Accurate theoretical spectroscopy of the lowest electronic states of CP radical

International audienc

A new theoretical approach of amelioration the CO2 uptake efficiency of ZIF. The substitution of imidazole by different function

AMOC 2015, Anharmonicity in médium-sized molecules and cluster, CSIC, Madrid (Spain), 26-30 April 2015; http://tct1.iem.csic.es/AMOC2015.htmNew capture and sequestration technologies have been proposed to mitigate CO2 emissions motivating the search for new materials such as MOFs, ZIFs and other porous solids. In this paper, the influence of the substitution of imidazole by different donor and acceptor groups on the CO2 uptake efficiency is analyzed. Imidazoles are important organic frameworks of the ZIF¿s [1]. Geometries and energies of the different complexes have been optimized using the Density Functional Theory and Möller-Plesset theory in connection with cc-pVTZ and aug-cc-pVTZ basis sets. For DFT calculations, the Wb97XD functional, suitable for the description of dispersion forces and Van Der Waals interactions, has been used. The preferred configurations of the substituted imidazoles are planar, favoring the CO2 approach to the sp2 type nitrogen. Binding energies are determined minimizing the basis set superposition error with the counterpoise method [2]. The interaction between imidazole and different greenhouse effect gases such as H2O, N2, CH4, NH3 and SO2 are also studied in order to demonstrate the selectivity of imidazole for CO2 capture. The imidazole molecules (or the ZIF¿s) can then be used for selective separation of CO2 in gas mixture CO2, N2, CH4 of industrial flues. However, it can be noticed that imidazoles are not adequate for gas mixture containing H2O, CO2 and NH3.Peer Reviewe

Influence of the functionalization of Imidazole on its CO2 uptake efficiency. A theoretical contribution

8 pags.; 6 figs.; 5 tabs.© 2015 Elsevier B.V. New capture and sequestration technologies have been proposed to mitigate CO2 emissions motivating the search for new materials such as MOF's, ZIF's and other porous solids. In this paper, the influence of the substitution of imidazole by different donor and acceptor groups on the CO2 uptake efficiency is analyzed. Imidazoles are important organic units of the ZIF's.Geometries and energies of the different complexes have been optimized using the Density Functional (DFT) and Möller-Plesset (MP2) theories with cc-pVTZ and aug-cc-pVTZ atomic orbitals basis sets. For DFT calculations, the WB97XD functional, suitable for the description of dispersion forces and Van der Waals interactions, has been used. The preferred configurations of the substituted imidazoles are planar, favoring the CO2 approach to the sp2 type nitrogen. Binding energies are determined minimizing the basis set superposition error and taking into account the zero point energies. The interaction between imidazole and different greenhouse effect gases such as H2O, N2, CH4, NH3 and SO2 are also studied in order to demonstrate the selectivity of imidazole for CO2 capture. The imidazole molecules (or the ZIF's) can then be used for selective separation of CO2 in gas mixture containing CO2, N2, and CH4 of industrial flues. However, it can be noticed that imidazoles are not adequate for gas mixture containing H2O and CO2 or NH3 and CO2. The behavior of imidazolates in dry or humid environments is predicted to be very different. The effect of the substitution of the imidazole hydrogens by one, two, or three active groups on the CO2 capture and storage is also analyzed. The selected groups are OH, CN, CH3, NH2, COH, Cl, CF3, OCH3 and C(CH3)3.This research was supported by a Marie Curie International Research Staff Exchange Scheme Fellowship within the 7th European Community Framework Program under Grant n° PIRSES-GA-2012-31754 and the FIS2013-40626-P project of the MINECO, Spain. The authors also acknowledge the COST Actions 1401 and 1405.Peer Reviewe

The formation of interstellar organic molecules: H2C3O a DFT and ELF theoretical study

15 pags., 12 figs., 9 tabs., 1 app.This quantum study at B3LYP/6-311 ++ G (d, p) with ELF analysis were performed in order to understand the formation of propynal and cyclopropenone, two molecules detected in the interstellar medium. The formation of these molecules is supposed to be through reactions between carbon monoxide (CO) and acetylene (C2H2) in the cold conditions of interstellar clouds. All the structures, reagents, products and transition states, have been optimized and the geometrical parameters are given as well as the dipole moments. The reaction paths are elaborated and discussed here using the IRC method implemented in the Gaussian program. The determined activation energies allow an estimation of the rate constants. The ELF analysis performed here seems to be a valuable tool for screening the evolution of the bonds during the formation processes. The two reactions probably occur in one step. The propadienone, another possible isomer, has been also studied. It is formed through a third reaction. A stable triplet ground state of this molecule, the thermodynamic consideration and a small dipole moment can explain the fact that it is not detected yet in the interstellar medium. M06-2X and WB97XD functional were also used for comparing results.This project has received funding from CSIC iCOOP 2018 program under the reference number COOPB20364 and from the Ministerio de Educación y FP (Spain) under grant number (FIS2016-76418-

Free Radical Scavenging Properties of Guaiacol Oligomers: A Combined Experimental and Quantum Study of the Guaiacyl-Moiety Role

International audienc

Theoretical spectroscopic study of acetyl (CH3CO), vinoxy (CH2CHO), and 1-methylvinoxy (CH3COCH2) radicals. Barrierless formation processes of acetone in the gas phase

24 pags., 10 figs., 11 tabs. -- [version 2; peer review: 2 approved]Background: Acetone is present in the earths atmosphere and extra-terrestrially. The knowledge of its chemical history in these environments represents a challenge with important implications for global tropospheric chemistry and astrochemistry. The results of a search for efficient barrierless pathways producing acetone from radicals in the gas phase are described in this paper. The spectroscopic properties of radicals needed for their experimental detection are provided. Methods: The reactants were acetone fragments of low stability and small species containing C, O and H atoms. Two exergonic bimolecular addition reactions involving the radicals CH 3, CH 3CO, and CH 3COCH 2, were found to be competitive according to the kinetic rates calculated at different temperatures. An extensive spectroscopic study of the radicals CH 3COCH 2 and CH 3CO, as well as the CH 2CHO isomer, was performed. Rovibrational parameters, anharmonic vibrational transitions, and excitations to the low-lying excited states are provided. For this purpose, RCCSD(T)-F12 and MRCI/CASSCF calculations were performed. In addition, since all the species presented non-rigid properties, a variational procedure of reduced dimensionality was employed to explore the far infrared region. Results: The internal rotation barriers were determined to be V 3=143.7 cm -1 (CH 3CO), V 2=3838.7 cm -1 (CH 2CHO) and V 3=161.4 cm -1 and V 2=2727.5 cm -1 (CH 3COCH 2).The splitting of the ground vibrational state due to the torsional barrier have been computed to be 2.997 cm -1, 0.0 cm -1, and 0.320 cm -1, for CH 3CO, CH 2CHO, and CH 3COCH 2, respectively. Conclusions: Two addition reactions, H+CH 3COCH 2 and CH 3+CH 3CO, could be considered barrierless formation processes of acetone after considering all the possible formation routes, starting from 58 selected reactants, which are fragments of the molecule. The spectroscopic study of the radicals involved in the formation processes present non-rigidity. The interconversion of their equilibrium geometries has important spectroscopic effects on CH 3CO and CH 3COCH 2, but is negligible for CH 2CHO.This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 872081. This work was also supported by the Ministerio de Ciencia, Innovación y Universidades of Spain through the grants EIN2019-103072 and FIS2016-76418-P; the CSIC i-coop+2018 program under the grant number COOPB20364; the CTI (CSIC) and CESGA and to the “Red Española de Computación” for the grants AECT-2020-2-0008 and RESAECT-2020-3-0011 for computing facilities. MC also acknowledges the financial support from the Spanish National Research, Development, and Innovation plan (RDI plan) under the project PID2019-104002GB-C21 and the Consejerı́a de Conocimiento, Investigación y Universidad, Junta de Andalucı́a and European Regional Development Fund (ERDF), Ref. SOMM17/6105/UGR

Interaction Potential Energy Surfaces of Imidazole+CO2 systems

Potential Energy Surfaces describing the interaction between imidazol and CO2 are explored within the frame of the CAPZEO FP7 project. For this purpose, the minimum energy geometries corresponding to the imidazole+CO2 system have been searched and optimized using MP2/aug-cc-pVTZ calculations. We present preliminary results for several planar and non-planar equilibrium structures. The complex formation process can follow energetically favored multi-channel.Peer Reviewe