DFT study and crystal structure analysis of a new nano-structure five coordinated Hg(II) complex involving C-H⋯O, N⋯O and π⋯π interactions in a supra-molecular structure

Some new nanostructure zinc complex: Synthesis, spectral analyses, crystal structure, Hirshfeld surface analyses, antimicrobial/anticancer, thermal behavior and usage as precursor for ZnO nanostructure

In this work, a new tridentate ligand, its some novel zinc halide/pseudohalide complexes and their antimicrobial and cytotoxic effects of them are described. Characterization data of these compounds have been achieved via several physical and micro analytical techniques. As typical one, X-ray crystal structure analysis of zinc azide complex was run showing zinc center is penta-coordinated by three nitrogen atoms from Schiff base ligand and two terminal azide nitrogen atoms as a distorted square pyramidal geometry. Hirshfeld surfaces analysis clears the important role of interactions related to azide groups (NH⋯N and CH⋯N hydrogen bonds) in the stabilization of its supramolecular structure. According to data obtained from thermal analysis (TG/DTG/DTA), all complexes are decomposed at four or more thermal stages below 1000 °C. Moreover antimicrobial activities of the compounds were screened against some gram positive and gram negative bacteria. Furthermore anticancer activities of the complexes were studied against MDA-MB468 and k562 as two cancer cell lines. In final, three zinc complexes were also synthesized in nano scale by sonochemical method and one of them was utilized as the precursor for preparation of nanostructure ZnO confirmed by XRD pattern and SEM image.

Structural, theoretic and spectroscopic analysis of 2-methyl-5-nitroaniline salts with various inorganic acids

Crystal structures of six new salts of 2-methyl-5-nitroaniline with inorganic acids [(H2Me5NA)Br, (H2Me5NA)I, (H2Me5NA)NO₃, (H2Me5NA)Cl, (H2Me5NA)HSO₄ and (H2Me5NA)I₃·0.5H₂O] are determined by single-crystal X-ray diffraction. The most important hydrogen-bonding patterns are formed by the ammonio group and respective anions composing 1D or 2D networks. The patterns are analysed using the graph-set approach and mathematical interrelations between graph-set descriptors are shown for comparative purposes. Analysis of IR spectra enables the strength of hydrogen bonds in the crystals to be assessed. The frequency of N-H and O-H stretching vibrations and NH₃ group libration indicates that the strongest hydrogen bonds are present in (H2Me5NA)HSO₄, whereas the weakest ones occur in (H2Me5NA)I₃·0.5H₂O. Hirshfeld surface analysis reveals that apart from obvious N-H...anion hydrogen bonds, the molecules are also connected to each other by exclusive C-H...O_NO2 interactions. The opposite occurs in the crystal structure of 2-methyl-4-nitroaniline salts, where a variety of O_NO2...π(N)_NO2 non-hydrogen bonding interactions are observed.

Phase transition in polar 2-nitroanilinium nitrate. Graph-set approach of hydrogen bonding patterns and analysis of vibrational spectra

A phase transition in new compound 2-nitroanilinium nitrate, (H2NA)NO₃, was found. A symmetry lowering from orthorhombic, Pmn2₁, to monoclinic one, P2₁, at 249 K is observed. During the phase transition, the H2NA⁺ and nitrate ions displace from the mirror plane in high-temperature phase. As a result, hydrogen bonding network constructed by the ammonio group and NO₃^- anion is changed. Especially, a bifurcated hydrogen bond disappears. Mathematical operations using both elementary and hydrogen bond graph-set descriptors were used for the first time to describe a mechanism of phase transition. Changes in hydrogen bonding network were also studied by means of vibrational spectroscopy. Band shift associated with stretching and bending vibrations of the ammonio group indicates that the energy of intermolecular interactions rises along with temperature decrease. SHG response for the studied compound is higher than KDP, I_(H2NA)NO3 = 1.1·I_KDP, although a decay of the signal was observed due to instability of the sample.

Comparison of hydrogen bonds and diverse weak interactions of the nitro group in 2-methyl-4-nitroanilinium nitrate, bisulfate and two hexafluoridosilicates: elementary graph-set approach

Crystal structures of (H2m4na)NO₃ (1), (H2m4na)HSO₄ (2), (H2m4na)₂SiF₆ (3) and (H2m4na)₂SiF₆·2H₂O (4), where 2m4na = 2-methyl-4-nitroaniline, are presented. Two layers of interactions occur in the structures, N-H...O/F hydrogen bonds and interactions with the nitro group. Although diverse, hydrogen-bonding patterns are compared with each other by means of interrelations among elementary graph-set descriptors and descriptors of hydrogen-bonding patterns. Using mathematical relations, the gradual expansion of the ring patterns was shown in the crystal structures. Parallel and perpendicular arranged nitro groups form weak π(N)_NO2...π(O)_NO2 and π(N)_NO2...O_NO2 interactions, respectively. The π_NO2...π_ring interaction has an impact to the stabilization of parallel oriented nitro groups. Generally, weak interactions constructed by the nitro group occur in the studied crystals as follows: π(N)_NO2...π(O)_NO2, π_ring...π_ring, C-H...O (1); π(N)_NO2...π(O)_NO2, π(N)_NO2...O_NO2 (2); π(N)_NO2...π(O)_NO2, π(N)_NO2...O_NO2 (3); C-H...O (4).

Structural and computational study of some new nano-structured Hg(ii) compounds: a combined X-ray, Hirshfeld surface and NBO analyses

Crystal structure, Hirshfeld surface, DFT and NBO analyses of two new distorted square-pyramidal mercury complexes are presented.

Crystal structures, Hirshfeld surface analyses and thermal behavior of two new rare tetrahedral terminal zinc(ii) azide and thiocyanate Schiff base complexes

Crystal structures, Hirshfeld surface and thermal analyses of two new rare tetrahedral terminal zinc(ii) thiocyanate and azide Schiff base complexes of [ZnL(NCS)₂] and [ZnL(N₃)₂] are presented.