Extending the family of stable heavier carbenes: New tetrylenes based on N,N,O-ligands

Abstract

A series of novel heavier carbene analogs 3–8, MeN(CH2CH2NTs)(CH2CR2O)M (M=Ge (3, R=H; 4, R=Ph), Sn (5, R=H; 6, R=Ph), Pb (7, R=H; 8, R=Ph)), was prepared by the interaction of M[N(SiMe3)2]2 (M=Ge, Sn, Pb) with substituted N,N,O-ligands, 1 and 2, MeN(CH2CH2NHTs)(CH2CR2OH) (1, R=H; 2, R=Ph). All the compounds were investigated by IR and multinuclear NMR spectroscopy and it was established that in a solution tin and lead compounds are agglomerated. An X-ray diffraction analysis of 3 revealed the monomeric structure with three-coordinated Ge atom. In contrast to germylenes, plumbylenes are associated in solid state. In the crystalline phase, the steric hindrance affects the degree of association. Thus, lead derivative 7 based on unsubstituted ligand, 1, forms dimers with strong bridging Pb–O bonding which further crystallize into chains. On contrary, plumbylene 8 based on phenyl substituted ligand, 2, is monomeric and only weak Pb⋯OSO contacts are observed is the solid state.