RESUMEN
Neonatal sepsis (NS) continues to be a diagnostic challenge and a prime cause of mortality. Forage for a lucid, cost-effective yet highly sensitive and specific marker in diagnosing this entity is an incessant task. This study aimed to evaluate the predictive value of mean platelet volume (MPV) in diagnosing NS. Neonates diagnosed with sepsis from January 2016 to March 2016 were included in the study. The subjects were stratified into the following: (i) culture-proven sepsis (group I); (ii) culture-negative clinical sepsis (group II); and (iii) control group (group III). Several hematologic markers such as hemoglobin, total leukocyte count, platelet count, MPV, plateletcrit, platelet distribution width, immature-to-mature neutrophil ratio, toxic change, serum urea, bilirubin, and C-reactive protein were analyzed. The results were compared among the groups, and their efficacy in diagnosing NS was appraised. The study involved 210 neonates, of which, groups I, II, and III constituted 64, 75, and 71 cases, respectively. The mean MPV among groups I, II, and III was 9.56, 8.86, and 8.58 fL, respectively (P<0.05). Strikingly higher values of platelet count, immature-to-mature neutrophil ratio, MPV, plateletcrit, and C-reactive protein were found in group I in contrast to those in groups II and III (P<0.05). The baseline MPV of patients with culture-proven sepsis was comparatively higher than controls and was found to be statistically significant. Hence, MPV can be a simple, economical, and specific predictor of NS.
Asunto(s)
Volúmen Plaquetario Medio/normas , Sepsis Neonatal/diagnóstico , Cultivo de Sangre , Estudios de Casos y Controles , Humanos , Recién Nacido , Enfermedades del Recién Nacido/diagnóstico , Volúmen Plaquetario Medio/economía , Sepsis Neonatal/economía , Proyectos Piloto , Valor Predictivo de las PruebasRESUMEN
Natural alkaloid, tryptanthrin (indolo[2,1-b]quinazoline-6,12-dione) and its analogues are found to exhibit potent anti-tubercular activity against MDR-TB. A novel class of indolo[2,1-b]quinazolinones have been synthesized to evaluate their anti-mycobacterial activity. Enoyl-acyl carrier protein reductase (InhA) of Mycobacterium tuberculosis is one of the key enzymes and has been validated as an effective anti-microbial target. In silico molecular docking study demonstrates that the synthesized compounds exhibit high affinity for the M. tuberculosis drug target InhA. Phaitanthrin is a natural product, which belongs to a family of tryptanthrin and exhibits structural similarity except at position 6. Phaitanthrin derivatives are prepared by modifying the keto functionality of tryptanthrin. These phaitanthrin congeners are found to display promising anti-tubercular activity.
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Antituberculosos/farmacología , Enoil-ACP Reductasa (NADH)/antagonistas & inhibidores , Inhibidores Enzimáticos/farmacología , Indoles/farmacología , Mycobacterium tuberculosis/efectos de los fármacos , Quinazolinonas/farmacología , Antituberculosos/síntesis química , Antituberculosos/química , Relación Dosis-Respuesta a Droga , Enoil-ACP Reductasa (NADH)/metabolismo , Inhibidores Enzimáticos/síntesis química , Inhibidores Enzimáticos/química , Indoles/síntesis química , Indoles/química , Pruebas de Sensibilidad Microbiana , Modelos Moleculares , Estructura Molecular , Quinazolinonas/síntesis química , Quinazolinonas/química , Relación Estructura-ActividadRESUMEN
E- and Z-9-Methyldeca-3,8-dien-1-ols undergo smooth cyclization with aldehydes in the presence of 20 mol% AgSbF6 under extremely mild conditions to generate the corresponding oxa-bicycles in good yields with excellent selectivity. In fact, E-olefin affords the trans-product exclusively, whereas the Z-olefin gives the cis-product predominantly. In the case of E- or Z-8-methylnona-3,8-dien-1-ol, the product is formed via the termination of Prins cyclization with an allylic C-H bond through olefin migration. The termination of Prins cyclization with tethered olefin is an unprecedented reaction, which provides a useful motif of various natural products.
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Compuestos Bicíclicos con Puentes/síntesis química , Compuestos Bicíclicos con Puentes/química , Ciclización , Estructura Molecular , EstereoisomerismoRESUMEN
Impacts of river discharge on coastal ocean processes are multi-dimensional. Studies on sinking particle fluxes, composition and their seasonal variability in coastal oceans are very limited. In this study, we investigated the impact of river discharge on seasonal variability in sinking fluxes of total mass, biogenic and lithogenic material in a river-dominated continental margin, western coastal Bay of Bengal. Higher POC, lithogenic and total mass fluxes were found during early southwest monsoon, and are decoupled with peak river discharge and elevated primary production. It is attributed to cross-shelf transport of re-suspended surface sediments from shelf region. Peak river discharge followed by elevated chlorophyll-a suggest nutrients supply though river discharge support primary production. Elemental C:N ratios, δ13C and δ15N results likely suggest that both marine and terrestrial sources contributed to sinking POM, . Overall, higher sinking fluxes during southwest monsoon than rest of the year suggest that seasonal river discharge exerts considerable impact on sinking fluxes in the western coastal Bay of Bengal.
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Bahías , Material Particulado , Monitoreo del Ambiente/métodos , Sedimentos Geológicos , Ríos , Carbono/análisisRESUMEN
Warming due to climate change stratifies the upper ocean and reduces nutrient input to the photic zone resulting in a decline in net primary production (NPP). On the other hand, climate change increases both anthropogenic aerosol input into the atmosphere and the river discharge due to the melting of glaciers on land resulting in enhanced nutrient inputs to the surface ocean and NPP. To examine the balance between these two processes, spatial and temporal variations in the rate of warming, NPP, aerosol optical depth (AOD), and sea surface salinity (SSS) were studied between 2001 and 2020 in the northern Indian Ocean. Strong heterogeneity in the warming of the sea surface was observed in the northern Indian Ocean with significant warming in the south of 12°N. Insignificant trends in warming were observed in the northern Arabian Sea (AS), north of 12°N, during winter and fall, and western Bay of Bengal (BoB) during winter, spring, and fall associated with higher levels of anthropogenic AOD (AAOD) due to a reduction in incoming solar radiation. The decline in NPP was observed in the south of 12°N in both AS and BoB and correlated inversely with SST suggesting that a weak supply of nutrients due to upper ocean stratification controlled NPP. Despite warming, the weak trends in NPP in the north of 12°N were associated with higher AAOD levels and their rate of increase suggesting that the deposition of nutrients from the aerosols seems to be compensating for declining trends due to warming. The decrease in sea surface salinity confirmed an increase in river discharge, and nutrient supply led to weak NPP trends in the northern BoB. This study suggests that the enhanced atmospheric aerosols and river discharge played a significant role in warming and changes in NPP in the northern Indian Ocean, and these parameters must be included in the ocean biogeochemical models for accurate prediction of possible changes in the upper ocean biogeochemistry in the future due to climate change.
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Atmósfera , Ecosistema , Océano Índico , Estaciones del Año , AerosolesRESUMEN
BACKGROUND: Salivary gland tumors are rare. Nevertheless, the accurate preoperative diagnosis of the malignant potential of the lesion is essential for appropriate patient management. The recently published Milan system for reporting salivary gland cytology (MSRSGC) is an effort to provide better communication regarding the nature of lesions to clinicians. Aim: To evaluate the diagnostic utility of fine-needle aspiration cytology (FNAC) of neoplastic salivary gland lesions and the MSRSGC applicability in risk stratification. MATERIALS AND METHODS: This was a retrospective study of the cytological and histopathological correlation between neoplastic lesions of salivary gland lesions conducted over four years (August 2010 - September 2014) in two tertiary care hospitals. There were 66 cases of FNAC of salivary gland neoplasms. The sensitivity, specificity, positive predictive value, negative predictive value, and overall diagnostic accuracy of FNAC were analyzed. The risk of malignancy for MSRSGC was calculated. RESULTS: The overall diagnostic accuracy, sensitivity, specificity, and positive and negative predictive values were 93.94; 95.5; 99.8; 96.8, and 98.7%, respectively. By correlating the cytological diagnosis of benign neoplasm with histopathological diagnosis, the risk of malignancy was 0% and risk of neoplasm was 100%. For cases in the category suspicious of malignancy, risk of neoplasm was 100% and risk of malignancy was 85%. CONCLUSION: The present study demonstrated that this salivary gland cytology reporting system was useful in classifying the lesions in well-delineated categories with ease. MSRSGC system of standardized reporting is helpful for guiding clinicians in appropriate management of the patient. However, many multicenter studies with large sample sizes and long-term follow-up are needed along with wide propagation of its standardized reporting format to be adopted universally.
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Neoplasias de las Glándulas Salivales , Glándulas Salivales , Humanos , Estudios Retrospectivos , Glándulas Salivales/patología , Neoplasias de las Glándulas Salivales/diagnóstico , Neoplasias de las Glándulas Salivales/patología , Biopsia con Aguja Fina , CitodiagnósticoRESUMEN
Aerosols are one of the significant external sources of soluble reactive nitrogen to the surface ocean and their deposition affects the primary productivity. Owing to rapid industrialization over South and Southeast Asia, an increasing trend in atmospheric pollutants was observed over the northern Indian Ocean (NIO). To assess the contribution of the aeolian supply of inorganic nitrogen to the NIO, the available compositional data of marine aerosols collected over this basin between 2001 and 2020 were compiled. Based on the observed relationship of mass load, and particulate nitrate and ammonium concentrations with the corresponding satellite-derived anthropogenic aerosol optical depth (AAOD), the temporal, spatial, and long-term variabilities were derived for the past two decades. In particular, high aerosol mass load, nitrate and ammonium levels were observed in the coastal aerosols of peninsular India during fall and winter and they were low in summer. The atmospheric input of inorganic nitrogen to the Arabian Sea is higher (AS; 1.7 TgN per year) compared to that of the Bay of Bengal (BoB; 0.9 TgN per year) and accounts for â¼30% of the total external sources of nitrogen to the NIO. The new production, supported by external sources of nitrogen, contributes to â¼23 and 53% of export production to the oxygen minimum zone (OMZ) in the AS and BoB respectively. A significant rate of increase in the aerosol mass load (0.05-1.67 µg per m3 per year), and nitrate (0.003-0.04 µg per m3 per year) and ammonium (0.006-0.11 µg per m3 per year) concentrations was observed between 2001 and 2020, likely because of the increased emission of anthropogenic pollutants over South and Southeast Asia and their subsequent long-range atmospheric transport to the NIO. Overall, these results suggest that an enhanced contribution of atmospheric nitrogen may potentially increase (1) the N/P ratio of the surface ocean that impacts phytoplankton composition, (2) export production to the OMZ leads to intensification, and (3) sequestration of atmospheric CO2. A decrease in primary production due to global warming is reported due to a decrease in vertical nutrient supply; however, the increase in atmospheric deposition of nutrients may compensate for this. Therefore, ocean models must be coupled with atmospheric models to better constrain the oceanic response to climate change in the NIO.
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Contaminantes Atmosféricos , Compuestos de Amonio , Contaminantes Ambientales , Nitrógeno , Océano Índico , Monitoreo del Ambiente/métodos , Nitratos , Dióxido de Carbono , Aerosoles/análisis , Polvo , Oxígeno , Contaminantes Atmosféricos/análisisRESUMEN
The protein corona (PC) that forms on nanoparticles (NPs) after in vivo injection influences their biodistribution, pharmacokinetics, and cell interaction. Although injected NPs traverse vascular networks, the impact of vascular features on the protein corona composition is mainly unexplored. Using an in vitro flow model that introduces bifurcations, a common feature of blood vessels, we show that vessels are not passive bystanders in the formation of the PC but that their features play active roles in defining the PC on NPs. The addition of bifurcation significantly increased the amount of proteins associated with NP. The bifurcation's introduction also changed the PC's composition on the NPs and affected the NP interactions with cells. Correlation analysis and modeling showed that these changes in the PC are mediated by both the branching and diameter reduction associated with vessel bifurcation and the resulting change in flow rate. The results indicate that blood vessel structures play an active part in the information of the PC, and their role should be studied critically for a better understanding of the PC and its biological implications.
RESUMEN
Perennial increase in atmospheric pollution over the Bay of Bengal (BoB) and South China Sea is reported due to increase in human population and industrial activity in South and Southeast Asia. Based on total aerosol optical depth (AOD) derived from MODIS (moderate resolution imaging resolution imaging spectroradiometer), natural and anthropogenic fractions were derived. The seasonality and spatial variability in rate of increase in total, natural, and anthropogenic AOD fractions were examined over the BoB using data collected between 2001 and 2019. Both total and anthropogenic AOD displayed statistically significant rate of increase in the northwest BoB (NWB) and western coastal BoB (WCB) regions during 2001 to 2019 whereas the long-term changes are insignificant in the other regions of BoB. Significant increase in AOD in the NWB and WCB regions is mainly contributed by dominant outflow of anthropogenic emissions from Indo-Gangetic Plain (IGP) area of Indian subcontinent. The magnitude of AOD decreased by half from northern BoB to equatorial region due to increase in distance from the source region. The contribution of anthropogenic AOD was >70% to total AOD with higher contribution during winter and lower during summer. The rate of increase in both total and anthropogenic AOD was close to 0.104 and 0.099 per decade in the NWB and 0.069 and 0.059 per decade in the WCB region between 2001 and 2019. The rate of increase in total and anthropogenic AOD decreased from 2001-2009 (0.164 and 0.115 per decade respectively) to 2010-2019 (0.068 and 0.076 per decade respectively) in the NWB region. Significant increase in anthropogenic AOD by 50 and 30% was observed during El Niño and La Niña periods respectively than normal year in both northwest BoB (NWB) and western coastal (WCB) regions due to change in strength and direction of winds. Although some fraction of anthropogenic AOD is found over the entire BoB, significant rate of increase in anthropogenic AOD is found only about 23% of the area of BoB than hitherto reported as entire BoB. The impact of atmospheric deposition of anthropogenic aerosols on biogeochemical processes, such as primary production and ocean acidification, needs further evaluation.
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Contaminantes Ambientales , Aerosoles , Bahías , Humanos , Concentración de Iones de Hidrógeno , Agua de MarRESUMEN
Friedel-Crafts alkylation of electron-rich arenes with aldehydes has been achieved in the presence of an active and selective Amberlyst-15 catalyst at the reaction temperature of 60 degrees C in solvent-free conditions. The catalyst exhibits a very high activity and offers the corresponding triarylmethanes in excellent yields with a high selectivity. The use of highly reactive and selective Amberlyist-15 makes this procedure simple, convenient, cost-effective, practical and environmentally friendly. This method provides an easy access to triarylmethanes in a single step using a readily available acidic ionic resin, which is a stable and easy to separate from the reaction mixture by a simple filtration technique.
RESUMEN
Haemorrhagic diathesis has been of much concern to health professionals including dentists. It is not infrequent that a dentist becomes the first person to diagnose a bleeding disorder while performing dental treatment. Haemophilia is an X linked disorder with a frequency of about 1:10,000 births. Haemophilia B is much less common than haemophilia A, and affects only 1:300,000 males born alive. The clinical features of haemophilia B are very similar to those of haemophilia A with a prolongation of activated partial thromboplastin time. This case report describes the dental management of a patient with an uncommon haematological disorder, namely, factor IX deficiency, which remained undiagnosed until the patient had to undergo dentofacial trauma with unexpected severe haemorrhage. Preventive dentistry remains vital to young haemophiliacs. Surgical dental procedures may be performed for haemophiliacs but they must be judiciously coordinated by dental and medical health professionals.
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Hematoma/tratamiento farmacológico , Hemofilia B/tratamiento farmacológico , Incisivo/lesiones , Labio/lesiones , Niño , Coagulantes/uso terapéutico , Factor IX/uso terapéutico , Hematoma/etiología , Hemofilia B/complicaciones , Hemofilia B/diagnóstico , Humanos , MasculinoRESUMEN
BACKGROUND: Fear and pain are the factors producing stress and there is evidence that dental fear acquired in childhood may persist to influence adult behavior. Dental treatment is often considered as anxiety producing and stressful. AIM: To assess the levels of stress displayed by the healthy children undergoing routine dental procedures like oral examination, restoration, and extraction by analyzing salivary levels of cortisol before, during, and after the procedures. MATERIALS AND METHODS: Twenty healthy children aged between 4 and 8 years having their first dental visit and requiring at least one restoration and one extraction were selected. In each patient, three procedures were carried out: (i) Routine dental examination, (ii) restoration, and (iii) extraction. Unstimulated salivary samples were collected 10 min before, during the procedure, and 30 min after each procedure at three different visits for comparison of cortisol production in response to anxiety and stress over time. Total 180 samples were collected to determine salivary cortisol levels using UBI-MAGIWEL TM kit and the readings were noted. STATISTICAL ANALYSIS USED: Statistical Package for Social Sciences (SPSS) software with paired t-test, two independent sample t-tests, and analysis of variance (ANOVA) were used to analyze the findings. RESULTS: A correlation between salivary cortisol and stress in dental procedure was noticed. Cavity preparation is more stressful procedure in children, so alternative methods can be used in anxious children. Stress associated with extraction persists to a postoperative period. No correlation exists in between Corah's anxiety scale and salivary cortisol.
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Ansiedad al Tratamiento Odontológico/psicología , Atención Dental para Niños/psicología , Hidrocortisona/metabolismo , Saliva/química , Niño , Preescolar , Femenino , Humanos , MasculinoRESUMEN
[reaction: see text] Synthesis of new meso aryl 30pi heptaphyrins 2, 3, and 4 is achieved. Spectroscopic studies reveal that 2, 3, and 4 are aromatic and possess an inverted structure.
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Porfirinas/síntesis química , Espectroscopía de Resonancia Magnética , Estructura Molecular , Porfirinas/químicaRESUMEN
Immune competence, resistance to Escherichia coli and growth were measured in female chicks of broiler male parent lines from four different commercial sources. These chicks were fed with three levels of dietary crude protein (CP) from day-old. The protein contents in the diets were 18%, 20.5% and 23%; these diets are referred to as the low-, medium- and high-protein diets, respectively. There was a significant genotype by dietary protein interaction for body weight at 35 days of age but not at 14 or 28 days of age. At 14 days of age, the chicks fed on the high-protein diet weighed significantly more than those fed on the low-protein diet, but there were no differences between the chicks fed on the medium-and low-protein diets. The influence of CP content on body weight had disappeared by 28 days of age. There were significant differences between the genotypes-in antibody production in response to sheep red blood cell (SRBC) inoculation, but no such differences were observed between the chicks fed the different levels of dietary protein. Chicks fed on the high-protein diet had lower lesion scores following E. coli inoculation than those fed on the low-protein diet. There were also significant differences in lesion scores among the genotypes. Genotypes with heavier body weights had significantly higher lesion scores and lower antibody titres than those with less body weight. Also, genotypes of lower body weight had a greater cutaneous basophilic hypersensitivity response to phytohaemaglutinin-P inoculation, and a better humoral response against SRBC and a lower heterophil to lymphocyte ratio.
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Pollos/crecimiento & desarrollo , Pollos/inmunología , Proteínas en la Dieta/farmacología , Infecciones por Escherichia coli/veterinaria , Escherichia coli , Enfermedades de las Aves de Corral/inmunología , Animales , Peso Corporal , Proteínas en la Dieta/administración & dosificación , Infecciones por Escherichia coli/inmunología , Femenino , Inmunidad Innata/efectos de los fármacos , MasculinoRESUMEN
A comprehensive understanding of root and root canal morphology of primary teeth is valuable for successful endodontic therapy. A supernumerary root is a developmental anomaly which can affect any tooth. An extra root placed lingually (radix entomolaris) or buccally (radix paramolaris) can be seen in mandibular molars nonetheless; bilateral association of an additional root in deciduous mandibular molars is rare. This report aimed to describe the diagnosis, significance and management of an extra root in deciduous mandibular molars bilaterally in perspective of modern clinical paediatric endodontics.
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Diente Molar/anomalías , Anomalías Dentarias/diagnóstico , Raíz del Diente/anomalías , Diente Primario/anomalías , Preescolar , Femenino , HumanosRESUMEN
About 4 different predominant adapted fungal strains (screened from effluent sample) Aspergillus sp., Penicillium sp., Fusarium sp. and Mucor sp. and 4 predominant non-adapted strains (screened from soil, water and fungal fruiting bodies) Aspergillus sp., Penicillium sp., Fusarium sp. and Rhizopus sp., with potential dye decolorization ability on Reactive black 5, Amido black-10B, Red 5B, Reactive red 120 and Anthraquinone violet R were isolated. These organisms were used to develop a consortium which was used in analyzing the bioremediation efficiency on textile effluents containing a mixture of azo dyes. There was about 67% of reduction in color along with 34% of COD reduction by non-adapted fungal consortium while effective bioremediation efficiency was observed in adapted fungal consortium (Color 75% and COD 50%). The regression co-efficient for Langmuir and Freundlich adsorption isotherms were found to be higher for adapted fungal consortium (R2 = 0.97 and R2 = 0.92) than the non-adapted consortium (R2 = 0.97 and R2 = 0.85) proving that both monolayer and multilayer adsorption of dyes were observed on treating the samples with the adapted fungal consortium. On analyzing the results observed through chi-square test, the calculated value (28.712) was higher than the tabulated value (9.49) at a 4 degree freedom hence the hypothesis was rejected. So, there was an association between adapted fungal consortium and non-adapted fungal consortium and hence the adapted fungal consortium could be considered potentially useful for the bioremediation of textile effluent.
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Compuestos Azo/metabolismo , Biodegradación Ambiental , Colorantes/metabolismo , Hongos/metabolismo , Hongos/fisiología , Residuos Industriales , Textiles , Adaptación Fisiológica , Negro de Almidón/química , Negro de Almidón/metabolismo , Antraquinonas/química , Antraquinonas/metabolismo , Compuestos Azo/química , Colorantes/química , Hongos/aislamiento & purificación , India , Estructura Molecular , Naftalenosulfonatos/química , Naftalenosulfonatos/metabolismo , Triazinas/química , Triazinas/metabolismoRESUMEN
The ligational behavior of meso-arylsapphyrins and rubyrins toward Rh(I) is investigated. Sapphyrins form monometallic complexes with coordination of one imine and amine type nitrogens of the bipyrrole unit in an eta2 fashion. The Rh(I) coordination is completed by the presence of two ancillary carbon monoxide ligands. Rubyrins form both monometallic and bimetallic complexes. Two types of bimetallic complexes have been isolated. In the first type, both rhodium atoms are projected above the mean rubyrin plane, while in the second type, one rhodium atom is projected above and the other below the mean plane. Detailed 1H and 2D NMR spectral analyses along with IR and UV-visible spectra of the complexes confirm the proposed binding modes for the rhodium complexes. Furthermore, the single-crystal X-ray analysis of one of the bimetallic complexes of rubyrin shows a bowl-shaped symmetric structure where both Rh(I) atoms are projected above the mean rubyrin plane at an angle of 71.73 degrees. The geometry around each rhodium center is approximately square planar [N1-Rh1-N2, 80.38(9) degrees; C15-Rh1-C16, 86.95(14) degrees; N1-Rh1-C15, 97.13(12) degrees; and N2-RH1-C16, 94.97(12) degrees ]. The omicronbserved distance of 4.313 A between the two rhodium centers reveals very little interaction between the two rhodium atoms. This type of metal binding is accompanied by a 180 degrees ring flip of the heterocyclic ring connecting the two bipyrrole units. In dioxarubyrin, where one of the pyrrole rings of the bipyrrole unit is inverted, Rh(I) binds at the periphery to the pyrrole nitrogen, leaving the rubyrin cavity empty. The absence of one amino and one imino nitrogen on the dipyrromethene subunits in the sapphyrins and rubyrins described here forces Rh(I) to bind to bipyrrole nitrogens.
RESUMEN
A variety of metal complexes of 5,10,15-triphenyl-21-monooxa-corrole 4 have been investigated. This monooxa corrole, where one of the pyrrole ring is replaced by a furan moiety, is synthesized by the alpha-alpha coupling reaction of 16-oxa tripyrrane and dipyrromethane. The single crystal X-ray structure of 4 indicates only small deviation of the inner-core heteroatoms from planarity and this macrocycle arrange themselves into a columnar structure. Insertion of metals further flattens the corrole framework. Specifically, oxacorrole 4 binds to Nil(II), Cu(II), and Co(II) with the participation of all heteroatoms in the coordination. However, Rh(I) ion binds to only one imino and one amino nitrogen of the macrocycle. The bond angles at the metal center in the Ni(II) and Rh(I) complexes reveal square planar geometry completed by two CO molecules for Rh(I). The EPR spectra of the paramagnetic that Cu(II) and Col(II) complexes display significant decreases in the metal hyperfine couplings compared with the corresponding porphyrin complexes. The presence of superhyperfine coupling in the Cu(II) complex suggests delocalization of unpaired electron density into the ligand orbitals. Electrochemical studies reveal easier oxidations and harder reductions relative to the corresponding porphyrin derivatives while, the metallated derivatives did not show their characteristic metal reductions due to the high energy of their LUMO.
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Compuestos Heterocíclicos/química , Compuestos Heterocíclicos/metabolismo , Metales/metabolismo , Pirroles/química , Pirroles/metabolismo , Cristalografía por Rayos X , Electroquímica , Espectroscopía de Resonancia por Spin del Electrón , Furanos/química , Furanos/metabolismo , Compuestos Heterocíclicos/síntesis química , Espectroscopía de Resonancia Magnética , Metales/química , Porfirinógenos/química , Porfirinógenos/metabolismo , Pirroles/síntesis química , Espectrofotometría , TetrapirrolesRESUMEN
An easy synthesis of core-modified meso-aryl smaragdyrins containing oxygen and sulfur in addition to pyrrole nitrogens has been achieved through an alpha-alpha coupling involving modified tripyrrane and dipyrromethane. The complexation behavior of these macrocycles toward anions (Cl-, F-, AMP-) and metal cations (Rh(I), Ni(II)) is reported. Specifically, it has been shown that the Rh(I) and Ni(II) ions bind to the smaragdyrin skeleton in its free base form. X-ray structural studies of Rh(I) complex 1 indicate an eta 2-type coordination involving only one imino and one amino nitrogen of the dipyrromethane unit. However, all four bipyrrole nitrogens participate in the coordination with the Ni(II) ion. Furthermore, Ni(II) coordination oxidizes the ligand, and the complex is formulated as the pi-cation radical of nickel(II) smaragdyrin. The anion complexation is followed in both the solid and solution phases. Solution studies reveal that the binding constants of the ions with the protonated form of smaragdyrin vary as F- > AMP- > Cl-. The X-ray structure of the chloride anion complex reveals that the chloride ion is bound above the cavity of the smaragdyrin macrocycle through three N-H...Cl hydrogen bonds. Crystal data with Mo K alpha (lambda = 0.710,73 A) are as follows: 1, C41H27N4O3Rh, a = 11.836(8) A, b = 12.495(9) A, c = 12.670(2) A, alpha = 69.09(6) degrees, beta = 78.78(6) degrees, gamma = 77.02(5) degrees, V = 1692.1(17) A3, Z = 2, triclinic, space group P-1, R1 (all data) = 0.0471; 4.HCl, C41H29N4O1Cl, a = 11.878(2) A, b = 17.379(4) A, c = 16.015(3) A, beta = 109.546(10) degrees, V = 3115.47(11) A3, Z = 4, monoclinic, space group P2(1)/c, R1(all data) = 0.0850.