Prediction study by ab initio / HF and DFT / B 3 LYP methods of modes Vibration molecular frequencies by IR spectroscopy with structure Architecture and substituting reactivity effect from microscopic scale of Thiohydantoin molecular to medicine (original) (raw)
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In this work, experimental and theoretical UV, NMR and vibrational spectra of 2-thiohydantoin (2-TH) were studied. We have used a combined FT-IR and FT-Raman spectroscopy along with Density Functional Theory (DFT) to study the effect of hydrogen bonding on molecular structure. Comparison between the gas phase and the solid phase data were also carried out. Our results support the hydrogen bonding pattern proposed by the reported crystal structure and provide valuable information on the structural relationship between the investigated polymorphs. The ultra violet absorption spectra of the compound dissolved in methanol were examined in the range 210-330 nm. The solid state 13 C NMR spectra were recorded. Isotropic chemical shifts were calculated using the gauge-invariant atomic orbital (GIAO) method. Comparison of the calculated NMR chemical shifts and absorption wavelengths with the experimental values revealed that DFT method produces good results.
Physicochemical Properties and Molecular Mechanics of Some Thiohydantoin Derivatives Complexes
The organic ligands Cinnamaldehydethiosemicarbazone(1), 3-(3-Phenyl-allylideneamino)-2-thioxoimidazolidine-4-one (2), [4-Oxo-3-(3-phenyl-allylideneamino)-2-thioxo-imidazolidin-1-yl]-acetic acid (3), 1-(1-aza-4-phenylbuta-1,3-dienyl)-2-methylthio-2-imidazolin-5-one (4) and 1-(1-aza-4-phenylbuta-1,3-dienyl)-2-methylthio-2-imidazolin-5-one (5) were prepared and characterized using spectroscopic and physico-chemical methods (Scheme 1). The modeling of the synthesized compounds (1 and 2) and the computation of the steric, Van der Waals, bending and stretching energy were calculated using the Molecular Mechanical method (MM2) using CS cheme Office program. For each conformation of the synthesized compounds (1, 2), the minimum energy one was determined and listed. The complexes of the compound 1 and 2 with Zn(II), Cu(II) and Ni(II) were prepared and characterized. The postulated spatial arrangements have been confirmed using the molecular modeling program, elemental analysis (CHNM %), conductance, IR, thermal analysis and mass spectra.
Design of Novel Thiohydantoin Derivatives and Exploration their Physico-Chemical Parameters
Oriental Journal Of Chemistry
Thiohydantoin analogues was heterocyclic non-aromatic five membered cyclic compounds obtained from aurones derivatives. In this article, we synthesized novel thiohydantoin derivatives and exploration of physicochemical parameters like density, viscosity, ultrasonic velocity, intermolecular free path, adiabatic compressibility etc. The structural elucidation of resultant compounds was done on the basis 1HNMR, IR, Mass etc. The present study revealed that, thiohydantoin analogues shows more structure making capacity in DMSO than DMF.
Ab initio and density functional theory studies on selected thioaldehydes and thioketones
Thials are generally more reactive than the thioketones, unhindered thioaldehydes are generally unstable. For instance, methenethial (H 2 C=S) condensed to the cyclic trimer 1,3,5trithione [1], however stable thials like thiobenzaldehydes have been isolated . The photoelectron studies of thioaldehydes and thioacetone revealed that their vertical ionization potentials are 8.98±0.02 and 8.60±0.05 eV respectively. The microwave rotational spectra showed hindered internal rotation of 1545±20 cal/mol and 1300± 50 cal/mol for the thioaldehydes and thioacetone respectively . Also, the nature of methyl internal rotational barrier in thioacetone has been investigated by relaxation effects, natural bond orbitals (NBO) analysis and Pauli exchange interactions and compared with its parent acetone . The enolization enthalpies at 0 and 298K for nine aliphatic carbonyl and nine aliphatic thiocarbonyl compounds have been theoretically studied with ab initio. The results revealed that enolization enthalpies of thiocarbonyls were much lower than corresponding carbonyls, this was attributed to weaker C=S bond than C=O. The enolization of cyclothioketones was significantly dependent on the size of the cyclic rings . The structures and energies of conformations of thioacetones and thiopronaldehyde have been studied by ab initio STO-3G and HF/3-21G basis sets. The results were compared with available data on acetone and propronaldehyde to assess the effects of oxygen-by-sulphur substitution on the molecular properties . In this work, we present the results of our unmitigation on simple thiocarbonyls and thioketones and due to scanty experimental data available in the literatures for these simple compounds, The structural and electronic properties of these two series of thioaldehydes and thioketones ( ) and possible geometrical relationship with electronics properties are compared experimental values where available.
Spectrochimica Acta Part A-molecular and Biomolecular Spectroscopy, 2003
Vibrational study of the biomolecule 2-thiouracil was carried out. Ab initio and density functional calculations were performed to assign the experimental spectra. A comparison with the uracil molecule was made, and specific scale factors were deduced and employed in the predicted frequencies of 2-thiouracil. Several scaling procedures were used. The geometry structure of the molecule was determined. The effect of sulfur substitution at C2 position in the uracil molecule, on the N1H and N3H frequencies and intensities reflects changes in proton donor abilities of these groups. Calculations with the 6-31 G** basis set with HF and DFT methods appear in general to be useful for interpretation of the general features of the IR and Raman spectra of the molecule. Using specific scale factors a very small error was obtained. The use of these specific scale factors resolve and correct some of the controversial assignments in the literature.
Journal of Institute of Science and Technology, 2018
We have presented molecular structure and vibrational wavenumber assignments of 7-methyl-2,3-dihydro-(1,3)thiazolo(3,2-a)pyrimidin-5-one. Both ab initio Hartree-Fock and density functional theory employing 6-311++G(d,p) basis set have been used for the calculations. The scaled values of the calculated vibrational frequencies were used for assignments on the basis of potential energy distribution. The structure-activity relation has been interpreted by mapping molecular electrostatic potential surface. Electronic properties have been analyzed by using time dependent density functional theory (TD-DFT) for both gaseous and solvent phase. The calculated HOMO (highest occupied molecular orbital) and LUMO (lowest unoccupied molecular orbital) energy values show that the charge transfer occurs within the molecule. Journal of Institute of Science and TechnologyVolume 22, Issue 2, January 2018, Page: 1-11
Two cycloalkanespiro-5-(2-thiohydantoins): Synthesis, spectral and structural characterization
2009
The presented study deals with the structural and spectral properties of two derivatives of 2-thiohydantoin employing experimental and theoretical methods. The crystal structures of two novel cycloalkanespiro-5-(2-thiohydantoins) are described and compared with the available data on their dithio-and dioxo-analogues. For cyclopentanespiro-5-(2-thiohydantoin)-compound 1, two independent molecules are present in the asymmetric unit in contrast to its dithio-analogue. Cyclohexanespiro-5-(2-thiohydantoin)-compound 2, crystallizes as a monohydrate similarly to the dioxo-analogue. The cyclopentane rings in 1 adopt envelope conformation, while the cyclohexane ring in 2 adopts chair conformation. Although that the molecules of 1 and 2 possess same proton donor and acceptor groups, the presence of the crystallization water in 2 leads to different hydrogen bonding types and patterns. In compound 1 NAHÁ Á ÁO and NAHÁ Á ÁS intermolecular hydrogen bonds are formed, while the intermolecular hydrogen bonds in compound 2 are of OAHÁ Á ÁO, OAHÁ Á ÁN and NAHÁ Á ÁS types. The performance of quantum chemical methods, HF and DFT, to predict the molecular structure of the studied compounds, 1 and 2, and their dithio-and dioxo-analogues is assessed in comparison with available crystallographic data. Detailed analyses of the vibrational frequencies and the 13 C NMR shifts are performed with regard to the effect of the sulphur atom on the structural and spectroscopic properties of the studied hydantoin derivatives.
Structure and stability of complexes of thiohydantoin derivative
Journal of Chemical Sciences, 1986
The formation constant of 4-phenylhydrazono-2-thiohydantoin with 3d transition metal ions has been determined. The factors affecting the stability of the metal chelates have been studied. Complexes of Ag(1), Cu(lI), Cd(lI) and Pd(II) with the ligand have been isolated and characterized by physico-chemical techniques. The ligand forms a 1 : 1 complex with Ag(l) and 1:2 complexes with the other metal ions. Keywords. 4-Phenylhydrazono-2-thiohydantoin; transition metal complexes with thiohydantoin; potentiometric studies; 1R spectra.
Vibrational assignments and electronic structure calculations for 6-thioguanine
Journal of Raman Spectroscopy, 2009
The Fourier transform Raman and Fourier transform infrared (FT-IR) spectra of thioguanine have been recorded. Ab initio and density functional computations of the vibrational (IR) spectrum, the molecular geometry, Highest Occupied Molecular Orbital (HOMO)-Lowest Unoccupied Molecular Orbital (LUMO) energy gaps and polarizabilities were studied. On the basis of the comparison between calculated and experimental results and the comparison with related molecules, assignments of fundamental vibrational modes are examined. The observed and simulated spectra were found to be well comparable. The electronic transition energies and intensities of spectral lines were carried out using TDDFT and ZINDO methods.