1,3,4-Thiadiazole and 1,2,4-triazole-5-thione derivatives bearing 2-pentyl-5-phenyl-2,4-dihydro-3H-1,2,4-triazole-3-one ring: Synthesis, molecular docking, urease inhibition, and crystal structure.

Two series of 1,3,4-thiadiazole (40a-o) and 1,2,4-triazole-5-thione (41a-l) derivatives bearing a 2-pentyl-5-phenyl-1,2,4-triazole-3-one ring were synthesized and then studied for their urease inhibitory activities using thiourea as a standard drug. Among the two groups, the first group (40a-o) did not show good activity while the second group (41a-l) showed excellent activity. Compound 41j (1091.24 ± 14.02 µM) of the second series of compounds showed lower activity than thiourea, while the remaining 11 compounds (41a-i, k, and l) showed better activity than thiourea (183.92 ± 13.14 µM). Among the 11 compounds, 41b (15.96 ± 2.28 µM) having the 3-F group on the phenyl ring showed the highest inhibitory activity. Urease kinetic studies of 41b, which is the most active compound, determined it to have an un-competitive inhibition potential. Moreover, in silico analysis against urease from jack bean with 27 new heterocyclic compounds and the reference molecule was carried out to see the necessary interactions responsible for urease activity. The docking calculations of all compounds supported stronger binding to the receptor than the reference molecule, with high inhibition constants. In addition, compound 40m was characterized by single-crystal X-ray diffraction analysis. X-ray analysis reveals that the structures of the compound 40m crystallize in the monoclinic P21/c space group with the cell parameters: a = 10.2155(9) Å, b = 22.1709(18) Å, c = 21.4858(17) Å, ß = 99.677(8)°, V = 4797.0(7) Å3 . X-ray diffraction analyses were also performed to gain insights into the role of weak intermolecular interactions and C-H…X (halogen) interactions in compound 40m that influence the crystal packing.

Crystal structure and computational study of 2,4-di-chloro-N-[(E)-(5-nitro-thio-phen-2-yl)methyl-idene]aniline.

The title compound, C11H6Cl2N2O2S, is a Schiff base that incorporates an N-bound 2,4-di-chloro-phenyl and a C-bound 5-nitro-thio-phene ring. The mol-ecule is approximately planar, the maximum deviation from the mean plane being 0.233 (4) Šfor the C=N N atom. The dihedral angle between the benzene and thio-phene rings is 9.7 (2)°. The C=N double bond has an E configuration. The crystal structure features C-H⋯O hydrogen bonds,forming sheets parallel to (10-1), and π-π stacking inter-actions between symmetry-related thio-phene and benzene rings, in which the distance between adjacent ring centroids is 3.707 (4) Å, forming a three-dimensional supramolecular structure. Geometric parameters from quantum-chemical calculations are in good agreement with experimental X-ray diffraction results.

Structural and spectroscopic characterization of a thiosemicarbazidatodioxouranium(VI) complex: a combined experimental and DFT study.

The title thiosemicarbazidatodioxouranium(VI) compound was synthesized and characterized by FT-IR, NMR and UV-vis spectroscopies. Solid-state structure of the compound was confirmed by X-ray crystallography. Besides, the molecular geometry, vibrational frequencies and gauge-independent atomic orbital (GIAO) (1)H and (13)C NMR chemical shift values of the compound in the ground state have been calculated using the density functional theory (DFT/B3LYP) method with the 6-311++G(d,p) basis set for the C, H, Cl, N, O, S atoms and SDD pseudo-potential for the U atom, and compared with the experimental data. Using the TD-DFT method, electronic absorption spectra of the compound have been predicted at same level. As a result, a good agreement is obtained between the experimental and theoretical ones.

Crystal structure and DFT calculations of 5-(4-Chlorophenyl)-1-(6-methoxypyridazin-3-yl)-1H-pyrazole-3-carboxylic acid.

The title compound, 5-(4-Chlorophenyl)-1-(6-methoxypyridazin-3-yl)-1H-pyrazole-3-carboxylic acid, has been characterized by using elemental analysis, MS, FT-IR, 1H NMR and 13C NMR spectroscopic, and crystallographic techniques. The title compound crystallizes in the triclinic space group P-1 with a=9.612(1), b=9.894(1), c=17.380(1)Å, α=90.213(5)°, ß=104.99(1)°, γ=111.072(5)°, V=1481.3(2)Å3 and Dx=1.483 g cm(-3) respectively. The structure of the compound has also been examined by using quantum chemical methods. The molecular geometry and vibrational frequencies of monomeric and dimeric form of the title compound in the ground state have been calculated by using the B3LYP/6-31G(d,p) level of the theory. The calculated results show that the optimized geometry and the theoretical vibration frequencies of the dimeric form are good agreement with experimental data. In addition, HOMO-LUMO energy gap, molecular electrostatic potential map, thermodynamic properties of the title compound were performed at B3LYP/6-31G(d,p) level of theory.

Molecular structure, quantum mechanical calculation and radical scavenging activities of (E)-4,6-dibromo-2-[(3,5-dimethylphenylimino)methyl]-3-methoxyphenol and (E)-4,6-dibromo-2-[(2,6-dimethylphenylimino)methyl]-3-methoxyphenol compounds.

In this study, (E)-4,6-dibromo-2-[(3,5-dimethylphenylimino)methyl]-3-methoxyphenol and (E)-4,6-dibromo-2-[(2,6-dimethylphenylimino)methyl]-3-methoxyphenol compounds have been synthesized and characterized by using X-ray crystallographic method, FT-IR and Density functional method. The molecular geometry, vibrational frequencies of the title compounds in the ground state have been calculated by using B3LYP with the 6-31G(d,p) basis set. The tautomeric form of the compounds has been demonstrated by using single crystal X-ray method, FT-IR spectrometer and DFT method. In addition, HOMO-LUMO energy gap, molecular electrostatic potential map and NBO analysis of the compounds are performed at B3LYP/6-31G(d,p) level. It may be remarked that the free radical scavenging activities of the title compounds were assessed using DPPH, DMPD+, and ABTS+ assays. The obtained results show that especially compound 2 has effective DPPH (SC50 1.52±0.14 µg/mL), DMPD+ (SC50 1.22±0.21 µg/mL), and ABTS+ (SC50 3.32±0.17 µg/mL) scavenging activities compared with standards (BHA, rutin, and trolox).

Crystal structure, DFT and HF calculations and radical scavenging activities of (E)-4,6-dibromo-3-methoxy-2-[(3-methoxyphenylimino)methyl]phenol.

In this study, (E)-4,6-dibromo-3-methoxy-2-[(3-methoxyphenylimino)methyl]phenol has been synthesized and characterized by using X-ray technique and FT-IR experimentally and using B3LYP/6-31G(d,p) and HF/6-31G(d,p) methods theoretically. The intermolecular and intramolecular interactions of the title compound have been determined according to X-ray results. The molecular geometry, vibrational frequencies of the title compound in the ground state have been calculated using the density functional B3LYP and HF method with the 6-31G(d,p) basis set and calculated bond parameters and vibrational frequencies values show good agreement with experimental values. Theoretical and experimental results show that tautomeric form of the structure is phenol-imine form. Besides HOMO-LUMO energy gap, molecular electrostatic potential map were performed at B3LYP/6-31G(d,p) level. It is worthy note of that, the free radical scavenging activities of the title compound were assessed using DPPH˙, DMPD˙(+), and ABTS˙(+) assays. The obtained results show that the title compound has effective DPPH˙ (SC50 2.61±0.09 µg/mL), DMPD˙(+) (SC50 2.82±0.14 µg/mL), and ABTS˙(+) (SC50 4.91±0.18 µg/mL) radical scavenging activities when compared with standard antioxidants (BHA, rutin, and trolox).

8-{(E)-[(4-Chloro-phen-yl)imino]-meth-yl}-1,1,7,7-tetra-methyl-1,2,3,5,6,7-hexa-hydro-pyrido[3,2,1-ij]quinolin-9-ol.

The title Schiff base, C23H27ClN2O adopts the phenol-imine tautomeric form, with an intra-molecular O-H⋯N hydrogen bond, which generates an S(6) ring motif. Three C atoms of the heterocyclic moiety of the hexa-hydro-pyrido-quinoline unit, as well as the two methyl groups bonded to one of these C atoms, are disordered over two set of sites, with anoccupancy ratio of 0.740 (4):0.260 (4).

(E)-(2,5-Difluoro-benz-yl)[(2-eth-oxy-naphthalen-1-yl)methyl-idene]amine.

In the title mol-ecule, C20H17F2NO, which adopts an E conformation with respect to the imine C=N double bond, the mean planes of the naphthalene ring system and the difluoro-phenyl ring form a dihedral angle of 85.82 (7)°. An intra-molecular C-H⋯N hydrogen bond occurs. In the crystal, weak C-H⋯F hydrogen bonds link the mol-ecules into zigzag chains along [010].

4-Meth-oxy-2-{(E)-[(thio-phen-2-yl)methyl-imino]-meth-yl}phenol.

The title Schiff base, C(13)H(13)NO(2)S, adopts the phenol-imine tautomeric form and reveals an intra-molecular O-H⋯N hydrogen bond involving the hy-droxy group and the imino N atom, forming an S(6) ring. The mol-ecule is highly twisted with respect to the central imine group, which is reflected in the dihedral angle of 67.83 (10)° formed by the thienyl and phenol rings. The crystal packing is characterized by weak C-H⋯O and C-H⋯π inter-actions.

(E)-3-Chloro-N-[(2-eth-oxy-naphthalen-1-yl)methyl-idene]aniline.

In the title compound, C(19)H(16)ClNO, the dihedral angle between the naphthalene ring system and the chloro-benzene ring is 61.90 (10)° and the C-N-C-C torsion angle is 174.6 (2)°. The mol-ecular structure is stabilized by an intra-molecular C-H⋯N hydrogen bond. The crystal structure features π-π stacking inter-actions [centroid-centroid distances = 3.7325 (17) and 3.8150 (17) Å].

(Z)-2-[(E)-2-(1-Benzothio-phen-3-yl-methyl-idene)hydrazin-1-yl-idene]-1,2-diphenyl-ethanone.

The title compound, C(23)H(16)N(2)OS, is not planar, the phenyl ring of the benzoyl group making a dihedral of 77.61 (7)° with the benzothio-phene system ring. The benzothio-phene system and the remaining phenyl ring make an angle of 12.71 (13)°. The conformation around the imine functions is E for the C=N bond towards the benzothio-phene system and Z for the C=N bond towards the benzoyl group. The packing of the mol-ecules shows C-H⋯π inter-actions. A weak intramolecular C-H⋯N bond also occurs.

(E)-4-Methyl-N-[(5-nitro-thio-phen-2-yl)methyl-idene]aniline.

In the crystal structure of the title compound, C(12)H(10)N(2)O(2)S, the benzene and the 2-nitro-thio-phene rings make a dihedral angle of 7.47 (12)°. The dihedral angle between the nitro group and the attached ring is 1.9 (6)°.

5-Diethyl-amino-2-[(E)-(2,4-dimeth-oxy-phen-yl)imino-meth-yl]phenol.

The title Schiff base, C(19)H(24)N(2)O(3), exists in the crystal structure in the phenol-imine tautomeric form with an intra-molecular O-H⋯N hydrogen bond. The planes of the aromatic rings form a dihedral angle of 36.8 (8)°. The crystal packing is characterized by C-H⋯O hydrogen bonds and π-π stacking inter-actions [centroid-centroid distance = 3.478 (4)Å].

(E)-N-(1-Benzothio-phen-3-yl-methyl-idene)-2,6-dimethyl-aniline.

In the title compound, C(17)H(15)NS, the benzothio-phene residue and the substituted benzene ring are oriented at a dihedral angle of 61.99 (7)°. An inter-molecular C-H⋯π inter-action contributes to the stability of the crystal structure.

(E)-3-[(2-Methyl-4-nitro-phen-yl)imino-meth-yl]-1-benzothio-phene.

In the title conpound, C(16)H(12)N(2)O(2)S, the 1-benzothio-phene residue and the substituted benzene ring are oriented at a dihedral angle of 53.36 (6)°. The mol-ecular conformation features a short C-H⋯N contact. There are no significant inter-molecular contacts.

Ammonium O,O-dicyclohexyl phosphorodithioate.

The structure of the title compound, NH4+.C12H22O2PS2-, consists of a polymeric arrangement of ammonium cations and O,O-dicyclohexyl phosphorodithioate anions linked through N-H...O and N-H...S hydrogen bonds. These interactions result in the formation of (100) sheets.

4-Bromo-2-[[4-(3-mesityl-3-methylcyclobutyl)thiazol-2-yl]hydrazonomethyl]phenol, with N-H...N, C-H...pi and pi-pi interactions.

The title compound, C24H26BrN3OS, crystallizes in the triclinic space group P-1, with two independent molecules in the asymmetric unit. The molecules adopt an E geometry about the azomethine C=N double bond. The structure is stabilized as dimers by N-H...N hydrogen bonding. C-H...pi and pi-pi interactions are also effective in the crystal packing.