Nuclear Magnetic Resonance Spectral Studies Research Articles

Bright yellow fluorescent nitrogen and boron doped-CNPs based turn “off–on” probe for highly sensitive and selective detection of glyphosate and hypochlorite

In the present work, water-soluble fluorescent nitrogen/boron-doped carbon nano particles (N/B-CNPs) were prepared using o-phenylenediamine and boric acid precursors by a simple one step hydrothermal (HT) method. High Resolution Transmission Electron Microscope (HR-TEM) analysis showed that the N/B-CNPs are spherical in shape with an average size of ∼ 15 nm. The functional and structural composition of N/B-CNPs were confirmed by Fourier Transform Infrared (FTIR), Raman and Nuclear Magnetic Resonance (NMR) spectral studies. N/B-CNPs exhibited excellent photophysical property and photostability at different physiological conditions. N/B-CNPs showed bright yellow fluorescence at 566 nm upon excitation at 400 nm. N/B-CNPs were utilized as a fluorometric probe towards the simultaneous detection of glyphosate and hypochlorite. The fluorescence intensity of N/B-CNPs was selectively quenched in the presence of glyphosate (turn-off) and quenched emission intensity was restored in the presence of hypochlorite (turn-on). The fluorescence quenching mechanism was further ascertained using Stern-Volmer and time resolved fluorescence analysis. The detection probe showed a linear response for glyphosate over the concentrations range of 5.00 to 85.00 µM, with a limit of detection value of 0.088 µM. While in the case of hypochlorite the turn-on assay exhibited good linearity over the range of 5.00 to 50.00 µM with limit of detection as low as 0.12 nM. The N/B-CNPs turn-off/turn-on fluorometric assay exhibited excellent sensitivity and selectivity towards glyphosate and hypochlorite, even in the presence of other interference ions. The practical applicability of the proposed assay was demonstrated by fabricating a paper strip-based sensor and fluorescent thin film. Furthermore, the in vivo toxicity of the N/B-CNPs was evaluated in plant by performing dosage dependent assay.

Insights into the adsorption and corrosion inhibition properties of newly synthesized diazinyl derivatives for mild steel in hydrochloric acid: synthesis, electrochemical, SRB biological resistivity and quantum chemical calculations.

Two azo derivatives, 4-((4-hydroxy-3-((4-oxo-2-thioxothiazolidin-5-ylidene)methyl)phenyl) diazinyl) benzenesulfonic acid (TODB) and 4-((3-((4,4-dimethyl-2,6-dioxocyclohexylidene) methyl)-4-hydroxyphenyl)diazinyl) benzenesulfonic acid (DODB) were synthesized and characterized using Fourier-transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance (1H-NMR) and mass spectral studies. Gravimetric methods, potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), electrochemical frequency modulation (EFM) techniques and inductive coupled plasma-optical emission spectroscopy were used to verify the above two compounds' ability to operate as mild steel (MS) corrosion inhibitors in 1 M HCl. Tafel data suggest that TODB and DODB have mixed-type characteristics, and EIS findings demonstrate that increasing their concentration not only alters the charge transfer (R ct) of mild steel from 6.88 Ω cm2 to 112.9 Ω cm2 but also changes the capacitance of the adsorbed double layer (C dl) from 225.36 to 348.36 μF cm-2. At 7.5 × 10-4 M concentration, the azo derivatives showed the highest corrosion inhibition of 94.9% and 93.6%. The inhibitory molecule adsorption on the metal substrate followed the Langmuir isotherm. The thermodynamic activation functions of the dissolution process were also calculated as a function of inhibitor concentration. UV-vis, scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDX) techniques were used to confirm the adsorption phenomenon. The quantum chemical parameters, inductively coupled plasma atomic emission spectroscopy (ICPE) measurements, and the anti-bacterial effect of these new derivatives against sulfate-reducing bacteria (SRB) were also investigated. Taken together, the acquired results demonstrate that these compounds can create an appropriate preventing surface and regulate the corrosion rate.

A multifunctional Schiff base with aggregation-induced enhanced emission, gelation, and mechanochromic properties for anti-counterfeiting applications

This work presents a systematic study of three closely related Schiff bases NpSB, AnSB, and PySB for their potential aggregation-induced enhanced emission, gelation, and mechanochromic properties. While aggregation-induced enhanced emission was observed in case of AnSB and PySB due to the suppression of photoinduced electron transfer; PySB also formed a stable gel in DMF‒water. Out of three Schiff bases, PySB exhibited reversible mechanochromism. Importantly, on applying pressure or a mechanical force, PySB changed its color from yellow to bright orange under the visible light while its emission wavelength shifted from 580 to 602 nm. More importantly, mechanical-force-induced changes were reversible after fuming with the vapors of CH2Cl2 or by heating at 100 °C. The mechanochromism of PySB was studied by a combination of powder X-ray diffraction, scanning electron microscope, differential scanning calorimetry, density functional theory, and nuclear magnetic resonance spectral studies. These studies concluded that the change in color and emission profile was due to change in the molecular packing of PySB after applying the pressure or mechanical force. The slippage of pyrene rings and the conversion of intramolecular H-bonding to intermolecular H-bonding resulted in the alteration of solid-state packing of PySB which was responsible for the mechanochromism. A noteworthy feature of the reversible mechanochromism of PySB was the reversible morphological changes as substantiated by the scanning electron microscope and powder X-ray diffraction studies. PySB was shown to illustrate noteworthy anti-counterfeiting and pressure-induced applications.

Phytochemical Analysis, Tuberculosis Effect, Purification and Characterization of Aerial Parts of Avicennia alba

The present study deals with phytochemical, pharmacological (In vitro antioxidant), purification and characterization studies of aerial parts of Avicennia alba. The phytochemical analysis for qualitative and quantitative investigation revealed the presence of more bioactive compounds in methanolic extract than hexane and chloroform extracts of Avicennia alba. The methanolic extract showed better activity on 2,2-diphenyl-1-picrylhydrazyl free radical than remaining free radical tests i.e hydrogen peroxide and hydroxyl radical. The methanolic extract was potent in inhibiting the free radicals upon comparison with standard ascorbic acid. The tuberculosis effect of the plant was not up to the mark when compared with standard control. The methanolic plant extract was subjected to column chromatography and three compounds were isolated. The isolated compounds were characterized by ultraviolet, fourier transform infrared spectroscopy, proton nuclear magnetic resonance, carbon nuclear magnetic resonance and mass spectral data studies and were identified as stigmasterol, beta-sitosterol and lupeol. The work carried out was distinctive as the source of plant was taken from coringa mangrove, Kakinada, first of its kind and the tuberculosis effect was also reported for the first time, though it was not up to the mark the work reported inspires the researcher to enlighten and save their time. The natural compounds selected were reported previously but an in depth characterization was reported for a thorough look.

Synthesis, characterization of novel coumarin dyes as corrosion inhibitors for mild steel in acidic environment: Experimental, theoretical, and biological studies

The new azo acetyl coumarin derivatives were synthesized and characterized using Fourier-transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance (1H NMR) and mass spectral studies. The ability for these three dyes to act as corrosion inhibitors for mild steel in 1.0 M HCl was confirmed by potentiodynamic polarization (PP) and electrochemical impedance spectroscopy (EIS). The state of mixed adsorption with the PP effect is shown. The azo acetyl coumarin derivatives showed the strongest corrosion inhibition of 85.29–93.01% at a corrosion of 7.5 × 10−4 M. Adsorption of the inhibitory molecules on the mild steel surface followed Langmuir adsorption isotherm. The adsorption phenomenon was verified using UV–Vis, scanning electron microscopy (SEM) and Energy dispersive X-ray spectroscopy (EDX) technique, whereas FTIR confirmed the presence of several functional groups containing heteroatoms. Also, quantum chemical parameters, inductively coupled plasma atomic emission spectroscopy, and the anti-bacterial effect of these new derivatives against sulfate reducing bacteria (SRB) were studied. All obtained results ensure that these derivatives can form an effective blocking layer and control the corrosion process.

In-vitro bio-potential and pharmacological studies of newly synthesized Schiff base Cd(II) complex

The post-transition '4d' Cd(II) metal complex were synthesized and characterized by the addition of neutral Schiff base (E)-N-(4-chlorobenzylidene)isonicotinohydrazide) as primary ligand and nitrite ion as mixed ligand. The Schiff base were synthesized with the addition of bio active Isoniazid and 4-chlorobenzaldehyde by eco-friendly technique (water as solvent). The synthesized complex where physically, chemically, spectroscopically and biologically characterized by various Physico-chemical, spectral and biological methods such as micro analytical data, namely elemental analysis & metal estimation, conductivity, Ultraviolet-visible, Infra-Red, Far-Infra Red, and Nuclear Magnetic Resonance (1H &13C) spectral studies. Based on the conductivity and spectral studies, the complex is neutral and non-electrolyte in nature. They have tetrahedral geometry around the Cd(II) metal ion. The in-vitro antibacterial and antifungal activities of Schiff base and Cd(II) complex were screened against E. coli and A. Niger by Agar disc diffusion method using Chloramphenicol and Fluconazole as standard control and DMSO as a solvent control. The results indicate that the complex have more potent than the Schiff base due to the chelation. The pharmacological studies of Schiff base and Cd(II) complex also predicted using a computational method by Swiss ADME software. The lipophilicity and medicinal chemistry importance of the Schiff base and Cd(II) complex were predicted and confirmed by the bio-potential activities.

Synthesis, antioxidant activity and bioinformatics studies of L-3-hydroxytyrosine templated N-alkyl/aryl substituted urea/thioureas

A new series of urea/thiourea derivatives have been efficiently synthesized from the reaction of L-3-hydroxytyrosine with selective isocyanates/isothiocyanates and characterized by Infra-red, proton & carbon-13 nuclear magnetic resonance spectral and mass spectrometry studies. All the synthesized compounds have been screened for their antioxidant activity by 1,1-diphenyl1-2-picrylhydrazyl radical assay, ferric reducing antioxidant power assay and also studied their molecular docking interaction profiles against 1N8Q and 3NRZ enzymatic proteins. The in vitro antioxidant activity has further supported by quantitative structure activity relationship, absorption, distribution, metabolism, and excretion & toxicity studies, bioactivity studies & enzyme inhibition assay and identified that they were potentially bound to ASP490 & ASP361 aminoacid residue in chain A of 1N8Q protein and GLN1194 aminoacid residue in chain L of 3NRZ protein and are responsible for potential antioxidant activity. It is proved that urea derivatives linked with 4-fluoro & 4-nitro and thiourea derivatives linked with 3-chloro & 4-fluoro have exhibited promising antioxidant activity. In eventual synthesized compounds have been identified as potential blood–brain barrier penetrable compounds and proficient central nervous system active neuro-protective antioxidant agents as they have envisaged as easily penetrable to blood–brain barrier thresholds, a neuroprotective property.

Synthesis, growth, structural, spectral and optical studies on 2-amino-4-picolinium 4-hydroxybenzoate single crystals

2-amino-4-picolinium-4-hydroxybenzoate (2A4P4HB) were grown as crystals using a controlled evaporation method in the present study. The lattice parameters of 2A4P4HB were affirmed using X-ray diffraction measurements. Using 1H and 13C nuclear magnetic resonance spectral studies, the proton and carbon position was determined. Linear optical study was used to determine the cut off wavelength and the wide optical operating window. Thermogravimetric and Differential Thermal Analysis were used to examine their thermal response. Vickers microhardness testing was used to determine mechanical stability at room temperature. Meyer's law was used to investigate the hardness results. The Z scan measurements were performed on 2A4P4HB.

Ring opening of 2,6‐diaryl‐3,5‐diphenyl piperidine‐4‐one by acetic acid: Structural studies and Hirshfeld surface analysis of (E)‐4‐aryl‐1,3‐diphenylbut‐3‐en‐2‐ones

AbstractSix α,β‐unsaturated carbonyl compounds have been obtained from 2,6‐diaryl‐3,5‐diphenylpiperidine‐4‐one by the treatment with acetic acid. A plausible mechanism for the ring opening of 2,6‐diaryl‐3,5‐diphenyl piperidin‐4‐ones is proposed. The resultant (E)‐4‐aryl‐1,3‐diphenylbut‐3‐en‐2‐ones have been characterized by 1H and 13C nuclear magnetic resonance (NMR) spectral studies. One of the compounds was completely characterized by 2D NMR techniques, and structure of the compound is further proved by single‐crystal X‐ray diffraction (XRD) analysis. The crystal structure, three‐dimensional framework of crystal, and Hirshfeld surface analysis of two of the compounds have been discussed. In the crystals, molecules are mainly linked by CH···O hydrogen bonding interactions, and this interaction forms an inversion dimer with R21(6) and R21(10) ring motifs in one of the compounds. Hirshfeld surface indicates the dominance of H···H contacts on the overall surface.

Synthesis of new azobenzene dyes clubbed with thiazolidinone moiety and their applications

Purpose The purpose of this paper is to synthesize some new azobenzene dyestuffs clubbed with thiazolidinone moiety and their solicitation in dyeing polyester fabrics representing their antibacterial evaluation. Design/methodology/approach Herein, the authors report the synthesis of new thiazolidinone moiety after the coupling of diazotized 4-aminoacetophenone with resorcinol. The newly synthesized dyes were characterized by IR, elemental analysis, mass spectroscopy and proton nuclear magnetic resonance (1H NMR) spectral studies. The characteristics of dyeing of these dyestuffs were evaluated at optimum conditions. Concurrent with dyeing of polyester fabric for synthesized dyes with their antibacterial activity was estimated. Antimicrobial activity of the dyed fabrics at different concentrations was evaluated against gram-positive and gram-negative bacteria. Findings Synthesized azobenzene dyestuffs clubbed with thiazolidinone dyes were applied on polyester fabrics. It was remarked that the modified dyes exhibited better colourfastness properties. Furthermore, the synthesized dyes revealed antimicrobial activity against gram-positive and gram-negative bacteria. Research limitations/implications The synthesized azobenzene dyes for polyester dyeing were not bore earlier. Practical implications The azobenzene dyes were accountable for giving improved colourfastness properties on polyester fabrics. Social implications The synthesized azobenzene derivatives are sensibly expensive and applicable dyes accompanied with good antimicrobial and anticancer activities. Originality/value A common process could be affording textiles of colour and antibacterial assets. The newly synthesized dyes containing thiazolidinone moieties with azobenzene coupler showed interesting disperse colourant for polyester with good antibacterial activity.

Preparation ,Characterization and The Biological Activity Study of A new heterocyclic (Azo-Schiff base) ligand and Their Complexation with {Co,Ni,Cu,Zn(II)}Ions

A new tetra dentate Schiff base ligand has been synthesized from condensation of compound (1): [( 4 -((1-H-imidazol-2-yldiazenyl)-1,5-dimethyl-2-phenyl-1Hpyrazol-3(2H)-one)]with compound (2) thio semicarbazaide. The general formula of complexes are [M(L)]Cl2 Where. M= Co(II) ,Ni (II)and Cu(II)Zn(II) are reported. The geometry structures of ligand and the complexes were determined through Fourier-transform infrared spectroscopy (FT-IR), Mass spectra, X-ray diffraction analysis, Ultra violet-Visible(UV-Vis), Proton nuclear magnetic resonance(1H NMR) spectral studies, magnetic moment measurement, elemental analysis, and molar conductance. These studies revealed square planar geometries for Ni(II)and Co(II) and Cu(II)complexes, except the Zn(II) complex was a tetrahedral geometry around the central metal ion. Complex formation studies via molar ratio and continuous variation methods were consisted to those found in the solid complexes with a ratio of (M:L) as (1:1) . Stability constant of complexes were calculated by spectrophotometric methods. Hyper Chem-8 program has been used to predict geometries structures of compounds in gas phase. The heat of formation (∆Hf) and binding energy (∆E b) at 298 K for the metal complexes were calculated by PM3 method. Biological activity studies of the ligand and their metal complexes against several organisms, bacteria Gram positive G(+ve)staphylococcus aureus and bacteria Gram negative G(- ve)Escherichia coli, klebsiella pneumonic, In addition to fungi like Aspergillus Niger, Rhizoclonia bataicola and Aspergillus flavus , are reported. Compounds exhibited the high activity on the growth of all types microorganisms in this study. This may be attributed to the impact of both the chelate effect of Schiff bases ligand and the role of the metal in these complexes.

Solvent-free mechanochemical synthesis, hirshfeld surface analysis, crystal structure, spectroscopic characterization and NBO analysis of Bis(ammonium) Bis((4-methoxyphenyl) phosphonodithioato)-nickel (II) dihydrate with DFT studies

Abstract The green chemistry route for synthesis of dithiophosphonate nickel complex of the type, [Ni{S2P(O) (4-C6H4–OMe)}2]·2NH4·2H2O was reported1 and the structure confirmed by single crystal XRD. This work deals with FT-IR, and NMR spectral, NBO and Hirshfeld surface studies on bis(ammonium) bis((4-methoxyphenyl) phosphonodithioato)-nickel dihydrate. The molecular structure, vibrational frequencies and intensity of the vibrational bands were interpreted with the aid of structure optimizations and geometrical parameter calculations based on density functional theory (DFT) method via mixed basis set at B3LYP/GENECP level of theory. The 13C and 1H Nuclear Magnetic Resonance (NMR) of the complex were computed by gauge independent atomic orbital (GIAO) method and compared with experimental chemical shift. The reported experimental and calculated results were correlated and was further expressed with correlation plots and correlation coefficient. Matching consistency resulted between computed data on optimized geometric parameters, vibrational frequencies and NMR chemical shifts and their corresponding experimental data. Computed Natural Bond Orbital (NBO) analysis explore the interactions as well as charge transfers among different orbitals and lone pairs happening within the compound. Hirshfeld surface analyses further establish and quantify intermolecular interactions of [Ni{S2P(O)·(4-C6H4–OMe)}2]·2NH4·2H2O.

A critical study of crystal structure, N—H---Br interaction, effect of charge transfer on third-order nonlinear optical properties and optical limiting behaviour of a new crystal: (4-Methoxyphenyl) methanaminium bromide

A new crystal, (4-Methoxyphenyl) methanaminium bromide (4MPMAB) was successfully developed by suitably functionalising the counter anion for nonlinear optical applications. Structural analysis was carried out and explores the monoclinic crystal system of P21/c space group. The methoxy group of the cation is co-planar with the phenylene moiety with an r.m.s deviation of 0.0294 Å from the mean plane (C1C8/O1). The donor mesomeric effect of methoxy group is revealed. The strong bonding nature and intermolecular NH---Br interaction between the ammonium cation and the halide anion are evidenced. In addition to that, CH---Br and CH---π interactions are also observed. As the protonation takes place by the hydrogen of hydrobromic acid (HBr), the contribution of HBr is highlighted in the formation of the 4MPMAB crystal. Powder X-ray diffraction (PXRD) study authenticates the good crystalline nature of the sample. Fourier transform infrared (FT-IR), 1H and 13C Nuclear magnetic resonance (NMR) spectral study ascertained the functional groups, the formation of the molecule and the NH---Br interaction of the grown crystal. The crystal is stable up to 219 °C. 4MPMAB has soft nature. The crystals have 65% optical transmission from 330 nm to 1100 nm with estimated optical band gap value of 3.5 eV.Z-scan study exhibits the higher third-order nonlinearity of 4MPMAB crystal. The influence of charge transfer on third-order nonlinear optical properties were revealed. Further, the optical limiting performance of 4MPMAB crystal has also been investigated.

Isolation, structure elucidation and antibacterial activity of methyl-4,8-dimethylundecanate from the marine actinobacterium Streptomyces albogriseolus ECR64

Around 120 actinobacterial colonies were isolated from various regions of marine East coast region of Tamil Nadu, India. Among them, 33 were morphologically distinct and they were preliminarily screened for their antibacterial activity against Pseudomonas fluorescens, Vibrio cholerae, V. parahaemolyticus, V. alginolyticus, and Aeromonas hydrophila by cross-streak plate technique. Among the isolated, the isolate ECR64 exhibited maximum zone of inhibition against fish pathogenic bacteria. The crude bioactive compounds were extracted from the isolate ECR64 using different organic solvents which exhibited maximum antibacterial activity. Separation and purification of the bioactive compounds were made by column chromatography which yielded 27 fractions and were re-chromatographed to obtain the active compound. Ultra violet (UV), Fourier transform infrared (FT-IR) and nuclear magnetic resonance (NMR) spectral studies were used to predict the structure of the active compound which was identified as methyl-4,8-dimethylundecanate. The potential isolate ECR64 was identified as Streptomyces albogriseolus by phylogenetic, phenotypic and genotypic (16S rRNA gene sequence) analyses. The identified compound methyl-4,8-dimethylundecanate can be used as potential and alternative drug in disease management of aquaculture.

SYNTHESIS, STRUCTURAL ELUCIDATION, CATALYTIC, ANTIBACTERIAL AND ANTIOXIDANT ACTIVITY OF THIOPHENE DERIVED MIXED LIGAND METAL COMPLEXES

The hexa-coordinated mixed ligand Cu(II), Zn(II), Ni(II) and Co(II) complexes of the type [MLX]Cl 2 where X=1,10-phenonthroline and ligand (L) have been synthesised from the condensation of thiophene-2-carboxaldehyde with o -phenylenediamine. They were characterised by elemental analysis, molar conductance, magnetic susceptibility, infrared, electronic absorption, proton magnetic resonance and mass spectral studies. An octahedral geometry has been proposed for all these complexes. The high molar conductance studies of the complexes show their electrolytic nature. The infrared spectra of the complexes show that the imine group of the Schiff base coordinate with the metal ion. The electronic absorption spectra of the complexes show the charge transfer, d-d transitions consistent with their proposed geometry. The proton magnetic resonance spectrum of the ligand shows the presence of CH=N group in the ligand. The mass spectral data also confirms the proposed structure of ligand and its complexes. The mixed ligand complexes possess good catalytic activity in the reaction of oxidation of alcohols using H 2 O 2 as oxidant. The antibacterial activity of the mixed ligand complexes has been carried out by disc diffusion method. Copper (II) complexes exhibit potent antibacterial activity when compared to the standard drug streptomycin. The above complexes also exhibited DPPH radical scavenging activity.

Optical and thermal characterization of double hydrogen bonded liquid crystals: Binary mixtures

ABSTRACTMethyl Malonic acid (MM) forms hydrogen bonds with octyloxy benzoic acid (8OBA), nonyloxy benzoic acid (9OBA), decyloxy benzoic acid (10OBA) labeled as MM+8OBA, MM+9OBA, and MM+10OBA respectively, all three mesogens exhibit mesogenic properties. Nine binary mixtures are prepared with MM+8OBA and MM+9OBA by varying their molar proportions in steps of 0.1 to 0.9. Similarly nine more binary mixtures are prepared with MM+8OBA and MM+10OBA. Two binary series namely MM+8OBA & MM+9OBA and MM+8OBA & MM+10OBA are analyzed. Various chemical and physical studies of these binary mixtures are investigated which includes Nuclear Magnetic Resonance spectral studies, FTIR, Polarizing Optical Microscopy and Differential Scanning Calorimetry. Phase diagram of above two binary series are constructed. Thermal studies derived from the DSC data include evaluation of order of phase transition, odd even effect, thermal stability factor, thermal equilibrium and variation of specific heat with temperature.

Synthesis and ion-exchange studies of resins derived from 2,2′-dihydroxybiphenyl-diamine-formaldehyde

Terpolymeric resins (2,2′-DHBPBDF) (DHBP = dihydroxybiphenyl; BD = butylenediamine; F = formaldehyde) were synthesized by the condensation of 2,2′-DHBP, 1,4-BD and formaldehyde in the presence of an acid catalyst with varied molar ratios of reacting monomers. Resin composition was determined on the basis of its elemental analyses. Their number-average molecular weight was determined by conductometric titration in non-aqueous media. The viscosity measurements were carried out in N,N-dimethylformamide at room temperature. Ultraviolet–visible, infrared and proton nuclear magnetic resonance spectral studies were undertaken to elucidate the structure of these resins. The thermal stability and kinetics of the thermal decomposition of these newly synthesized resins have been evaluated on the basis of thermogravimetric analysis and differential thermal analysis. The ion-exchange properties of these resins were studied for different metal ions. A batch equilibrium method was employed to study the selectivity of metal ion uptake. The study was carried out over a wide range of pH and ionic strengths of different electrolytes.

Dielectric dispersion, relaxation dynamics and thermodynamic studies of Beta-Alanine in aqueous solutions using picoseconds time domain reflectometry

The aqueous solution of beta-alanine characterised and studied by their dispersive dielectric properties and relaxation process in the frequency domain of 10×106Hz to 30×109Hz with varying concentration in mole fractions and temperatures. The molecular interaction and dielectric parameters are discussed in terms of counter-ion concentration theory. The static permittivity (ε0), high frequency dielectric permittivity (ε∞) and excess dielectric parameters are accomplished by frequency depended physical properties and relaxation time (τ). Molecular orientation, ordering and correlation factors are reported as confirmation of intermolecular interactions. Ionic conductivity and thermo dynamical properties are concluded with the behaviour of the mixture constituents. Solute–solvent, solute–solute interaction, structure making and breaking abilities of the solute in aqueous medium are interpreted. Fourier Transform Infrared (FTIR) spectra of beta- alanine single crystal and liquid state have been studied. The 13C Nuclear Magnetic Resonance (NMR) spectral studies give the signature for resonating frequencies and chemical shifts of beta-alanine.

Synthesis and characterization of oxime-modified phenylimido vanadium(V) isopropoxide and their hydrolytic study

Heteroleptic complexes of the type [V(NPh)(O i Pr)3-n {(ONC)(CH3)(C4H3O-2)} n ] {where n = 1 (1), 2 (2) and 3 (3)} were synthesized by the reactions of [V(NPh)(O i Pr)3] (A) with 2-acetylfuryl oxime in different molar ratios in anhydrous benzene. All these new derivatives have been characterized by elemental analyses, Fourier transform infrared spectroscopy, nuclear magnetic resonance (1H, 13C {1H}), 51V) and fast atom bombardment mass spectral studies. Spectral studies appear to be indicating mono-dentate and bi-dentate mode of attachment of the oximato moieties in the solution and solid state, respectively. Fast atom bombardment mass study of one of the representative derivative, [V(NPh){(ONC)(CH3)(C4H3O-2)}3] (3) suggests the monomeric nature of all these complexes. Thermogravimetric curve of [V(NPh){(ONC)(CH3)(C4H3O-2)}3] (3) shows large thermal events. Hydrolysis of [V(NPh)(O i Pr)3] (A) and [V(NPh){(ONC)(CH3)(C4H3O-2)}3] (3) in moist propan-2-ol medium yielded vanadia, (a) and (b), respectively. However, hydrolysis of [V(NPh)(O i Pr)3] (A) in n-hexane medium using calculated amount of water yielded hybrid material, (vn).The presence of (V = NPh) group in (vn) is confirmed by Fourier transform infrared spectroscopy and nuclear magnetic resonance spectral studies as well as by the thermogravimetric study. The X-ray diffraction patterns of vanadia, (a) and (b) indicate formation of orthorhombic phase and the scanning electron microscope images of (a) and (b) show rod like morphology of the crystallites. Absorption spectra of vanadia, (a) and (b) indicate energy band gaps of 2.62 and 2.43 eV, respectively. Heteroleptic complexes of the type [V(NPh)(O i Pr)3-n {(ONC)(CH3)(C4H3O-2)} n ] {where n = 1, 2 and 3} were synthesized by the reactions of [V(NPh)(O i Pr)3] with 2-acetylfuryl oxime. Hydrolysis of [V(NPh)(O i Pr)3] and [V(NPh){(ONC)(CH3)(C4H3O-2)}3] in moist propan-2-ol medium yielded vanadia in orthorhombic phase, whereas, hydrolysis of [V(NPh)(O i Pr)3] in n-hexane medium yielded hybrid material containing (V = NPh) linkages.

Synthesis, spectroscopic, and computational studies of charge-transfer complexation between benzidine with 2,3-dichloro-5,6-dicyano-p-benzoquinone and chloronil

The solid charge transfer (CT) complexes that have been formed from the reactions of donor benzidine (BZ) and the π-acceptors such as 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) and chloronil (CHL) have been studied and characterized experimentally and theoretically. The experimental work which includes the use of UV-visible spectroscopy to identify the CT band of the CT-complex. The composition of the complexes has been investigated successfully by using spectrophotometric titration and Job method of continuous variation to be 1:1. Furthermore, to calculate the formation constant and molar extinction coefficient, we have used the Benesi-Hildebrand equation. Infrared and proton nuclear magnetic resonance spectral studies were used to characterize and confirm the formation of CT-complex. The experimental studies were well supported by quantum chemical simulations by using density functional theory. The computational analysis of molecular geometry, Mulliken charges, and molecular electrostatic potential surfaces of reactants and complexes is very much helpful in assigning the CT route. The C═O bond length of DDQ and CHL increased upon complexation with BZ. We have also observed that the substantial amount of charge has been transferred from BZ to DDQ and CHL in the process of complexation. An excellent consistency has been achieved between experimental and theoretical results.