Alejandro Pedro Ayala

Universidade Federal do Ceará | UFC · Departamento de Física

Low-dimensional metal halides, such as the CsPb2X5 family (X = Cl, Br, I), demonstrate exceptional optoelectronic properties, making them attractive for various applications. In this study, we explore the impact of iodine substitution on the structural, vibrational, and photoluminescence properties of the low-dimensional CsPb2(Br1–xIx)5 solid solut...

O Distrito Pegmatítico de Solonópole-Banabuiú (DPSB) está localizado na porção centro-oeste do Estado do Ceará, encaixado no embasamento paragnáissico do Domínio Ceará Central da Província Borborema. É o de maior expressão econômica da região e tem suas principais mineralizações associadas ao caráter lítio-berilo-tantalífero dos corpos. Nesta pesqu...

Halide perovskites have attracted intense research interest owing to their multifaceted and versatile applications in optoelectronics. This intrigue is further fueled by their propensity to undergo intricate structural modifications under extreme conditions, thereby instigating property changes. Within this context, in this paper, we delve deep int...

In this paper, novel mixed Tutton salts with the chemical formulas K2Mn0.03Ni0.97(SO4)2(H2O)6 and K2Mn0.18Cu0.82(SO4)2(H2O)6 were synthesized and studied as compounds for thermochemical heat storage potential. The crystallographic structures of single crystals were determined by X-ray diffraction. Additionally, a comprehensive computational study,...

Saturated monocarboxylic fatty acids with long carbon chains are organic compounds widely used in several applied fields, such as energy production, thermal energy storage, antibactericidal, antimicrobial, among others. In this research, a new polymorphic phase of arachidic acid (AA) crystal was synthesized and its structural and vibrational proper...

presente invenção é referente ao crescimento de um cristal ternário complexado a Fe2+ com fórmula empírica C28H29FeN4O10. A obtenção do cristal decorreu do método de evaporação lenta do solvente com os compostos doravantes 1,10-fenantrolina (Composto 1), ácido succínico (Composto 2), e óxido(II,III) de ferro (Composto 3), em solução mista de água/m...

Though ferulic acid presents great hypoglycemic potential, it possesses limited aqueous solubility, and low oral bioavailability. When associated with metformin, the first-choice drug in Type 2 diabetes treatment, FA demonstrates synergistic hypoglycemic effects, however, it also causes certain undesirable dose-related effects. This study aimed to...

Criminal minds create new psychoactive substances (NPS) to dribble the Drug Regulatory System. Early Warning Systems (EWA) were instituted worldwide to combat this practice. Brazilian government has started establishing EWA at a national level since August 2021. The role of drug analysis laboratories in EWA is very important and experts working at...

The discotic liquid crystal 4-((2, 3, 4-tris (octyloxy) phenyl) diazenyl) benzoic acid, hereafter referred as DLC A8, exhibited in dimeric form has been studied using a combination of quantum chemical approaches and vibrational spectroscopy. This study investigates the structural alteration of DLC A8 associated with phase transition. The phase tran...

Since the global COVID-19 pandemic began, the scientific community has dedicated efforts to finding effective antiviral drugs to treat or minimize the effects caused by the SARS-CoV-2 coronavirus. Some targets can act as inhibitor substrates, highlighting the Main Protease (Mpro), which plays an essential role in the translation and transcription o...

The effect of pressure on the α and β polymorphs of a derivative of Blatter’s radical, 3-phenyl-1-(pyrid-2-yl)-1,4-dihydrobenzo[e][1,2,4]triazin-4-yl, has been investigated using single-crystal X-ray diffraction to maximum pressures of 5.76 and 7.42 GPa, respectively. The most compressible crystallographic direction in both structures lies parallel...

Histamine, an important biological chemical that occurs naturally and mainly in seafood, causes an undesirable inflammatory response when consumed in large amounts. Food and health regulatory bodies around the world limit its concentration, and histamine is usually detected by conventional methods, in slow processes. As an efficient option, Molecul...

Five unusual kaurane diterpenes, designated as bezerraditerpenes A-E (1-5), along with six known ones (6-11), were isolated from the hexane extract of the stems of Erythroxylum bezerrae. Their structures were elucidated based on the interpretation of the NMR spectroscopy, mass spectrometry, and X-ray diffraction analysis. The anti-inflammatory pote...

Diastereomeric salts of (S,S)-Sertraline, (Srt), with L- and D-tartaric acids have been prepared and their physical-chemical properties have been analyzed. Single-crystals of these salts have been grown and characterized by...

In contrast to the widespread polymorphism of single component drugs, polymorphism in cocrystals is still uncommon and often poorly understood. While there are numerous reports of polymorphic forms of single...

We present a temperature-dependent Raman scattering study of a [(CH3)3NH][Mn(N3)3] hybrid organic-inorganic azide-perovskite, in which we have analysed in detail the wavenumber and full width at half-maximum (FWHM) of lattice modes and internal modes of the NC3 skeleton, N3– and CH3 molecular groups. In general, the modes exhibited unusual behaviou...

We have investigated the first-order structural phase transition undergone by [(CH3)2NH2]PbBr3 at T = 250 K and its lattice dynamics using both temperature-dependent synchrotron X-ray powder diffraction (SXRPD) and Raman spectroscopy techniques. Very interestingly, we find that this compound exhibits an unusual uniaxial thermal expansion, which we...

Recently, hybrid metal–halide perovskite-like compounds have emerged as promising materials for optoelectronic applications. Such materials show optical properties that are usually tunable by the so-called perovskite dimensionality as well as octahedral distortion and connectivity. In this study, we have investigated the optical properties of an al...

Withajardins, uncommon modified withanolide-type steroids, have been isolated exclusively from plants of the Solanaceae family so far. Two undescribed withajardins and the known tuboanosigenin were isolated from the hexane/EtOAc 1:1 extract from Athenaea velutina leaves. Their structures were established by an extensive analysis of 1D and 2D-NMR an...

Glucocorticoid-induced osteoporosis (GIO) has emerged as a challenge after long-term glucocorticoids (GCs) administration. Exercise has been an important non-pharmacological option, while medications modulate bone remodeling despite adverse effects. In this way, milk Kefir (MK) therapy stands out as a safe alternative to improve bone metabolism. Ou...

Chalconas, flavonóides, isoflavonóides e outras substâncias derivadas têm sido muito estudadas nos anos recentes apresentando várias atividades farmacológicas e em alguns casos apresentando propriedades físicas muito importantes como as propriedades óticas não lineares (ONL). Recentemente observou-se que o composto 1-(2'-hidroxifenil)-3-hidroxi-3-(...

The aim of the present study was to perform morphological and chemical characterizations of microplastics (MPs) found in seawater samples from the coast of the city of Fortaleza (CE) using Fourier-transform infrared (FTIR) spectroscopy, Raman spectroscopy and differential scanning calorimetry (DSC). Sampling was performed using a neuston sampler. M...

Dihydrochalcones are promising structures in medicinal chemistry. They differ from chalcones by the reduction of unsaturated carbons present in the chalcone structure. In this work, the dihydrochalcone 3-(4-chlorophenyl)-3-hydroxy-1-(2-hydroxyphenyl) propan-1-one (DIHYDROCHAL) was synthesized and characterized by single-crystal X-ray Diffraction (X...

Recently, a model based on a combined ab initio/time-differential perturbed γ−γ angular correlation (TDPAC) study in the In111(→Cd111)-doped SnO2 semiconductor was proposed to enlighten the origin of the dynamic hyperfine interactions (HFIs) observed in oxides after the electron-capture (EC) decay of the probe nucleus of the In111 parent. It was de...

Chalcones are a large and promising source of molecules that can be used for drug development, as they have a wide variety of pharmacological activities associated with their structural diversity. In this work, the chalcone named (3E)‐4‐[4‐(dimethylamine)phenyl]but‐3‐en‐2‐one (DMAP) was synthesized, crystallized, and characterized by single-crystal...

Quinizarin, an anthracyclin-like compound, was used to prepare a binuclear complex, [(Fe(cyclam)) 2 Qz]Cl(PF 6 ) 3 , which showed damage to DNA with glutathione. This mimic of anthracyclin drugs might explain undesired side effects of these compounds.

The aim of the present study was to perform morphological and chemical characterizations of microplastics (MPs) found in seawater samples from the coast of the city of Fortaleza (CE) using Fourier-transform infrared (FTIR) spectroscopy, Raman spectroscopy and differential scanning calorimetry (DSC). Sampling was performed using a neuston sampler. M...

Estradiol 17β valerate (E2V) is a hormonal medicine widely used in hormone replacement therapy. E2V undergoes a reversible isosymmetric structural phase transition at low temperature (̴ 250 K) which results from the reorientation of the valerate chain. The reversible isosymmetric structural phase transition follows Ehrenfest’s classification when d...

The interplay between coordination geometry and reactivity in copper complexes has been widely studied for years. For CuII, it is known that the reduction is favored when the geometry is closer to that of the CuI state, which is mainly tetrahedral. Conversely, the reduction of CuII complexes in the absence of exogenous reducers has been barely addr...

The spectroscopic properties, molecular stability in terms of conformational analysis, and biological activities of cephalexin have been studied by quantum mechanical methods from combined experimental and computational approaches. The entire calculation was performed using density functional theory (DFT) employing Becke's three-parameter hybrid fu...

The search for materials with strong magnetoelectric coupling has been intense since interesting properties were discovered in the perovskite TbMnO3. Among the manganese-based perovskite family (RMnO3), magnetic and electric orders coexist in the orthorhombic phase of the distorted perovskite TmMnO3.The antiferromagnetic phase induces ferroelectric...

The structural, spectroscopic (FT-IR and FT-Raman), and physicochemical properties of ricobendazole (RBZ) has been presented with the help of combined experimental and computational approaches. A comparison between the observed and simulated spectra show good agreement with each other. The conformational analysis was performed around eight flexible...

This study reports on the synthesis, structural characterization and cytotoxic activity of four new Palladium/pyridylporphyrin complexes, with general formula {TPyP[PdCl(P-P)] 4 }(PF 6 ) 4 , where P-P are the 1,2-bis(diphenylphosphino)ethane (dppe), 1,3-bis(diphenylphosphino)propane (dppp), 1,2-bis(diphenylphosphino)butane (dppb)...

Here we report the cytotoxic effects of the two ternary copper(II) complexes [Cu(Phen)(l-methionine)H2O]Cl·1.5H2O (Cu(PHEN)(MET)) and [Cu(Phen)(l-asparagine)H2OCl]H2O (Cu(PHEN)(ASN)), which showed high chemotherapy potential against cancer cells lines. A novel ternary copper(II) complex, Cu(PHEN)(ASN) has been synthesized and its crystalline struct...

The present work focused on the chemical study of the main alkaloid component in Brazilian indigenous Amaryllidaceae species Hippeastrum puniceum (Lam.) Kuntze. The strategy applied was based on a distinct partitioning process and chromatographic-purification steps using the crude methanolic extract as the starting material. In this way, the glycos...

The polymorph selection during the discovery and development of new drugs is a crucial factor in ensuring the efficacy of a formulation. Thus, the physicochemical properties, including crystal structure, need to be considered in the decision tree that leads to a drug candidate. Riparins, natural alkamides isolated and later synthesized from Aniba r...

This study aims to investigate the structural and vibrational features of cefradine (the first-generation cephalosporin antibiotic) based on spectroscopic experiments and theoretical quantum chemical approach. The fundamental structural aspects of cefradine have been examined based on optimized geometry, spectroscopic behavior, intermolecular inter...

Six previously undescribed tropane alkaloids, designated as erythrobezerrines A-F, were isolated from the EtOH extract from the stem bark of Erythroxylum bezerrae Plowman. Their structures were elucidated based on the interpretation of the NMR and MS data and in some instances, confirmed by X-ray diffraction analysis. The cytotoxicity of the isolat...

This study aims to investigate the structural and vibrational features of cefradine (the first-generation cephalosporin antibiotic) based on spectroscopic experiments and theoretical quantum chemical approach. The fundamental structural aspects of cefradine have been examined based on optimized geometry, spectroscopic behavior, intermolecular inter...

Bismuth layer-structured ferroelectric Bi3R2Ti3FeO15 (R = Bi, Nd, and Gd) ceramics were synthesized by conventional solid-state reaction. All the samples showed an orthorhombic structure with A21am space group. Bi3Nd2Ti3FeO15 and Bi3Gd2Ti3FeO15 presented a reduction in the orthorhombicity when compared to Bi5Ti3FeO15. The magnetic susceptibility of...

Herein we report the synthesis and structural characterization of a new Ni-bis(hydrazone) complex with the chemical formula [Ni2(L)2(Cl)2](Cl)2·2H2O (L = 2-(heptylthio)-4,6-bis(2-((E)-pyridin-2-ylmethylene)hydrazineyl)pyrimidine). Suitable crystals for X-ray diffraction showed the supramolecular interactions of this complex to exhibit a helical str...

Bismuth layer-structured ferroelectric Bi3R2Ti3FeO15 (R = Bi, Nd, and Gd) ceramics were synthesized by conventional solid-state reaction. All the samples showed an orthorhombic structure with A21am space group. Bi3Nd2Ti3FeO15 and Bi3Gd2Ti3FeO15 presented a reduction in the orthorhombicity when compared to Bi5Ti3FeO15. The magnetic susceptibility of...

Background: This study aimed to evaluate the X-linked hypophosphatemic rickets (XLHR)-related compositional and microhardness tooth aspects. Material and methods: One affected and one non-affected teeth by XLHR were sectioned transversely, and each section was separated for Micro-Raman spectroscopy, Knoop microhardness and scanning electron micr...

Benznidazole, the primary drug used in Chagas’ disease treatment, has known side effects, which may limit its widespread use. Its low solubility could negatively interfere in the bioavailability, even accentuating the toxic effects. Cocrystals have been extensively used to modify and optimize physicochemical properties, but, as single-component raw...

In this work we present a study of the structural and vibrational properties of the chalcone (2E)-1-(4-aminophenyl)-3-(furan-2-yl)prop-2-en-1-one monohydrate, C13H11O2N·H2O, a strong candidate for fluorescent probes, luminescent materials and optoelectronic devices. The crystalline structure of this chalcone monohydrate was determined at 273 K usin...

The structural stability of the multiferroic four-layer Aurivillius ceramic Bi5FeTi3O15 (BFTO) under hydrostatic pressure was investigated in situ by synchrotron X-ray powder diffraction (SXRPD) and Raman spectroscopy. Measurements performed up to 15 GPa allowed the identification of two well-defined structural phase transitions. The orthorhombic p...

Monoclinic BiCrO3, synthesized at high pressure and high temperature, presents interesting properties with anomalies of magnetic origin observed around 110 and 80 K, which are associated, respectively, with the rise of a G-type antiferromagnetic structure and the spin reorientation along one of the monoclinic axes. In this study, we report a strong...

The cis-[Ru(bpy)2(Met)](PF6)2 complex, where Met = l-methionine and bpy = 2,2′-bipyridine, was prepared and fully characterized. This complex was subjected to blue and green light photolysis (453 and 505 nm, respectively) in aqueous solution, leading to the release of methionine and formation of the cis-[Ru(bpy)2(H2O)2]2+ ion. This latter photoprod...

Novel ternary systems with β-cyclodextrin or maltodextrin and triethanolamine as the third component were developed with the aim of improving the oral bioavailability of furosemide. These new solids were characterized by solid-state nuclear magnetic resonance, Fourier transform infrared and Raman spectroscopy, X-ray powder diffractometry, scanning...

Cephalosporins are among the most frequently used broad-spectrum antimicrobial agents. Ceftazidime is a semisynthetic β-lactam antibiotic for parenteral administration widely used in the clinical practice, which has been categorized as a third-generation cephalosporin antibiotic. This drug crystallizes as a pentahydrate and, as all cephalosporin, i...

Three new 3-hydroxy-N-methyl-2-oxindole (1 and 2) and 4-hydroxy-pyran-2-one (3) derivatives, along with the known 3-hydroxy-N-methyl-2-oxindole (4) and 6-methoxy-N-methylisatin (5) were isolated from a marine Salinispora arenicola strain from sediments of the St. Peter and St. Paul Archipelago, Brazil. The structures of the new compounds were eluci...

A dihydropyrimidine (DHPM) derivative was synthesized, characterized by X-ray diffraction and searched in silico for its inhibitory activities against AccD5 enzyme, the CT domain of a Mycobacterium tuberculosis ACCase. Its molecular structure was compared to another DHPM derivative (DHPM II ). The results have shown that the (±)2,6-methano-4-thioxo...

Salinaphthoquinones A-E (1-5) were isolated from a marine Salininispora arenicola strain, recovered from sediments of the St. Peter and St. Paul Archipelago, Brazil. The structures of the compounds were elucidated using a combination of spectroscopic (NMR, IR, HRESIMS) data, including single-crystal X-ray diffraction analysis. A plausible biosynthe...

Albendazole is an effective antihelmintic drug, which has an unpredictable therapeutic response due to its low solubility in biological fluids that limits its oral absorption. In an attempt to improve solubility, Albendazole Hydrochloride, a soluble pharmaceutical salt, was obtained and characterized by X-ray diffraction together with magic angle s...

The use of supramolecular synthons as a strategy to control crystalline structureis a crucial factor in developing new solid forms with physicochemical propertiesoptimized by design. However, to achieve this objective, it is necessary tounderstand the intermolecular interactions in the context of crystal packing. Thefeasibility of a given synthon d...

The interest in therapeutical applications of carbon monoxide to physiological targets has led us to explore CO releasing molecules (CORM's), particularly those that decomposes upon a specific stimuli, i.e. light irradiation. Here, we prepared a photoactivated, air stable and water soluble ruthenium(II) complex, cis-[Ru(bpy) 2 (SO 3 )(CO)], which r...

Multiferroics materials have been intensively investigated for applications into photovoltaic cells. KBiFe 2 O 5 (KBFO) emerged as a strong candidate for such applications since it exhibits low bandgap energy. It is usually orthorhombic at room temperature and pressure, however, phase diagrams investigations determined that it transforms into a mon...

Since interesting magnetodielectric properties were discovered in terbium-based manganites, the search for new magnetodielectric multiferroic materials with high Curie temperatures and strong magnetodielectric coupling has been intense. Recently, it was reported that synthetic melanothalllite, the oxahalide Cu2OCl2, is a spin-driven multiferroic ma...

The current study was aimed to investigate febuxostat-salicylic acid (FXT-SAA) eutectic system using two polymorphs of FXT, form Q and form A. FXT, a BCS class II drug and SAA, water soluble co-former were used to formulate FXT-SAA eutectic system. The formed system was further confirmed using binary phase diagram and powder X-ray diffraction (PXRD...

The physicochemical stability and bioavailability of oncocalyxone A (onco A), a quinone isolated from Auxemma oncocalyx tree, could be improved by supramolecular inclusion complexes with cyclodextrins (CDs). The aim of this study was thus to elucidate the complexation of onco A with different CDs using isothermal titration calorimetry (ITC) and mol...

In the present work, we analyzed the multiferroic material copper chloride in its anhydrous (CuCl2) and dihydrated (CuCl2·2H2O) forms, monitoring its thermal behavior by Raman scattering spectroscopy and thermal analysis. The vibrational modes characteristic of the Raman spectrum at room temperature of the two phases are discussed. It was possible...

In this paper the isolation of 2-Hydroxy-3,4,6-trimethoxyacetophenone (C11O5H14) from the stem bark of Croton anisodontus Müll. Arg. (Euphorbiaceae) is presented and its structure is characterized using Nuclear Magnetic Resonance and single crystal X-ray diffraction. The crystalline structure of this natural compound, which presents potential antim...

Febuxostat (FXT) is a urate-lowering drug and xanthine oxidase inhibitor which is used for the treatment of hyperuricemia and gout caused by increased levels of uric acid in the blood (hyperuricemia). The present study aims to provide deeper knowledge of the structural, vibrational spectroscopic and physiochemical properties of FXT based on monomer...

Solid solutions could represent a viable alternative to better understand and control structure-property relationships of drugs, in order to optimize their properties for practical applications. Lamivudine (3TC) and emtricitabine (FTC) are nucleoside analogue reverse transcriptase inhibitor antiretroviral drugs, which have similar molecular structu...

Albendazole, an effective broad-spectrum anthelmintic agent, showed unpredictable therapeutic response caused by poor water solubility and slow dissolution rate. Then, novel binary and multicomponent supramolecular systems of two different solid forms of albendazole (I and II) with maltodextrin alone or with glutamic acid were studied as an alterna...

Raloxifene hydrochloride is a benzothiophene derivative mainly used in the prevention and treatment of osteoporosis, but exhibits a low bioavailability hindered by its poor water solubility. In this study, a mechanochemical approach based on neat and liquid-assisted grinding was applied to produce new solid forms of raloxifene hydrochloride. The so...

Furosemide is the most commonly prescribed diuretic drug in spite of its suboptimal biopharmaceutical properties. In this work, the addition of different amino-acids was studied with the aim of selecting an enhancer of the furosemide solubility. The best results were obtained with arginine. Also, binary (furosemide:arginine) and ternary (furosemide...

Furosemida (FUR), un fármaco usado para el tratamiento de la hipertensión y el edema, presenta problemas de biodisponibilidad oral asociados a su baja solubilidad acuosa y mala permeabilidad intestinal [1]. Trietanolamina (TEA) es una amina ternaria y un triol que, en estudios preliminares, demostró que interactúa en solución con FUR, incrementando...

Plant based natural products cover a major sector of the medicinal field, as such focus on plant research has been increased all over the world. As an attempt to aid that research, we have performed structural and spectroscopic analysis of a natural product, an alkaloid: canadine. Both ab initio Hartree-Fock (HF) and density functional theory (DFT)...

Rifampicin is a semi-synthetic drug derived from rifamycin B, and currently integrates the fixed dose combination tablet formulations used in the treatment of tuberculosis. It is also used in the leprosy polychemotherapy and prophylaxis, which are diseases classified as neglected according to the World Health Organization. Rifampicin is a polymorph...

Cocrystal of nitrofurantoin with urea (C8H6N4O5)•(CH4N2O), a non-ionic supramolecular complex, has been studied. Nitrofurantoin (NF) is a widely used antibacterial drug for the oral treatment of infections of the urinary tract. The characterization of the cocrystal of nitrofurantoin with urea (NF-urea) performed spectroscopically by employing FT-IR...

Supramolecular interactions between β-lapachone (β-lap) and cyclodextrins (CDs) were investigated by isothermal titration calorimetry. The most favorable host: guest interaction was characterized using X-ray powder diffraction (XRD), differential scanning calorimetry and thermogravimetry (DSC/TG), spectroscopy (FT-IR), spectroscopy (2D ROESY) nucle...

The crystalline binary adduct between the trimethylamine N-oxide (TMANO) and 2,4-dichlorobenzoic acid (2,4-DCBA) molecules was obtained by slow evaporation from acetonitrile. The obtained molecular complex is formed by a racemic mixture of molecular complexes crystallizing in the orthorhombic space group Pbca. An exhaustive analysis of the temperat...