7 results on '"Tatiana Woller"'
Search Results
2. Quest for the Most Aromatic Pathway in Charged Expanded Porphyrins
- Author
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Irene Casademont‐Reig, Tatiana Woller, Victor García, Julia Contreras‐García, William Tiznado, Miquel Torrent‐Sucarrat, Eduard Matito, Mercedes Alonso, European Commission, Chemistry, and General Chemistry
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charged macrocycles ,annulene model ,Organic Chemistry ,porphyrinoids ,aromaticity ,General Chemistry ,ring currents ,Catalysis - Abstract
Despite the central role of aromaticity in the chemistry of expanded porphyrins, the evaluation of aromaticity remains difficult for these extended macrocycles. The presence of multiple conjugation pathways and different planar and nonplanar π-conjugation topologies makes the quantification of global and local aromaticity even more challenging. In neutral expanded porphyrins, the predominance of the aromatic conjugation pathway passing through the imine-type nitrogens and circumventing the amino NH groups is established. However, for charged macrocycles, the question about the main conjugation circuit remains open. Accordingly, different conjugation pathways in a set of neutral, anionic, and cationic expanded porphyrins were investigated by means of several aromaticity indices rooted in the structural, magnetic, and electronic criteria. Overall, our results reveal the predominance of the conjugation pathway that passes through all nitrogen atoms to describe the aromaticity of deprotonated expanded porphyrins, while the outer pathway through the perimeter carbon atoms becomes the most aromatic in protonated macrocycles. In nonplanar and charged macrocycles, a discrepancy between electronic and magnetic descriptors is observed. Nevertheless, our work demonstrates AVmin remains the best tool to determine the main conjugation pathway of expanded porphyrins. M.A. and I.C.R. wish to acknowledge the VUB for a Strategic Research Program awarded to ALGC. The resources and services used in this work were provided by the Flemish Supercomputer Center (VSC), funded by the Research Foundation - Flanders (FWO), and the Flemish Government. I.C.R. acknowledges co-funding from the European Union′s Horizon 2020 research and innovation Maria Skłodowska-Curie Actions, under grant agreement number 945380. It has been also supported by grants from the Spanish government MICINN (PGC2018-098212-B-C21, PID2019-104772GB, PID2019-105488GB-I00, and PCI2019-103657), Diputación Foral de Gipuzkoa (2019-CIEN-000092-01), Gobierno Vasco (IT1346-19, IT1254-19, and PIBA19-0004), and the DIPC (DIPC_INV_003132). Open Access funding provided by University of Basque Country.
- Published
- 2022
3. Fine-Tuning of Nonlinear Optical Contrasts of Hexaphyrin-Based Molecular Switches Using Inverse Design
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Eline Desmedt, Tatiana Woller, Jos L. Teunissen, Freija De Vleeschouwer, Mercedes Alonso, Chemistry, Faculty of Sciences and Bioengineering Sciences, and General Chemistry
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Chemistry ,expanded porphyrins ,best-first search algorithm ,nonlinear optical properties ,(time-dependent) density functional theory ,General Chemistry ,inverse design ,molecular switches ,QD1-999 ,Original Research - Abstract
In the search for new nonlinear optical (NLO) switching devices, expanded porphyrins have emerged as ideal candidates thanks to their tunable chemical and photophysical properties. Introducing meso-substituents to these macrocycles is a successful strategy to enhance the NLO contrasts. Despite its potential, the influence of meso-substitution on their structural and geometrical properties has been scarcely investigated. In this work, we pursue to grasp the underlying pivotal concepts for the fine-tuning of the NLO contrasts of hexaphyrin-based molecular switches, with a particular focus on the first hyperpolarizability related to the hyper-Rayleigh scattering (βHRS). Building further on these concepts, we also aim to develop a rational design protocol. Starting from the (un)substituted hexaphyrins with various π-conjugation topologies and redox states, structure-property relationships are established linking aromaticity, photophysical properties and βHRS responses. Ultimately, inverse molecular design using the best-first search algorithm is applied on the most favorable switches with the aim to further explore the combinatorial chemical compound space of meso-substituted hexaphyrins in search of high-contrast NLO switches. Two definitions of the figure-of-merit of the switch performance were used as target objectives in the optimization problem. Several meso-substitution patterns and their underlying characteristics are identified, uncovering molecular symmetry and the electronic nature of the substituents as the key players for fine-tuning the βHRS values and NLO contrasts of hexaphyrin-based switches.
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- 2021
4. Towards the Design of Optically Active Thiophene S-Oxides using Quantum Chemistry
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Mercedes Alonso, Steven Verlinden, Frank De Proft, Tatiana Woller, Guido Verniest, Faculty of Sciences and Bioengineering Sciences, Chemistry, and Department of Bio-engineering Sciences
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chemistry.chemical_classification ,Atropisomer ,010405 organic chemistry ,Chemistry ,Organic Chemistry ,Enantioselective synthesis ,Alkyne ,Aromaticity ,General Chemistry ,010402 general chemistry ,01 natural sciences ,Catalysis ,Cycloaddition ,0104 chemical sciences ,chemistry.chemical_compound ,Enantiopure drug ,Computational chemistry ,Thiophene ,Chirality (chemistry) - Abstract
The importance of axially chiral biaryls has risen steeply in the recent decades. This structural motif proved to be successful in catalytic asymmetric synthesis and the configuration of the biaryl axis is decisive for the biological activity. A new approach for the atroposelective synthesis of biaryls would be through a cycloaddition between an enantiopure phenyl-substituted thiophene S-oxide and an alkyne. Importantly, the chiral center of the thiophene S-oxide needs to be stable enough to avoid pyramidal inversion during the cycloaddition. Considering that the racemization of thiophene monoxides has been scarcely investigated so far, we perform a thorough quantum chemical study on the inversion barriers of a large number of chiral thiophene S-oxide derivatives. Our main goal is to identify substitution patterns leading to stable atropisomers at room temperature. Appealingly, the role of stereoelectronic effects and the position of the substituents as well as the importance of aromaticity on the pyramidal inversion barrier are elucidated for the first time.
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- 2019
5. Understanding the Fundamental Role of π/π, σ/σ, and σ/π Dispersion Interactions in Shaping Carbon-Based Materials
- Author
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Frank De Proft, Julia Contreras-García, Tatiana Woller, Mercedes Alonso, Francisco J. Martin-Martinez, Paul Geerlings, Faculty of Sciences and Bioengineering Sciences, Chemistry, General Chemistry, and Quantum Chemistry - Molecular Modelling
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Models, Molecular ,Stacking ,Naphthalenes ,Sodium Chloride ,London dispersion force ,Catalysis ,Delocalized electron ,chemistry.chemical_compound ,Computational chemistry ,Cyclohexanes ,Journal Article ,Non-covalent interactions ,Benzene ,chemistry.chemical_classification ,Chemistry ,carbon ,Research Support, Non-U.S. Gov't ,Organic Chemistry ,Aromaticity ,General Chemistry ,Chemical physics ,Quantum theory ,Thermodynamics ,Density functional theory ,Dispersion (chemistry) ,Dimerization - Abstract
Noncovalent interactions involving aromatic rings, such as π-stacking and CH/π interactions, are central to many areas of modern chemistry. However, recent studies proved that aromaticity is not required for stacking interactions, since similar interaction energies were computed for several aromatic and aliphatic dimers. Herein, the nature and origin of π/π, σ/σ, and σ/π dispersion interactions has been investigated by using dispersion-corrected density functional theory, energy decomposition analysis, and the recently developed noncovalent interaction (NCI) method. Our analysis shows that π/π and σ/σ stacking interactions are equally important for the benzene and cyclohexane dimers, explaining why both compounds have similar boiling points. Also, similar dispersion forces are found in the benzene⋅⋅⋅methane and cyclohexane⋅⋅⋅methane complexes. However, for systems larger than naphthalene, there are enhanced stacking interactions in the aromatic dimers adopting a parallel-displaced configuration compared to the analogous saturated systems. Although dispersion plays a decisive role in stabilizing all the complexes, the origin of the π/π, σ/σ, and σ/π interactions is different. The NCI method reveals that the dispersion interactions between the hydrogen atoms are responsible for the surprisingly strong aliphatic interactions. Moreover, whereas σ/σ and σ/π interactions are local, the π/π stacking are inherently delocalized, which give rise to a non-additive effect. These new types of dispersion interactions between saturated groups can be exploited in the rational design of novel carbon materials.
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- 2014
6. Cover Picture: Understanding the Fundamental Role of π/π, σ/σ, and σ/π Dispersion Interactions in Shaping Carbon-Based Materials (Chem. Eur. J. 17/2014)
- Author
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Tatiana Woller, Julia Contreras-García, Frank De Proft, Francisco J. Martin-Martinez, Paul Geerlings, and Mercedes Alonso
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chemistry.chemical_classification ,Chemical physics ,Chemistry ,Organic Chemistry ,Dispersion (optics) ,chemistry.chemical_element ,Non-covalent interactions ,Aromaticity ,Cover (algebra) ,General Chemistry ,Carbon ,Catalysis - Published
- 2014
7. A Benchmark of Density Functional Approximations For Thermochemistry and Kinetics of Hydride Reductions of Cyclohexanones
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Guido Verniest, Xavier Deraet, Tatiana Woller, Ruben Van Lommel, Frank De Proft, Mercedes Alonso, Chemistry, and Faculty of Sciences and Bioengineering Sciences
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Materials science ,Chemistry, Multidisciplinary ,Kinetics ,COUPLED-CLUSTER SINGLES ,Substituent ,Thermodynamics ,010402 general chemistry ,01 natural sciences ,Quantum chemistry ,lcsh:Chemistry ,quantum chemistry ,chemistry.chemical_compound ,benchmark ,TRANSITION-METAL ,NUCLEOPHILIC ADDITIONS ,Thermochemistry ,FACIAL SELECTIVITY ,Non-covalent interactions ,Wave function ,ORGANIC-COMPOUNDS ,ALKALINE CATION ,chemistry.chemical_classification ,MAIN-GROUP THERMOCHEMISTRY ,Science & Technology ,hydride reduction ,Full Paper ,010405 organic chemistry ,Hydride ,stereochemistry ,Solvation ,CORRELATION-ENERGY ,General Chemistry ,Full Papers ,0104 chemical sciences ,Chemistry ,lcsh:QD1-999 ,chemistry ,FUNDAMENTAL ROLE ,Physical Sciences ,density functional calculations ,NONCOVALENT INTERACTIONS - Abstract
The performance of density functionals and wavefunction methods for describing the thermodynamics and kinetics of hydride reductions of 2-substituted cyclohexanones has been evaluated for the first time. A variety of exchange correlation functionals ranging from generalized gradient approximations to double hybrids have been tested and their performance to describe the facial selectivity of hydride reductions of cyclohexanones has been carefully assessed relative to the CCSD(T) method. Among the tested methods, an approach in which single-point energy calculations using the double hybrid B2PLYP-D3 functional on ωB97X-D optimized geometries provides the most accurate transition state energies for these kinetically-controlled reactions. Moreover, the role of torsional strain, temperature, solvation, noncovalent interactions on the stereoselectivity of these reductions was elucidated. Our results indicate a prominent role of the substituent on the cis/trans ratios driven by the delicate interplay between torsional strain and dispersion interactions. ispartof: Chemistryopen vol:8 issue:6 pages:788-806 ispartof: location:Germany status: Published online
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