Structure-Directing Interplay between Tetrel and Halogen Bonding in Co-Crystal of Lead(II) Diethyldithiocarbamate with Tetraiodoethylene

The co-crystallization of the lead(II) complex [Pb(S₂CNEt₂)₂] with tetraiodoethylene (C₂I₄) gave the co-crystal, [Pb(S₂CNEt₂)₂]∙½C₂I₄, whose X-ray structure exhibits only a small change of the crystal parameters than those in the parent [Pb(S₂CNEt₂)₂]. The supramolecular organization of the co-crystal is largely determined by an interplay between Pb⋯S tetrel bonding (TeB) and I⋯S halogen bonding (HaB) with comparable contributions from these non-covalent contacts; the TeBs observed in the parent complex, [Pb(S₂CNEt₂)₂], remain unchanged in the co-crystal. An analysis of the theoretical calculation data, performed for the crystal and cluster models of [Pb(S₂CNEt₂)₂]∙½C₂I₄, revealed the non-covalent nature of the Pb⋯S TeB (-5.41 and -7.78 kcal/mol) and I⋯S HaB (-7.26 and -11.37 kcal/mol) interactions and indicate that in the co-crystal these non-covalent forces are similar in energy.