Experimental and theoretical study of Pb⋯S and Pb⋯O σ-hole interactions in the crystal structures of Pb(ii) complexes

We report here the synthesis of two new PbIJII) compounds in which the lead center is coordinated by organic ligands via S and O donor atoms. Remarkably, in both compounds the Pb coordination is hemidirectional, which facilitates the approach of extra donors to establish interactions at longer distances. Such interactions are of σ-hole nature between the Pb and O/S atoms, acting as Lewis acid and bases, respectively. Interestingly, the Pb⋯S/O distances are closer to the sum of the covalent radii than to the van der Waals ones, which suggests a considerably strong interaction. We have performed a structural analysis of the crystal structures as well as a theoretical analysis based on DFT calculations to gain deeper insight into the origin and features of these σ-hole interactions. Moreover, the nature of the Pb⋯S/O interactions have been further analysed by means of AIM, MEP and NBO calculations.