The molecular structure of a new Schiff base, 2-[4-hydroxy benzylidene]-amino naphthalene (HBAN) has been examined by HF and B3LYP/6-311++G(d,p) calculations. The X-ray structure was determined in order to establish the conformation of the molecule. The compound, C17H13NO, crystallizes in the orthorhombic, P212121 space group with the cell dimension, a=6.2867(2), b=10.2108(3), c=19.2950(6) Å, α=β=γ=90° and z=4. The asymmetric unit contains a molecule of a Schiff base. A strong intermolecular O-H⋯N and a weak C-H⋯O hydrogen bonds stabilized the crystal structure. The vibrational spectra of HBAN have been calculated using density functional theoretical computation and compared with the experimental. The study is extended to the HOMO-LUMO analysis to calculate the energy gap (Δ), Ionization potential (I), Electron Affinity (A), Global Hardness (η), Chemical Potential (μ) and Global Electrophilicity (w). The calculated HOMO and LUMO energy reveals that the charge transfer occurs within the molecule.
This work describes a RP-HPLC method for the determination and interaction studies of cefpirome with ACE-inhibitors (captopril, enalapril and lisinopril) in various buffers. The separation and interaction of cefpirome with ACE-inhibitors was achieved on a Purospher Star, C18 (5 μm, 250×4.6 mm) column. Mobile phase consisted of methanol: water (80:20, v/v, pH 3.3); however, for the separation of lisinopril, it was modified to methanol-water (40:60, v/v, pH 3.3) and pumped at a flow rate of 1 mL min(-1). In all cases, UV detection was performed at 225 nm. Interactions were carried out in physiological pH i.e., pH 1 (simulated gastric juice), 4 (simulated full stomach), 7.4 (blood pH) and 9 (simulated GI), drug contents were analyzed by reverse phase high performance liquid chromatography. Method was found linear in the concentration range of 1.0-50.0 μg mL(-1) with correlation coefficient (r(2)) of 0.999. Precision (RSD%) was less than 2.0%, indicating good precision of the method and accuracy was 98.0-100.0%. Furthermore, cefpirome-ACE-inhibitors' complexes were also synthesized and results were elucidated on the basis of FT-IR, and (1)H NMR. The interaction results show that these interactions are pH dependent and for the co-administration of cefpirome and ACE-inhibitors, a proper interval should be given.
A novel (2E)-1-(5-chlorothiophen-2-yl)-3-(naphthalen-2-yl)prop-2-en-1-one [C17H11ClOS] compound has been synthesized and its structure has been characterized by FT-IR, Raman and single-crystal X-ray diffraction techniques. The isomers, optimized geometrical parameters, normal mode frequencies and corresponding vibrational assignments of the compound have been examined by means of the density functional theory method, employing, the Becke-3-Lee-Yang-Parr functional and the 6-311+G(3df,p) basis set. Reliable vibrational assignments and molecular orbitals have been investigated by the potential energy distribution and natural bonding orbital analyses, respectively. The compound crystallizes in the monoclinic space group P2₁/c with the unit cell parameters a=5.7827(8)Å, b=14.590(2)Å, c=16.138(2)Å and β=89.987 (°). The CC bond of the central enone group adopts an E configuration. There is a good agreement between the theoretically predicted structural parameters and vibrational frequencies and those obtained experimentally.
The structure of 2-acetyl-5-chlorothiophene (ACT) has been characterized by FT-IR, Raman and single-crystal X-ray diffraction techniques. The isomers, optimized geometric parameters, normal mode frequencies and corresponding vibrational assignments of ACT (C6H5ClOS) have been examined by the density functional theory, with the Becke-3-Lee-Yang-Parr functional and the 6-311+G(3df,p) basis set. Reliable vibrational assignments have been investigated by the potential energy distribution analysis. ACT crystallizes in monoclinic space group C2/c with the O,S-cis isomer. There is a good agreement between the theoretically predicted structural parameters and vibrational frequencies and those obtained experimentally.
2-(4-Chlorophenyl)-2-oxoethyl 3-nitrobenzoate is synthesized by reacting 4-chlorophenacyl bromide with 3-nitrobenzoic acid using a slight excess of potassium or sodium carbonate in DMF medium at room temperature. The structure of the compound was confirmed by IR and single-crystal X-ray diffraction studies. FT-IR spectrum of 2-(4-chlorophenyl)-2-oxoethyl 3-nitrobenzoate was recorded and analyzed. The crystal structure is also described. The vibrational wavenumbers were computed using HF and DFT methods and are assigned with the help of potential energy distribution method. The first hyperpolarizability and infrared intensities are also reported. The geometrical parameters of the title compound obtained from XRD studies are in agreement with the calculated (DFT) values. The stability of the molecule arising from hyper-conjugative interaction and charge delocalization has been analyzed using NBO analysis. The HOMO and LUMO analysis are used to determine the charge transfer within the molecule. MEP was performed by the DFT method.
2-(4-Chlorophenyl)-2-oxoethyl 3-methylbenzoate is synthesized by reacting 4-chlorophenacyl bromide with 2-methylbenzoic acid using a slight excess of potassium or sodium carbonate in DMF medium at room temperature. The structure of the compound was confirmed by IR and single-crystal X-ray diffraction studies. FT-IR spectrum of 2-(4-chlorophenyl)-2-oxoethyl-3-nitrobenzoate was recorded and analyzed. The crystal structure is also described. The vibrational wavenumbers were computed using HF and DFT methods and are assigned with the help of potential energy distribution method. The first hyperpolarizability and infrared intensities are also reported. The geometrical parameters of the title compound obtained from XRD studies are in agreement with the calculated (DFT) values. The stability of the molecule arising from hyper-conjugative interaction and charge delocalization has been analyzed using NBO analysis. The HOMO and LUMO analysis are used to determine the charge transfer within the molecule. MEP was performed by the DFT method.
2-(4-Chlorophenyl)-2-oxoethyl 2-chlorobenzoate has been synthesized, its structural and vibrational properties have been reported using FT-IR and single-crystal X-ray diffraction (XRD) studies. The conformational analysis, optimized geometric parameters, normal mode frequencies and corresponding vibrational assignments of the synthesized compound (C15H10Cl2O3) have been examined by means of Becke-3-Lee-Yang-Parr (B3LYP) density functional theory (DFT) method together with 6-31++G(d,p) basis set. Furthermore, reliable conformational investigation and vibrational assignments have been made by the potential energy surface (PES) and potential energy distribution (PED) analyses, respectively. Calculations are performed with two possible conformations. The title compound crystallizes in orthorhombic space group Pbca with the unit cell dimensions a=12.312(5) Å, b=8.103(3) Å, c=27.565(11) Å, V=2750.0(19) Å(3). B3LYP method provides satisfactory evidence for the prediction of vibrational wavenumbers and structural parameters.
Bis(dithiolene) tungsten carbonyl complex, W(S2C2Ph2)2(CO)2 was successfully synthesized and the structure, frontier molecular orbital and optical properties of the complex were investigated theoretically using density functional theory calculations. The investigation started with a molecular structure construction, followed by an optimization of the structural geometry using generalized-gradient approximation (GGA) in a double numeric plus polarization (DNP) basis set at three different functional calculation approaches. Vibrational frequency analysis was used to confirm the optimized geometry of two possible conformations of [W(S2C2Ph2)2(CO)2], which showed distorted octahedral geometry. Electronic structure and optical characterization were done on the ground states. Metal to ligand and ligand to metal charge transfer were dominant in this system.
A metal-free mesoporous carbon nitride (MCN) was investigated for the first time as an adsorbent for N-nitrosopyrrolidine (NPYR), which is one of the nitrosamine pollutants. Under the same condition, the adsorption capability of the MCN was found to be higher than that of the MCM-41. Since the adsorption isotherm was consistent with Langmuir and Freundlich model equations, it was suggested that the adsorption of NPYR molecules on the MCN occurred in the form of mono-molecular layer on the heterogeneous surface sites. It was proposed that MCN with suitable adsorption sites was beneficial for the adsorption of NPYR. The evidence on the interaction between the NPYR molecules and the MCN was supported by fluorescence spectroscopy. Two excitation wavelengths owing to the terminal N-C and N=C groups were used to monitor the interactions between the emission sites of the MCN and the NPYR molecules. It was confirmed that the intensity of the emission sites was quenched almost linearly with the concentration of NPYR. This result obviously suggested that the MCN would be applicable as a fluorescence sensor for detection of the NPYR molecules. From the Stern-Volmer plot, the quenching rate constant of terminal N-C groups was determined to be ca. two times higher than that of the N=C groups on MCN, suggesting that the terminal N-C groups on MCN would be the favoured sites interacted with the NPYR. Since initial concentration can be easily recovered, the interactions of NPYR on MCN were weak and might only involve electrostatic interactions.
The interaction behaviours between components of polyacrylate (PAc)/poly(ethylene oxide) (PEO) and lithium perchlorate (LiClO(4)) were investigated in detail by Attenuated Total Reflectance (ATR)-Fourier Transformed Infrared (FTIR) spectroscopy. Solution cast films of the PAc/PEO and PAc/PEO/LiClO(4) were examined. No obvious shifting of the characteristic ether and ester group stretching modes of PEO and PAc was observed, indicating incompatibility of the binary PAc/PEO blend. The spectroscopic studies on the PAc/PEO/LiClO(4) blends reveal that Li(+) ions coordinate individually to the polymer components at the ether oxygen of PEO and the C-O of the ester group of PAc. Frequency changes observed on the nu(C-O-C) and omega(CH(2)) of PEO confirm the coordination between PEO and Li(+) ions resulting in crystallinity suppression of PEO. The absence of experimental evidence on the formation of PEO-Li(+)-PAc complexes suggests that LiClO(4) does not enhance the compatibility of PAc/PEO blend.
Fourier transform infrared (FTIR) spectroscopy studies of poly(vinyl alcohol) (PVA), and chitosan polymer blend doped with ammonium nitrate (NH(4)NO(3)) salt and plasticized with ethylene carbonate (EC) have been performed with emphasis on the shift of the carboxamide, amine and hydroxyl bands. 1% acetic acid solution was used as the solvent. It is observed from the chitosan film spectrum that evidence of polymer-solvent interaction can be observed from the shifting of the carboxamide band at 1660 cm(-1) and the amine band at 1591 cm(-1) to 1650 and 1557 cm(-1) respectively and the shift of the hydroxyl band from 3377 to 3354 cm(-1). The hydroxyl band in the spectrum of PVA powder is observed at 3354 cm(-1) and is observed at 3343 cm(-1) in the spectrum of the PVA film. On addition of NH(4)NO(3) up to 30 wt.%, the carboxamide, amine and hydroxyl bands shifted from 1650, 1557 and 3354 cm(-1) to 1642, 1541 and 3348 cm(-1) indicating that the chitosan has complexed with the salt. In the PVA-NH(4)NO(3) spectrum, the hydroxyl band has shifted from 3343 to 3272 cm(-1) on addition of salt from 10 to 30 wt.%. EC acts as a plasticizing agent since there is no shift in the bands as observed in the spectrum of PVA-chitosan-EC films. The mechanism of ion migration is proposed for the plasticized and unplasticized PVA-chitosan-NH(4)NO(3) systems. In the spectrum of PVA-chitosan-NH(4)NO(3)-EC complex, the doublet CO stretching in EC is observed in the vicinity 1800 and 1700. This indicates that there is some interaction between the salt and EC.
Polymer electrolytes based on poly(ethylene oxide)-lithium triflate (PEO-LiCF3SO3) and poly(ethylene oxide)-lithium sulphate (PEO-Li2S4) were prepared by using solution casting method. Measurements of conductivity and dielectric were carried out on these films as a function of frequency at various temperatures. It was observed that PEO-LiCF3SO3 polymer electrolytes have higher conductivity. The interaction between PEO and Li salts were studied by Fourier transform infrared (FTIR).
The polymer electrolytes composing of the blend of polyvinyl chloride-polymethyl methacrylate (PVC/PMMA) with lithium triflate (LiCF3SO3) as salt, ethylene carbonate (EC) and dibutyl phthalate (DBP) as plasticizers and silica (SiO2) as the composite filler were prepared. FTIR studies confirm the complexation between PVC/PMMA blends. The CCl stretching mode at 834 cm-1 for pure PVC is shifted to 847 cm-1 in PVC-PMMA-LiCF3SO3 system. This suggests that there is interaction between Cl in PVC with Li+ ion from LiCF3SO3. The band due to OCH3 at 1150 cm-1 for PVC-PMMA blend is shifted to 1168 cm-1 in PVC-PMMA-LiCF3SO3 system. This shift is expected to be due to the interaction between Li+ ion and the oxygen atom in PMMA. The symmetric vibration band and the asymmetric vibration band of LiCF3SO3 at 1033 and 1256 cm-1 shifted to 1075 and 1286 cm-1 in the DBP-EC plasticized PVC-PMMA-LiCF3SO3 complexes. The interaction between Li+ ions and SiO2 will lead to an increase in the number of free plasticizers (which does not interact with Li+ ions). When the silica content increases from 2% to 5%, the intensity of the peak at 896 cm-1 (due to the ring breathing vibration of free EC) increases in PVC-PMMA-LiCF3SO3-DBP-EC system.
Chemical modification of natural rubber (NR) has frequently been attempted to improve the performance in specific application. 30% poly(methyl metacrylate) (PMMA) grafted into NR (MG30) has been explored as a potential candidate for polymer electrolytes. The complexation effect of salt and plasticizer in polymer host electrolytes had been investigated using FTIR. The carbonyl stretch of MG30 locates at 1729 cm-1, with the addition of lithium trimethanesulfonate (LiCF3SO3) salt, new band evolves at lower frequency region at 1643-1645 cm-1. The nondegenerate vibrational mode of nus(SO3) of salted electrolytes appearing at 1031-1034 cm-1 comes from 'free' trimethanesulfonate anions and the 1040-1046 cm-1 absorption from the monodentate ion paired with triflates. These indicate MG30-salt interaction. When MG30 and ethylene carbonate (EC) formed film, the CH3 asymmetric bend of MG30 appearing at 1447cm-1 is shifted to 1449 cm-1 in the EC-polymer complex. The CO stretching at 1729 cm-1 also shifted to 1728 cm-1. Hence, the EC-MG30 system is complexed to each other. EC-LiCF3SO3 interactions are indicated by the shifting of CO bending band of EC from 718 cm-1 being shifted to 720 cm-1 in the complex. In Li+-EC interaction where the ring breathing region at 897 cm-1 in EC has shifted to 899 cm-1 in EC-salt spectrum. The band appearing at 1643-1645 cm-1 due to the coordination of Li+
Fourier transform infrared (FT-IR) spectroscopic studies have been undertaken to investigate the interactions among components in a system of hexanoyl chitosan-lithium trifluoromethanesulfonate (LiCF(3)SO(3))-diethyl carbonate (DEC)/ethylene carbonate (EC). LiCF(3)SO(3) interacts with the hexanoyl chitosan to form a hexanoyl chitosan-salt complex that results in the shifting of the N(COR)(2), CONHR and OCOR bands to lower wavenumbers. Interactions between EC and DEC with LiCF(3)SO(3) has been noted and discussed. Evidence of interaction between EC and DEC has been obtained experimentally. Studies on polymer-plasticizer spectra suggested that there is no interaction between the polymer host and plasticizers. Competition between plasticizer and polymer on associating with Li(+) ions was observed from the spectral data for gel polymer electrolytes. The obtained spectroscopic data has been correlated with the conductivity performance of hexanoyl chitosan-based polymer electrolytes.
We synthesized 2-aminonicotinic acid (2-ANA) complexes with metals such as Co(II), Fe(III), Ni(II), Mn(II), Zn(II), Ag(I),Cr(III), Cd(II) and Cu(II) in aqueous media. The complexes were characterized and elucidated using FT-IR, UV-Vis, a fluorescence spectrophotometer and thermo gravimetric analysis (TGA). TGA data showed that the stoichiometry of complexes was 1:2 metal/ligand except for Ag(I) and Mn(II) where the ratio was 1:1. The metal complexes showed varied antibacterial, fungicidal and nematicidal activities. The silver and zinc complexes showed highest activity against Bacillus subtilis and Bacillus licheniformis respectively. Fusarium oxysporum was highly susceptible to nickel and copper complexes whereas Macrophomina phaseolina was completely inert to the complexes. The silver and cadmium complexes were effective against the root-knot nematode Meloidogyne javanica.
Two new ether substituted azodyes were synthesized and characterized by different spectral analysis such as (1)H NMR, (13)C NMR, FTIR and UV/Vis. Synthesized compounds were used to study the photoisomerization phenomenon by using UV-Vis spectro-photometer. Interesting polarity dependent effect is observed for the first time on these materials. Trans-cis (E-Z) and cis-trans (Z-E) conversion occurred within 41 s and 445 min, respectively for both the compounds in solutions. Polarizing optical microscopy studies revealed that there is no liquid crystal phase for both the compounds. The dramatic variation in the optical property is speculated to be the polarity of the chemical species. These derivatives are useful to fabricate optical data storage devices.
Testosterone thiosemicarbazone, L and its nickel (II) complex 1 were synthesized and characterized by using FTIR, CHN, (1)H NMR, and X-ray crystallography. X-ray diffraction study confirmed the formation of L from condensation of testosterone and thiosemicarbazide. Mononuclear complex 1 is coordinated to two Schiff base ligands via two imine nitrogens and two tautomeric thiol sulfurs. The cytotoxicity of both compounds was investigated via MTT assay with cisplatin as positive reference standard. L is more potent towards androgen-dependent LNCaP (prostate) and HCT 116 (colon). On the other hand, complex 1, which is in a distorted square planar environment with L acting as a bidentate NS-donor ligand, is capable of inhibiting the growth of all the cancer cell lines tested, including PC-3 (prostate). It is noteworthy that both compounds are less toxic towards human colon cell CCD-18Co. The intrinsic DNA binding constant (Kb) of both compounds were evaluated via UV-Vis spectrophotometry. Both compounds showed Kb values which are comparable to the reported Kb value of typical classical intercalator such as ethidium bromide. The binding constant of the complex is almost double compared with ligand L. Both compounds were unable to inhibit the action topoisomerase I, which is the common target in cancer treatment (especially colon cancer). This suggest a topoisomerase I independent-cell death mechanism.
Deep eutectic solvents (DESs) are novel solvent media that are currently under investigation as an alternative to ionic liquids and conventional solvents. The physical properties of DESs as well as their mild environmental footprint and potentially critical industrial application necessitate understanding the interaction of functional groups on both the salt and hydrogen bond donor (HBD). In this study, four DESs were prepared by mixing triethylenglycol, diethylenglycol, ethylenglycol, and glycerol as HBDs with methyltriphenylphosphonium bromide as a salt at a molar ratio of 1:4. Fourier transform infrared spectroscopy was conducted to highlight the chemical structure and mechanism of the combination of the four DESs. New spectra illustrating the combination of the functional groups of the HBDs and salt were observed and interpreted. This study is the first to investigate the properties of neoteric phosphonium-based DESs.
A novel (2E)-1-(5-chlorothiophen-2-yl)-3-{4-[(E)-2-phenylethenyl]phenyl}prop-2-en-1-one [C21H15ClOS] compound has been synthesized and its structure has been characterized by FT-IR, Raman and single-crystal X-ray diffraction techniques. The conformational isomers, optimized geometric parameters, normal mode frequencies and corresponding vibrational assignments of the compound have been examined by means of HF, MP2, BP86, BLYP, BMK, B3LYP, B3PW91, B3P86 and M06-2X functionals. Reliable vibrational assignments and molecular orbitals have been investigated by the potential energy distribution and natural bonding orbital analyses, respectively. The compound crystallizes in the triclinic space group P-1 with the cis-trans-trans form. There is a good agreement between the experimentally determined structural parameters and vibrational frequencies of the compound and those predicted theoretically using the density functional theory with the BLYP and BP86 functionals.