Search results for "bonds"
showing 5 items of 155 documents
Tetrameric and Dimeric [N∙∙∙I+∙∙∙N] Halogen-Bonded Supramolecular Cages
2017
Tripodal N‐donor ligands are used to form halogen‐bonded assemblies via structurally analogous Ag+‐complexes. Selective formation of discrete tetrameric I6L4 and dimeric I3L2 halonium cages, wherein multiple [N⋅⋅⋅I+⋅⋅⋅N] halogen bonds are used in concert, can be achieved by using sterically rigidified cationic tris(1‐methyl‐1‐azonia‐4‐azabicyclo[2.2.2]octane)‐mesitylene ligand, L1(PF6)3, and flexible ligand 1,3,5‐tris(imidazole‐1‐ylmethyl)‐2,4,6‐trimethylbenzene, L2, respectively. The iodonium cages, I6L14(PF6)18 and I3L22(PF6)3, were obtained through the [N⋅⋅⋅Ag+⋅⋅⋅N]→ [N⋅⋅⋅I+⋅⋅⋅N] cation exchange reaction between the corresponding Ag6L14(PF6)18 and Ag3L22(PF6)3 coordination cages, prepare…
Selective Formation of S4- and T-Symmetric Supramolecular Tetrahedral Cages and Helicates in Polar Media Assembled via Cooperative Action of Coordina…
2020
We report on the synthesis and self-assembly study of novel supramolecular monomers encompassing quadruple hydrogen-bonding motifs and metal coordinating 2,2’-bipyridine units. When mixed with metal ions such as Fe2+ or Zn2+, the tetrahedron cage complexes are formed in quantitative yields and full diastereoselectivity, even in highly polar acetonitrile or methanol solvents. The symmetry of the complexes obtained has been shown to depend critically on the flexibility of the ligand. Restriction of the rotation of the hydrogen-bonding unit with respect to the metal coordinating site results in a T-symmetric cage, whereas by introducing flexibility either through a methylene linker or rotating…
N-[3-Methyl-1-phenyl-1-(1H-tetrazol-1-yl)butan-2-yl]acetamide
2016
In the molecule of the title compound, C14H19N5O, the dihedral angle formed between the tetrazole and phenyl rings is 68.39 (4)°. In the crystal, molecules are linked by N—H...N, C—H...N and C—H...O hydrogen bonds to form two-dimensional networks extending parallel to thebcplane.
Crystal structure and Hirshfeld surface analysis of (Z)-4-chloro-N′-(4-oxothiazolidin-2-ylidene)benzenesulfonohydrazide monohydrate
2018
The asymmetric unit of the title thiazole derivative containing a sulfonylhydrazinic moiety, C9H8ClN3O3S2·H2O, consists of two independent molecules and two water molecules. The central parts of the molecules are twisted as both the molecules are bent at both the S and N atoms. In the crystal, N—H...N, N—H...O, C—H...O and O—H...O hydrogen-bonding interactions connect the molecules, forming layers parallel to the ab plane. Two-dimensional fingerprint plots associated with the Hirshfeld surface show that the largest contributions to the crystal packing come from O...H/H...O (32.9%) and H...H (22.6%) interactions.
Role of Weak Hydrogen Bonds and Halogen Bonds in 5-Halo-1,3-dimethyluracils and Their Cocrystals : A Combined Experimental and Computational Study
2016
Seven single crystals containing either N,N-dimethyluracil (DMHU) or one of its 5-halogenated derivatives (DMXU; X = F, Cl, Br, I) were prepared using N,N-dimethylformamide as the crystallization solvent. Single crystal X-ray diffraction and quantum chemical calculations carried out at the spin component scaled local MP2 level of theory were then used to study the intramolecular halogen and nonconventional hydrogen bonds present in the structures. The results were compared to and contrasted with the previously reported data for uracil and its halogenated derivatives. In particular, the intermolecular interactions in DMIU were compared to the halogen and hydrogen bonds in 5-iodouracil that, …