The use of C₃-symmetric tripodal ligands in crystal engineering

The use of chiral tripodal ligands in the assembly of non-centrosymmetric crystal lattice is illustrated with the triamide ligand tris[N-(S)-(-)-(α)-methylbenzylcarbamoylmethyl]amine (H₃1^S-mbz). In the crystal phase, this tripodal ligand assembles into C₃-symmetric chiral columns that are stabilized by hydrogen bonds and aryl-aryl interactions. Intercolumnar assembly is driven by the clustering of edge-to-face aryl and methyl-to-aryl interactions. Thrice deprotonation of H₃1^S-mbz and binding of an Ni(II)-F moiety also produces a non- centrosymmetric lattice which is noteworthy for its six-fold symmetric open framework structure and the alignment of all the molecular Ni-F bonds in the lattice along the crystallographic c-axis. Crystal data: H₃1^S-mbz crystallizes in the rhombohedral system, space group R3 with cell dimensions a = b = 22.352(5) Å, c = 4.882(1) Å, α = β = 90°, γ= 120°, and Z = 3; [NEt₄]₂[Ni1^S-mbz(F)] crystallizes in the hexagonal system, space group P6₃ with cell dimensions a = b = 12.0780(1) Å, c = 18.1231(1) Å, α = β = 90°, γ = 120°, and Z = 2.