed kinetic, thermodynamic and DFT studies. The isostructural germanium system showed a different reactivity pattern. Treatment with aliphatic electrophiles and iodine leads to cationic Ge(IV) oxidative addition products, whereas reactivity towards heterocumulenes was not observed. The Lewis basic behaviour was also investigated, revealing that the germanium lone pair coordinates to copper(I) iodide. The synthesis of an isostructural mercury system was also attempted, resulting in the formation of the first homoleptic bis­‐β­‐diketiminate complex bound through the γ­‐carbons.ududII. Monosubstituted paracyclophane was exploited in the synthesis of a novel β­‐diketimine and enaminone both possessing planar chirality. These were used to stabilise N,N'- and N,O-­chelated scandium and zirconium complexes, potentially suitable for asymmetric hydroamination catalysis. Preliminary tests show nocatalytic activity.