Theoretical modelling of chiral modifier/substrate interaction for Enantioselective Hydrogenation of p-Isobutylacetophenone

Se estudió a nivel DFT la interacción entre el modificador quiral y el sustrato para la reacción de hidrogenación enantioselectiva del tipo de Orito. Se realizó el modelado molecular a nivel DFT para estudiar la interacción entre el (R)-(-)-1-aminoindano y (S)-(+)-1-aminoindano como modificadores quirales y la p-isobutilacetofenona (intermediario en la síntesis del ibuprofeno). A partir de los cálculos teóricos e implementando un análisis de interacciones no covalentes, se demostró que la interacción responsable de la formación del complejo entre el modificador quiral y el sustrato es un enlace tipo puente de hidrógeno. Teniendo en cuenta las energías libres para la formación de cada complejo se calculó de forma teórica los excesos enantioméricos utilizando cada modificador quiral, encontrándose un exceso de alrededor del 30% del enantiómero R del producto cuando se utiliza el (R)-(-)-1-aminoindano, mientras que el exceso sería 30% pero para el enantiómero S del producto cuando se utiliza como modificador el (S)-(+)-1-aminoindano.DFT level calculations were carried out to study the interaction between chiral modifier and substrate for Orito type enantioselective hydrogenation. Molecular modelling on a DFT level was developed to study the interaction between (R)-(-)-1-aminoindane and (S)-(+)-1-aminoindane as chiral modifiers and pisobutylacetophenone (intermediary the synthesis of Ibuprofen). Judging from theoretical calculations and implementing a non-covalent interaction analysis, it was shown that the interaction responsible for the formation of a complex between chiral modifier and substrate is a hydrogen bond. Taking into account the free energies of formation for each complex, a theoretical calculation was performed for the enantiomeric excess obtained from either chiral modifier, finding an excess of about 30% of the R enantiomer product when using (R)-(-)-1-aminoindane, while the excess would be of 30% for the S enantiomer product if the modifier is (S)-(+)-1-aminoindane.Centro de Investigación y Desarrollo en Ciencias Aplicada

Theoretical modelling of chiral modifier/substrate interaction for Enantioselective Hydrogenation of p-Isobutylacetophenone

Se estudió a nivel DFT la interacción entre el modificador quiral y el sustrato para la reacción de hidrogenación enantioselectiva del tipo de Orito. Se realizó el modelado molecular a nivel DFT para estudiar la interacción entre el (R)-(-)-1-aminoindano y (S)-(+)-1-aminoindano como modificadores quirales y la p-isobutilacetofenona (intermediario en la síntesis del ibuprofeno). A partir de los cálculos teóricos e implementando un análisis de interacciones no covalentes, se demostró que la interacción responsable de la formación del complejo entre el modificador quiral y el sustrato es un enlace tipo puente de hidrógeno. Teniendo en cuenta las energías libres para la formación de cada complejo se calculó de forma teórica los excesos enantioméricos utilizando cada modificador quiral, encontrándose un exceso de alrededor del 30% del enantiómero R del producto cuando se utiliza el (R)-(-)-1-aminoindano, mientras que el exceso sería 30% pero para el enantiómero S del producto cuando se utiliza como modificador el (S)-(+)-1-aminoindano.DFT level calculations were carried out to study the interaction between chiral modifier and substrate for Orito type enantioselective hydrogenation. Molecular modelling on a DFT level was developed to study the interaction between (R)-(-)-1-aminoindane and (S)-(+)-1-aminoindane as chiral modifiers and pisobutylacetophenone (intermediary the synthesis of Ibuprofen). Judging from theoretical calculations and implementing a non-covalent interaction analysis, it was shown that the interaction responsible for the formation of a complex between chiral modifier and substrate is a hydrogen bond. Taking into account the free energies of formation for each complex, a theoretical calculation was performed for the enantiomeric excess obtained from either chiral modifier, finding an excess of about 30% of the R enantiomer product when using (R)-(-)-1-aminoindane, while the excess would be of 30% for the S enantiomer product if the modifier is (S)-(+)-1-aminoindane.Centro de Investigación y Desarrollo en Ciencias Aplicada

Licensed professions: a new look at the association between social origins and educational attainments in Italy

It has long been known that Italy is characterized by the highest levels of professional regulation in Europe, but little attention has been given to the link between professional regulation and educational stratification. This article investigates the association between social origins and education by focusing on fields of study within tertiary education and by disaggregating the upper class of social origin into different micro-classes of professionals. Thus, since these professions are regulated in the first place by educational fields of study, it assesses how processes of social closure enhance occupational intergenerational immobility in the professional employment in Italy. Recently, deregulation of liberal professions in Italy has been central in many public and political debates. It contributes to these debates by examining the micro-level dynamics in the professionals' social reproduction and related practises of social exclusion, which may have strong implications for policy interventions. By using ISTAT's "Sbocchi Professionali dei Laureati" survey (2011), and employing multinomial logistic regressions, it shows how social selection into highly regulated fields of study is guided by parents' professional domain. The analyses indicate that both sons and daughters of licensed professionals are more inclined to graduate in a field of study that is in line with the father's profession and that this propensity is stronger among children of regulated self-employed professionals

AVIFAUNA DE LOS BOSQUES RIBEREÑOS DE LAS SELVAS PEDEMONTANAS DEL NOROESTE ARGENTINO

RESUMEN Los bosques de ribera usualmente hacen referencia a un cuerpo de agua y su bosque asociado, y representan una zona de transición entre el ambiente acuático y el entorno. Estos bosques, constituyen hábitats particulares que proveen sitios de alimentación y reproducción, y rutas de paso para numerosas especies. En general, albergan una rica y abundante fauna en comparación con los ambientes no ribereños circundantes. Las aves constituyen un grupo conspicuo en los bosques de ribera, tanto en regiones templadas como tropicales y frecuentemente los ensambles son diferentes y de mayor riqueza específica que los de áreas vecinas. En este estudio examinamos en detalle la diversidad de los ensambles de aves en seis bosques de ribera de la selva pedemontana del noroeste de la Argentina (Yungas Australes) y comparamos la riqueza y abundancia de las aves entre la temporada seca y húmeda. Encontramos un total de 207 especies de aves. Las especies migratorias latitudinales y altitudinales representaron el 15% y 9% de las especies de aves, respectivamente. Los ensambles de aves entre las temporadas seca y húmeda fueron significativamente diferentes (ANOSIM: R = 0,32, p = 0,02) si bien estas diferencias fueron moderadas. El 30% de las 56 especies que más contribuyeron a esta diferenciación fueron aves migratorias. El gremio trófico más representativo fue el de las aves insectívoras, seguido de las granívoras. Los bosques de ribera estuvieron dominados por especies de aves que típicamente habitan bosques maduros de las Yungas Australes. Registramos una especie clasificada globalmente como “Casi Amenazada” y cuatro especies consideradas Amenazadas a escala nacional. Este trabajo resalta la importancia de los bosques de ribera en su rol como refugio tanto para las especies de aves migratorias como residentes, contribuyendo a la diversidad regional. ABSTRACT ∙ Bird assemblages of riparian forests of premontane forests in northwestern ArgentinaRiparian forests usually refer to a water‐body and its associated forest, and represent a transitional zone between the aquatic environment and the surrounding area. These forests are singular habitats that provide feeding and breeding sites as well as migration routes for many species. Usually, the fauna found in riparian forests is more diverse and abundant than in surrounding, non‐riparian habitats. Birds are a conspicuous group in riparian forests, both in temperate and tropical regions, and they often form very distinctive assemblages compared to neighboring areas. In this study, we examined in detail the diversity of bird assemblages at six riparian forests within the piedmont of a subtropical montane forest from NW Argentina (Southern Yungas), assessing their richness and abundance in the wet and dry seasons. We found a total of 207 bird species. Latitudinal and altitudinal migrants represented 15% and 9% of species, respectively. Birds assemblages in the wet and dry seasons were significantly different (ANOSIM: R = 0.32, p = 0.02) although differences were relatively small. Thirty percent of the 56 species that contribute most to this difference were migratory birds. Insectivorous birds, followed by granivorous birds, were the best represented trophic guilds. Riparian forests were dominated by bird species that typically occur in undisturbed, mature forests of the Southern Yungas. We recorded one species classified as “Near Threatened” at a global scale, and four species considered “Threatened” at a national scale. This study points out the importance of riparian forests as refuges for migratory as well as resident bird species, which can be crucial for the maintenance of the regional bird diversity

Licensed Professionals and Intergenerational Big-, Meso- and Micro-Class Immobility within the Upper Class; Social Closure and Gendered Outcomes among Italian Graduates

This article examines how processes of social closure promote persistence at the top of the occupational hierarchy and how they vary by gender. We focus on the links between professional closure strategies and intergenerational immobility in professional employment among Italian graduates. Italy displays the highest levels of service market regulation across Europe, and professionals are the largest occupational group within the upper class; therefore, it is crucial to analyse the link between professional closure and labour market outcomes among Italian graduates. Using ISTAT's survey on Italian graduates' labour outcomes and replicating the analyses of men in the ILFI survey, the origin-destination association is investigated at the big-, meso-, and micro-levels. We employ log-linear nested models and logistic regressions. The SPL sample offers a unique opportunity to analyse social mobility at the beginning of professionals' careers and provide in-depth explanations of the micro-level dynamics of social reproduction. The analyses indicate that children of regulated professionals have a higher propensity to follow in their parents' footsteps (micro-classes). Self-employment among professionals strongly increases intergenerational immobility at the top of the occupational hierarchy. The findings demonstrate that the combination of specific parental resources strongly helps professionals' sons and daughters to avoid social demotion

Transesterification of soybean oil with methanol on alumina-supported cao catalysts modified with MgO or ZnO

Con el fin de estudiar la reacción de transesterificación de aceite de soja empleando metanol, se prepararon catalizadores de CaO, MgO y ZnO soportados en γ-Al2O3, y mezclas en relaciones molares 0.25, 0.5, 1 y 5 entre Mg/Ca y Zn/Ca. Los catalizadores fueron caracterizados empleando difracción de rayos X, fisisorción de N2 y microscopía de barrido electrónico. Los catalizadores preparados presentaron en todos los casos características de sólidos mesoporosos, de gran área superficial, exhibiendo la fase cristalina óxido. Los catalizadores mezcla de MgO y CaO exhibieron selectividades a ésteres metílicos de ácidos grasos (FAME) muy cercanas al 100%, aunque ninguno superó en rendimiento a FAME al catalizador puro de MgO, que presentó un máximo de 57%. Los catalizadores mezcla de ZnO y CaO de proporciones 0.25, 0.5 y 1 Zn/Ca presentaron selectividades a FAME muy cercanas al 100%, y un rendimiento a FAME máximo de 37% para el catalizador 1 Zn/Ca.In order to study the transesterification reaction of soybean oil with methanol, γ-Al2O3-supported CaO, MgO and ZnO catalysts were prepared, as well as mixtures of Mg/Ca and Zn/Ca having molar ratios of 0.25, 0.5, 1 and 5. The catalysts were characterized using X-ray diffraction (XRD), N2 physisorption and electron scanning microscopy (SEM). The results were consistent in all the cases with mesoporous solids, with large surface areas, exhibiting the oxide crystalline phase. Mg/Ca mixed catalysts presented fatty acids methyl esters (FAME) selectivities of almost 100%. Nevertheless, no mixture exceeded the FAME yield of the pure MgO catalyst, which showed a maximum of 57%. Zn/Ca mixed catalysts of 0.25, 0.5 and 1 atomic ratios, showed FAME selectivities very close to 100%. A maximum FAME yield of 37% was obtained with the Zn/Ca catalyst having an atomic ratio of 1.Fil: Navas, Marisa Belén. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Ciencias Aplicadas "Dr. Jorge J. Ronco". Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Ciencias Aplicadas; ArgentinaFil: Ruggera, José Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Ciencias Aplicadas "Dr. Jorge J. Ronco". Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Ciencias Aplicadas; ArgentinaFil: Casella, Mónica Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Ciencias Aplicadas "Dr. Jorge J. Ronco". Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Ciencias Aplicadas; Argentin

Experimental and theoretical investigation of the enantioselective hydrogenation of ethyl pyruvate with a Pt catalyst with new non-cinchona chiral modifiers

The enantioselective hydrogenation of ethyl pyruvate using a Pt/SiO2 catalyst modified with six different chiral modifiers was studied. The chiral modifiers chosen were: (S)-(+)-1-aminoindan, (R)-(−)-1-aminoindan, (1R,2S)-(+)-cis-1- amino-2-indanol, (1S,2R)-(−)-cis-1-amino-2-indanol, (S)-(+)-1-indanol and (R)-(−)-1-indanol.An excess of the (R) enantiomer of the product of 63% and 45% with (S)-(+)-1-aminoindan and (R)-(−)-1-aminoindan modifiers, respectively was obtained. When using (1S,2R)-(−)-cis-1-amino-2-indanol and (1R,2S)-(+)-cis-1-amino-2-indanol, the enantiomeric excess (ee%) obtained was 30% and 5%, respectively, while with both indanols ee% did not exceed 8%. Molecular modeling of the complex formed between the chiral modifier and ethyl pyruvate performed by DFT calculations allowed predicting the values of ee% obtained experimentally. The low ee% value obtained both aminoindanol chiral modifiers were used, could be explained by the analysis of non-covalent interactions (NCI) method. These calculations demonstrated the presence of an intramolecular hydrogen bond in the structure of these modifiers.Centro de Investigación y Desarrollo en Ciencias Aplicada

Educational equalization stalled? Trends in inequality of educational opportunity between 1930 and 1980 across 26 European nations

This article assesses trends over time in the influence of social origins on educational attainment in 26 European countries. We use a cumulative dataset that merges the European Social Survey (waves 2002–2010), the International Social Survey Programme (1999, 2009) and the European Value Study (2008). Our contribution to the literature is threefold. First, we replicate as closely as possible the previous study by Breen et al. [(2009) ‘Nonpersistent in educational attainment: Evidence from eight European countries’, American Journal of Sociology 114: 1475–1521] and extend it to a larger set of countries and to more recent cohorts. Second, we reassess the argument that equalization does not involve Higher Education. Third, we consider whether our conclusions change if we use a more comprehensive measurement of social origins that jointly incorporates indicators of social class, social status and parental education. We detect a generalized reduction of educational inequalities in the post-war decades. When we focus on Higher Education, we still detect evidence of equalization, although to a lower extent. Our analyses do not support the claim that, when using a more comprehensive treatment of social origins, the patterns for different indicators evolve in opposite directions.</p

Transition metal-based bimetallic catalysts for the chemoselective hydrogenation of furfuraldehyde

In this work, the liquid-phase chemoselective hydrogenation of furfural was studied, employing Pt, Rh and Ni-based catalysts. Bimetallic systems, containing different amounts of tin, were obtained by means of controlled surface reactions between a monometallic catalyst and Sn(C4H 9)4. The results obtained when monometallic catalysts were employed suggest a relationship between metal properties and the activity and selectivity obtained. All systems allowed obtaining furfuryl alcohol with high selectivity (99, 97 and 76% were achieved with Pt, Rh and Ni catalysts, respectively). The addition of tin has different effects on the three systems, both in terms of conversion and selectivity. An interesting result was obtained for the Ni-based catalysts, for which the addition of tin led to a significant increase in furfuryl alcohol selectivity and, depending on the Sn/Ni ratio, also to an increase in the catalytic activity of the system.Centro de Investigación y Desarrollo en Ciencias Aplicada