A Computational Study of 2-Selenobarbituric Acid: Conformational Analysis, Enthalpy of Formation, Acidity and Basicity.

Peer Reviewe

MECHANISM FOR CROSS PROCESS COMMUNICATION WITH ANR CHECKING AND AUTOMATIC OBJECT SERIALIZATION

A host and a client may perform inter-process communication (IPC) with automatic object serialization and deserialization and with application not responding (ANR) checking. A sender (e.g., a host process, host application, host device, a client process, client application, client device, etc.) may automatically serialize an object by using reflection (e.g., the ability of a process to examine, introspect, and modify its own structure and behavior) to recursively obtain all fields and corresponding key-value pairs from each layer of the object (as well as any parent object with inheritance). The sender may bundle the fields and key-value pairs and transmit the bundle to a receiver (e.g., the client if the host is the sender, the host if the client is the sender, etc.) via a network. The receiver may examine the bundle and determine the type of the object (e.g., arrays, string classes, interfaces, etc.) based on the fields and/or the key-value pairs stored in the bundle. The receiver may then implement the appropriate process for reconstructing the object from the based on the fields and the corresponding key-pairs. This serialization and deserialization process may be performed for each communication transmitted between the sender and the receiver. Additionally or alternatively, when the sender communicates with the receiver, the sender may send a message via a binder that causes the receiver to send a generic callback to the sender. In some examples, if the sender does not receive the callback before a predetermined period expires (e.g., the call timed-out), the sender may output a notification that the receiver (e.g., the application executing at the receiver) is not responding. In this way, the binder may provide ANR checking that informs the user whether an error has occurred or not

Termólisis de ß-hidroxicetonas-ß-aril sustituidas. un estudio computacional.

Estudios teóricos de la termólisis de 9-hidroxicetonas-9-aril sustituidas (m,p) para producir mezclas de aldehídos aromáticos y acetona a 429,15K se llevaron a cabo utilizando métodos ab-initio a niveles MP2/6- 31G(d)//HF/6-31G(d). Los perfiles de reacción para los sustituyentes m y p estudiados muestran en todos los casos que la segunda etapa de la reacción tautomerización de acetona (9G≠=217.6 kJmol-1) es la etapa mas lenta. La primera etapa incluye un estado de transición cíclico de seis miembros y sobre ésta se centraron los estudios de una posible relación lineal de energía libre. Los resultados muestran que no hay una buena correlación Hammett indicativo de efecto perpendicular a la coordenada de reacción

Experimental and theoretical study of the structures and enthalpies of formation of the synthetic reagents l,3-thiazolidine-2-thione and l,3-oxazolidine-2-thione

This paper reports an experimental and a theoretical study of the structures and standard (po = 0.1 MPa) molar enthalpies of formation of the synthetic reagents 1,3-thiazolidine-2-thione [CAS 96-53-7] and 1,3-oxazolidine-2-thione [CAS 5840-81-3]. The enthalpies of combustion and sublimation were measured by rotary bomb combustion calorimetry, and the Knudsen effusion technique and gas-phase enthalpies of formation values at T = 298.15 K of (97.1 ± 4.0) and −(74.4 ± 4.6) kJ·mol−1 for 1,3-thiazolidine-2-thione and 1,3-oxazolidine-2-thione, respectively, were determined. G3-calculated enthalpies of formation are in reasonable agreement with the experimental values. In the solid state, 1,3-thiazolidine-2-thione exists in two polymorphic forms (monoclinic and triclinic) and 1,3-oxazolidine-2-thione exits in the triclinic form. The isostructural nature of these compounds and comparison of their molecular and crystal structures have been analyzed. The experimental X-ray powder diffractograms have been compared with the calculated patterns from their structures for identification of the polymorphic samples used in this study. A comparison of our results with literature thermochemical and structural data for related compounds is also reported.M.T. would like to thank MEC/SEUI, FPU AP2002-0603, Spain, for financial support. A.V.D. thanks the National Science Foundation (CHE-0547566) and the American Heart Association (0855743G) for financial support of this research. The support of the Spanish Ministerio de Educación y Ciencia under Projects CTQ2007-60895/BQU and CTQ2006-10178/BQU is gratefully acknowledged

Strain Effects in Protonated Carbonyl Compounds. An Experimental and ab Initio Treatment of Acyclic Carboxamides and Ketones

Strain effects have been quantitatively evaluated for a set of 22 compounds including ketones (R2CO), carboxamides (RCONH2), and N,N-dimethylcarboxamides (RCONMe2), where R = Me, Et, i-Pr, t-Bu, 1-adamantyl (1-Ad), in their neutral and protonated forms. To this end, use was made of the gas-phase proton affinities and standard enthalpies of formation of these compounds in the gas phase, as determined by Fourier transform ion cyclotron resonance mass spectrometry (FT ICR) and thermochemical techniques, respectively. The structures of 1-AdCOMe and (1-Ad)2CO were determined by X-ray crystallography. Quantum-mechanical calculations, at levels ranging from AM1 to MP2/6-311+G(d,p)//6-31G(d), were performed on the various neutral and protonated species. Constrained space orbital variation (CSOV) calculations were carried out on selected protonated species to further assess the contributions of the various stabilizing factors. Taking neutral and protonated methyl ketones as references, we constructed isodesmic reactions that provided, seemingly for the first time, quantitative measures of strain in the protonated species. A combination of these data with the results of theoretical calculations (which also included several “computational experiments”) lead to a unified, conceptually satisfactory, quantitative description of these effects and their physical link to structural properties of the neutral and protonated species.This work was supported by grants PB 93-0289-C02 and PB-93-0142-C03-01 from the Spanish D.G.I.C.Y.T. Work by H.H. was supported by the Moroccan Ministry of Education and C.S.I.C

Experimental and Theoretical Study of the Structures and Enthalpies of Formation of the Synthetic Reagents 1,3-Thiazolidine-2-thione and 1,3-Oxazolidine-2-thione

This paper reports an experimental and a theoretical study of the structures and standard (p o ) 0.1 MPa) molar enthalpies of formation of the synthetic reagents 1,3-thiazolidine-2-thione and 1,3-oxazolidine-2-thione . The enthalpies of combustion and sublimation were measured by rotary bomb combustion calorimetry, and the Knudsen effusion technique and gas-phase enthalpies of formation values at T ) 298.15 K of (97.1 ( 4.0) and -(74.4 ( 4.6) kJ · mol -1 for 1,3-thiazolidine-2-thione and 1,3-oxazolidine-2-thione, respectively, were determined. G3-calculated enthalpies of formation are in reasonable agreement with the experimental values. In the solid state, 1,3-thiazolidine-2-thione exists in two polymorphic forms (monoclinic and triclinic) and 1,3-oxazolidine-2-thione exits in the triclinic form. The isostructural nature of these compounds and comparison of their molecular and crystal structures have been analyzed. The experimental X-ray powder diffractograms have been compared with the calculated patterns from their structures for identification of the polymorphic samples used in this study. A comparison of our results with literature thermochemical and structural data for related compounds is also reported

Caracterización y modelación molecular de la fotodegradación catalítica con TiO2 del Clorobenceno

La contaminación del aire es uno de los problemas ambientales más graves, ocasionadas no sólo por las emisiones de gases de los automotores, sino, también, por la emisión de enormes cantidades de productos residuales, potencialmente nocivos, emanados, principalmente, de industrias e incineradores. Los compuestos orgánicos volátiles son considerados como unas de los contaminantes antropogénicos más importantes generados y liberados en áreas urbanas e industriales. La detección de hidrocarburos clorados, como el clorobenceno, en el ambiente, ha sido objeto de estudio, debido a los graves problemas potenciales producidos como precursor de dioxinas y furanos. El proceso de fotodegradación produce la mineralización de contaminantes, convirtiéndose en sustancias ambientalmente menos nocivas, tales como el dióxido de carbono, CO2; ácido clorhídrico, HCl y agua (figura 1). Clorobenceno en fase gas, presente en una corriente de aire, fue degradado en continuo en un fotorreactor irradiado con lámparas UV-A (radiación principal a 365 nm). El fotocatalizador fue soportado en forma de películas de TiO2-SiO2 sobre tubos de vidrio borosilicato, la matriz de sílice se sintetizó, por el método sol-gel, usando tetraetilortosilicato, agua e isopropanol en medio ácido, luego el TiO2 se dispersó en la sílice a altas velocidades e inmediatamente los tubos fueron sumergidos a velocidad controlada en la suspensión. Los materiales soportados fueron caracterizados por medio de FTIR, UV-vis, SEM y TG. Se alcanzó una degradación del 68% de clorobenceno en pruebas fotocatalíticas realizadas a temperatura ambiente y 0.84 atm. Abstract Air pollution is one of the most serious environmental problems caused not only from vehicular traffic but also from incinerators and industry emissions. This is to the launching of potentially injurious residual products in the ecosystems. In consequence, the volatile organic compounds are considered as one of the more important anthropogenic polluting agents generated in the urban and industrial areas. Chlorinated hydrocarbons, like the chlorobenzene, can produce compounds like dioxins and furans, so their effects on human health and the environment have been object of study in many investigations. The photodegradation process produces the mineralization of many polluting agents which become in less injurious substances, such as carbon dioxide, CO2; hydrochloric acid, HCl and water, Figure 1. Chlorobenzene in gaseous phase, diluted in air, was degraded in a continuous photorreactor, irradiated with UV lamps (main radiation to 365 nm). The photocatalyst was supported on borosilicate glass tubes, as TiO2-SiO2 films. The silica matrix was synthesized by the Sol-Gel method using tetraethyl orthosilicate, water and propan2-ol, in acidic medium. Then, the TiO2 was dispersed in the silica at high velocities and the tubes were submerged at speed controlled in the suspension. The supported materials were characterized by FTIR, UV-Vis, SEM and TGA. Chlorobenzene degradation reached 68% in photocatalytic tests carried out to room temperature and 0.84 atm

Promoción de convenios de doble titulación del MU en Estudios Avanzados en Filosofía de la USAL y los Mestrados em Filosofía de las Universidades de Porto y Lisboa

Memoria ID-0266. Ayudas de la Universidad de Salamanca para la innovación docente, curso 2014-2015