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In this study, we explore the role of tetrel bonds (TtBs) and hydrogen bonds (H-bonds) in directing supramolecular crystal packing via self-assembly in two lead(II) chelates: Pb( tren )( i-mnt ) ( 1 ) and Pb 4 ( tetraen ) 2 ( i-mnt ) 4 ( 2 ) i-mnt –2 = 1,1-dicyanoethylene-2,2-dithiolate, tren = diethylene triamine, and tetraen = tris(2-aminoethyl)amine. Both complexes were synthesized and isolated, and their solid-state structures were determined through single-crystal X-ray diffraction analysis. The secondary ligands ( tren, tetraen ) influence the coordination pattern of i-mnt –2 toward the Pb 2+ center, generating diverse asymmetric geometries. Complex 1 is a vacant octahedral chelate, while complex 2 is a cocrystalline aggregate of crystallographically independent two cationic Pb( tetraen ) +2 and two anionic Pb( i-mnt ) 2 −2 inversion twins, each displaying seesaw geometry. These hemidirected lead(II) complexes with aliphatic ligands are the first of their class that display Pb ··· S, Pb ··· N TtB type secondary interactions in self-assembly processes, building homo- and heterodimers. Apart from TtBs, N–H ··· N, N–H ··· S, C–H ··· N, and C–H ··· S type H-bonds also engineer the supramolecular networks, generating diverse chain and ring geometry with requisite stability. DFT calculations and quantum theory of atoms-in-molecules analyses explored the nature of TtBs between hemidirected Pb(II) and the thiolate/cyano end of i-mnt –2 in formed dimers and their pivotal role in stabilizing and elucidating the electronic architecture of dimers. In addition, Hirshfeld surface analysis corroborates with X-ray and DFT results, exploring the existence of TtBs, H-bonds, and other noncovalent interactions that assist in the construction of stable supramolecular networks.
Bhattacharjee et al. (Fri,) studied this question.