IR Absorption Bands Research Articles

Direct Observation of the Dynamics of Ylide Solvation by Hydrogen-bond Donors Using Time-Resolved Infrared Spectroscopy.

The photoexcitation of α-diazocarbonyl compounds produces singlet carbene intermediates that react with nucleophilic solvent molecules to form ylides. The zwitterionic nature of these newly formed ylides induces rapid changes in their interactions with the surrounding solvent. Here, ultrafast time-resolved infrared absorption spectroscopy is used to study the ylide-forming reactions of singlet carbene intermediates from the 270 nm photoexcitation of ethyl diazoacetate in various solvents and the changes in the subsequent ylide–solvent interactions. The results provide direct spectroscopic observation of the competition between ylide formation and C–H insertion in reactions of the singlet carbene with nucleophilic solvent molecules. We further report the specific solvation dynamics of the tetrahydrofuran (THF)-derived ylide (with a characteristic IR absorption band at 1636 cm–1) by various hydrogen-bond donors and the coordination by lithium cations. Hydrogen-bonded ylide bands shift to a lower wavenumber by −19 cm–1 for interactions with ethanol, −14 cm–1 for chloroform, −10 cm–1 for dichloromethane, −9 cm–1 for acetonitrile or cyclohexane, and −16 cm–1 for Li+ coordination, allowing the time evolution of the ylide–solvent interactions to be tracked. The hydrogen-bonded ylide bands grow with rate coefficients that are close to the diffusional limit. We further characterize the specific interactions of ethanol with the THF-derived ylide using quantum chemical (MP2) calculations and DFT-based atom-centered density matrix propagation trajectories, which show preferential coordination to the α-carbonyl group. This coordination alters the hybridization character of the ylidic carbon atom, with the greatest change toward sp2 character found for lithium-ion coordination.

Heat annealing influences the optical properties of 2D-MoS2 nanoparticles

Numerous structural defects, such as vacancies, dislocations, admixtures, grain boundaries and edges in the 2 D-MoS2 particles change their optical, mechanical, and electrical properties that influences their application. Here we investigate the heat annealing of MoS2 particles at 700 °C in an argon atmosphere, and demonstrate the appearance of sulfur vacancies in them using FTIR spectroscopy. The new IR absorption bands belonging to deformation and stretching vibrations of anions centered at 614 cm−1 and 1115 cm−1, respectively, were registered after annealing. In both MoS2 samples, those before and after the heat annealing, the Mo-Ox vibrations were registered by FTIR and Raman spectroscopy. Negligible changes observed in the Raman spectra of the title compound are discussed.

Elucidation of molecular interactions of aspartic acid with aqueous potassium sorbate and sodium benzoate: Volumetric, viscometric and FTIR spectroscopic investigation

Aspartic acid (Asp), a nonessential amino acid has been taken for the present study. Solutions of different concentrations of aspartic acid were prepared by dissolving it in water and {water + (1.5, 2.0 and 2.5 m) Potassium sorbate (PS)/sodium benzoate (SB)}. Density and viscosity of the solutions were experimentally determined at T = (293.15, 298.15, 303.15, 308.15 and 313.15) K. Volumetric parameters like apparent molar volume (V∅), partial apparent molar volume (V∅0), partial apparent molar expansibility (E∅0) were computed by using standard formulations. Stronger ion-ion, ion-hydrophilic and hydrophilic-hydrophilic interactions between zwitterionic centers (COO- and NH3+) and polar groups of aspartic acid (COOH and NH2) and ions present in aqueous PS/SB are found to dominate the hydrophobic interactions between the nonpolar organic segments of amino acid and PS/SB. Structure building character of aspartic acid in presence of PS/SB are established by the positive values of Hepler’s constant (∂2V∅0/∂T2)P for all compositions of solutions. Positive viscosity B-coefficient (BJ) and negative (∂BJ/∂T)values further establish the structure building character of aspartic acid. Thermodynamic parameters for viscous flow (Δμ20,#,ΔS0,#andΔH0,#) suggest that transition state for viscous flow is less stable than the ground state and formation of transitions state is not thermodynamically favoured. Shifting of IR absorption band for O-H stretching due to H-bonding at 3300–3340 cm-1 confirms changes in solvent structure due to ion-ion and ion–solvent interactions occurring in the investigated systems.

Preliminary Characterization of Mucus Crude Extracts from Mushroom Phallus indusiatus

Skin diseases, such as dermatitis, allergies and eczema, are one of the most leading causes of global diseases, affecting millions of people worldwide. Most of them are associated with the skin dehydration condition, caused by the loss of natural moisturizing factors (NMFs) in the corneocyte skin layer. To resolve this issue, the exogenously administered hyaluronic acid (HA) therapeutics were introduced. Nonetheless, HA sources from microbial fermentation is still expensive with potential toxicity from the toxin protein impurities. We demonstrated an alternative NMFs source from the mucus extracts of the Phallus indusiatus ( P. indusiatus) mushroom. For this, the fresh mucus was partially purifi ed by the sequential chelation (CaCl2/EDTA). A combined use of both IR and 13C-NMR spectroscopic techniques confi rmed the presence of glucuronic acid (GlcA) in the crude extracts, as convinced by the presence of the IR absorption bands at 1600-1603 cm−1 (C=O stretching), 3000-3800 cm−1 (-OH stretching), and at 1402-1410 cm−1 (C-O stretching), together with the 13C-NMR resonances at 101 ppm, 79 ppm and 81 ppm. The disappearance of the NMR characteristic peaks, corresponding to the N-acetyl glucosamine (GlcNAc) at 1.9-2.0 ppm (1H-NMR) and 23-25 ppm (13C-NMR), suggested the extremely low level of the HA in the crude extracts. Nonetheless, these crude extracts showed the higher water content, comparing to the HA standard, highlighting their potential use as an alternative NMFs sources for dry skin therapeutics.

Isotope Effects in the Spectra of Hydrogen-Bonded Complexes. Calculation of the Structure and Vibrational Absorption Spectra of the H-=SUB=-2-=/SUB=-O...HF, H-=SUB=-2-=/SUB=-O...DF, D-=SUB=-2-=/SUB=-O...HF, and D-=SUB=-2-=/SUB=-O...DF Complexes

The frequencies and intensities of IR absorption bands of the H2O...HF, H2O...DF, D2O...HF, and D2O...DF hydrogen-bonded complexes are calculated using the second-order vibrational perturbation theory. The MP2/aug-cc-pVTZ method with the basis set superposition error taken into account is used to calculate the electronic wave functions in determining the equilibrium configuration, the potential energy and dipole moment surfaces of these complexes, as well as in calculating spectral parameters. It is shown that upon complexation the frequencies and intensities of the stretching vibration of HF (DF) molecules and the intensities of stretching vibrations of H2O (D2O) molecules change most significantly. A variational calculation of librational motion of the water molecule in the two-well potential explained the reason for the higher value of the fundamental transition frequency of the ν1(H-F) mode as compared to the frequency of this mode upon hot transition from the first excited librational state. The dependence of the intermode anharmonic interaction on isotope substitution was analyzed. Keywords: hydrogen bond, calculations of spectra of molecular complexes, anharmonic interactions, isotope effects.

Synthesis, crystal structure and electrochemical properties of a new methylammonium sodium decavanate salt Na3(CH3NH3)3[V10O28].(CH3NH2).14H2O

A new hybrid decavanadate Na3(CH3NH3)3[V10O28].(CH3NH2).14H2O was obtained by a simple synthesis in solution and the crystal structure was determined by single-crystal X-ray diffraction. The compound consists of decavanadate anions [V10O28]6- isolated between sodium and methylammonium cations. The UV–Visible absorption, IR spectroscopy as well as electrochemical properties were characterized. The compound crystalizes in a triclinic system (space group P-1) with the unit cell parameters: a = 10.1584(11) Å, b = 10.8123(5) Å, c = 11.1582(7) Å, α = 107.723(4)°, β = 106.811(5)°, γ = 94.238(7)°. UV–Visible absorption spectroscopy shows a strong absorption band at 300 nm. The main IR absorption bands appear at: 954 cm-1, 800 cm-1, 732 cm-1 and 580 cm-1.The electrochemical measurement of this compound shows two reversible one-electron redox process -105 mV (I-I’) and 335mV(II-II’), which was attributed to two consecutive one-electron VV → VIV reductions.

Measuring in situ CO2 and H2O in apatite via ATR-FTIR

We present a new approach to determine in situ CO2 and H2O concentrations in apatite via attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR). Absolute carbon and hydrogen measurements by nuclear reaction analysis (NRA) and elastic recoil detection (ERD) are used to calibrate ATR-FTIR spectra of CO2 and H2O in apatite. We show that CO2 and H2O contents in apatite can be determined via linear equations (r2 > 0.99) using the integrated area of CO2 and H2O IR absorption bands. The main benefits of this new approach are that ATR-FTIR analyses are non-destructive and can be conducted on polished sample material surfaces with a spatial resolution of ~ 35 μm. Furthermore, the wavenumber of the phosphate IR absorption band can be used to determine the crystallographic orientation of apatite, which allows for accurate quantification of CO2 and H2O in randomly orientated apatite grains. The limit of quantification of H2O in apatite is ~ 400 ppm and ~ 100 ppm for CO2. Via two examples, one from a carbonatite and one from a metasedimentary rock, we show that this new technique opens up new possibilities for determining volatile concentrations and behavior in a wide range of hydrothermal, igneous, and metamorphic systems.

Fabrication of clay soil/CuFe2O4 nanocomposite toward improving energy and shielding efficiency of buildings

In this research, the energy and shielding efficiency of brick, fabricated by clay soil, as a practical building material was reinforced using CuFe2O4 nanoparticles. Initially, the nanoparticles were fabricated using the sol–gel method and then loaded in the brick matrix as a guest. The architected samples were characterized by X-ray powder diffraction (XRD), Fourier transform infrared (FTIR), diffuse reflection spectroscopy (DRS), field emission scanning electron microscopy (FE-SEM), High-resolution transmission electron microscopy (HRTEM), vibrating-sample magnetometer (VSM), differential scanning calorimetry (DSC) thermograms, and vector network analyzer (VNA) analyses. IR absorption of the tailored samples was monitored under an IR source using an IR thermometer. IR absorption and energy band gap attested that inserting the nanoparticles in brick medium led to the acceleration of a warming brick, desirable for energy efficiency in cold climates. It is worth noting that the brick/CuFe2O4 nanocomposite achieved a strong reflection loss (RL) of 58.54 dB and gained an efficient bandwidth as wide as 4.22 GHz (RL > 10 dB) with a thickness of 2.50 mm, meanwhile it shielded more than 58% of the electromagnetic waves at X-band by only a filler loading of 10 wt%. The microwave absorbing and shielding characteristics of the composite are mainly originated from conductive loss, electron hopping, natural and exchange resonance, relaxation loss, secondary fields, as well as eddy current loss. Interestingly, the shielding property of the nanocomposite was significantly generated from its absorbing features, reducing the secondary electromagnetic pollutions produced by the shielding materials applying the impedance mismatching mechanism.

Dielectric permittivity of organosilicate glass thin films on a sapphire substrate determined using time-domain THz and Fourier IR spectroscopy

The engineering of dielectrics such that they have low dielectric constants is an important challenge in the semiconductor industry. The IR absorption and THz relaxation make a significant contribution to the low-frequency dielectric constant of porous organosilicate glass (OSG) thin films used in the interconnects of integrated circuits as low-k dielectrics. Determination of the dielectric contributions with the aid of the electric dipole absorption bands in the THz region has certain methodological limitations owing to the effect of the substrate. To overcome this problem, we used a c-cut sapphire plate as a substrate, which is optically isotropic and transparent in the THz range. The parameters of both the IR and THz absorption bands in the OSG films were measured using Fourier IR and pulsed THz spectroscopy and analysed using the classical oscillator model. The contribution of the THz relaxation is responsible for approximately 15%–17% of the value of the low-frequency dielectric constant.

Water vapour self-continuum in near-visible IR absorption bands: Measurements and semiempirical model of water dimer absorption

The nature of the water vapour continuum has been of great scientific interest for more than 60 years. Here, water vapour self-continuum absorption spectra are retrieved at temperatures of 398 K and 431 K and at vapour pressures from 1000 to 4155 mbar in the 8800 and 10,600 cm−1 absorption bands using high-resolution FTS measurements. For the observed conditions, the MT_CKD-3.2 model underestimates the observed continuum on average by 1.5–2 times. We use the hypothesis that water dimers contribute to the continuum absorption to simulate the experimentally-retrieved self-continuum absorption spectra, and to explain their characteristic temperature dependence and spectral behaviour. The values of the effective equilibrium constant are derived for the observed temperatures. We find that the dimer-based model fits well to the measured self-continuum from this and previous studies, but requires a higher effective equilibrium constant compared to the modern estimates within the temperature range (268–431 K) and spectral region studied. It is shown that water dimers are likely responsible for up to 50% of the observed continuum within these bands. Possible causes of the incomplete explanation of the continuum are discussed. Extrapolating these measurements to atmospheric temperatures using the dimer-based model, we find that the newly-derived self-continuum reduces calculated surface irradiances by 0.016 W m−2 more than the MT_CKD-3.2 self-continuum in the 8800 cm−1 band for overhead-Sun mid-latitude summer conditions, corresponding to a 12.5% enhancement of the self-continuum radiative effect. The change integrated across the 10,600 cm−1 band is about 1%, but with significant differences spectrally.

Diffusion processes in germanium and silicon films grown on Si3N4 substrates

In this article, the results of investigation of processes occurring during the molecular-beam deposition of germanium layers on Si$_3$N$_4$ dielectric substrates within a wide range of the Ge film growth temperatures (30 to 600{\deg}C) are presented. The intensity of the IR absorption bands related to the vibrations of the N$-$H and Si$-$N bonds are established to decrease with the increase of the Ge deposition temperature. It appears that this phenomenon cannot be explained only as a thermally activated process. Simultaneously, the peak corresponding to the Ge$-$N vibration bonds emerges in the X-ray photoelectron spectra. We suppose that the deposition of germanium layers on Si3N4 dielectric substrates containing hydrogen atoms causes the diffusion of hydrogen atoms from the dielectric layer into the growing film. The experimental results may be interpreted in terms of a model, according to which the migration of hydrogen atoms from the Si$_3$N$_4$ layer into the growing germanium film is due to the difference in chemical potentials of hydrogen atoms in the dielectric layer and the germanium film. This process initiates the diffusion of germanium atoms in the opposite direction, into the Si$_3$N$_4$ layer, where they connect to free bonds of nitrogen atoms arising due to the escape of hydrogen atoms. The analogous processes occur during the deposition of silicon layers on Si$_3$N$_4$ substrates.

Shift of the Infrared Absorption and Emission Spectra of Transition Metal Ions in Solid Solutions of Semiconductor Compounds

A universal theoretical model is proposed that explains the observed shift of IR absorption and emission bands in the spectra of transition metal ions in solid solutions of semiconductor compounds. The model has been used for estimating the long-wavelength shift of luminescence bands in the spectra of semiconductor solid solutions with increasing concentration in application to crystals of the ternary systems ZnMgSe(Cr2+) and CdMnTe(Fe2+). Description of the phenomenon is generalized to the case of multicomponent solid solutions.

Tunable cationic distribution and structure-related magnetic and optical properties by Cr3+ substitution for Zn2+ in nanocrystalline Ni-Zn ferrites

We report a microwave-combustion synthesis and structure-related physical properties of Ni0.4Zn0.6−xCrxFe2O4 (0.0 ≤ x ≤ 0.6) nanocrystals in a study of effects by substitution among cations with different oxidation states, Cr3+ for Zn2+. High-quality nanocrystals with an average particle size of 26–33 nm and crystallite size ranged in 23–32 nm are revealed by transmission electron microscopy (TEM) and X-ray diffraction (XRD). Structural properties and cationic redistribution are studied by the XRD Rietveld analysis implying different preferences of Zn2+ and Cr3+ ions to occupy the tetrahedral and octahedral sites, respectively. Further characterization for the characteristic IR absorption bands, ionic valence states, chemical compositions and morphology have been performed by employing the Fourier transform infrared (FT-IR), X-ray photoelectron spectroscopy (XPS) and electron dispersive X-ray spectroscopy (SEM-EDX). XPS analysis indicates partial reduction of Fe3+ to Fe2+ and further confirms the estimated cationic distribution. UV–Vis absorbance measurements indicated a gradual decrease in the optical energy gap which implies the emergence of sub-band-gap energy levels by the Cr substitution. The magnetic properties were investigated by magnetization measurements showing highly soft magnetic behavior. The values and trend of the observed magnetic moment are consistent with the theoretically calculated magnetic moment based on cationic distributions estimated from the XRD and XPS. Ni-Zn-Cr spinel nanoferrites with soft magnetic properties, magnetization up to 106 emu/g and coercivity down to 70 Oe, tunable by cationic redistribution are introduced for high-frequency power applications.

Coupled hydrogen and fluorine incorporation in garnet: New constraints from FTIR, ERDA, SIMS, and EPMA

Abstract It is well known that some garnet compositions can incorporate hydrogen and/or fluorine at levels up to several wt%. However, accurate measurement of these elements can be difficult at trace to minor concentration levels, so they are frequently ignored in routine chemical analysis. Furthermore, the mechanisms of H incorporation are still under debate, and only one mechanism for F substitution is commonly considered. We employed infrared spectroscopy (FTIR), elastic recoil detection analysis (ERDA), secondary ion mass spectrometry (SIMS), and electron probe microanalysis (EPMA) to measure H and F concentrations and constrain incorporation mechanisms in ten grossular garnets. We also present SIMS data for 11 spessartine and two andradite garnets. Three grossular garnets were measured with ERDA to obtain an infrared integral molar absorption coefficient (εi) for H2O of 13 470 L/(mol·cm2). Grossular H2O and F concentrations range from 0.017 to 0.133 wt% and 0.012 to 0.248 wt%, respectively. Correlations between 16OH and 19F and interpretation of FTIR spectra prompt us to consider various coupled substitutions of H and F for Si, which can explain some high-frequency IR absorption bands that have been attributed previously to “hydrogrossular clusters” (variably sized clusters in which 4H substitute for Si) or to inclusions of hydrous minerals. A strong correlation between 16OH and 19F in spessartine and similar high-frequency IR bands implies a similar role for H-F substitution. Coupled H-F substitution is also probably relevant to some andradite-rich garnets, rare pyrope from the Dora Maira massif, and some synthetic garnets. Improvements in analytical methods for trace to minor H and F open up more possibilities for using these elements to calculate the activities of H2O and F-species in fluids that were in equilibrium with garnet-bearing phase assemblages, as well as constraining the recycling of these elements into the mantle via study of xenoliths.

Dielectric contribution of the IR absorption bands of porous organosilicate glass thin films on a platinum sublayer

Reduction of interconnect capacitance is one of the key ways to increase the speed of an ultra-large-scale integrated circuit (ULSI). A porous organosilicate glass (OSG) thin film on a platinum sublayer was used as a test vehicle for modelling the conductor–insulator electrodynamic properties in an ULSI. Investigation of the structure and residual effect on the dielectric contributions of the IR absorption bands is a direct approach to control the dielectric properties of the film. The absorption band dispersion was simulated by the Drude–Lorentz equations within a framework consisting of a two-layer medium model. The contributions to the dielectric permittivity of IR absorption bands in thin OSG films with different volume porosities were determined. It was shown that the total dielectric permittivity in the IR region was approximately 10% lower than that at low frequencies of the order of 100 kHz. An additional contribution can arise as a result of low-energy excitations and H2O electrodipole relaxation in the microwave—THz range.

On-site contactless surface analysis of modern paintings from Galleria Nazionale (Rome) by reflectance FTIR and Raman spectroscopies

Seven artworks representing the diversity of paints used around the 1960s and created by German and Italian painters (J. Albers, A. Bonalumi, L. Boille, T. Scialoja and M. Schifano) were studied on-site at the Galleria Nazionale d'Arte Moderna (Rome) with mobile instruments. We present a methodology based on Specular Reflectance Infrared Spectroscopy (SR-FTIR) adapted to unvarnished paintings. Complementary measurements have been performed by Raman spectroscopy. Characteristic bands regarding as-recorded infrared reflectance spectra and Kramers-Kronig Transformation-converted absorbance spectra are identified according to literature and reference spectra recorded on representative commercially available paints. To distinguish the different binders by SR-FTIR, we propose spectroscopic markers as the comparison of the intensity of carbonyl band around 1730-1735 cm−1 with bands at ~1160 (for acrylic), ~1230 (for PVAc), and 1270 cm−1 (for alkyds). On the other hand, oil/resin binders are characterized by intense and thin νCH2, νCH3 IR absorption bands around 2920-2850 cm−1, combined with an intense 1260 cm−1 band and a characteristic concave cradle shape (between ca. 1750 and 1260 cm−1). The results obtained establish the relevance of the implemented mobile non-invasive infrared spectroscopy analytical approach by successfully identifying acrylic, vinylic, oil media and enamel paints, with or without opacifiers, which is supplemented by Raman analyses for pigment identification.

Influence of Yb3+ ion incorporation in the structure of Yttrium Divanadate(V) on the properties of a new ceramic solid solution Y8-yYbyV2O17

New substitutional, limited solid solution of the formula Y8-yYbyV2O17 where 0 < y ≤ 2.0 was synthesized by the high-temperature reaction in the air from mixtures of α-Y8V2O17 with Yb8V2O17. The new Y8-yYbyV2O17 were characterized by powder XRD, DTA–TGA, IR, UV–vis-DRS and SEM methods. The structure, thermal stability, unit cell volume, band gap energies as well as the position of the IR absorption bands in the spectrum of Y8-yYbyV2O17 were determined. The solid solution was established to have the same structure as β-Y8V2O17 and it was found that with increasing concentration of Yb3+ ions in its crystal lattice the volume of its unit cell decreases along with its energy gap decreasing to 2.4 eV (for y = 2.0), while the IR absorption bands are shifted towards higher wavenumbers. The morphologies of the high temperature polymorph of Y8V2O17 and solid solution were analyzed.

Comparative Analysis of Alkaline-Extracted Hemicelluloses from Beech, African Rose and Agba Woods using FTIR and HPLC

The vast application of hemicellulose in industry is greatly influenced by its chemical components. The hydroxyl spectra vibrations (3919-3671 cm -1 ) from the FTIR spectra indicates the presence of non-hydrogen bonded OH stretch and normal polymeric OH stretch (3454-3211 cm -1 ) in the three samples. The samples contained residual lignin indicated by IR absorption bands at 1592 and 1525 cm -1 . The presence of C=O stretching vibrations of acetyl groups at 1734 cm -1 indicated that African rosewood was generally an acetylated molecule. Each heteropolysaccharide also contained reducing monosaccharides at their ends suggested by the C-H stretching vibrations. Infrared absorptions characteristic of asymmetric β-1,6-glycosidic stretching was present in Beechwood and Agbawood, respectively, and African rosewood gave three absorption bands β-1,3-glycosidic stretch, β-1,4-glycosidic stretch and an asymmetric β 1,6-glycosidic stretch, respectively. Agbawood gave a major absorption band at 923.75 cm -1 corresponding to the absorption band at β-1,4-glycosidic stretching. African rosewood contained 96% mannose and 4% of an unidentified sugar. Beechwood contained primarily glucose, but Agbawood contained 20, 14, 8 and 57% glucose, mannose, galactose, and an unidentified sugar, respectively.

Microstructure, magnetic properties of Ho3+ substituted Ni-Cu-Zn spinel ferrites and application for one pot synthesis of dihydropyrimidinones

Nanoparticles of Ni-Cu-Zn spinel ferrites with Ho3+ substitution were synthesized through the sol–gel auto combustion route. It is illustrated from thermogravimetric analysisand differential thermal analysiscurve that the decomposition of precursors takes place in the temperature range 350–460 oC. The Energy dispersive spectroscopy confirmed the mixing of the Fe, Ni, Cu, Zn, Ho and oxygen elements in stoichiometry proportion in pure and substituted spinel ferrites with desired stoichiometry. X-ray diffraction pattern confirmed the formation of cubic spinel structure without any impurity phases. Lattice constant, X-ray density increases while average crystallite size decreases with increased Ho3+substitution in Ni-Cu-Zn ferrites. The two strong IR absorption bands observed in the range 565–568 (ν1) and 409–438 (v2) cm−1. The obtained crystallite size lies between of 18 – 26 nm, confirmed from transmission electron microscopy. The microstructures of the calcinated spinel ferrites were evaluated by SEM and TEM. It is observed that the increase in concentration of Ho3+ ions saturation magnetization decreases. Prepared Ho3+ substituted Ni-Cu-Zn spinel ferrites were used as catalyst to synthesize the 3,4-dihydropyrimidin-2(1H)-ones.[copyright information to be updated in production process]

Метод определения констант образования межмолекулярной Н-связи по данным ИК-спектроскопии

An experimental method is proposed for determining the efficiency of the formation of intermolecular hydrogen bonds by determining the formation constant of the H-complex (K). The essence of the experiment to determine the value of K is that for one initial concentration of the proton donor, it is necessary to register the change in the optical density at the absorption wavelength of the monomers and the change in the optical density of the complexes of IR absorption bands at two concentrations of the proton acceptor. This approach was tested on the example of the interaction of butyl alcohol (proton donor) with 4-chloromethyl-1.3-dioxolane (proton acceptor). The obtained value of the equilibrium constant was 72.2 M-1. It is concluded that the proposed method for determining the value of K can be used not only in IR, but also in UV-visible spectroscopy.