129 research outputs found
Conformational analysis of cyclohexyl hydroperoxide by rotational spectroscopy
No full texthttp://dx.doi.org/10.13039/100005156 Alexander von Humboldt-Stiftunghttp://dx.doi.org/10.13039/501100001659 Deutsche Forschungsgemeinschaf
Progressive polarization of phenanthridine with increasing hydration degree evidenced by quadrupole and its comparison with formamide clusters
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Previous issue date: 2019-06-18The structure of the microsolvated complexes of phenanthridine (PAN) with up to three water molecules has been investigated previously using chirped pulse Fourier transform microwave (CP-FTMW) spectroscopy from 2-8 GHz. In this work, the effect of Resonance Assisted Hydrogen Bonding (RAHB), also called \textit{}–cooperativity, on those complexes has been studied. In the resonant forms, the increase of the electronic density around the nitrogen nucleus enhances its hydrogen acceptor capabilities. Thus, the main effects expected due to the resonance of the multiple conjugated \textit{}–bonds in the structure of the complexes are a strengthening of the hydrogen bonds and a lengthening of the N-C bonds. However, due to the subtle changes that occur on the molecular structure, the effect on the N-C distances could not be detected experimentally and only a shortening of the hydrogen bonds has been observed. Therefore, the use of the quadrupole coupling interactions as a probe for the polarization has been used to investigate these effects on the almost planar structures of PAN-(HO) n=1-3. This form of analysis has been shown to be effective in similar studies with formamide.\footnote{S. Blanco, P. Pinacho, J. C. López, \textit{Angew. Chem. Int. Ed.}, 2016, \textbf{128}, 9477-9481.}\footnote{S. Blanco, P. Pinacho, J. C. López, \textit{J. Phys. Chem. Lett.}, 2017, \textbf{8}, 6060-6066.} The experimental quadrupole coupling constant \textit{} shows a clear trend from isolated PAN to complexes with higher hydration degree, illustrating how the electronic environment at the N nucleus is altered by microsolvation
The many forms of alpha-methoxy phenylacetic acid in the gas phase: flexibility, internal dynamics, and their intramolecular interactions
No full textFive conformers of the flexible molecule alpha-methoxy phenylacetic acid were identified using rotational spectroscopy. The conformational landscape, internal dynamics, and intramolecular interactions were investigated.We present a rotational spectroscopy study of alpha-methoxy phenylacetic acid in the gas phase. This acid is a derivative of mandelic acid and is used in various organic reactions. The conformational landscape of alpha-methoxy phenylacetic acid was explored to gain insight into its intramolecular dynamics. A rich rotational spectrum was obtained using chirped-pulse Fourier transform microwave spectroscopy in the 2–8 GHz range. Five conformers out of six calculated low-energy forms were identified in the spectrum, and the assignment of the
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C singly substituted isotopologues for the lowest-energy conformer led to its accurate structure determination. Splitting patterns were analyzed and attributed to the internal rotation of a methyl top. The analysis of the non-covalent interactions within the molecule highlights the subtle balance in the stabilization of the different conformers. We thus provide high-level structural and intramolecular dynamics information that is also used to benchmark the performance of quantum-chemical calculations.Deutsche Forschungsgemeinschaft https://doi.org/10.13039/501100001659Fundación Alfonso Martín Escudero https://doi.org/10.13039/100008052Alexander von Humboldt-Stiftung https://doi.org/10.13039/100005156Agencia de Innovación y Desarrollo de Andalucía https://doi.org/10.13039/50110000646
Suplementary material for : Exploring atmospheric nucleation processes: hydration and fluoroalcoholic complexation of pyruvic acid
No full textPeer reviewe
Neoechinorhynchus (Neoechinorhynchus) golvani Salgado-Maldonado 1978
No full textNeoechinorhynchus (Neoechinorhynchus) golvani Salgado-Maldonado, 1978 (Fig. 2 d) Mexico: CAMPECHE: Hool (19 ° 30 ’ 51.82 ’’N 90 ° 26 ’ 55.13 ’’W); Thorichthys meeki (this study). Lago el Centenario (18 ° 37 ’ 50 ’’N 91 ° 56 ’ 21 ’’W); Amphilophus robertsoni, Cichlasoma rectangulare, Cichlasoma urophthalmum, Parachromis managuensis and Petenia splendida (Salgado-Maldonado et al. 1997); Herichthys pearsei and Vieja synspila (Vidal-Martínez 1995). Laguna El Vapor (18 ° 18 ’ 38 ’’N 91 ° 50 ’ 9 ’’W); Cichlasoma geddesi, Cichlasoma urophthalmum, Herichthys pearsei, Parachromis managuensis and Petenia splendida (Pineda-López 1994; Salgado-Maldonado et al. 1997); Cichlasoma urophthalmum (Vidal-Martínez 1995; Salgado- Maldonado & Kennedy 1997); Petenia splendida (Vidal-Martínez 1995). Laguna de Términos, Río Palizada (18 ° 17 ’ 16 ’’N 91 ° 56 ’ 52 ’’W); Cichlasoma urophthalmum (Salgado-Maldonado & Kennedy 1997; Salgado- Maldonado et al. 1997). Laguna de Términos, el Cayo (18 ° 30 ’ 10 ’’N 91 ° 41 ’ 20 ’’W); Cichlasoma urophthalmum (Salgado-Maldonado & Kennedy 1997; Salgado-Maldonado et al. 1997). Laguna de Términos, Santa Gertrudis (18 ° 26 ’ 51 ’’N 91 ° 49 ’ 38 ’’W); Cichlasoma urophthalmum (Salgado-Maldonado et al. 1997). Lago Atasta (18 ° 37 ’ 8 ’’N 92 ° 6 ’ 15 ’’W); Cichlasoma urophthalmum and Paraneetroplus synspilus (Vidal-Martínez 1995; Salgado-Maldonado et al. 1997). Río Champotón (19 ° 21 ’0’’N 90 ° 40 ’0’’W); Cichlasoma urophthalmum (Salgado- Maldonado et al. 1997); Thorichthys helleri (Salgado-Maldonado 2013). Laguna de Términos, Llanuras (18 ° 19 ’ 13 ’’N 91 ° 44 ’ 36 ’’W); Paraneetroplus synspilus (Vidal-Martínez & Kennedy 2000). Silvituc (18 ° 37 ’0’’N 91 ° 56 ’0’’W); Amphilophus robertsoni, Paraneetroplus synspilus and Paraneetroplus bifasciatus (Salgado- Maldonado 2013). CHIAPAS: Presa Chicoasen (16 ° 56 ’ 2 ’’N 93 ° 5 ’ 16 ’’W); Vieja pearsei (Martínez-Aquino et al. 2009; García-Varela et al. 2011; Pinacho-Pinacho et al. 2012). Presa Nezahualcoyolt (17 ° 10 ’ 49 ’’N 93 ° 36 ’ 49 ’’W); Vieja pearsei (Martínez-Aquino et al. 2009; Pinacho-Pinacho et al. 2012). Río Lacantún, el Remolino (16 ° 14 ’ 46 ’’N 90 ° 50 ’ 8 ’’W); Cichlasoma urophthalmum and Thorichthys helleri (Salgado-Maldonado et al. 2011). Río San Pedro, Tzendales (16 ° 17 ’ 54 ’’N 90 ° 53 ’ 13 ’’W); Petenia splendida (Salgado-Maldonado et al. 2011). Río la Urbina (15 ° 46 ’ 27 ’’N 93 ° 15 ’ 21 ’’W); Gobiomorus maculatus (Salgado-Maldonado et al. 2011). GUERRERO: Presa Tepecoacuilco (18 ° 18 ’ 1 ’’N 99 ° 28 ’ 16 ’’W); Cichlasoma istlanum (Salgado-Maldonado et al. 2001 a; Salgado- Maldonado 2013); Amphilophus macracanthus (Salgado-Maldonado 2013). HIDALGO: Río Tempoal, Atlapexco (20 ° 55 ’ 16 ’’N 98 ° 17 ’ 27 ’’W); Amatitlania nigrofasciata, Herichthys cyanoguttatus and Herichthys labridens (Salgado-Maldonado et al. 2004); Herichthys labridens (Salgado-Maldonado 2013). NAYARIT: Río Santiago, Presa Aguamilpa (21 ° 46 ’ 42 ’’N 104 ° 55 ’ 36 ’’W); Cichlasoma beani (Salgado-Maldonado et al. 2001 b; Salgado- Maldonado 2013). OAXACA: Temascal (18 ° 14 ’ 13 ’’N 96 ° 25 ’ 0.27 ’’W); Cichlasoma urophthalmum, Cichlasoma salvini (this study); Petenia splendida (Morales-Sosa 2008; Salgado-Maldonado 2013). San Juan Evangelista; Rocio octofasciata, Thorichthys ellioti (Salgado-Maldonado 2013). TABASCO: Río Carrizal (18 ° 1 ’ 45 ’’N 92 ° 55 ’0’’W); Cichlasoma urophthalmum (Martínez-Aquino et al. 2009; Pinacho-Pinacho et al. 2012; García- Varela et al. 2011). Lago Canitzan, Tenosique (17 ° 28 ’ 57 ’’N 91 ° 25 ’ 27 ’’W); Parachromis friedrichstalii (Martínez- Aquino et al. 2009; Pinacho-Pinacho et al. 2012). Laguna las Ilusiones (17 ° 59 ’ 46 ’’N 92 ° 56 ’ 17 ’’W); Cichlasoma urophthalmum (Pérez-Ponce de León et al. 1996; Martínez-Aquino et al. 2009; Pinacho-Pinacho et al. 2012); Cichlasoma salvini (Vidal-Martínez et al. 2001); Thorichthys helleri, Thorichthys pasionis and Paraneetroplus synspilus (Ramírez-Jiménez 1993; García-Magaña 1990; Pineda-López 1994; Salgado-Maldonado et al. 1997). Lago el Rosario (17 ° 50 ’0’’N 93 ° 45 ’0’’W); Ariopsis felis, Cathorops melanopus, Paraneetroplus synspilus and Hyporhamphus mexicanus (Fucugauchi-Suárez del Real et al. 1988); Strongylura sp. (Fucugauchi-Suárez del Real et al. 1988; Vidal-Martínez 1995); Cichlasoma geddesi (Pineda-López 1994); Thorichthys helleri (Fucugauchi- Suárez del Real et al. 1988; Pineda-López 1994; Vidal-Martínez 1995). Lago Santa Anita (18 ° 22 ’ 15 ’’N 92 ° 53 ’ 10 ’’W); Cichlasoma geddesi, Cichlasoma rectangulare, Cichlasoma urophthalmum, Cichlasoma pearsei, Petenia splendida, Paraneetroplus fenestratus and Paraneetroplus synspilus (Pineda-López et al. 1985; Pineda- López 1994; Salgado-Maldonado et al. 1997). Estanque Tucta (18 ° 10 ’ 40 ’’N 92 ° 56 ’ 1 ’’W); Cichlasoma geddesi, Cichlasoma urophthalmum, Parachromis friedrichstahlii, Thorichthys pasionis and Paraneetroplus synspilus (Salgado-Maldonado et al. 1997). Lago el Chiribital (17 ° 59 ’ 24 ’’N 93 ° 4 ’ 22 ’’W; 17 ° 59 ’0’’N 93 ° 4 ’0’’W); Cichlasoma rectangulare, Cichlasoma urophthalmum, Cichlasoma pearsei, Petenia splendida, Thorichthys meeki, Thorichthys pasionis, Paraneetroplus fenestratus, and Ictalurus furcatus (Salgado-Maldonado 1985); Cichlasoma sp., Cichlasoma urophthalmum, Petenia splendida, Thorichthys meeki and Thorichthys pasionis (Osorio-Sarabia et al. 1987); Cichlasoma urophthalmum, Thorichthys meeki and Thorichthys pasionis (Salgado-Maldonado 2013). Lago el Espino (18 ° 14 ’ 57 ’’N 92 ° 49 ’ 59 ’’W); Cichlasoma rectangulare, Cichlasoma urophthalmum, Cichlasoma pearsei, Petenia splendida, Thorichthys meeki, Thorichthys pasionis, Paraneetroplus fenestratus and Ictalurus furcatus (Salgado-Maldonado 1985); Cichlasoma sp., Cichlasoma urophthalmum, Petenia splendida and Thorichthys meeki (Osorio-Sarabia et al. 1987); Cichlasoma urophthalmum and Thorichthys helleri (Pineda-López 1994); Parachromis motaguensis, Thorichthys helleri, and Thorichthys pasionis (Vidal-Martínez et al. 2001); Paraneetroplus synspilus (Pérez-Ponce de León et al. 1996). Río San Pedro (17 ° 45 ’0’’N 91 ° 23 ’0’’W); Cichlasoma rectangulare, Cichlasoma urophthalmum, Cichlasoma pearsei, Petenia splendida, Thorichthys meeki, Thorichthys pasionis, Paraneetroplus fenestratus and Ictalurus furcatus (Salgado-Maldonado 1985); Petenia splendida (Salgado-Maldonado 2013). Rio Vicente Guerrero (18 ° 24 ’ 20 ’’N 92 ° 54 ’ 35 ’’W); Cichlasoma rectangulare, Cichlasoma urophthalmum, Cichlasoma pearsei, Petenia splendida, Thorichthys meeki, Thorichthys pasionis, Paraneetroplus fenestratus and Ictalurus furcatus (Salgado-Maldonado 1985); Cichlasoma urophthalmum, Parachromis fenestratus and Cichlasoma rectangulare (Salgado-Maldonado 2013). Río Usumacinta, Emiliano Zapata (17 ° 45 ’0’’N 91 ° 46 ’0’’W); Cichlasoma urophthalmum, Parachromis managuensis and Petenia splendida (Pineda-López et al. 1985). Río Usumacinta, El Corozal (17 ° 44 ’0’’N 91 ° 35 ’ 33 ’’W); Cichlasoma urophthalmum and Parachromis managuensis (Pineda-López 1994; Salgado-Maldonado et al. 1997). Aguada Santa Elena; Cichlasoma urophthalmum (Salgado-Maldonado et al. 1997). Pantanos de Centla (17 ° 57 ’0’’N 92 ° 6 ’0’’W); Cichlasoma urophthalmum (López-Jiménez 2001); Parachromis managuensis (Salgado-Maldonado et al. 2005 a; Salgado-Maldonado 2013); Petenia splendida (Salgado-Maldonado 2013). Lago el Manguito (18 ° 12 ’ 50 ’’N 92 ° 50 ’ 5 ’’W); Parachromis managuensis (Salgado-Maldonado et al. 2005 a). Lago el Pozo (18 °0’ 35 ’’N 92 ° 48 ’ 11 ’’W); Parachromis managuensis (Salgado-Maldonado et al. 2005 a); Thorichthys pasionis (Vidal- Martínez et al. 2001). Río Usumacinta, Balancán (17 ° 45 ’ 8 ’’N 91 ° 32 ’ 45 ’’W); Parachromis managuensis (Salgado- Maldonado et al. 2005 a). Camellones Chontales (17 ° 45 ’ 8 ’’N 92 ° 35 ’ 10 ’’W); Thorichthys pasionis (Vidal-Martínez 1995). VERACRUZ: Lago de Catemaco (18 ° 25 ’0’’N 95 ° 7 ’0’’W); Paraneetroplus fenestratus (Salgado- Maldonado 1978; Salgado-Maldonado et al. 1992; Jiménez-García 1993; Salgado-Maldonado et al. 2005 b; Martínez-Aquino et al. 2009; Pinacho-Pinacho et al. 2012). Arrollo San Juan Evangelista; Rocio octofasciata and Thorichthys ellioti (Salgado-Maldonado et al. 2005 b). Río Tecolutla (20 ° 26 ’0’’N 97 ° 10 ’0’’W); Gobiomorus dormitor (Páez-Rodríguez et al. 2002). Río la Antigua (19 ° 20 ’0’’N 96 ° 23 ’0’’W); Gobiomorus dormitor (Páez- Rodríguez et al. 2002). YUCATAN: Cenote Chen-há (20 ° 41 ’ 24 ’’N 89 ° 52 ’ 36 ’’W); Cichlasoma urophthalmum (Scholz et al. 1996). Ría Celestun (20 ° 45 ’0’’N 90 ° 15 ’0’’W); Cichlasoma urophthalmum (Salgado-Maldonado & Kennedy 1997; Salgado-Maldonado et al. 1997; Salgado-Maldonado 2013). Mitza (21 ° 26 ’ 36 ’’N 89 ° 41 ’ 50 ’’W); Cichlasoma urophthalmum (Vidal-Martínez 1995; Vidal-Martínez et al. 1998). Costa Rica: Quebrada Puercos (10 ° 51 ’0’’N 85 ° 34 ’0’’W); Amatitlania nigrofasciata (Martínez-Aquino et al. 2009). Lago Jalapa (10 ° 31 ’ 52 ’’N 84 ° 1 ’ 50 ’’W); Parachromis managuensis, Parachromis loisellei, Amphilophus longinamus, Heterotilapia multiespinosa and Archocentrus centrarchus (this study). Nicaragua: Loonku creek (11 ° 59 ’ 5 ’’N 83 ° 46 ’ 48 ’’W); Amphilophus alfari and Heterotilapia multiespinosa (Aguirre-Macedo et al. 2001). Puente Chino (12 °0’ 30 ’’N 83 ° 46 ’ 13 ’’W); Parachromis managuensis and Heterotilapia multiespinosa (Aguirre-Macedo et al. 2001). Caño Negro (12 °0’ 55 ’’N 84 ° 1 ’ 10 ’’W); Parachromis managuensis) (Aguirre-Macedo et al. 2001). Specimens deposited. CNHE (8592, 6757, 6755, 6756, 6767, 6754, 601, 603, 604, 606, 631, 632, 6783, 8593, 8594, 6758, 8595, 8404, 8398, 8397, 8391, 8396, 8395, 8394, 8392, 8390, 8389, 8388, 8387, 8386, 8385, 8384, 8383, 8382, 8370, 6783, 5623, 650, 652 - 57, 660). Note. This species was described from juvenile specimens in the Lago de Catemaco, Veracruz, Mexico from Paraneetroplus fenestratus (Salgado-Maldonado 1978), which was taxonomically incorrect, the same author four decades later described features, such as the size and shape of adult of male and female as well as the structure of the eggs (Salgado-Maldonado 2013).Published as part of Pinacho-Pinacho, Carlos Daniel, Sereno-Uribe, Ana L., León, Gerardo Pérez-Ponce De & García-Varela, Martín, 2015, Checklist of the species of Neoechinorhynchus (Acanthocephala: Neoechinorhynchidae) in fishes and turtles in Middle-America, and their delimitation based on sequences of the 28 S rDNA, pp. 98-116 in Zootaxa 3985 (1) on pages 103-105, DOI: 10.11646/zootaxa.3985.1.5, http://zenodo.org/record/24107
Escáner de seguridad y métricas de riesgo operacional para chatbots basados en LLMs.
No full textTesis presentada para optar al título de Ingeniero/a Civil Informático/a.Recientemente han ocurrido enormes avances en el área de los chatbots y grandes modelos de lenguaje (LLM), principalmente potenciado y popularizado por el lanzamiento de ChatGPT el pasado 30 de noviembre de 2022 [1]. Un chatbot es un programa de computador que simula y procesa conversaciones humanas (ya sea escritas o habladas), permitiendo a los humanos interactuar con dispositivos digitales como si estuvieran comunicándose con una persona real [2]. Sin embargo, hasta hace unos meses, la mayoría de estos chatbots constaban con una limitada capacidad de interacción, con respuestas automáticas o muy simples.Facultad de IngenieríaDepartamento de Ingeniería Informática y Ciencias de la ComputaciónConcepció
Un siglo en 100 artículos
No full textFicha técnica:
Justino SinovaLa esferaMadrid, 2002526 pp.ISBN: 978-84-973-4031-
Interplay Of Intermolecular Interactions: Complexes Of 2-decalone With Water, Benzene, And Phenol
No full textHere we report the study on complexes between 2-decalone (CHO) and water, benzene, and phenol, respectively. The goal was to compare the interactions between the complex partners and the contributions of electrostatic and dispersion forces and which of them dominates when both forces are present. For that, a small hydrogen bond donor, water, was selected. Benzene is a good example for forming dispersion interactions, while in phenol both a phenyl ring and a hydrogen bond donor group are present and there could be competition between both forces. The complexes were studied in the gas phase in a cold and isolated environment generated by a supersonic expansion. The spectra were recorded using chirped-pulse Fourier transform microwave (CP-FTMW) spectroscopy in the 2-8 GHz frequency region. The sample consists of cis and trans 2-decalone, and complexes with both isomers were detected. In total five water complexes were identified with dominant electrostatic interactions between the complex partners. Three complexes with benzene were assigned showing mostly dispersion interactions. Another three complexes were identified with phenol. The analysis revealed that they have a higher percentage of electrostatic than dispersion forces and display a preference for a hydrogen bond when in competition with dispersion interactions.
\includegraphics[width=0.7\textwidth]{cisNScomplexes.eps
The formamide2-H2O complex: Structure and hydrogen bond cooperative effects
No full textThe adduct formamide-H0 has been detected in a supersonic expansion and its rotational spectra in the 5-13 GHz frequency region characterized by narrow-band molecular beam Fourier transform microwave spectroscopy (MB-FTMW). The spectrum shows the hyperfine structure due to the presence of two N-nuclei. This hyperfine structure has been analyzed and the determined quadrupole coupling constants together with the rotational constants have been a key for the identification of the adduct structure on the light of ab initio computations. The rotational parameters are consistent with the formation of a three body cycle thanks to the double proton acceptor/proton donor character of both formamide and water. The low value of the planar moment of inertia \textit{P} indicates that the heavy atom skeleton of the cluster is essentially planar. A detailed analysis of the results reveals the subtle effects of hydrogen bond cooperative effects in this system.Made available in DSpace on 2017-01-26T21:38:24Z (GMT). No. of bitstreams: 4
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