Compositional and structural variety of diphenyllead(IV) complexes obtained by reaction of diphenyllead dichloride with thiosemicarbazones

DFT computational analysis of piracetam

Density functional theory calculation with B3LYP using 6-31G(d,p) and 6-31++G(d,p) basis set have been used to determine ground state molecular geometries. The first order hyperpolarizability (β0) and related properties (β, α0 and Δα) of piracetam is calculated using B3LYP/6-31G(d,p) method on the finite-field approach. The stability of molecule has been analyzed by using NBO/NLMO analysis. The calculation of first hyperpolarizability shows that the molecule is an attractive molecule for future applications in non-linear optics. Molecular electrostatic potential (MEP) at a point in the space around a molecule gives an indication of the net electrostatic effect produced at that point by the total charge distribution of the molecule. The calculated HOMO and LUMO energies show that charge transfer occurs within these molecules. Mulliken population analysis on atomic charge is also calculated. Because of vibrational analysis, the thermodynamic properties of the title compound at different temperatures have been calculated. Finally, the UV-Vis spectra and electronic absorption properties are explained and illustrated from the frontier molecular orbitals.

Synthesis, experimental, theoretical characterization and biological activities of 4-ethyl-5-(2-hydroxyphenyl)-2H-1,2,4-triazole-3(4H)-thione

This work presents the characterization of 4-ethyl-5-(2-hydroxyphenyl)-2H-1,2,4-triazole-3(4H)-thione (III) by quantum chemical calculations and spectral techniques. The molecular geometry, vibrational frequencies and gauge including atomic orbital (GIAO) (1)H and (13)C NMR chemical shift values of III in the ground state have been calculated using the density functional method (B3LYP) with the 6-31G(d) basis set. The calculated results show that the optimized geometry can well reproduce the crystal structure, and the theoretical vibrational frequencies and chemical shift values show good agreement with experimental values. To determine conformational flexibility, the molecular energy profile of the title compound was obtained by DFT calculations with respect to the selected torsion angle, which was varied from -180° to +180° in steps of 10°. The energetic behavior of III in solvent media was examined using the B3LYP method with the 6-31G(d) basis set by applying the Onsager and the polarizable continuum model (PCM). The predicted nonlinear optical properties of III are greater than ones of urea. In addition, DFT calculations of molecular electrostatic potentials and frontier molecular orbitals of III were carried out at the B3LYP/6-31G(d) level of theory. The title compound was screened for antibacterial, antifungal and antioxidant activities.

N-cyclohexyl-2-[5-(4-pyridyl)-4-(p-tolyl)-4H-1,2,4-triazol-3-ylsulfanyl]-acetamide dihydrate: synthesis, experimental, theoretical characterization and biological activities

The triazol compound N-cyclohexyl-2-[5-(4-pyridyl)-4-(p-tolyl)-4H-1,2,4-triazol-3-ylsulfanyl]-acetamide dihydrate has been synthesized and characterized by (1)H NMR, (13)C NMR, IR, and X-ray single-crystal determination. The molecular geometry, vibrational frequencies and gauge including atomic orbital (GIAO) (1)H and (13)C NMR chemical shift values of III in the ground state have been calculated using the density functional method (B3LYP) with the 6-31G(d) basis set. The calculated results show that the optimized geometry can well reproduce the crystal structure, and the theoretical vibrational frequencies and chemical shift values show good agreement with experimental values. The energetic behavior of III in solvent media was examined using the B3LYP method with the 6-31G(d) basis set by applying the Onsager and the polarizable continuum model (PCM). The predicted nonlinear optical properties of III are greater than ones of urea. In addition, DFT calculations of molecular electrostatic potentials, frontier molecular orbitals and thermodynamic properties of III were carried out at the B3LYP/6-31G(d) level of theory. The title compound was screened for antibacterial, antifungal and antioxidant activities.

Di-μ-azido-κ(4)N(1):N(1')-bis-({1-[(E)-phen-yl(pyridin-2-yl-κN)methyl-idene]thio-semi-carbazidato-κ(2)N(1),S}copper(II))

In the title compound, [Cu₂(C₁₃H₁₁N₄S)₂(N₃)₂], the Cu^II cation is N,N′,S-chelated by the deprotonated Schiff base ligand and is coordinated by the azide anion, while an N atom from an adjacent azide anion bridges the Cu^II cation at the apical position with a longer Cu—N distance of 2.533 (3) Å, completing the distorted N₄S square-pyramidal coordination geometry. A pair of azide anions bridge the two Cu^II cations, forming a centrosymmetric binuclear mol­ecule. In the crystal, the binuclear mol­ecules are linked by an N—H⋯N hydrogen bond into a ribbon running along the a axis.

Crystal structure, spectroscopic investigations and density functional studies of 4-(4-methoxyphenethyl)-5-benzyl-2H-1,2,4-triazol-3(4H)-one monohydrate

The triazol compound 4-(4-methoxyphenethyl)-5-benzyl-2H-1,2,4-triazol-3(4H)-one monohydrate (I) has been synthesized and characterized by (1)H NMR, (13)C NMR, IR, and X-ray single-crystal determination. The molecular geometry, vibrational frequencies and gauge including atomic orbital (GIAO) (1)H and (13)C NMR chemical shift values of (I) in the ground state have been calculated using the density functional method (B3LYP) with the 6-31G(d) basis set. The calculated results show that the optimized geometry can well reproduce the crystal structure, and the theoretical vibrational frequencies and chemical shift values show good agreement with experimental values. The energetic behavior of (I) in solvent media was examined using the B3LYP method with the 6-31G(d) basis set by applying the Onsager and the polarizable continuum model (PCM). The predicted non-linear optical properties of (I) are greater than ones of urea. In addition, DFT calculations of molecular electrostatic potentials, frontier molecular orbitals and thermodynamic properties of (I) were carried out at the B3LYP/6-31G(d) level of theory.

Quantum-chemical, spectroscopic and X-ray diffraction studies of (E)-2-[(2-Bromophenyl)iminomethyl]-4-trifluoromethoxyphenol

The Schiff base compound (E)-2-[(2-Bromophenyl)iminomethyl]-4-trifluoromethoxyphenol has been synthesised and characterised by IR, UV-vis, and X-ray single-crystal determination. The molecular geometry from X-ray determination of the title compound in the ground state has been compared using the Hartree-Fock (HF) and density functional theory (DFT) with the 6-311++G(d,p) basis set. The calculated results show that the DFT and HF can well reproduce the structure of the title compound. Using the TD-DFT and TD-HF methods, electronic absorption spectra of the title compound have been predicted and good agreement with the TD-DFT method and the experimental determination was found. The predicted nonlinear optical properties of the title compound are much greater than those of urea. In addition, DFT calculations of the title compound, molecular electrostatic potential (MEP), natural bond orbital (NBO), and thermodynamic properties were performed at B3LYP/6-311++G(d,p) level of theory.

Poly[di-μ(2)-chlorido-tri-μ(2)-terephthalato-tetra-lead(II)]

The title compound, [Pb₄(C₈H₄O₄)₃Cl₂]_n, consists of a three-dimensional inorganic–organic hybrid framework. The asymmetric unit contains two Pb²⁺ cations, one Cl⁻ anion and one and a half terephthalate anions, the latter being completed by inversion symmetry. The two Pb²⁺ cations are each surrounded by five O atoms and one Cl atom in the form of irregular polyhedra. The cations are linked by μ₂-O and μ₂-Cl atoms into binuclear units, which are further extended through Pb—O inter­actions into an undulated inorganic layer parallel to (001). These layers are connected along [001] by the terephthalate groups into a three-dimensional framework.

Mn(II), Co(II) and Zn(II) complexes with heterocyclic substituted thiosemicarbazones: synthesis, characterization, X-ray crystal structures and antitumor comparison

Transition metal complexes Mn(L(1))(2) (1), Mn(L(2))(2) (2), Co(L(3))(2)Cl 4H(2)O (3), Zn(L(3))(2) DMF (4), Co(HL(4))(2)(ClO(4))(2) 3H(2)O (5) and Zn(L(5))(2) DMF (6) where HL(1)=2-acetylpyridine thiosemicarbazone, HL(2)=2-acetylpyridine N(4)-methylthiosemicarbazone, HL(3)=2-benzoylpyridine thiosemicarbazone, HL(4)=2-benzoylpyridine N(4)-methylthiosemicarbazone and HL(5)=2-benzoylpyridine N(4)-phenylthiosemicarbazone, have been synthesized. The complexes 1, 2, 5 and 6 were characterized by elemental analysis, IR spectra and single-crystal X-ray diffraction studies. Preliminary in vitro screening indicated that all the tested compounds showed significant antitumor activity against K562 leucocythemia cancer cell line.

Crystal structure of tris(pyridine)(salicylaldehyde semicarbazonato(2-))cobalt(III)-trichloropyridinecobaltate(II) at 293 and 120K

The crystal structure of [CoIII(L)(py)3][CoIICl3(py)] (H2L=salicylaldehyde semicarbazone)was determined by X-ray analysis based on two single crystal X-ray experiments performed at 120 K and 293 K, respectively. It was found that the pyridine ligand of the complex anion is disordered over two positions. The preferential position of this pyridine found at120Kwas explained in terms of the C-H...Cl intermolecular interaction between the tetrahedral [CoII(py)Cl3]- anions. The mer-octahedral geometry of the cation in the presented crystal structure was compared with previously published structures of similar composition, [CoIII(L1)(py)3]+[CoIICl3(py)]-?EtOH and [CoIII(LI)(py)3]+I3-(H2LI = salicylaldehyde S-methylisothiosemicarbazone). Although the tetrahedral [CoIICl3(py)]- anions possess the same charge, they mutually form different intermolecular interactions which can be realized either by C-H...Cl hydrogen bonds or by ?-? interactions between the pyridine rings.