FT-IR and Raman spectroscopic analysis of hydrated cesium borates and their saturated aqueous solution

Hydrated cesium borates have been synthesized by the reaction of Cs(2)CO(3) with H(3)BO(3) aqueous solution. After reaction equilibria were reached, liquid and solid phases were separated and the FT-IR difference and Raman spectra of each phase were recorded, respectively. The assignments of the recorded FT-IR absorption frequencies and Raman shift are given. The main polyborate anions and their interaction in borate aqueous solution have been proposed. The relations between the existing forms of polyborate anions and the crystallizing solid phases, Cs(2)B(4)O(7).5H(2)O and CsB(5)O(8).4H(2)O, have been gained.     

Hydrated double carbonates – A Raman and infrared spectroscopic study

The Raman spectra of selected double carbonates including pirssonite, gaylussite, shortite and quintinite complemented with infrared spectra have been used to characterise the structure of these carbonate minerals. By using a Libowitzky type function hydrogen bond distances for these minerals of 2.669–2.766 Å are estimated. The variation in the hydrogen bond distances contributed to the stability of the mineral. The Raman spectrum of pirssonite shows a single band at 1080 cm⁻¹ attributed to the (CO₃)²⁻ symmetric stretching mode, in contrast to shortite and quintinite where two bands are observed. Multiple bands are observed for the antisymmetric stretching and bending region for these minerals proving that the carbonate unit is distorted in the structure of pirssonite and gaylussite.     

Temperature study of Raman, FT-IR and photoluminescence spectra of ZnPc thin layers on Si substrate

The temperature study of zinc phthalocyanine (ZnPc) thin layers deposited on (0 0 1) Si substrate using Raman, FT-IR absorption and photoluminescence (PL) methods are reported. The Raman scattering spectra of ZnPc layers were investigated in the spectral range 1250–1650 cm⁻¹ and in the temperature range 100–500 K. The changes of spectral parameters such as the band position, integrated intensity and full width at half maximum (FWHM) of selected Raman modes while heating and cooling processes have been determined. The fast decrease of the frequency and the intensity of these modes observed with the increase of the temperature above 420 K, can be probably caused by the change of crystalline form of ZnPc thin layer. The FT-IR measurements have been performed in the temperature range 98–523 K. Our study allowed us to estimate the orientation of the molecular plane similar to these of CuPc thin films deposited on Si substrate. The Raman spectra have been compared with FT-IR spectra of ZnPc molecules in KBr pellets and thin layers of ZnPc on (0 0 1) Si substrate. The PL spectra of ZnPc layers were measured in the spectral range 350–1200 nm and in the temperature range 13–320 K. With increasing temperature from 13 to 175 K we observed the increase of PL bands at 1.76 and 1.85 eV which disappear reaching temperature above 200 K.     

FT-IR and Raman spectroscopic study of di-urea cross-linked poly(oxyethylene)/siloxane ormolytes doped with Zn ions

The interactions occurring in di-urea (NHC(O)NH) cross-linked poly(oxyethylene) (POE)/siloxane hybrids (di-ureasils) doped with zinc triflate (Zn(CF₃SO₃)₂) were investigated by Fourier Transform infrared (FT-IR) and Raman (FT-Raman) spectroscopies. Bonding of the Zn²⁺ ions to the urea carbonyl oxygen atoms occurs in the entire range of compositions studied (∞ > n ≥ 1, where n, salt content, is the molar ratio of oxyethylene moieties per Zn²⁺ ion). At n > 20 the incorporation of the guest cations progressively reduces the number of free CO groups. At n = 20 the saturation of the urea cross-links is attained and the Zn²⁺ ions start to coordinate to the POE chains giving rise to the formation of a crystalline POE/Zn(CF₃SO₃)₂ complex. The latter process occurs at the expense of the destruction of the hydrogen-bonded POE/urea structures of the host di-ureasil structure. New hydrogen-bonded associations, more ordered than the urea–urea aggregates present in the non-doped matrix and including Zn²⁺OC coordination, emerge in parallel. “Free” and weakly coordinated CF₃SO₃⁻ ions, present in all the xerogels studied, appear to be the main charge carriers of the conductivity maximum of this family of ormolytes located at n = 60 at 30 °C. In materials with n ≤ 20 contact ion pairs, “cross-link separated” ions pairs and higher ionic aggregates appear. The data reported demonstrate that the behaviour of the di-ureasils doped with triflate salts depends on the type of cation.     

Raman spectroscopic study of aqueous (NH4)2SO4 and ZnSO4 solutions

The Raman spectra of the v₁-SO ₄ ^2– band in 0.5–2.5 molar aqueous (NH₄)₂SO₄ and ZnSO₄ solutions in the temperature range 25–85°C were studied. The molar scattering coefficient of the v₁ band is the same for all forms of sulfate in (NH₄)₂SO₄ and ZnSO₄ solutions and is independent of temperature up to 85°C. The v₁ band profile is symmetrical in (NH₄)₂SO₄ solutions. In ZnSO₄ solutions, a shoulder appears on the high frequency side which increases slightly in intensity with increasing concentration and temperature. This high frequency component is attributed to the formation of the contact ion pair (Zn²⁺·SO ₄ ^2– ). The enthalpy of formation for the contact ion pair is estimated from the Raman data to be approximately 3 kJ-mol^–1 which is in reasonable agreement with measurements by other methods.     

Raman and infrared spectroscopic study of the anhydrous carbonate minerals shortite and barytocalcite

The Raman spectra of shortite and barytocalcite complimented with infrared spectra have been used to characterise the structure of these carbonate minerals. The Raman spectrum of barytocalcite shows a single band at 1086cm(-1) attributed to the (CO(3))(2-) symmetric stretching mode, in contrast to shortite where two bands are observed. The observation of two bands for shortite confirms the concept of more than one crystallographically distinct carbonate unit in the unit cell. Multiple bands are observed for the antisymmetric stretching and bending region for these minerals proving that the carbonate unit is distorted in the structure of both shortite and barytocalcite.     

FT-IR spectroscopic study on the variations of molecular structures of some carboxyl acids induced by free electron laser

Free electron laser has been developed as tunable lasers over a wide range of wavelengths. Devices irradiating in the region of 6-16 microm (1666-625 cm-1) are operable in the Beijing free electron lasers facilities (BFEL). For understanding the interactions between FEL and biological tissues, in this study wavelength-selective infrared-induced structure changes of substances under irradiation by FEL were measured using FT-IR spectroscopy. The carboxyl acids and carboxylates samples investigated include salicylic acid, sulfosalicylic acid, cholic acid, deoxycholic acid, sodium cholate and sodium deoxycholate. The changes of the FT-IR spectra of the molecules prove that the spectral variations of the samples induced by FEL are closely related to their hydrogen bond networks.     

X-ray diffraction,spectroscopic (IR,Raman) and DSC studies of bis(betainium) p-toluenesulfonate monohydrate crystal

Bis(betainium) p-toluenesulfonate monohydrate (abbreviated as BBTSH) was studied at various temperatures by X-ray diffraction, differential scanning calorimetry and vibrational spectroscopy methods. DSC curves of BBTSH show a peak at about 349 K which corresponds to water escape from the crystal, and reveal the “cold crystallization” phenomenon. BBTSH crystallizes in the P2₁/c space group of monoclinic system. After heating above 349 K the compound dehydrates, the crystal system changes to triclinic, the monocrystalline samples become non-merohedral twins. The BBTSH crystal comprises p-toluenesulfonic anions, monoprotonated betaine dimers and water molecules. Three kinds of hydrogen bonds are present in the crystal: strong, asymmetric and almost linear OH⋯O hydrogen bond (R(O⋯O) = 2.463(2) Å), weak O_wH⋯O hydrogen bonds (R(O_w⋯O) = 2.820(2) − 2.822(2) Å) and weak CH⋯O hydrogen bonds (R(C⋯O) = 3.295(2) − 3.416(2) Å). The ν_aOHO vibration of the strongest hydrogen bond in the crystal gives rise to an intense broad absorption with numbers of transmission windows in the low wavenumber region of the infrared spectra. Coupling between νCO stretching vibrations of two COO groups of the betaine dimer was detected. The process corresponding to the loss of water is accompanied by the breakage of strong OH⋯O hydrogen bonds in betaine dimers and rearrangement inside half of the betaine dimers. This rearrangement results in formation of the new betaine dimers with OH∙∙∙O hydrogen bond of similar strength as corresponding bond in the hydrated form (BBTSH).     

Gamma ray induced changes on vibrational spectroscopic properties of strontium alumino-borosilicate glasses

The present investigation reports the effect of influence of aluminum ions on radiation damage of strontium borosilicate glasses studied by means of spectroscopic (viz., optical absorption (OA), infrared and Raman spectra). The composition of the glasses chosen for the study is 40SrO–xAl₂O₃–(15-x) B₂O₃–40SiO₂ (x = 5, 7.5, 10), all in mol%. The glasses were synthesized by conventional melt quenching method. Later, the samples were exposed to gamma (γ) radiation dose of strengths 10 kGy and 30 kGy with a dose rate of 1.5 Gy/s using ⁶⁰Co as radiation source. The infrared spectra (IR), Raman spectra and optical absorption (OA) spectra of the samples were recorded at ambient temperature before and after irradiation. The OA spectra of the pre-irradiated samples do not exhibit any absorption bands in the UV–vis regions and IR and Raman spectra exhibited conventional vibrational bands due to different borate, silicate AlO₄ and AlO₆ structural units. The OA spectra of post irradiated samples exhibited a broad absorption band in the wavelength region 600–750 nm; it is attributed to electron trapped color centers. The intensity of this peak is observed to increase with increase of the γ-ray dose. Considerable changes in the intensities of various bands in the IR and Raman spectra were also observed. The changes were explained based on structural modifications taking place in the glass network due to γ-ray irradiation and finally it is concluded that the glasses mixed with 10.0 mol% of Al₂O₃ are relatively more radiation resistant.     

Raman spectroscopic study on the formation of an adduct of acetonitrile with formamide

Raman spectra of binary mixtures of acetonitrile (ACN) and formamide (FA) in different compositions were obtained. The appearance of a new band at 2257 cm⁻¹, whose intensity shows large dependence on the FA concentration, is assigned to a FA–ACN adduct. This has been possible owing to the two H-bond donor sites of FA and the strong donor character of ACN, becoming the environment propitious for the donor–acceptor reaction. Quantitative measurements performed in the CN stretching region in the binary mixtures give a 1:1 stoichiometry in this adduct in the limit of infinite dilution. In the N–H stretching region of FA, the band at 3270 cm⁻¹ is assigned to (FA–FA)_n interactions, via hydrogen bonding.

The experimental evidence of the 1:1 FA–ACN adduct is presented for the first time using Raman spectroscopy. The results described here open new possibilities to study this adduct and to evaluate thermodynamics parameters of interest.     

Raman spectroscopic characteristics of octa-substituted bis(phthalocyaninato) rare earth complexes peripherally substituted with (4-methoxy)phenoxy derivatives

The Raman spectroscopic data in the range 500-1800 cm⁻¹ for a series of 15 rare earth double-deckers with tervalent rare earths M^III[Pc(MeOPhO)₈]₂ (M = Y, La, …, Lu, except Ce, Pr and Pm), reduced state HPr[Pc(MeOPhO)₈]₂ and intermediate-valent cerium Ce[Pc(MeOPhO)₈]₂ have been collected using laser excitation source emitting at 632.8 nm. With excitation at 632.8 nm, which is in close resonance with the main Q absorption band of the phthalocyanine ligand, typical Raman marker bands of the monoanion radical [Pc(MeOPhO)₈]⁻ were observed at 1500-1528 cm⁻¹ as very strong bands resulting from the coupling of pyrrole CC and aza CN stretchings. For Ce[Pc(MeOPhO)₈]₂ and HPr[Pc(MeOPhO)₈]₂, a very strong band at 1499 cm⁻¹ with contributions from both pyrrole CC and aza CN stretchings and also isoindole stretching was the marker Raman band of [Pc(MeOPhO)₈]²⁻. In addition, the influence of ionic radius of the rare earth metal and substituent species on the Raman scatting characteristics of sandwich-type compounds has also been tentatively studied.     

Crystal and molecular structure, hydrogen bond and electrostatic interactions of bis(1-methylisonicotinate)hydrogen perchlorate studied by X-ray diffraction, DFT calculations, FT-IR, Raman and NMR spectroscopes

The crystal structure of bis(1-methylisonicotinate)hydrogen perchlorate, (MIN)₂H·ClO₄, has been studied by X-ray diffraction, DFT calculations, FT-IR, Raman, ¹H and ¹³C NMR spectra. The crystals are monoclinic, space group P2₁/n, with a pair of MIN molecules bridged by a short asymmetrical O·H·O hydrogen bond of 2.461(5) Å. The COO groups are twisted by 80.55° with respect to the plane of the pyridine ring. The anion interacts electrostatically with the positively charged nitrogen atoms of the neighbouring MIN molecules. The most stable conformer of isolated (MIN)₂H·ClO₄ and two homoconjugated cations, (MIN)₂H, have been analyzed by the B3LYP/6-31G(d,p) calculations in order to determine the influence of the anion on the hydrogen bonds in MIN·H·MIN unit. The FT-IR spectrum of the (MIN)₂H·ClO₄ shows a broad and intense absorption in the 1500–400 cm⁻¹ region, typical of short hydrogen bonds. The isotopic ratio, νOHO/νODO, is close to unity, indicating that the hydrogen bond is acentric (pseudo-type A).     

Experimental (FT-IR, FT-Raman, H, C NMR) and theoretical study of alkali metal 2-aminonicotinates

The influence of lithium, sodium, potassium, rubidium and cesium on the electronic system of 2-aminonicotinic acid (2-ANA) was studied by the methods of molecular spectroscopy. The vibrational (FT-IR, FT-Raman) and NMR (¹H and ¹³C) spectra of 2-aminonicotinic acid and its alkali metal salts were recorded. Characteristic shifts and changes in intensities of bands along the metal series were observed. The changes of chemical shifts of protons (¹H NMR) and carbons (¹³C NMR) in the series of studied alkali metal 2-aminonicotinates (2-AN) were observed too.Optimized geometrical structures of the studied compounds were calculated by the B3LYP method using the 6-311++G** basis set. Aromaticity indices, atomic charges, dipole moments and energies were also calculated. The theoretical chemical shifts in ¹H and ¹³C NMR spectra and theoretical wavenumbers and intensities of IR and Raman spectra were determined. The calculated parameters were compared to the experimental characteristics of the studied compounds.     

Raman spectroscopic study of Lactarius spores (Russulales, Fungi)

Fungi are important organisms in ecosystems, in industrial and pharmaceutical production and are valuable food sources as well. Classical identification is often time-consuming and specialistic. In this study, Raman spectroscopy is applied to the analysis of fungal spores of Lactarius, an economically and ecologically important genus of Basidiomycota. Raman spectra of spores of Lactarius controversus Pers.: Fr., Lactarius lacunarum (Romagn.) ex Hora, Lactarius quieticolor Romagn. and Lactarius quietus (Fr.: Fr.) Fr. are reported for the first time. The spectra of these species show large similarity. These spectra are studied and compared with the Raman spectra of reference substances known to occur in macrofungi, including saccharides, lipids and some minor compounds that may serve as specific biomarkers (adenine, ergosterol and glycine). Most Raman bands could be attributed to specific components. In agreement with the biological role of fungal spores, high amounts of lipids were observed, the main fatty acid being oleate. In addition to different types of lipids and phospholipids, the polysaccharides chitin and amylopectin could be detected as well. The presence of trehalose is not equivocally shown, due to overlapping bands. Raman band positions are reported for the observed bands of the different species and reference products.     

Raman spectroscopic and DSC studies of diglycine-perchlorate (DGPCl)

Single crystals of diglycine perchlorate (DGPCl) and deuterated diglycine perchlorate (DDGPCl) are synthesized and studied using differential scanning calorimetry (DSC) and Raman spectroscopy. DSC data indicated that both DGPCl and DDGPCl undergo a reversible first-order phase transition (solid-solid) at −11.5 °C and −9.3 °C, respectively. The Raman spectra of DGPCl and DDGPCl obtained at ambient temperature are analyzed to infer on the strength of hydrogen bonding in this compound relative to the parent compounds. The occurrence of NH stretching frequency at higher value in DGPCl in comparison with glycine suggests presence of a weak N–H?O hydrogen bond in DGPCl than in glycine. The lower isotropic melting temperature of DGPCl as compared to that of glycine is understood on the basis of the relative strength of hydrogen bonding in these compounds.     

氯柱硼镁石在盐酸溶液中溶解及相转化平衡溶液的振动光谱分析

The FT-IR difference spectroscopy and the Raman spectroscopy were used to identify the polyborate ions in saturated aqueous solutions during dissolution and transformation of 2MgO·2B₂O₃·MgCl₂·14H₂O in different HCl solutions at 30℃. The assignments of the recorded IR-Spectroscopic frequencies and Raman shift of the borate aqueous solution are given. The existing forms of polyborate anions in saturated aqueous solution and their inter-action have been discussed. The relationships between the existing forms of polyborate anions and the crystallizing solid phases have been gained.     

Raman spectra of Sr3(PO4)2 and Ba3(PO4)2 orthophosphates at various temperatures

The Raman spectra for Sr₃(PO₄)₂ and Ba₃(PO₄)₂ were investigated in the temperature range from 80 to 1623 K at atmospheric pressure. An unexpected melting of each sample was observed around 1573–1583 K in this study. In the temperature range from 80 to 1323 K, the Raman wavenumbers of all observed bands for Sr₃(PO₄)₂ and Ba₃(PO₄)₂ continuously decrease with increasing temperature. A quantitative analysis on the wavenumbers of Raman bands for both samples reveals that the ν₃ antisymmetric stretching vibrations show the strongest temperature dependence and the ν₂ symmetric bending vibration displays the weakest temperature dependence. The effects of cations on Raman bands are discussed. The reason for the unexpected melting of both samples is mainly attributed to the significant contribution from excess surface energy and the grain-boundary energy that has apparently lowered the melting points of the small samples, i.e., Gibbs–Thomson effect.     

四(对-硝基苯基)卟啉配合物的红外和拉曼光谱

本文研究了四(对-硝基苯基)卟啉及其Cr(Ⅲ)、Mn(Ⅲ)、Fe(Ⅲ)、Co(Ⅱ)、Ni(Ⅱ)、Cu(Ⅱ)、Zn(Ⅱ)配合物的3500～220cm~(-1)的红外光谱和1700～100cm~(-1)的拉曼光谱.谱带归属表明,～250cm~(-1)谱带是M—N伸缩振动和卟啉环变形振动的复合振动.金属敏感带出现在～1600、～1582、～1547、～1284、～1190、～355和～245cm~(-1)处,其中二价金属配合物金属敏感带频率按Ni>Co>Cu>Zn顺序递减.用金属半径和d_x~2 y~2电子排斥作用解释了金属敏感带变化规律.     

Studies of wall painting fragments from Kaiping Diaolou by SEM/EDX, micro Raman and FT-IR spectroscopy

The multi-technique analytical approach has proved to be a very effective tool for the analysis of artwork, as demonstrated by various studies. In this work, four micro-analysis methods were used to analyze the wall painting fragments in Kaiping Diaolou, a world cultural heritage enlisted in 2007. Field-emission scanning electron microscopy (FE-SEM), energy dispersive X-ray micro-analysis (EDX), combined with micro Raman and Fourier transform infrared (FT-IR) spectroscopy, provided a vast amount of information concerning the raw materials present in the pigments, organic binder, plasters and mortars of the wall painting. Four types of pigments (goethite, lazurite, chromium green and calcite) were identified on the surface layer of the wall paintings. The substrate under the pigment layer was found to be composed of cubic-like calcite (CaCO₃), micro-rod bundle-shaped syngenite (K₂Ca(SO₄)₂·H₂O), gypsum (CaSO₄·2H₂O) and silica (SiO₂). The organic binder can be attributed to animal glue (such as egg) and drying oil by micro FT-IR spectroscopy. These analysis results can provide important information for the conservation and restoration of the Kaiping Diaolou.     

Raman spectroscopic study of bacterial endospores

Endospores and endospore-forming bacteria were studied by Raman spectroscopy. Raman spectra were recorded from Bacillus licheniformis LMG 7634 at different steps during growth and spore formation, and from spore suspensions obtained from diverse Bacillus and Paenibacillus strains cultured in different conditions (growth media, temperature, peroxide treatment). Raman bands of calcium dipicolinate and amino acids such as phenylalanine and tyrosine are more intense in the spectra of sporulating bacteria compared with those of bacteria from earlier phases of growth. Raman spectroscopy can thus be used to detect sporulation of cells by a characteristic band at 1,018 cm^–1 from calcium dipicolinate. The increase in amino acids could possibly be explained by the formation of small acid-soluble proteins that saturate the endospore DNA. Large variations in Raman spectra of endospore suspensions of different strains or different culturing conditions were observed. Next to calcium dipicolinate, tyrosine and phenylalanine, band differences at 527 and 638 cm^–1 were observed in the spectra of some of the B. sporothermodurans spore suspensions. These bands were assigned to the incorporation of cysteine residues in spore coat proteins. In conclusion, Raman spectroscopy is a fast technique to provide useful information about several spore components. Figure A difference spectrum between Raman spectra of B. licheniformis LMG 7634 cultured for 6 days and 1 day, together with the reference Raman spectrum of calcium dipicolinate