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The phenomenon of vibrational resonance (VR) in the classical Morse oscillator influenced by narrow band and wide band frequency modulated signals is numerically studied. Vibrational resonance is found to occur when the amplitudes f and g and frequencies ω and Ω of the signals are varied. The dynamics of the system is studied in the presence of both signals separately. Vibrational resonance and dynamics of the system are characterized using the response amplitude and bifurcation diagram.

The asymmetric unit of the title compound, C22H36N2, comprises one half-molecule, the other half being generated by a center of inversion. The piperidine ring adopts a chair conformation, with the exocyclic N—C bond in an equatorial orientation. A short intramolecular C—H...N hydrogen bond occurs and forms an S(6) motif. No directional interactions beyond van der Waals contacts are observed between the molecules, which form a wave-like supramolecular architecture.

In the title hydrate, C13H11N3O·H2O, the benzotriazole ring system is planar (r.m.s. deviation = 0.007 Å) and is almost orthogonal to the phenyl ring to which it is linked by a methylene group, forming a dihedral angle of 81.87 (15)°. In the crystal, molecules are linked into chains along [001] by O—H...O hydrogen bonds. The chains are consolidated into a three-dimensional architecture by C—H...O, C—H...π and π–π [centroid–centroid distance between the five- and six-membered rings of the benzotriazole ring system = 3.595 (3) Å] interactions.

In the title compound, C6H5N3O·C13H11N3O, the benzotriazole ring system in the 1-benzyl-1H-benzotriazole 3-oxide (A) molecule is close to being planar (r.m.s. deviation = 0.011 Å); its mean plane forms a dihedral angle of 67.56 (7)° with that of the attached phenyl ring. The benzotriazole ring system in the 1-hydroxybenzotriazole (B) molecule is also close to being planar (r.m.s. deviation = 0.010 Å). In the crystal, weak C—H...O and C—H...π interactions are present. The A and B molecules are linked by an O—H...N hydrogen bond.

In the title compound, C13H11N3O, the dihedral angle between the benzotriazole ring system [maximum deviation = 0.027 (16) Å] and the benzene ring is 10.28 (9)°. The C—C—O—N bond adopts an anti conformation [torsion angle = −177.11 (16)°]. In the crystal, the molecules interact via weak C—H...π interactions and aromatic π–π stacking [centroid-to-centroid distance = 3.731 (12) Å].

In the structure of the title compound, [KPt(C6H4N3O)Cl2(C6H5N3O)(C12H24O6)], the PtII atom is in a distorted square-planar geometry. The crystal structure is consolidated by O—H...O hydrogen bonds. The measured crystal was a non-merohedral twin with four components.

In the title compound, [K2PtCl4(C12H24O6)2], the PtII ion is located on an inversion centre and is coordinated by four Cl atoms, forming a square-planar geometry. The KI ion is coordinated by six O atoms of the crown ether and two bridging Cl atoms. The KI ion is displaced by 0.756 (2) Å from the mean plane of the six O atoms of the crown ether. The molecules are connected by weak C—H...O hydrogen bonds, forming an infinite two-dimensional network parallel to the (10overline{2}) plane. Intra- and intermolecular C—H...Cl hydrogen bonds are also observed.

In the title compound, C16H17N3O, the benzotriazole ring forms a dihedral angle of 77.25 (6)° with the phenyl ring. The benzotriazole ring is essentially planar with a maximum deviation of 0.012 (19) Å. Weak intermolecular C—H...O hydrogen bonds form R22(10) motifs. The crystal packing is consolidated by π—π interactions with centroid–centroid distances of 3.5994 (12) Å together with very weak C—H...π interactions.

There are two monomeric units in the asymmetric unit of the polymeric title compound, [Na(C5H4NOS)(C10H8N2O2S2)(H2O)]n. The NaI ions are six coordinated by four O atoms, one S atom and one water molecule, forming a slightly distorted octahedral geometry. An intramolecular O—H...O hydrogen bond stabilizes the conformation of the molecule. The crystal packing is consolidated by intermolecular O—H...O, O—H...N and O—H...S hydrogen bonds, π–π interactions [with centroid–centroid distances of 3.587 (2) Å] together with weak C—H...π interactions. The molecules are linked into polymeric chains along the b-axis direction.

In the title compound, (C5H7N2)2[CoCl4], the cobalt(II) ion is coordinated by four chloride ions in a slightly distorted tetrahedral geometry. The crystal packing is stabilized by intermolecular N—H...Cl hydrogen bonding, forming a three-dimensional network. The crystal was a non-merohedral twin emulating tetragonal symmetry, but being in fact orthorhombic.

In the title compound, C17H19N3O, the benzotriazole ring is essentially planar, with a maximum deviation of 0.0069 (15) Å. The mean plane of the benzotriazole ring forms a dihedral angle of 13.16 (4)° with the mean plane of the benzene ring. The crystal packing is stabilized by π–π stacking interactions, with a centroid–centroid distance of 3.8077 (12) Å, together with weak C—H...π interactions. Molecules are stacked along the a axis.

In the centrosymmetric title compound, [Ni(C8H8NO3S)2(H2O)4], the NiII ion, which lies on an inversion centre, is six coordinated by four water molecules and two propionate O atoms from two 2-pyridylsulfanylpropionate N-oxide ligands, forming a slightly distorted octahedral geometry. An intramolecular O—H...O hydrogen bond stabilizes the molecular conformation. The crystal packing is consolidated by intermolecular O—H...O and C—H...O hydrogen bonding.

The complete molecule of the title compound, C24H24N6O2, is generated by a crystallographic inversion centre. The benzotriazole rings form dihedral angles of 2.10 (7)° with the central aromatic ring. The crystal packing is consolidated by π–π interactions, with centroid–centroid distances of 3.6234 (10) Å, together with weak C—H...π interactions.

In the crystal structure of the title compound, 4C21H22N2O2S2·0.5C3H6O·11.5H2O, there are four crystallographically independent molecules (A, B, C, D) with similar geometries, 11 water molecules and a solvent acetone molecule which is disordered with a water molecule with occupancy factors of 0.5:0.5. The dihedral angles formed by the mesitylene ring with the two pyridyl rings are 82.07 (3) and 78.39 (3)° in molecule A, 86.20 (3) and 82.29 (3)° in molecule B, 81.05 (3) and 76.0 (4)° in molecule C, 86.0 (3) and 80.9 (3)° in moleule D. The two pyridyl rings form dihedral angles of 41.17 (4), 64.01 (3), 81.9 (3) and 82.25 (3)° in molecules A, B, C and D, respectively. The crystal structure is stabilized by intermolecular O—H...O hydrogen bonds and possible weak C—H...π interactions. Some short intramolecular S...O contacts are apparent [2.684 (4)–2.702 (4) Å].

In the title compound, [Ni2(CO3)(C5H6N2)8(H2O)]Cl2·5H2O, one of the the NiII ions is six-coordinated in a distorted octahedral geometry, with the equatorial plane defined by four pyridine N atoms from four aminopyridine ligands, the axial positions being occupied by one water O and a carbonate O atom. The other NiII ion is also six-coordinated, by four other pyridine N atoms from four other aminopyridine ligands and two carbonate O atoms to complete a distorted octahedral geometry. In the crystal structure, molecules are linked into an infinite three-dimensional network by O—H...O, N—H...Cl, N—H...O, O—H...N, C—H...O, C—H...N and C/N—H...π interactions involving the pyridine rings.

In the title compound, C16H19NOS, the durene ring and the oxopyridyl ring form a dihedral angle of 82.26 (7)°. The crystal structure is stabilized by intermolecular C—H...O hydrogen bonds, weak C—H...π interactions and π–π interactions [centroid–centroid distance of 3.4432 (19) Å], together with intramolecular S...O [2.657 (2) Å] short contacts.

In the title compound, C15H17NOS·H2O, the benzene and pyridine rings form a dihedral angle of 71.18 (2)°. The intramolecular S...O distance [2.737 (3) Å] is shorter than expected and, in terms of hybridization principles, the N—C—S angle [114.1 (2)°] is smaller than expected. The crystal structure is stabilized by intermolecular O—H...O and weak C—H...O hydrogen bonds. In addition, weak π–π stacking interactions with a centroid–centroid distance of 3.778 (3) Å are also observed.

In the title compound, C12H11NOS, the dihedral angle between the oxopyridinium and phenyl rings is 58.40 (1)°. The crystal structure is stabilized by C—H...O hydrogen bonds, π–π stacking interactions involving the pyridinium rings [centroid–centroid distance = 3.6891 (9) Å] and C—H...π interactions.

In the crystal structure of the title complex, [Pt(C5H4NOS)2], the Pt atom is coordinated by two O atoms and two S atoms in a cis configuration, forming a distorted square-planar coordination geometry. The molecule exhibits pseudo-C2v symmetry and is essentially planar, with a maximum deviation from planarity of 0.0124 (2) Å. The dihedral angle between the two pyridine rings is 5.85 (2)°.

Molecules of the title compound, C22H24N2O2S2, lie across centres of inversion. The two thiopyridine N-oxide groups adopt a stepped trans configuration with respect to the benzene ring, by virtue of the symmetry. The oxopyridinium ring forms a dihedral angle of 79.9 (2)° with the benzene ring. The crystal structure is stabilized by a strong π–π interaction between the pyridinium rings of adjacent molecules [ring centroid–centroid distance = 3.464 (3) Å].

Biologically important macromolecule 1, 1', 3, 3' Bis - [2,3,5,6-Tetramethyl-p-phenylenebis(methylene)] dibenzotriazlinium dibromide hydrate (BTD) was synthesized and characterized using FT-IR, NMR and single-crystal XRD (SCXRD). SCXRD revealed that the compound was crystallized as a monoclinic system and associated through weak intermolecular interactions like H-bonding and π- π stacking interactions. These weak intermolecular interactions in BTD were studied using Crystal Explorer and Gaussian. The calculated energies for the Highest Occupied Molecular Orbital (HOMO) and the Lowest Unoccupied Molecular Orbital (LUMO) showed the stability and reactivity of the title compound. Molecular electrostatic potential (MEP) surface analysis was used to investigate the crystal's nucleophilic and electrophilic reactive sites. The molecular shape and intermolecular interactions in the crystal structure were determined using Hirshfeld surface analysis and fingerprint plots. Anticancer, anti-bacterial and DNA binding ability of BTD were investigated by experimental and theoretical techniques. The obtained results suggest that BTD possesses better anti-cancer, anti-bacterial and DNA binding abilities. The mode of action of antibiotic and anticancer approach was discussed. This provides promising therapeutic advantages for further development., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Nowadays, over 200 countries face a wellbeing emergency because of epidemiological disease COVID-19 caused by the SARS-CoV-2 virus. It will cause a very high effect on the world's economy and the worldwide health sector. The present work is an investigation of the newly synthesized 4-benzyl-1-(2,4,6-trimethyl-benzyl)-piperidine (M1BZP) molecule's inhibitory potential against important protein targets of SARS-CoV-2 using computational approaches. M1BZP crystallizes in monoclinic type with P1211 space group. For the title compound M1BZP, spectroscopic characterization like 1 H NMR, 13 C NMR, FTIR, were carried out. The geometry of the compound had been optimized by the DFT method and its results were compared with the X-ray diffraction data. The calculated energies for the Highest Occupied Molecular Orbital (HOMO) and the Lowest Unoccupied Molecular Orbital (LUMO) showed the stability and reactivity of the title compound. Intermolecular interactions in the crystal network were determined using Hirshfeld surface analyses. The molecular electrostatic potential (MEP) picture was drawn using the same level of theory to visualize the chemical reactivity and charge distribution on the molecule. Molecular docking study performed for the synthesized compound revealed an efficient interaction with the COVID-19 protease and resulted in good activities. We hope the present study would help workers in the field to develop potential vaccines and therapeutics against the novel coronavirus. Virtual ADME studies were carried out as well and a relationship between biological, electronic, and physicochemical qualifications of the target compound was determined. Toxicity prediction by computational technique for the title compound was also carried out., (Copyright © 2021 Elsevier Inc. All rights reserved.)

In the title compounds, 4-aminopyridinium 4-aminobenzoate dihydrate, C(7)H(6)NO(2)(-).C(5)H(7)N(2)(+).2H(2)O, (I), and 4-aminopyridinium nicotinate, C(5)H(7)N(2)(+).C(6)H(4)NO(2)(-), (II), the aromatic N atoms of the 4-aminopyridinium cations are protonated. In (I), the asymmetric unit is composed of two 4-aminopyridinium cations, two 4-aminobenzoate anions and four water molecules, and the compound crystallizes in a noncentrosymmetric space group. The two sets of independent molecules of (I) are related by a centre of symmetry which is not part of the space group. In (I), the protonated pyridinium ring H atoms are involved in bifurcated hydrogen bonding with carboxylate O atoms to form an R(1)(2)(4) ring motif. The water molecules link the ions to form a two-dimensional network along the (101) plane. In (II), an intramolecular bifurcated hydrogen bond generates an R(1)(2)(4) ring motif and inter-ion hydrogen bonding generates an R(4)(2)(16) ring motif. The packing of adduct (II) is consolidated via N-H...O and N-H...N hydrogen bonds to form a two-dimensional network along the (102) plane.

The asymmetric unit of the title compound, [Pt(C(5)H(4)NOS)Cl(C(2)H(6)OS)], contains two independent complex mol-ecules having similar geometries. Each Pt(II) atom is four-coordinated in a distorted square-planar geometry by S and O atoms of one pyridine N-oxide ligand, the S atom of one dimethyl sulfoxide mol-ecule and one terminal Cl(-) ion. The mol-ecules are linked into a three-dimensional framework by C-H⋯O and C-H⋯Cl hydrogen bonds.

In the title compound, C(27)H(27)N(3)O(3)S(3)·CH(4)O, the dihedral angles formed by the mesitylene ring with the three oxopyridyl rings are 89.6 (1), 75.5 (1) and 80.69 (1)°, indicating that all three are nearly perpendicular to the mesitylene ring. Intra-molecular C-H⋯S hydrogen bonds generate S(6) ring motifs. The crystal structure is stabilized by intra-molecular C-H⋯S and inter-molecular C-H⋯O hydrogen bonds and weak C-H⋯π inter-actions.