Stepwise isolation of low-valent, low-coordinate Sn and Pb mono- and dications in the coordination sphere of platinum.

Synthetic access to low-coordinate Pb mono- and dications is in general impeded due to their poor solubility and highly electrophilic nature. However, the electrophilicity of these cations can be tamed by attaching them to electron-rich transition metals. Following this principle we have isolated low-valent Pb mono- ([(CyP)Pt-PbCl][AlCl], ) and dications ([(CyP)Pt(Pb)][AlCl], ) in the coordination sphere of platinum. The same approach then has been implemented for the isolation of analogous low-valent Sn mono- () and dications (). An energy decomposition analysis (EDA-NOCV) was performed to investigate the nature of Pt-Pb and Pb-Cl bonding in [(CyP)Pt(PbCl)] (), and . The results show that the Pt-Pb bonds in and are electron-sharing in nature, whereas that of the precursor is a dative bond. The breakdown of attractive interactions in , and reveals that the ionic interactions in the analyzed Pt-Pb and Pb-Cl bonds are always stronger than the covalent interactions, except for the Pb-Cl bond in . The calculated D3 dispersion energies show that dispersion interactions play a key role in the thermodynamic stability of , and .