Preparation of Germanium(IV) Monocation and Di-cation as Sigma Acceptor Ligand towards Transition Metals

Abstract

Sigma acceptor type ligands are useful in transition metal catalysed Lewis acid catalysis. Placing of such type of ligands around the transition metal may increase the Lewis acidity of transition metals and interesting catalytic activity arises from it. This has been an active research area and there is a handful of literature on such ligand type using Group 14 elements. Herein, we have utilized the peri-framework to prepare such ligands. In this thesis we reported the synthesis of novel germanium(IV) cationic compound [R2GeCl]+[GeCl3] - using the phosphine substituted acenaphthene 5Br,6P(iPr)2-Acenaphthene as precursor. Exploring the chemistry of this novel germanium cationic compound, anion exchange reactions with germanium cationic compound have been done. We reported the anion exchange reactions of compound (1) [R2GeCl][GeCl3] to produce SbF6 bearing compound (2), [R2GeCl][SbF6] and OTf bearing compound (3), [R2GeCl][OTf]. Reactions involving the chlorine abstraction from germanium centre have also been carried out and successfully reported the synthesis of novel germanium(IV) dicationic compound (4), [R2Ge][OTf]2. We have carried out the synthesis of transition metal complexes using these ligands and reported the synthesis of gold complex (5) of Ge monocationic compound.