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1.
Anal Chem ; 96(22): 9262-9269, 2024 06 04.
Artigo em Inglês | MEDLINE | ID: mdl-38760019

RESUMO

Dual-organelle molecular localizers represent powerful new tools allowing the exploration of interorganelle physical contacts and subcellular chemical communication. Here, we describe new dynamic molecular probes to localize mitochondria and lipid droplets taking advantage of the differential proton gradients present in these organelles as well as the activity of mitochondrial esterase. We unveil their potential utility when organelle retention mechanisms and proton gradients are synchronized, an insight that has not been documented previously. Our discoveries indicate that dual-organelle probes serve as a valuable multiplexing assay during starvation-induced autophagy. The pioneering molecular mechanism they employ opens doors to avoid using labile esters such as acetoxymethyl derivatives which are not optimal in imaging microscopy assays.


Assuntos
Corantes Fluorescentes , Gotículas Lipídicas , Mitocôndrias , Prótons , Gotículas Lipídicas/metabolismo , Gotículas Lipídicas/química , Mitocôndrias/metabolismo , Mitocôndrias/química , Corantes Fluorescentes/química , Humanos , Células HeLa , Autofagia
2.
Org Biomol Chem ; 22(16): 3314-3327, 2024 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-38578064

RESUMO

The design, synthesis, and characterization of seven novel steroid-coumarin conjugates with diverse steroidal nuclei as lipophilic fluorescent materials for bioimaging applications are presented. The conjugates were synthesized through amidation, characterized using spectroscopic and spectrometric methods, and their main photophysical properties were determined. Dioxane : water titration experiments revealed their ability to self-assemble, forming J-aggregates as evidenced by new spectral bands at higher wavelengths. Monocrystal X-ray diffraction analysis disclosed distinctive aggregation patterns exhibiting J- or H-aggregates for selected compounds. Bioimaging studies demonstrated cell membrane localization for most conjugates, with some of them displaying an interesting selectivity for lipid droplets. Notably, the presence of the steroid fragments significantly influenced both the self-assembly patterns and the cellular localization of the fluorescent probes.

3.
Gac Med Mex ; 158(Suplement 2): 1-116, 2023 Jan 20.
Artigo em Espanhol | MEDLINE | ID: mdl-36763412

RESUMO

With the advancement of knowledge in relation to the physiopathogenesis of atopic dermatitis (AD), several new therapeutic forms have been developed. There are also new guidelines for self-care. On the other hand, there is still an underdiagnosis of AD in Mexico. Thus, the need was seen to develop a national guide, with a broad base among the different medical groups that care for patients with AD. The Atopic Dermatitis Guidelines for Mexico (GUIDAMEX) was developed with the ADAPTE methodology, with the endorsement and participation of ten national medical societies, from physicians in Primary Healthcare to allergists and dermatologists. Throughout the manuscript, key clinical questions are answered that lead to recommendations and suggestions for the diagnosis of AD (including differential diagnosis with immunodeficiency syndromes), the recognition of comorbidities and complications, non-pharmacological treatment including therapeutic education, treatment of flares and maintenance therapy. The latter encompasses general measures to avoid triggering factors, first-line treatment focussed on repair of the skin barrier, second-line treatment (topical proactive therapy), and third-line phototherapy or systemic treatment, including dupilumab and JAK inhibitors.


Con el avance de los conocimientos en relación con la fisiopatogenia de la dermatitis atópica (DA) se han desarrollado varias formas terapéuticas nuevas. Asimismo, existen nuevos lineamientos para el autocuidado. Por otro lado, aún existe un subdiagnóstico de la DA en México. Así, se vio la necesidad de desarrollar una guía nacional, con base amplia entre las diferentes agrupaciones médicos que atienden pacientes con DA. Se desarrolló la Guía de DA para México (GUIDAMEX) con la metodología ADAPTE, con el aval y la participación de diez sociedades médicas nacionales, desde médicos del primer contacto hasta alergólogos y dermatólogos. A lo largo del escrito se contestan preguntas clínicas clave que llevan a recomendaciones y sugerencias para el diagnóstico de la DA (incluyendo diagnóstico diferencial con síndromes de inmunodeficiencia), el reconocer de las comorbilidades y complicaciones, las medidas generales (tratamiento no farmacológico) incluyendo la educación terapéutica, el tratamiento de los brotes y el tratamiento de mantenimiento. Este último abarca las medidas generales de evitar agravantes, el tratamiento de primera línea reparador de la barrera cutánea, de segunda línea (manejo proactivo tópico), hasta la fototerapia y el tratamiento sistémico de la tercera línea, incluyendo dupilumab y los inhibidores de la cinasa de Jano.


Assuntos
Dermatite Atópica , Humanos , Dermatite Atópica/terapia , Dermatite Atópica/tratamento farmacológico , México , Comorbidade , Diagnóstico Diferencial , Fototerapia/métodos
4.
Molecules ; 27(1)2021 Dec 22.
Artigo em Inglês | MEDLINE | ID: mdl-35011258

RESUMO

Hydrothermal pretreatment (HP) is an eco-friendly process for deconstructing lignocellulosic biomass (LCB) that plays a key role in ensuring the profitability of producing biofuels or bioproducts in a biorefinery. At the laboratory scale, HP is usually carried out under non-isothermal regimes with poor temperature control. In contrast, HP is usually carried out under isothermal conditions at the commercial scale. Consequently, significant discrepancies in the values of polysaccharide releases are found in the literature. Therefore, laboratory-scale HP data are not trustworthy if scale-up or retrofitting of HP at larger scales is required. This contribution presents the results of laboratory-scale batch HP for wheat straw in terms of xylan and glucan release that were obtained with rigorous temperature control under isothermal conditions during the reaction stage. The heating and cooling stages were carried out with fast rates (43 and -40 °C/min, respectively), minimizing non-isothermal reaction periods. Therefore, the polysaccharide release results can be associated exclusively with the isothermic reaction stage and can be considered as a reliable source of information for HP at commercial scales. The highest amount of xylan release was 4.8 g/L or 43% obtained at 180 °C and 20 min, while the glucan release exhibited a maximum of 1.2 g/L or 5.5%. at 160 °C/180 °C and 30 min.


Assuntos
Fermentação , Polissacarídeos/biossíntese , Temperatura , Triticum/química , Biomassa , Celulose/química , Glucanos/biossíntese , Calefação , Hidrólise , Cinética , Xilanos/biossíntese
5.
Anal Chem ; 92(5): 3888-3895, 2020 03 03.
Artigo em Inglês | MEDLINE | ID: mdl-32000491

RESUMO

Membrane tension pores determine organelle dynamics and functions, giving rise to physical observables during the cell death process. While fluorescent organelle-targeted probes for specific chemical analytes are increasingly available, subcellular dynamic processes involving not only chemical parameters but also physicochemical and physical parameters are uncommon. Here, we report a mitochondrial chemical probe, named RCN, rationally designed to monitor osmotic effects during transmembrane tension pore formation by using local mitochondrial polarity and a subcellular localization redistribution property of the probe. Utilizing fluorescence spectroscopy, high-resolution confocal imaging, and spectrally resolved confocal microscopy, we provide a new correlation between mitochondrial dynamics and bleb vesicle formation using osmotic pressure stimuli in the cell, where the mitochondrial local polarity was found to drastically increase. The RCN provides a reliable protocol to assess transmembrane pore formation driven by osmotic pressure increments through local polarity variations and is a more robust physicochemical parameter allowing the health and decease status of the cell to be measured.


Assuntos
Corantes Fluorescentes/química , Microscopia Confocal , Mitocôndrias/química , Dinâmica Mitocondrial/fisiologia , Linhagem Celular Tumoral , Humanos , Pressão Osmótica/fisiologia
6.
Chemistry ; 26(69): 16530-16540, 2020 Dec 09.
Artigo em Inglês | MEDLINE | ID: mdl-32608048

RESUMO

A set of BODIPY-carboranyl dyads synthesized by a Sonogashira cross-coupling reaction, where different C-substituted ortho- and meta-carboranyl fragments have been linked to a BODIPY fluorophore is described. Chemical, photophysical and physicochemical analyses are presented, including NMR and single XRD experiments, optical absorption/emission studies and partition coefficient (log P) measurements. These studies, supported by DFT computations (M06-2X/6-31G**), provide an explanation to the largely divergent cell income that these fluorescent carboranyl-based fluorophores display, for which a structural or physicochemical explanation remains elusive. By studying the cell uptake efficiency and subcellular localization for our set of dyads on living HeLa cells, we tracked the origins of these differences to significant variations in their static dipole moments and partition coefficients, which tune their ability to interact with lipophilic microenvironments in cells. Remarkably, m-carboranyl-BODIPY derivatives with a higher lipophilicity are much better internalised by cells than their homologous with o-carborane, suggesting that m-isomers are potentially better theranostic agents for in vitro bioimaging and boron carriers for boron neutron capture therapy.


Assuntos
Compostos de Boro/química , Terapia por Captura de Nêutron de Boro , Células HeLa , Humanos , Modelos Teóricos
7.
J Org Chem ; 85(2): 633-649, 2020 01 17.
Artigo em Inglês | MEDLINE | ID: mdl-31830777

RESUMO

A multicomponent diversity-oriented synthesis of new highly emissive tetracyclic isoquinolines that target specific organelles is described. The title compounds were prepared via a three-step protocol starting with an Ugi four-component reaction, followed by either an intramolecular alkyne hydroarylation and subsequent alkene isomerization or through a Pomeranz-Fritsch-type cyclization with a final intramolecular Heck reaction. Subcellular localization studies of these compounds using green channel confocal microscopy revealed remarkable and distinctive distribution patterns in live cells, showing an unprecedented high selectivity and imaging contrast. The differentiated organelle visualization-including localizers for mitochondria, lysosomes, Golgi apparatus, endoplasmic reticulum, and plasma membrane-was achieved by varying the nature of the tetracyclic system and substituent pattern, changing the original four-component set in the starting Ugi reaction.


Assuntos
Corantes Fluorescentes/química , Isoquinolinas/síntese química , Isoquinolinas/metabolismo , Frações Subcelulares/metabolismo , Células HeLa , Humanos , Isoquinolinas/química
8.
Molecules ; 25(16)2020 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-32824757

RESUMO

Polymeric nanocarriers (PNs) have demonstrated to be a promising alternative to treat intracellular infections. They have outstanding performance in delivering antimicrobials intracellularly to reach an adequate dose level and improve their therapeutic efficacy. PNs offer opportunities for preventing unwanted drug interactions and degradation before reaching the target cell of tissue and thus decreasing the development of resistance in microorganisms. The use of PNs has the potential to reduce the dose and adverse side effects, providing better efficiency and effectiveness of therapeutic regimens, especially in drugs having high toxicity, low solubility in the physiological environment and low bioavailability. This review provides an overview of nanoparticles made of different polymeric precursors and the main methodologies to nanofabricate platforms of tuned physicochemical and morphological properties and surface chemistry for controlled release of antimicrobials in the target. It highlights the versatility of these nanosystems and their challenges and opportunities to deliver antimicrobial drugs to treat intracellular infections and mentions nanotoxicology aspects and future outlooks.


Assuntos
Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Sistemas de Liberação de Medicamentos , Nanomedicina , Nanopartículas/química , Preparações Farmacêuticas/química , Polímeros/química , Animais , Humanos , Nanopartículas/administração & dosagem
9.
Phys Chem Chem Phys ; 21(28): 15779-15786, 2019 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-31282523

RESUMO

Small-molecule fluorescent probes having optimized optical properties, such as high photostability and brightness, local microenvironment sensitivity and specific subcellular localizations, are increasingly available. Although the basis for designing efficient fluorophores for bioimaging applications is well established, implementing an improvement in a given photophysical characteristic always tends to compromise another optical property. This problem has enormous consequences for in vivo imaging, where ensuring a specific localization and precise control of the probe response is challenging. Herein we discuss a fluorescent probe, CC334, as a case study of the chromenylium-cyanine family that commonly exhibits highly complex photophysical schemes and highly interfered bioanalytical responses. By an exhaustive and concise analysis of the CC334 optical responses including detailed spectroscopic calibrations, steady-state microenvironment effects, ultrafast photophysics analysis and computational studies, we elucidate a new strategy to apply the probe in the singlet oxygen reactive oxygen species (1O2-ROS) monitoring using in vitro and in vivo models. The probe provides a new avenue for designing fluorescent probes to understand the dynamic behavior of subcellular environments.


Assuntos
Benzopiranos/química , Corantes Fluorescentes/química , Corantes Fluorescentes/metabolismo , Cobalto/química , Ferrocianetos/química , Quinolinas/química , Espécies Reativas de Oxigênio/química , Análise Espectral
10.
Gac Med Mex ; 155(Suppl 1): S38-S44, 2019.
Artigo em Espanhol | MEDLINE | ID: mdl-31182875

RESUMO

BACKGROUND: The promotion of health is carried out in preventive services of medical units, in educational programs and textbooks from the general perspective of the population. OBJECTIVE: To determine baseline characteristics of health education for pre-school children, their parents and teachers, by means of specialist doctors. METHOD: Cross-sectional study of an educational program for preschool children. Life skills and health competencies were evaluated. RESULTS: The preschoolers developed resilience (84.12%), empathy (92.23%), assertive communication (93.5%), interpersonal relationships (91.0%), correct decision making (92.56%), problem solving (81.05%), creative thinking (98%), critical thinking (86.08%), emotion management (80.76%), physical activation (97.94%), self-knowledge (98.96%), hygienic habits (94.90%) and co-responsibility (86.25%); 95.59% liked the workshop and 95.75% chose the correct option in the problems described. 63.04% of parents generated changes in their habits and those of their children. CONCLUSION: The educational program implemented can promote empowerment in health from childhood.


ANTECEDENTES: La promoción de la salud se realiza en servicios preventivos de unidades médicas, en programas educativos y libros de texto desde la perspectiva general de la población. OBJETIVO: Determinar características basales de educación en salud a preescolares, sus padres y maestros, mediante médicos especialistas. MÉTODO: Estudio transversal de un programa educativo para preescolares en estancias infantiles. Se evaluaron habilidades para la vida y competencias para la salud. RESULTADOS: Los preescolares desarrollaron resiliencia (84.12%), empatía (92.23%), comunicación asertiva (93.5%), relaciones interpersonales (91.0%), toma correcta de decisiones correctas (92.56%), solución de problemas (81.05%), pensamiento creativo (98%), pensamiento crítico (86.08%), manejo de emociones (80.76%), activación física (97.94%), autoconocimiento (98.96%), hábitos higiénicos (94.90%) y corresponsabilidad (86.25%); al 95.59% les agradó el taller y el 95.75% eligió la opción correcta en los problemas descritos. El 63.04% de los padres generaron cambios en sus hábitos y en los de sus hijos. CONCLUSIÓN: El programa educativo implementado puede favorecer el empoderamiento en salud desde la infancia.


Assuntos
Educação em Saúde , Creches , Pré-Escolar , Estudos Transversais , Feminino , Educação em Saúde/métodos , Educação em Saúde/organização & administração , Promoção da Saúde/métodos , Humanos , Masculino
11.
Gac Med Mex ; 155(Suppl 1): S28-S34, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31638615

RESUMO

BACKGROUND: The promotion of health is carried out in preventive services of medical units, in educational programs and textbooks from the general perspective of the population. OBJECTIVE: To determine baseline characteristics of health education for pre-school children, their parents and teachers, by means of specialist doctors. METHOD: Cross-sectional study of an educational program for preschool children. Life skills and health competencies were evaluated. RESULTS: The preschoolers developed resilience (84.12%), empathy (92.23%), assertive communication (93.5%), interpersonal relationships (91.0%), correct decision making (92.56%), problem solving (81.05%), creative thinking (98%), critical thinking (86.08%), emotion management (80.76%), physical activation (97.94%), self-knowledge (98.96%), hygienic habits (94.90%) and co-responsibility (86.25%); 95.59% liked the workshop and 95.75% chose the correct option in the problems described. 63.04% of parents generated changes in their habits and those of their children. CONCLUSION: The educational program implemented can promote empowerment in health from childhood.


Assuntos
Creches , Educação em Saúde/métodos , Pais/educação , Escolas Maternais , Capacitação de Professores , Pré-Escolar , Comunicação , Estudos Transversais , Currículo , Tomada de Decisões , Empatia , Feminino , Humanos , Relações Interpessoais , Masculino , Resolução de Problemas , Resiliência Psicológica , Pensamento
12.
Biotechnol Lett ; 40(3): 569-575, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29218548

RESUMO

OBJECTIVES: To assess the effect of one-step temperature increase, from 35 to 55 °C, on the methane production of a mesophilic granular sludge (MGS) treating wine vinasses and the effluent of a hydrogenogenic upflow anaerobic sludge blanket (UASB) reactor. RESULTS: One-step temperature increase from mesophilic to thermophilic conditions improved methane production regardless of the substrate tested. The biomethane potentials obtained under thermophilic conditions were 1.8-2.9 times higher than those obtained under mesophilic conditions. The MGS also performed better than an acclimated thermophilic digestate, producing 2.2-2.5 times more methane than the digestate under thermophilic conditions. Increasing the temperature from 35 to 55 °C also improved the methane production rate of the MGS (up to 9.4 times faster) and reduced the lag time (up to 1.9 times). Although the temperature increase mediated a decrease in the size of the sludge granules, no negative effects on the performance of the MGS was observed under thermophilic conditions. CONCLUSIONS: More methane is obtained from real agroindustrial effluents at thermophilic conditions than under mesophilic conditions. One-step temperature increase (instead of progressive sequential increases) can be used to implement the thermophilic anaerobic digestion processes with MGS.


Assuntos
Agroquímicos/metabolismo , Metano/metabolismo , Esgotos/química , Temperatura , Eliminação de Resíduos Líquidos/métodos , Agroquímicos/análise , Agroquímicos/isolamento & purificação , Anaerobiose , Biocombustíveis , Reatores Biológicos , Metano/análise
13.
Angew Chem Int Ed Engl ; 57(29): 8891-8895, 2018 07 16.
Artigo em Inglês | MEDLINE | ID: mdl-29808513

RESUMO

The measurement of physicochemical parameters in living cells can provide information on individual cellular organelles, helping us to understand subcellular function in health and disease. While organelle-specific chemical probes have allowed qualitative evaluation of microenvironmental variations, the simultaneous quantification of mitochondrial local microviscosity (ηm ) and micropolarity (ϵm ), along with concurrent structural variations, has remained an unmet need. Herein, we describe a new multifunctional mitochondrial probe (MMP) for simultaneous monitoring of ηm and ϵm by fluorescence lifetime and emission intensity recordings, respectively. The MMP enables highly precise measurements of ηm and ϵm in the presence of a variety of agents perturbing cellular function, and the observed changes can also be correlated with alterations in mitochondrial network morphology and motility. This strategy represents a promising tool for the analysis of subtle changes in organellar structure.


Assuntos
Cumarínicos/química , Corantes Fluorescentes/química , Mitocôndrias/química , Mitocôndrias/ultraestrutura , Quinoxalinas/química , Células HeLa , Humanos , Microscopia de Fluorescência , Imagem Óptica , Peptídeos/química , Espectrometria de Fluorescência , Viscosidade
14.
J Enzyme Inhib Med Chem ; 32(1): 1129-1135, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28868930

RESUMO

Identification of a new class of antitumor agent capable to induce apoptosis without triggering necrotic cell death event is challenging. The present communication describes the multicomponent synthesis of seven new (1S,4S)-2,5-diazabicyclo[2.2.1]heptane-dithiocarbamates and their in vitro antiproliferative activity on cervical cancer cell line (CaSki), breast cancer cell line (MDA-MB231), lung cancer cell line (SK-Lu-1) and human lymphocytes. Among the synthesized dithiocarbamates, compound 9e displayed significant antiproliferative activity without inducing any necrotic cell death (both on tumour cells and lymphocytes) and induced apoptosis in tumor cells by the caspase dependent apoptotic pathway. The compound 9e also exhibited greater tumor selectivity than human lymphocytes. In silico ADME predictions revealed that compound 9e has the potential to be developed as a drug candidate. Rapid chemical modifications of this lead are thus highly necessary for further investigation as a drug like safer antitumor candidate and also to achieve compounds with better activity profile.


Assuntos
Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Compostos Azabicíclicos/farmacologia , Tiocarbamatos/farmacologia , Antineoplásicos/síntese química , Antineoplásicos/química , Compostos Azabicíclicos/síntese química , Compostos Azabicíclicos/química , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Estrutura Molecular , Relação Estrutura-Atividade , Tiocarbamatos/síntese química , Tiocarbamatos/química
15.
Histochem Cell Biol ; 146(3): 325-36, 2016 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-27225491

RESUMO

Growth arrest specific 1 (GAS1) is a GPI-anchored protein that inhibits proliferation when overexpressed in tumors but during development it promotes proliferation and survival of different organs and tissues. This dual ability is caused by its capacity to interact both by inhibiting the signaling induced by the glial cell line-derived neurotrophic factor and by facilitating the activity of the sonic hedgehog pathway. GAS1 is expressed as membrane bound in different organs and as a secreted form by glomerular mesangial cells. In the developing central nervous system, GAS1 is found in neural progenitors; however, it continues to be expressed in the adult brain. Here, we demonstrate that soluble GAS1 is present in the cerebrospinal fluid (CSF) and it is expressed in the choroid plexus (CP) of the adult rat, the main producer of CSF. Additionally, we confirm the presence of GAS1 in blood plasma and liver of the adult rat, the principal source of blood plasma proteins. The pattern of expression of GAS1 is perivascular in both the CP and the liver. In vitro studies show that the fibroblast cell line NIH/3T3 expresses one form of GAS1 and releases two soluble forms into the supernatant. Briefly, in the present work, we show the presence of GAS1 in adult rat body fluids focusing in the CSF and the CP, and suggest that secreted GAS1 exists as two different isoforms.


Assuntos
Proteínas de Ciclo Celular/líquido cefalorraquidiano , Proteínas de Ciclo Celular/metabolismo , Plexo Corióideo/metabolismo , Animais , Células Cultivadas , Proteínas Ligadas por GPI/líquido cefalorraquidiano , Proteínas Ligadas por GPI/metabolismo , Camundongos , Células NIH 3T3 , Ratos , Ratos Wistar
16.
Analyst ; 141(13): 4108-20, 2016 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-27156709

RESUMO

Non-classical protomerism of Schiff bases offers several advantages; for example, specific interactions in the -C[double bond, length as m-dash]N- linkage can be controlled and differentiated because the interactions are not governed by keto-enol tautomerism. Herein, the pH sensing properties of a new protomeric Schiff base probe () are reported. In particular, among several acids, the probe displays significant optical responses upon interaction with hydrochloric acid (HCl). X-ray structural analysis confirmed the existence of an intermolecular interaction with HCl through a -C[double bond, length as m-dash]NH-ClO- linkage. Moreover, an optical response via a second channel is manifested as photochromic fluorescence behavior. The properties of were investigated by UV-vis and fluorescence spectroscopy in a solution and the solid state. Its strong acidofluorochromic behavior was analyzed and its pKa and values were determined, which revealed a photobasic character. Positive solvatochromism that resulted from specific interactions taking place in was studied using four different solvent scales, namely, Lippert-Mataga, Kamlet-Taft, Catalán and the recently proposed scale of Laurence et al., which yielded consistent results. Finally, theoretical calculations were conducted to analyze the mechanism of the probe in terms of natural transition orbitals (NTOs) and the spatial extent of charge transfer excitations.

17.
Inorg Chem ; 55(23): 12451-12469, 2016 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-27934408

RESUMO

A homologous series of dithiocarbamate ligands derived from N-substituted amino acids was reacted with different diorganotin dichlorides to give 18 diorganotin complexes. Spectroscopic and mass spectrometric analysis evidenced the formation of assemblies with six-coordinate tin atoms embedded in skewed-trapezoidal bipyramidal coordination environments of composition C2SnS2O2. Single-crystal X-ray diffraction analysis for three of the compounds revealed a one-dimensional polymeric structure for the complex with the ligand derived from 5-aminopentanoic acid, which through further intermolecular Sn···O interactions generated an overall two-dimensional coordination polymer containing 40-membered hexanuclear tin macrocycles. On the contrary, the ligands derived from 6-aminohexanoic and 8-aminooctanoic acid provided the expected 22- and 26-membered dinuclear macrocyclic structures. Density functional theory calculations for a representative series of macrocyclic complexes of composition [Me2SnLx]2 with Lx = ¯S2CN(Me)-(CH2)x-COO¯ (x = 3-12) enabled a detailed analysis of the variations in the molecular conformation, shape, and cavity size of the macrocycles in dependence of the aliphatic spacer. Because of odd-even effects, the difunctional ligands can adopt either a curved or a twisted-pincer shape, while the SnSxO4-x (x = 0-4) moieties can act either as linear or angular tectons with varying connectivity angles.

18.
J Phys Chem A ; 120(25): 4314-24, 2016 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-27281172

RESUMO

Design parameters derived from structure-property relationships play a very important role in the development of efficient molecular-based functional materials with optical properties. Here, we report on the linear and nonlinear optical properties of a fluorene-derived dipolar system (DS) and its octupolar analogue (OS), in which donor and acceptor groups are connected by a phenylacetylene linkage, as a strategy to increase the number of delocalized electrons in the π-conjugated system. The optical nonlinear response was analyzed in detail by experimental and theoretical methods, showing that, in the octupolar system OS, the dipolar effects induced a strong two-photon absorption process whose magnitude is as large as 2210 GM at infrared wavelengths. Solvatochromism studies were implemented to obtain further insight on the charge transfer process. We found that the triple bond plays a fundamental role in the linear and nonlinear optical responses. The strong solvatochromism behavior in DS and OS was analyzed by using four empirical solvent scales, namely Lippert-Mataga, Kamlet-Taft, Catalán, and the recently proposed scale of Laurence et al., finding consistent results of strong solvent polarizability and viscosity dependence. Finally, the role of the acceptor groups was further studied by synthesizing the analogous compound 2DS, having no acceptor group.

19.
Chem Biodivers ; 13(12): 1715-1719, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27603914

RESUMO

Chemical analysis, antimicrobial activity and cytotoxic effects of essential oils (EOs) from leaves of Piper aduncum var. ossanum from two localities Bauta (EO-B) and Ceiba (EO-C), Artemisa Province, Cuba, were determined. EOs were obtained by hydrodistillation and analyzed by gas chromatography/mass spectrometry. EO-B demonstrated higher activity against S. aureus and L. amazonensis; while a lower cytotoxicity on mammalian cells was observed. Both EOs displayed the same activity against Plasmodium falciparum, Trypanosoma cruzi, Trypanosoma brucei, and Leishmania infantum. Both EOs were inactive against Escherichia coli and Candida albicans.


Assuntos
Antibacterianos/farmacologia , Antifúngicos/farmacologia , Antiparasitários/farmacologia , Citotoxinas/farmacologia , Óleos Voláteis/farmacologia , Óleos Voláteis/toxicidade , Piper/química , Animais , Antibacterianos/química , Antibacterianos/isolamento & purificação , Antifúngicos/química , Antifúngicos/isolamento & purificação , Antiparasitários/química , Antiparasitários/isolamento & purificação , Candida albicans/efeitos dos fármacos , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Citotoxinas/química , Citotoxinas/isolamento & purificação , Relação Dose-Resposta a Droga , Escherichia coli/efeitos dos fármacos , Humanos , Leishmania infantum/efeitos dos fármacos , Macrófagos/efeitos dos fármacos , Camundongos , Testes de Sensibilidade Microbiana , Óleos Voláteis/química , Óleos Voláteis/isolamento & purificação , Testes de Sensibilidade Parasitária , Folhas de Planta/química , Plasmodium falciparum/efeitos dos fármacos , Relação Estrutura-Atividade , Trypanosoma/efeitos dos fármacos
20.
Analyst ; 140(17): 6031-9, 2015 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-26192046

RESUMO

Two simple and low cost 2,4-di-tert-butyl-6-[(1-hydroxycyclohexylmethylimino)methyl]phenol (L1) and 2-[{(1-hydroxycyclohexyl)methylimino}methyl]phenol (L2) Schiff base sensors exhibiting selectivity for Zn(2+) in water:methanol (95:5, v/v, 10 mM HEPES) are described. L1 and L2 display an "off-on" fluorescence effect forming the L1·Zn and L2·Zn complexes, respectively. In the case of L1·Zn, the emission response is quenched by the addition of Cu(2+) forming the respective L1·Cu complex; in spite of that, the fluorescence signal can be completely restored only by the addition of tartrate anions (C4H4O6(2-)) forming again L1·Znvia the "off-on" displacement approach. However, in the case of L2·Zn no Cu(2+) interference is observed, which is a typical problem for Zn(2+) sensors. Here we describe that a very subtle structural change in the ligand during transition from the enol-imine tautomer in L1 to the keto-enamine tautomer in L2 is enough to modulate the Zn(2+)/Cu(2+) selectivity. Also, the Zn(2+)vs. Cd(2+) discrimination for L1 and L2 is proved. Moreover, we found that the interaction between both L·Zn complexes and tartrate anions completely restored the free ligands by the ligand substitution mechanism even in a more efficient association than phosphate anions. Further, a second colorimetric response channel upon addition of Fe(2+) was observed for L1 and L2. Then, TD-DFT theoretical calculations were conducted in order to study the efficiency of the sensors to give different responses in the presence of such metal ions. Finally, the L2 sensor successfully detects Zn(2+) in Jurkat cells cultured with and without Zn(2+) enriched medium.


Assuntos
Cobre/química , Corantes Fluorescentes/química , Microscopia de Fluorescência , Bases de Schiff/química , Zinco/análise , Complexos de Coordenação/química , Humanos , Concentração de Íons de Hidrogênio , Íons/química , Células Jurkat , Ligantes , Fenóis/química , Teoria Quântica , Espectrometria de Fluorescência
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