Papers by Martín José Yañez
Chemical Physics Letters, 1988
Journal of Organic Chemistry, 1997
Strain effects have been quantitatively evaluated for a set of 22 compounds including ketones (R ... more Strain effects have been quantitatively evaluated for a set of 22 compounds including ketones (R 2 -CO), carboxamides (RCONH 2 ), and N,N-dimethylcarboxamides (RCONMe 2 ), 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) 2 CO 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.
Europhysics Letters (EPL), 1987
... [51 HELLMAN H., Acta Fix. Chim. USSR, 1 (1935) 913. [61 GOMBAS P., 2. Phys., 118 (1941) 164. ... more ... [51 HELLMAN H., Acta Fix. Chim. USSR, 1 (1935) 913. [61 GOMBAS P., 2. Phys., 118 (1941) 164. [7] PHILLIPS JC and KLEINMAN L., Phys. Rev., 116 (1959) 287. [81 WEEKS JD, HAZI A. and RIC~S. A., Adv. Chem. Phys., 16 (1969) 283. [91 PEACH G., Comm. At. Mol. ...
En los últimos años se han producido cambios significativos en los sistemas de producción de carn... more En los últimos años se han producido cambios significativos en los sistemas de producción de carne bovina en nuestro país. Estos fueron consecuencia de la irrupción de nuevas tecnologías de producto y de procesos, tales como la recría y engorde a corral, mayor utilización de la suplementación, mejores productos biológicos, implementación de planes sanitarios oficiales a nivel nacional, y en las puertas de la selección genética asistida por marcadores y la genómica.
Uploads
Papers by Martín José Yañez