High Resolution FTIR Research Articles

Rovibrational study of the 2ν2 band of D213CO by high-resolution Fourier transform infrared spectroscopy

The high-resolution FTIR spectrum of the 2ν2 band (3250–3380 cm−1) of D213CO was recorded at an unapodized resolution of 0.0063 cm−1. A total of 747 rovibrational transitions have been assigned and fitted up to J″ = 32 and Ka″ = 10 using the Watson’s A-reduced Hamiltonian in the Ir representation. A set of accurate upper state (v2 = 2) rovibrational constants, three rotational and five quartic centrifugal distortion constants, were determined for the first time. The band center of the 2ν2 band was found to be 3326.765109 ± 0.000079 cm−1. The rms deviation of the rovibrational fit was 0.00096 cm−1.

Fe(II)-substituted cobalt ferrite nanoparticles against multidrug resistant microorganisms

The present study is focused on the determination the influence of cobalt content in the magnetic cobalt ferrite nanoparticles (Nps) on their antibacterial efficiency against gram-negative Escherichia coli and gram-positive Staphylococcus aureus bacteria and several Candida species, in particular C. parapsilosis and C. albicans. For the synthesis of Fe(II) substituted cobalt ferrite Nps by co-precipitation way, the L-lysine was used as the capping biocompatible agent and the particle size was successfully controlled to be in the range of 5–6.4 nm. The antimicrobial efficiencies of the CoxFe1-xFe2O4@Lys Nps, where x varies from 0.2 to 1.0, were evaluated through the quantitative analysis by comparing with that of Fe3O4@Lys Nps and l-lysine. In this way, it was evidenced that increase in the Co2+ content in the similar sized cobalt ferrite Nps resulted in an increase in their antimicrobial potency into 93.1–86.3 % for eukaryotic and into 96.4–42.7 % for prokaryotic strains. For characterization the composition, structure, and morphology of the tested herein Nps inductively coupled plasma optical emission spectrometry, X-ray diffraction, high-resolution transmission electron microscopy, Mössbauer, and FTIR spectroscopy techniques were conferred.

High resolution FTIR spectroscopy of the ν7 band of CD3CCH

The high-resolution Fourier transform spectrum of propyne-d3 (CD3CCH) at room temperature has been recorded in the region of the ν7 band (950–1200 cm−1) at an apodized resolution of 0.004 cm−1. About 2400 lines consisting of a total of 25 sub-bands ranging from KΔK = −13 to 12 have been assigned in the ν7 band of CD3CCH. In the fitting analysis, the ν4 = 1 state to which transitions have not been identified in the experimental spectrum included as a “shadow” state. The data have been analyzed taking into account of the strong x-y Coriolis interaction of the ν7 = 1 state with the ν4 = 1 state. l-type interactions between the ±l components of the ν7 = 1 state, and a weak k-type doubling interaction between ν7 = 1 and ν4 = 1 states have been included in the analysis. The vibration-rotation transitions for K ≥ 8 show fairly large amount of deviation and most likely interacted by other nearby states. The transitions upto K = 7 and Jmax = 61 could be fitted with a standard deviation of 0.0007 cm−1.

Highly efficient upconversion luminescence in hexagonal NaYF4:Yb3+, Er3+ nanocrystals synthesized by a novel reverse microemulsion method

A new reverse microemulsion system is proposed for the first time to synthesize NaYF4:Yb,Er nanocrystals, which demonstrated high upconversion emission in 550 and 662 nm at 980 nm diode laser excitation. The reverse microemulsion (μEs) system is comprised of CTAB and oleic acid as surfactant and 1-butanol co-surfactant and isooctane oil phase. The surfactant to water ratio is able to tune the microemulsion droplet size from 14 to 220 nm, which eventually controls the crystallinity and particulate morphology of NaYF4:Yb,Er. Also, the microemulsion precursor and calcination temperature plays certain role in transforming the cubic NaYF4:Yb,Er to highly luminescent hexagonal crystal structured upconversion material. Single phase hexagonal NaYF4:YbEr nanorod prepared by water-in-oil reverse microemulsion (μEs) gives intense red upconversion emission. Both nanosphere and nanorod shaped NaYF4:Yb,Er was obtained, but nanorod morphology resulted an enhanced upconversion luminescence. The structural, morphological, thermal and optical luminescence properties of the NaYF4:Yb,Er nanoparticles are discussed in detail by employing powder X-ray diffraction, dynamic light scattering, high resolution electron microscopy, TGA-DTA, UV-DRS, FTIR and photoluminescence spectroscopy. Intense upconversion emission achieved in the microemulsion synthesized NaYF4:Yb3+,Er3+ nanocrystal can make it as useful optical phosphor for solar cell applications.

Synthesis, photophysics of a novel green light emitting 1,3,4-oxadiazole and its application in FRET with ZnSe/ZnS QDs donor

The design and synthesis of a novel molecule 2-(4-((E)-2-(5-((E)-4-(5-(4-tert-butylphenyl)-1,3,4-oxadiazol-2-yl)styryl)thiophen-2-yl)vinyl)-5-(4-tert-butylphenyl)1,3,4-oxadiazole (2TVPO) based on Donor-π-Acceptor strategy through the Wittig reaction as well as characterization by 1H, 13C NMR spectroscopy, high resolution mass spectrometry and FT-IR spectroscopy form the central theme of the present work. Thermal (TGA and DSC), photophysical and electrochemical properties have been studied in detail for this novel probe. In addition, fluorescence resonance energy transfer (FRET) employing steady state and time resolved spectroscopy methods has been studied using core-shell ZnSe/ZnS QDs (7 and 8nm) and 2TVPO fluorescent probe, respectively, as the energy donor and acceptor. Results of these studies reveal that (i) FRET pairs show a strong dipole-dipole interaction tendency to transfer energy from donor to acceptor; (ii) they possess high FRET efficiency and (iii) strong dependence of the acceptor emission on the overlap integral, quantum dot size and donor-acceptor distance. Further, the type of quenching is analyzed by Stern–Volmer plots.

A Ratiometric Fluorescence Universal Platform Based on N, Cu Codoped Carbon Dots to Detect Metabolites Participating in H2O2-Generation Reactions.

In this work, a new kind of N, Cu codoped carbon dots (N/Cu-CDs) was prepared via a facile one-pot hydrothermal method by using citric acid monohydrate, copper acetate monohydrate and diethylenetriamine. The prepared N/Cu-CDs with a high quantum yield (50.1%) showed excitation-independent emission at 460 nm. The structure and fluorescence properties of N/Cu-CDs were characterized by high-resolution transmission electron microscopy, fluorescence spectrofluorometer, FT-IR spectrometer, UV-visible spectrophotometer and X-ray photoelectron spectroscopy. N/Cu-CDs were applied to establishing a ratiometric fluorescence probe toward H2O2 based on the inner filter effect (IFE) between N/Cu-CDs and DAP (2,3-diaminophenazine, the oxidative product of o-phenylenediamine (OPD)), and provided a ratiometric fluorescence universal platform for detection of the metabolites participating in H2O2-generation reactions (cholesterol and xanthine). The proposed method was demonstrated to be ultrasensitive and highly selective for cholesterol and xanthine assay with detection limits of 0.03 and 0.10 μM, respectively. The fluorescence probe built was applied to the determination of cholesterol and xanthine in human serum with satisfactory results.

Line intensity measurements and analysis in the ν3 band of ruthenium tetroxide

Ruthenium tetroxide (RuO4) is a heavy tetrahedral molecule characterized by an unusual volatility near ambient temperature. Because of its chemical toxicity and the radiological impact of its 103Ru and 106Ru isotopologues, the possible remote sensing of this compound in the atmosphere has renewed interest in its spectroscopic properties. The present contribution is the first investigation dealing with high-resolution line-by-line intensity measurements for the strong fundamental band observed near 10 μm, associated with the excitation of the infrared active stretching mode ν3. It relies on new, high resolution FTIR spectra recorded at room temperature, using a specially constructed cell and an isotopically pure sample of 102Ru16O4. Relying on an effective Hamiltonian and associated effective dipole moment [S Reymond–Laruinaz et al, J Mol Spectrosc 2015;315:46–54], the measured line intensities were assigned and dipole moment parameters determined. A HITRAN-formatted frequency and intensity line list was generated.

Sensitive and Low-potential Electrochemical Detection of Hydroquinone Using a Nanodiamond Modified Glassy Carbon Electrode

© 2017 The Authors. The present work describes the sensitive and low-potential detection of hydroquinone (HQ) using a glassy carbon electrode (GCE) modified with nanodiamond (ND). The presence of ND was confirmed by high-resolution scanning electron microscopy, FTIR and Raman spectroscopy. The cyclic voltammetry results reveal that ND modified GCE has high electrocatalytic activity towards oxidation of HQ than unmodified GCE. In addition, the ND modified GCE shows a significantly lower oxidation potential towards CC than unmodified GCE, which is due to the presence of -OH functional groups in ND. The CV studies confirm that the redox electrochemical behavior of CC is a diffusion controlled electrochemical process on ND modified electrode. The ND modified electrode was able to detect the HQ across a linear response range from 1.0 to 78.0 μM. The limit of detection of the sensor was 0.19 μM. The sensor shows an appropriate selectivity in the presence of 20-fold concentrations of benzenediols and neurotransmitters. The practicality of the sensor is appropriate and shows excellent recovery of HQ in lab water samples.

Dielectric and optical properties of graphitic carbon nitride–titanium dioxide nanocomposite with enhanced charge seperation

Graphitic carbon nitride (g-C3N4) a polymeric semiconductor material is appealing research topic because of enhanced absorption capability in visible region. g-C3N4–TiO2 composite material was prepared with varying composition (g-C3N4: TiO2) in the range of 0.25:1–2:1 and studied using various characterization techniques including X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM) and FTIR spectroscopy for structural and morphological analysis. Optical properties were studied using UV–Vis, and photoluminescence (PL) spectroscopic techniques and dielectric properties were studied using impedance analyser. UV–visible spectra show a shift toward the higher wavelength region in composite owing to the decrease in the band gap value of g-C3N4–TiO2 composites. The dielectric constant was found increased with increasing content of g-C3N4 till the composition of 1.5:1 and decreased for higher content. The optimum composition based on above studies was found to be 1:1 and 1.5:1 with optical absorption in the range of 280–420 nm covering UV and small portion of visible light, and recombination of photogenerated charge carriers were also reduced compared to g-C3N4.

Structural and properties correlation in PANI–Mo doped CoFe2O4 nanocomposite

PANI–CoFe1.9Mo0.1O4 nano-composites were synthesized with different weight ratio applying the citrate and in situ polymerization methods. Testing the functionality of the obtained nanocomposite is performed utilizing X-ray diffraction (XRD), high resolution transmission electron microscope and FTIR spectroscopy. XRD structural analysis revealed the increase of lattice parameter, crystallite size and the lattice microstrain of embedded ferrite as the amount of PANI increases in the nanocomposite. Refined structural parameters are correlated with the lattice mismatch between ferrite and PANI. Magnetic measurements manifested that the saturation magnetization (Ms) and remanent magnetization (Mr) increase while the coercive field (Hc) first increases then slightly decreases as the ferrite content increases in nanocomposite. The frequency dependence of dielectric constant (e), dielectric loss (tanδ), a.c. conductivity (σac) and electromagnetic interference shielding effectiveness (SE) have been studied in the range 42 Hz–5 MHz at room temperature. Results indicated the a.c. conductivity of nano composite is higher than pure PANI and the SE has high value at low frequency.

High-resolution infrared spectroscopy of the asymmetric NO stretch band of jet-cooled nitromethane and assignment of the lowest four torsional states

A high-throughput CW slit-jet apparatus coupled to a high-resolution FTIR was used to record the asymmetric NO stretch band of nitromethane. The b-type band, including torsionally excited states with m≤3, has been assigned for Ka″≤10, J″≤20. The ground state combination differences derived from these assigned levels were fit with the RAM36 program to give an RMS deviation of 0.0006cm−1. The band origin is 1583.0 (±0.1) cm−1 and the torsional level spacing is nearly identical to that in the ground state. The upper state levels are split into multiplets by perturbations. A subset of the available upper state combination differences for m=0, Ka′≤7, J′≤10 were fit with the same program, but with rather poorer precision (0.01cm−1) than for the ground state.

PAMAM dendrimer hydrogel film—biocompatible material to an efficient dermal delivery of drugs

We report the preparation, characterization, and drug release kinetics of a pH-responsive hydrogel film from a dendrimer megamer. The megamer (GP32) is a three-dimensional reticulated structure with a mean diameter of 71.16 nm (PDI 0.150) and was prepared by the reaction between Poly(amidoamine) generation4 (PAMAM G4) dendrimer and glutaraldehyde (G:P molar ratio 32). The crosslinking units in the megamer are provided mainly by the bicyclic dimer 2-hydroxy-3,4,4a,7,8,8a–hexahydro-2H-chromene-6-carbaldehyde as determined by high-resolution (800 MHz) 1H NMR and FTIR. The hydrogel film (F[GP32]) is formed upon evaporation of a methanolic solution of the megamer and has a high degree of organization and homogeneity. Further crosslinking with glutaraldehyde (CLF[GP32]) enhanced the mechanical properties of the hydrogel film. The chemical constitution and unique megamer architecture enable the hydrogel film to carry both lipophilic and hydrophilic substances. The film did not cause any dermal irritation or clinical signs of toxicity in tests on rabbits, allowed for a sustained release of ketoprofen and played an important role in the process of drug delivery into the receptor medium. This performance taken together with the absence of toxicity makes this hydrogel film a good choice for dermal sustained drug release.

Application of high resolution NMR, FTIR, and GC–MS to a comparative study of some indigenous seed oils from Botswana

Abstract Spectroscopic techniques utilizing FTIR, 1 H and 13 C NMR spectral fingerprints of the neat oils, as well as standard titrimetric and GC–MS analyses were all employed to determine the quality parameters and fatty acid (FA) profiles for Soxhlet-extracted seed oils of four indigenous plants from Botswana: Tylosema esculentum (morama), Schinziophyton rautanenii (mungongo), Citrullus lanatus (kgengwe) and Bauhinia petersiana (mogose). The physicochemical parameters and FA composition obtained from spectroscopic methods were found to be similar to those obtained from classical procedures indicating that oil quality parameters can reliably be obtained from spectroscopic data. The FA analysis showed the presence of 73–84% unsaturated FAs in the four seed oils. In addition, spectroscopic data clearly established the presence of the uncommon tri-unsaturated FA, α -eleostearic acid ( α -ESA) in mungongo seed oil which was quantified as 25% by 13 C NMR. Generally, the high levels of unsaturated FAs in the oils indicate their suitability in health food supplements. Industrial relevance The four plants studied are highly treasured in the areas where they grow due to the fact that they have for centuries provided food security, and means of livelihood for populations living in the Kalahari Desert and other marginal regions of the southern Africa region. Currently, there is a drive to add value to such often underutilized plants to aid in poverty alleviation by processing and marketing the products as healthy food supplements or cosmetic formulations. To this end, reliable methods for characterization and comparison of the FA composition of the seed oils from different geographical locations is required. The development of rapid, non-destructive spectroscopic techniques that can be applied directly on the neat oils is therefore an important venture.

New Resorcinol Derivatives from a Sponge-Derived Fungus Hansfordia sinuosae.

Ten new resorcinol derivatives named hansfordiols A-J (1-10) were isolated from the fermentation broth of the sponge-derived fungus Hansfordia sinuosae. High resolution electron ionization mass spectrometry, FT-IR spectroscopy, and NMR techniques were used to elucidate the structures of these compounds, and the absolute configurations were established by the modified Mosher's method and their specific optical rotation. The structures of compounds 8-10 were featured with various chlorination at aromatic rings. Their antioxidant activities on ABTS, cytotoxicity on the HCT-8, Bel-7402, BGC-823, A549, and A2780 cell lines, and antibacterial activities were evaluated.

High-resolution infrared spectroscopy and analysis of the ν2/ν4 bending dyad of ruthenium tetroxide

RuO4 is a heavy tetrahedral molecule of interest in several fields. Due to its chemical toxicity and radiological impact of its 103 and 106 isotopologues, the possible remote sensing of this compound in the atmosphere has renewed interest in its spectroscopic properties. We investigate here, for the first time at high resolution, the bending modes region in the far infrared. High resolution FTIR spectra have been recorded near room temperature, using a specially designed cell and an isotopically pure sample of 102RuO4. New assignments and effective Hamiltonian parameter fits for the main isotopologue (102RuO4) have been performed, treating the whole ν2/ν4 bending mode dyad. We provide precise effective Hamiltonian parameters, including band centers and Coriolis interaction parameters.

A new prenylated flavone from Pleione bulbocodioides

A new prenylated flavone, 3,5,7,3′-tetrahydroxy-8,4′-dimethoxy-6-(3-methylbut-2- enyl)flavone (1), together with three known flavone derivatives (2–4), two known dihydrophenanthrenes (5–6), two known lignin derivatives (7–8), and three known phenolic glycoside compounds (9–11) were isolated from the n-BuOH extract of Pleione bulbocodioides. High-resolution electrospray ionization mass spectroscopy (HRESIMS), FTIR spectroscopy, and NMR techniques were used to elucidate the structures of these compounds. Biological investigations showed that compound 5, 4,7-dihydroxy-2-methoxy-9,10-dihydrophenanthrene, exhibited potent anti-inflammatory activity on LPS-stimulated NO production in BV-2 microglial cells, with IC50 value of 5.44 μM.

Combined synchrotron-based high resolution FTIR and IR-diode laser supersonic jet spectroscopy of the chiral molecule CDBrClF

The rovibrational spectrum of Deuterobromochlorofluoromethane CDBrClF has been measured with a resolution of better than 0.001cm−1 at room temperature with the Zurich Bruker IFS spectrometer prototype (ZP 2001) using a globar source, and with the Bruker prototype 2009 interferometer connected to the Swiss Light Source (SLS) synchrotron as a radiation source providing a resolution of 0.0007cm−1 in the range 600–1100cm−1. In addition CDBrClF has been measured at low rotational temperature (Trot=15K) with our diode laser supersonic jet setup around 748cm−1 in the ν5 region (resolution 0.0013cm−1). The spectra of the two major isotopomers CD79Br35ClF and CD81Br35ClF have been analyzed within the ν5 (CCl-stretch, ν̃0=748.2998cm−1 (CD79Br35ClF), ν̃0=748.1541cm−1 (CD81Br35ClF)), ν4 (CF-stretch, ν̃0=1082.8116cm−1 (CD79Br35ClF), ν̃0=1082.7963cm−1 (CD81Br35ClF)) and ν3 (DCF-bend, ν̃0=918.3715cm−1 (CD79Br35ClF), ν̃0=918.0206cm−1 (CD81Br35ClF)) regions. A detailed rovibrational analysis of these bands is presented. A combined analysis of the ν3,ν4 and ν5 fundamental bands provides accurate rotational and quartic centrifugal distortion constants for the vibrational ground state and for the states ν3,ν4 and ν5 of CD79Br35ClF and CD81Br35ClF. The results are discussed in relation to intramolecular (ro)vibrational redistribution (IVR) and also possible experiments pertaining to the experimental detection of molecular parity violation.

Isolation and characterization of novel degradation products of Doxofylline using HPLC, FTIR, LCMS and NMR

Forced degradation of Doxofylline (DFL) in different stress (base and peroxide) conditions gave rise to two potential unknown impurities. These unknown degradation products DFL DEG-I and DFL DEG-II were evaluated using a new-reverse-phase high performance liquid chromatography (HPLC), where it was eluted at 0.44 and 1.09 relative retention times to DFL peak. DFL DEG-I and DFL DEG-II were isolated using preparative HPLC from degradation mixtures. The structure of DFL DEG-I and DFL DEG-II were elucidated using high resolution MS, multi-dimensional NMR and FTIR spectroscopic techniques, and characterized. The stereochemistry of the enantiomers in DFL DEG-II has further been investigated using computational techniques. To the best of our knowledge, DFL DEG-I and DFL DEG-II are novel impurities and not reported elsewhere.

Line parameters for CO2- and self-broadening in the ν1 band of HD16O

Lorentz half-width coefficients and their temperature dependence exponents for CO2 broadening in the fundamental bands of HDO are important for reliable and accurate interpretation of Mars and Venus atmospheric data and to determine D/H. Uncertainties in the temperature dependences of the CO2-broadened half-width coefficients lead to large errors in the retrieved mixing ratios and hence in HDO column abundances. In this high-resolution FTIR laboratory study, we report first measurements of the temperature dependences of half-width coefficients for HDO transitions in the ν1 and 2ν2 bands broadened by CO2. Accurate line positions, intensities, CO2-broadened width and pressure shift coefficients, their temperature dependences, collisional line mixing coefficients for HDO-CO2 system and quadratic speed dependence parameters have been retrieved for a large number of transitions in the ν1 band. Room-temperature self-broadened half-width coefficients, self-shift coefficients, and collisional line-mixing coefficients for HDO-HDO system were also measured for the same number of ν1 transitions. Positions and intensities were measured for nearly 60 transitions in the weaker 2ν2 band along with a few room-temperature measurements of CO2- and self-broadening and pressure-shift coefficients. These results were obtained from simultaneous nonlinear least squares fittings of ten high-resolution absorption spectra recorded with the Bruker IFS-125HR FTS at JPL and two coolable sample cells. Modified Complex Robert-Bonamy (MCRB) formalism was applied to compute both types of broadening and pressure shift coefficients, and the temperature dependences of the CO2- and self-broadening parameters. Present measurements are compared with the MCRB calculations and other theoretical values reported in the literature.

FTIR imaging of the molecular burden around Aβ deposits in an early-stage 3-Tg-APP-PSP1-TAU mouse model of Alzheimer's disease.

Alzheimer's disease is one of the major causes of dementia in the elderly. The disease is caused by the misfolding of water soluble alpha-helical proteins, which leads to the accumulation of β-sheets in the form of amyloid plaques, which can subsequently affect surrounding tissue areas by oxidative stress neurotoxicity. The aim of the present study was to design a novel methodology to analyze the extent to the neuronal burden around protein-rich Aβ plaques suspected to affect molecular components by oxidative stress induced by inflammatory states. To do so, sagittal brain tissue sections from triple transgenic APPxPSP1xTAU mice were used to carry high magnification FTIR-FPA bench-top chemical imaging. The study used the combination of chemometric procedures involving spectral curve fitting and image processing to study the molecular changes occurring around the plaques. The study shows the performance of the approach by demonstrating its usefulness to co-localize molecular changes to different areas around the plaques. The results, although very preliminary, point to the strong interplay between the distance from the plaque and co-accumulation of molecular components indicative of inflammatory states.