A Single Tetrel Atom Skeletal Editing Strategy for Tuning Geometric and Energetic Features of Tetrel Bonding

Tuning the strength and directionality of tetrel bonding (TtB) in the R−Tt···Nu supramolecular synthon (R = all residues covalently bonded to Tt; Tt = C, Si, Ge, Sn, or Pb; Nu = nucleophile) by changing R, Tt, or Nu is an effective strategy for controlling/improving the function and properties of tetrel compounds in chemistry and chemical biology. In this work, we experimentally and theoretically investigate the impact of altering a single tetrel atom Tt on the strength and directionality of inter- or intramolecular TtBs in a series of tetrel compounds taken from the Cambridge Structural Database. Due to the non-metal → metalloid → metal transitions in Group 14 (from C to Pb) and the steric crowding around tetravalent Tt atoms, there are multifaceted trends for the TtB features (e.g., donor ability of the tetrel atom, strength, and geometric features of the Tt···Nu interaction). The experimental insights are corroborated by DFT calculations performed at the PBE0-D3/def2-TZVP level of theory and rationalized using several computational tools.