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The methylated organic salt L-tyrosine methyl ester hydrochloride (LTMEHCl) crystal was synthesized by the slow solvent evaporation method. The crystal structure was verified through Powder X-ray Diffraction. Three-dimensional periodic Density Functional Theory calculations (DFT) were conducted to identify the Raman active modes. A high-pressure Raman study was carried out on this material, encompassing a wavenumber range of 50-3450 cm -1 and a pressure range from 0.0 to 9.0 GPa. Spectral modifications, including wavenumber discontinuities, the emergence and disappearance, broadening and attenuation, as well as the inversion of relative intensities in specific bands associated with both external and internal modes, were observed. These observations indicate a conformational phase transition in LTMEHCl crystal around 1.0 GPa, followed by a second phase transition near 6.0 GPa, which correlates with anincrease in structural disorder. The methylation process likely led to a reduction in hydrogen bond formation ability and an increase in the mobility of the methylated L-tyrosine under high pressure. Consequently, L-tyrosine methyl ester hydrochloride exhibited greater susceptibility to conformational modifications than its non-methylated analogue, L-tyrosine hydrochloride. Furthermore, upon the release of pressure, several bands either reappeared weakly or did not reappear. This behavior suggests a partial amorphization of the material, potentially influenced by the mineral oil medium and its hydrostatic limit., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

In this study, metal-doped niobates and perovskites were obtained by a solid-state reaction. The solids were evaluated in the esterification of glycerol in the presence of acetic acid to produce valuable esters of glycerol. The structural features of the solids indicated the ZnNb 2 O 6 , Pb 2.8 Nb 2 O 7.8 and CuNb 2 O 6 columbite main phases and La 2 MnFeO 6 double-perovskite. Density functional theory (DFT) studies of Pb 2.8 Nb 2 O 7.8 clearly confirmed the existence of a robust orthorhombic structure and its electronic properties were correlated with the Nb and Pb interactions. The morphological and elemental analyses also indicated that not all surface elements, as well as morphology, were crucial for catalytic properties. All solids were active and selective toward triacetin formation upon glycerol esterification with acetic acid. The catalytic performance depends mainly on the availability of the surface and its structural stability, as well as defects formation. Recyclability studies indicated that the La 2 MnFeO 6 double-perovskite was an efficient catalyst, achieving glycerol conversion of 68% and triacetin selectivity of 25% up to 4 cycles of use in the reaction. The structural defects near the Mn 4+ /Mn 3+ surface sites resulted in the diffusion of anions and an increased concentration of oxygen vacancies contributed to the stable performance of the solid in glycerol ester production.

This work presents a pressure-dependent behavior of silver trimolybdate dihydrate (Ag 2 Mo 3 O 10 ·2H 2 O) nanorods using in situ Raman scattering. The Ag 2 Mo 3 O 10 ·2H 2 O nanorods were obtained by the hydrothermal method at 140 °C for 6 h. The structural and morphological characterization of the sample was performed by powder X-ray diffraction (XRD) and scanning electron microscopy (SEM). Pressure-dependent Raman scattering studies were performed on Ag 2 Mo 3 O 10 ·2H 2 O nanorods up to 5.0 GPa using a membrane diamond-anvil cell (MDAC). The vibrational spectra under high pressure showed splitting and emergence of new bands above 0.5 GPa and 2.9 GPa. Reversible phase transformations under pressure were observed in silver trimolybdate dihydrate nanorods: Phase I - ambient phase (1 atm - 0.5 GPa) → Phase II (0.8 GPa - 2.9 GPa) → Phase III (above 3.4 GPa)., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

The high-pressure Raman spectra of L-tyrosine hydrobromide crystal (LTHBr) were obtained from 1.0 atm to 8.1 GPa in the 100-3200 cm -1 spectral region. The structural conformation and dimensions of the monoclinic unit cell were estimated using the powder X-ray diffraction (PXRD) method and Rietveld refinement using the GSAS program. At atmospheric pressure, the Raman spectrum was obtained in the spectral range of 100-3200 cm -1 and the assignment of the normal modes based on density functional theory calculations was provided. Large wavenumber shifts of modes at 106, 123, and 157 were observed, which were interpreted as the large displacement of the atoms, making the molecule a flexible structure. The change in the slope (dɷ / dP) of these bands between the pressures of 3.0 and 4.0 GPa and the appearance of a mode of low wavenumber indicate the occurrence of a structural phase transition. A band initially observed at 181 cm -1 in the spectrum recorded at 0.7 GPa change the relative intensity with a band at 280 cm -1 (recorded at 5.8 GPa), indicating a conformational transition. In the region of the internal modes, the spectra show changes that reinforce the conformational phase transition since the bands initially at 1247 and 1264 cm -1 observed at 1.0 GPa have their intensities reversed, and at 3.0 GPa it is observed the fusion of the bands at 1264 and 1290 cm -1 (values recorded at ambient pressure). Thus, we can assume that the LTHBr crystal has undergone a structural phase transition and a conformational phase transition in the pressure range investigated., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

The larval-pupal endoparasitoid Diachasmimorpha longicaudata (Ashmead, 1905) is considered one of the main biological control agents of fruit flies Ceratitis capitata Wiedemann (1824) and Anastrepha fraterculus Wiedemann (1830) in Central and South America. The application of pesticides for disease and insect-pest management in fruit species may have adverse effects on the parasitoid. The objective of this study was to evaluate the lethal and sublethal effects via residual contact of commercial pesticide formulations on D. longicaudata. The active ingredients thiamethoxam, indoxacarb, chlorpyrifos, deltamethrin, spinetoram, spinosad, phosmet, lambda-cyhalothrin, malathion, dimethoate, and methidationa showed high toxicity to adults (100% mortality) after 96 h and were classified as harmful (Class 4). In contrast, the formulations of azadirachtin (Agroneem 850 EC, Azact 2.4 EC, Azamax 12 EC, and Fitoneem 850 EC), chlorantraniliprole, bordeaux mixture, sulfur, lufenuron, lime sulphur, novalurom, and mancozeb were rated as innocuous (<10% mortality). In addition, the formulations azadirachtin did not reduce the parasitism and the emergence rate of the F0 generation, the same pesticides added to chlorantraniliprole, azadirachtin A+B (Agroneem 850 EC), and lufenuron did not cause reduction in parasitism and emergence rate of the F1 generation of D. longicaudata. The use of pyrethroids, organophosphates, spinosyns, oxadiazines, and neonicotinoids should be used with caution in IPM programs. While pesticides chlorantraniliprole, azadirachtin formulations, bordeaux mixture, lufenuron, lime sulphur, and mancozeb do not cause lethal and sublethal effects for D. longicaudata adults. The results of this study provide important information for use in integrated pest management programs for fruit fly management., (© The Author(s) 2021. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Pathogenic assessment of a baculovirus-based biopesticide containing Spodoptera frugiperda multiple nucleopolyhedrovirus (SfMNPV: Baculoviridae: Alphabaculovirus) infecting fall armyworm, Spodoptera frugiperda (J. E. Smith, 1797) (Lepidoptera: Noctuidae) is reported. In the bioassays, neonates were infected with different doses of SfMNPV applied on Cry1Ac Bt soybean and non-Bt soybean. Our findings indicated that S. frugiperda neonates did not survive at 10 d post infection or develop into adults on Bt and non-Bt soybean sprayed with the field recommended dose of SfMNPV. In contrast, a proportion of the infected neonates developed into adults when infected with lower doses of SfMNPV (50%, 25%, and 10% of field dose) in both Bt and non-Bt soybean. However, S. frugiperda neonates surviving infection at the lowest virus doses on both soybean varieties showed longer neonate-to-pupa and neonate-to-adult periods, lower larval and pupal weights, reduced fecundity, and increased population suppression. Nevertheless, more pronounced pathogenicity of SfMNPV infecting neonates of S. frugiperda were verified on larvae that developed on Bt soybean. These findings revealed that, beyond mortality, the biopesticide containing SfMNPV also causes significant sublethal pathogenic effects on neonates of S. frugiperda developing on Bt and non-Bt soybean and suggested an additive effect among SfMNPV and Cry1Ac insecticidal protein expressed in Bt soybean., (© The Author(s) 2021. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

The multicomponent glycinium maleate single crystal was grown by the slow evaporation method. The crystal was submitted to pressures ranging from 1 atm to 5.6 GPa and Raman spectroscopy was used as a spectroscopic probe. The modifications of relative intensity bands related to the lattice modes at 0.3 GPa were associated with rearrangements of hydrogen bonds. Moreover, between 1.7 and 4.8 GPa the Raman results indicate that the crystal experience a long structural phase transition, which was confirmed by PCA analysis. DFT calculations gave us more precision in the assignments of modes. The behavior of the internal modes under pressure showed that the maleic acid molecule undergoes greater modifications than glycine amino acid. All observed modifications were reversible when the pressure was released., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

The polymorphism is a characteristic of several active principles, and can affect the bioavailability of a drug. Among the drugs used in the treatment of heart diseases, captopril is one of the most widely used in the world. Despite the knowledge of vibrational properties of captopril under high temperature and under high pressure, a lack of information impedes the understanding of the substance in the crystal form at low temperatures. In this research, we investigated the vibrational properties of captopril crystals under cryogenic conditions in the 300-8 K interval using Raman spectroscopy. By observing the behavior of the inter- and intra-molecular vibrations it was possible to infer that the captopril molecules suffered a rearranging into the unit cell due slight orientational changes mainly involving CH⋯O hydrogen bonds. The phenomenon occurs in a large temperature range. However, the observed changes do not suggest the occurrence of a structural phase transition and the Raman spectra indicate that the trans conformation is recorded down to the lowest temperature available in the experiments., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

We report here the analysis of vibrational properties of the ZnMoO4 by using theoretical and experimental approaches, well as results of high pressure experiments in this system. The analysis of the lattice dynamics calculations through the classical rigid ion model, was applied to determine the mode assignment in the triclinic phase of the ZnMoO 4 . Additionally, the experimental high-pressure Raman spectra of the ZnMoO 4 were carried out from 0 GPa up to 6.83 GPa to shed light on the structural stability of this system. The pressure-dependent studies showed that this crystal undergoes a first order phase transition at around 1.05 GPa. The Raman spectrum analysis of the new phase shows a significant change in the number of modes for the spectral range of 20-1000 cm -1 . The instability of this phase occurs due to the decrease of the MoO bond lengths in the high-pressure phase, connected with tilting and/or rotations of the MoO 4 tetrahedra leading to a disorder at the MoO 4 sites. The second and third phase transformations were observed, respectively, at about 2.9 GPa and 4.77 GPa, with strong evidences, in the Raman spectra, of crystal symmetry change. The principal component analysis (PCA) and the hierarchical cluster analysis (HCA) were used in order to infer the intervals of pressure where the different phases do exist. Discussion about the number of non equivalent sites for Mo ions and the kind of coordination for molybdenum atoms is also furnished., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

The vibrational properties of the dipeptide l-leucyl-l-leucine hydrate were investigated through Raman and infrared spectroscopy. With the aid of first principle calculations using the density functional theory, the assignment of the vibrational modes from the material was furnished. In addition, the behavior of the crystal under high pressure was investigated using Raman spectroscopy (~8 GPa) and synchrotron X-ray diffraction (~26 GPa). The results show significant changes in both the X-ray diffractogram and the Raman spectra, suggesting that l-leucyl-l-leucine hydrate undergoes a phase transition between 2.3 and 2.9 GPa. Finally, for pressures above 16 GPa the broadening of X-ray peaks suggests a disorder in the crystal lattice induced by high-pressure effects., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2019. Published by Elsevier B.V.)

This work reports a theoretical and experimental study on the electronic and vibrational properties of Bi 2 (MoO 4 ) 3 . First-principle calculations were applied to increase the understanding on the properties of the chemical composition through the energy bands. The conduction band minimum (CBM) is found at the high symmetric Γ-point, while the valence-band maximum (VBM) is located between the Z and the Γ-points. Therefore, these facts confirm that the Bi 2 (MoO 4 ) 3 crystal is a semiconductor compound with an indirect band-gap of about 2.1 eV. Moreover, lattice dynamic properties were calculated using density functional perturbation theory (DFPT) in order to assign the experimental Raman bands. In addition, we performed temperature-dependent Raman spectroscopic studies in the Bi 2 (MoO 4 ) 3 crystals to obtain information on structural changes induced by effects of the temperature change. From the changes observed in the Raman spectra phase transitions at ∼ 668 and 833 K were inferred, with the last one possibly related to the disorder due to the heating process., (Copyright © 2019 Elsevier B.V. All rights reserved.)

In this study, the vibrational frequencies of myristic acid (CH 3 (CH 2 ) 12 COOH) were obtained using density functional theory calculations, and the results were compared with experimental Raman and infrared data. Additionally, Raman spectra of crystalline myristic acid were recorded in the 300-20 K range. Raman spectroscopy gives important insights into the effect of low temperatures on its monoclinic phase. X-ray diffraction was performed from 298 to 133 K to provide additional information about the cryogenic behavior of the crystals. These undergo a phase transformation, which was confirmed by differential scanning calorimetry through an enthalpy anomaly observed at low temperatures. Raman spectra and X-ray diffraction refinement of the cell parameters in combination with differential scanning calorimetry at low temperatures revealed slight modifications, confirming a conformational change in the myristic acid molecules involving rearrangement of dimers within the unit cell., (Copyright © 2018. Published by Elsevier B.V.)

A complete experimental study on the vibrational properties of palmitic and stearic acids crystallized in the B m and C forms, both belonging to the monoclinic system with the P2 1 /a (C 2h 5 ) space group, through polarized Raman and infrared spectroscopy, is reported in this paper. Density functional theory calculations were also performed to assign the normal modes and to help in the interpretation of the experimental data. The different polarizations were compared and their influence on the spectral profiles, in both the lattice and the internal mode regions, was discussed. In general, the Raman and infrared spectra exhibit accentuated differences among the polymorphic forms, which are associated with the different molecular modifications, defined as gauche and all-trans conformations. Insights about interaction among different groups are also furnished.