1
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Sidat A, Ingham M, Rivera M, Misquitta AJ, Crespo-Otero R. Performance of point charge embedding schemes for excited states in molecular organic crystals. J Chem Phys 2023; 159:244108. [PMID: 38149734 DOI: 10.1063/5.0177278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Accepted: 12/04/2023] [Indexed: 12/28/2023] Open
Abstract
Modeling excited state processes in molecular crystals is relevant for several applications. A popular approach for studying excited state molecular crystals is to use cluster models embedded in point charges. In this paper, we compare the performance of several embedding models in predicting excited states and S1-S0 optical gaps for a set of crystals from the X23 molecular crystal database. The performance of atomic charges based on ground or excited states was examined for cluster models, Ewald embedding, and self-consistent approaches. We investigated the impact of various factors, such as the level of theory, basis sets, embedding models, and the level of localization of the excitation. We consider different levels of theory, including time-dependent density functional theory and Tamm-Dancoff approximation (TDA) (DFT functionals: ωB97X-D and PBE0), CC2, complete active space self-consistent field, and CASPT2. We also explore the impact of selection of the QM region, charge leakage, and level of theory for the description of different kinds of excited states. We implemented three schemes based on distance thresholds to overcome overpolarization and charge leakage in molecular crystals. Our findings are compared against experimental data, G0W0-BSE, periodic TDA, and optimally tuned screened range-separated functionals.
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Affiliation(s)
- Amir Sidat
- School of Physical and Chemical Sciences, Queen Mary University of London, London, United Kingdom
| | - Michael Ingham
- Department of Chemistry, University College London, London, United Kingdom
| | - Miguel Rivera
- Department of Chemistry, University College London, London, United Kingdom
| | - Alston J Misquitta
- School of Physical and Chemical Sciences, Queen Mary University of London, London, United Kingdom
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2
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Nabi R, Staab JK, Mattioni A, Kragskow JGC, Reta D, Skelton JM, Chilton NF. Accurate and Efficient Spin-Phonon Coupling and Spin Dynamics Calculations for Molecular Solids. J Am Chem Soc 2023; 145. [PMID: 37917936 PMCID: PMC10655086 DOI: 10.1021/jacs.3c06015] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Revised: 10/16/2023] [Accepted: 10/18/2023] [Indexed: 11/04/2023]
Abstract
Molecular materials are poised to play a significant role in the development of future optoelectronic and quantum technologies. A crucial aspect of these areas is the role of spin-phonon coupling and how it facilitates energy transfer processes such as intersystem crossing, quantum decoherence, and magnetic relaxation. Thus, it is of significant interest to be able to accurately calculate the molecular spin-phonon coupling and spin dynamics in the condensed phase. Here, we demonstrate the maturity of ab initio methods for calculating spin-phonon coupling by performing a case study on a single-molecule magnet and showing quantitative agreement with the experiment, allowing us to explore the underlying origins of its spin dynamics. This feat is achieved by leveraging our recent developments in analytic spin-phonon coupling calculations in conjunction with a new method for including the infinite electrostatic potential in the calculations. Furthermore, we make the first ab initio determination of phonon lifetimes and line widths for a molecular magnet to prove that the commonplace Born-Markov assumption for the spin dynamics is valid, but such "exact" phonon line widths are not essential to obtain accurate magnetic relaxation rates. Calculations using this approach are facilitated by the open-source packages we have developed, enabling cost-effective and accurate spin-phonon coupling calculations on molecular solids.
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Affiliation(s)
- Rizwan Nabi
- Department
of Chemistry, University of Manchester, Manchester M13 9PL, U.K.
| | - Jakob K. Staab
- Department
of Chemistry, University of Manchester, Manchester M13 9PL, U.K.
| | - Andrea Mattioni
- Department
of Chemistry, University of Manchester, Manchester M13 9PL, U.K.
| | - Jon G. C. Kragskow
- Department
of Chemistry, University of Manchester, Manchester M13 9PL, U.K.
- Department
of Chemistry, University of Bath, Bath BA2 7AY, U.K.
| | - Daniel Reta
- Department
of Chemistry, University of Manchester, Manchester M13 9PL, U.K.
- Faculty
of Chemistry, University of the Basque Country
UPV/EHU, 20018 Donostia, Spain
- Donostia
International Physics Center (DIPC), 20018 Donostia, Spain
- IKERBASQUE,
Basque Foundation for Science, 48013 Bilbao, Spain
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3
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Turelli M, Ciofini I, Wang Q, Ottochian A, Labat F, Adamo C. Organic compounds for solid state luminescence enhancement/aggregation induced emission: a theoretical perspective. Phys Chem Chem Phys 2023; 25:17769-17786. [PMID: 37377211 DOI: 10.1039/d3cp02364h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/29/2023]
Abstract
Organic luminophores displaying one or more forms of luminescence enhancement in solid state are extremely promising for the development and performance optimization of functional materials essential to many modern key technologies. Yet, the effort to harness their huge potential is riddled with hurdles that ultimately come down to a limited understanding of the interactions that result in the diverse molecular environments responsible for the macroscopic response. In this context, the benefits of a theoretical framework able to provide mechanistic explanations to observations, supported by quantitative predictions of the phenomenon, are rather apparent. In this perspective, we review some of the established facts and recent developments about the current theoretical understanding of solid-state luminescence enhancement (SLE) with an accent on aggregation-induced emission (AIE). A description of the macroscopic phenomenon and the questions it raises is accompanied by a discussion of the approaches and quantum chemistry methods that are more apt to model these molecular systems with the inclusion of an accurate yet efficient simulation of the local environment. A sketch of a general framework, building from the current available knowledge, is then attempted via the analysis of a few varied SLE/AIE molecular systems from literature. A number of fundamental elements are identified offering the basis for outlining design rules for molecular architectures exhibiting SLE that involve specific structural features with the double role of modulating the optical response of the luminophores and defining the environment they experience in solid state.
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Affiliation(s)
- Michele Turelli
- Chimie ParisTech, PSL University, CNRS, Institute of Chemistry for Life and Health Sciences, Theoretical Chemistry and Modeling Team, 75005 Paris, France.
| | - Ilaria Ciofini
- Chimie ParisTech, PSL University, CNRS, Institute of Chemistry for Life and Health Sciences, Theoretical Chemistry and Modeling Team, 75005 Paris, France.
| | - Qinfan Wang
- Chimie ParisTech, PSL University, CNRS, Institute of Chemistry for Life and Health Sciences, Theoretical Chemistry and Modeling Team, 75005 Paris, France.
| | - Alistar Ottochian
- Chimie ParisTech, PSL University, CNRS, Institute of Chemistry for Life and Health Sciences, Theoretical Chemistry and Modeling Team, 75005 Paris, France.
| | - Frédéric Labat
- Chimie ParisTech, PSL University, CNRS, Institute of Chemistry for Life and Health Sciences, Theoretical Chemistry and Modeling Team, 75005 Paris, France.
| | - Carlo Adamo
- Chimie ParisTech, PSL University, CNRS, Institute of Chemistry for Life and Health Sciences, Theoretical Chemistry and Modeling Team, 75005 Paris, France.
- Institut Universitaire de France, 103 Boulevard Saint Michel, F-75005 Paris, France
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4
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Jiang G, Liu J, Zhou P. Unraveling the Mechanism of ACQ-to-AIE Transformation of Fluorescein Derivatives. J Phys Chem A 2023. [PMID: 37294934 DOI: 10.1021/acs.jpca.3c02244] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Although fluorescein derivatives have excellent properties and strong practicability, they are typical aggregation-induced quenching (ACQ) molecules, which are not conducive to working in the solid state. Recently, the fluorescein derivative Fl-Me with aggregation-induced emission (AIE) property was synthesized, which brought a new dawn for the research and development of fluorescein-based materials. In this study, the AIE mechanism of Fl-Me was investigated based on time-dependent density functional theory and the ONIOM method. The results revealed that an effective dark-state deactivation pathway leads to the fluorescence quenching of Fl-Me in a solution environment. Accordingly, the AIE phenomenon originates from the closure of the dark-state quenching channel. It is worth emphasizing that we found that the carbonyl group of molecular Fl-Me has intermolecular hydrogen bonding interaction with the adjacent molecules, which caused the increase of the dark-state energy in the crystalline state. Moreover, the restriction of the rotational motion and the nonexistence of the π-π stacking interaction are beneficial to the enhancement of fluorescence upon aggregation. Finally, the ACQ-to-AIE transformation mechanisms of fluorescein derivatives have been discussed. This work provides deeper insight into the photophysical mechanism for the fluorescein derivatives Fl-Me with AIE feature and eventually is expected to help researchers to develop more fluorescein-based AIE materials with remarkable properties for various fields.
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Affiliation(s)
- Gaoshang Jiang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning, P. R. China
- University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Jianyong Liu
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning, P. R. China
| | - Panwang Zhou
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning, P. R. China
- Institute of Molecular Sciences and Engineering, Institute of Frontier and Interdisciplinary Science, Shandong University, Qingdao 266237, Shandong, P. R. China
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5
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Sidat A, Hernández FJ, Stojanović L, Misquitta AJ, Crespo-Otero R. Competition between ultralong organic phosphorescence and thermally activated delayed fluorescence in dichloro derivatives of 9-benzoylcarbazole. Phys Chem Chem Phys 2022; 24:29437-29450. [PMID: 36453725 DOI: 10.1039/d2cp04802g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Optoelectronic materials based on metal-free organic molecules represent a promising alternative to traditional inorganic devices. Significant attention has been devoted to the development of the third generation of OLEDs which are based on the temperature-activated delayed fluorescence (TADF) mechanism. In the last few years, several materials displaying ultra-long organic phosphorescence (UOP) have been designed using strategies such as crystal engineering and halogen functionalisation. Both TADF and UOP are controlled by the population of triplet states and the energy gaps between the singlet and triplet manifolds. In this paper, we explore the competition between TADF and UOP in the molecular crystals of three dichloro derivatives of 9H-carbazol-3-yl(phenyl)methanone. We investigate the excited state mechanisms in solution and the crystalline phase and address the effects of exciton transport and temperature on the rates of direct and reverse intersystem crossing under the Marcus-Levich-Jortner model. We also analyse how the presence of isomeric impurities and the stabilisation of charge transfer states affect these processes. Our simulations explain the different mechanisms observed for the three derivatives and highlight the role of intramolecular rotation and crystal packing in determining the energy gaps. This work contributes to a better understanding of the connection between chemical and crystalline structures that will enable the design of efficient materials.
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Affiliation(s)
- Amir Sidat
- School of Physical and Chemical Sciences, Queen Mary University of London, London, UK.
| | - Federico J Hernández
- School of Physical and Chemical Sciences, Queen Mary University of London, London, UK.
| | - Ljiljana Stojanović
- School of Physical and Chemical Sciences, Queen Mary University of London, London, UK.
| | - Alston J Misquitta
- School of Physical and Chemical Sciences, Queen Mary University of London, London, UK.
| | - Rachel Crespo-Otero
- School of Physical and Chemical Sciences, Queen Mary University of London, London, UK.
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6
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Seeber P, Seidenath S, Steinmetzer J, Gräfe S. Growing Spicy
ONIOMs
: Extending and generalizing concepts of
ONIOM
and many body expansions. WIRES COMPUTATIONAL MOLECULAR SCIENCE 2022. [DOI: 10.1002/wcms.1644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
- Phillip Seeber
- Institute of Physical Chemistry Friedrich Schiller University Jena Jena Germany
| | - Sebastian Seidenath
- Institute of Physical Chemistry Friedrich Schiller University Jena Jena Germany
| | | | - Stefanie Gräfe
- Institute of Physical Chemistry Friedrich Schiller University Jena Jena Germany
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7
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Yue Q, Li Y, Wang Y, Zhao Y. Vibrational and Electronic Absorption Spectroscopic and Density Functional Theoretical Studies on the 2(3H)-Benzothiazolone and Its Anion. J Mol Struct 2022. [DOI: 10.1016/j.molstruc.2022.134060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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8
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Stoerkler T, Pariat T, Laurent AD, Jacquemin D, Ulrich G, Massue J. Excited-State Intramolecular Proton Transfer Dyes with Dual-State Emission Properties: Concept, Examples and Applications. Molecules 2022; 27:molecules27082443. [PMID: 35458640 PMCID: PMC9024454 DOI: 10.3390/molecules27082443] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2022] [Revised: 04/08/2022] [Accepted: 04/08/2022] [Indexed: 11/30/2022] Open
Abstract
Dual-state emissive (DSE) fluorophores are organic dyes displaying fluorescence emission both in dilute and concentrated solution and in the solid-state, as amorphous, single crystal, polycrystalline samples or thin films. This comes in contrast to the vast majority of organic fluorescent dyes which typically show intense fluorescence in solution but are quenched in concentrated media and in the solid-state owing to π-stacking interactions; a well-known phenomenon called aggregation-caused quenching (ACQ). On the contrary, molecular rotors with a significant number of free rotations have been engineered to show quenched emission in solution but strong fluorescence in the aggregated-state thanks to restriction of the intramolecular motions. This is the concept of aggregation-induced emission (AIE). DSE fluorophores have been far less explored despite the fact that they are at the crossroad of ACQ and AIE phenomena and allow targeting applications both in solution (bio-conjugation, sensing, imaging) and solid-state (organic electronics, data encryption, lasing, luminescent displays). Excited-State Intramolecular Proton Transfer (ESIPT) fluorescence is particularly suitable to engineer DSE dyes. Indeed, ESIPT fluorescence, which relies on a phototautomerism between normal and tautomeric species, is characterized by a strong emission in the solid-state along with a large Stokes’ shift, an enhanced photostability and a strong sensitivity to the close environment, a feature prone to be used in bio-sensing. A drawback that needs to be overcome is their weak emission intensity in solution, owing to detrimental molecular motions in the excited-state. Several strategies have been proposed in that regard. In the past few years, a growing number of examples of DSE-ESIPT dyes have indeed emerged in the literature, enriching the database of such attractive dyes. This review aims at a brief but concise overview on the exploitation of ESIPT luminescence for the optimization of DSE dyes properties. In that perspective, a synergistic approach between organic synthesis, fluorescence spectroscopy and ab initio calculations has proven to be an efficient tool for the construction and optimization of DSE-ESIPT fluorophores.
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Affiliation(s)
- Timothée Stoerkler
- Institut de Chimie et Procédés pour l’Energie, l’Environnement et la Santé (ICPEES), Equipe Chimie Organique pour la Biologie, les Matériaux et l’Optique (COMBO), UMR CNRS 7515, Ecole Européenne de Chimie, Polymères et Matériaux (ECPM), Université de Strasbourg, 25 Rue Becquerel, CEDEX 02, 67087 Strasbourg, France; (T.S.); (T.P.); (G.U.)
| | - Thibault Pariat
- Institut de Chimie et Procédés pour l’Energie, l’Environnement et la Santé (ICPEES), Equipe Chimie Organique pour la Biologie, les Matériaux et l’Optique (COMBO), UMR CNRS 7515, Ecole Européenne de Chimie, Polymères et Matériaux (ECPM), Université de Strasbourg, 25 Rue Becquerel, CEDEX 02, 67087 Strasbourg, France; (T.S.); (T.P.); (G.U.)
| | - Adèle D. Laurent
- Chimie et Interdisciplinarités: Synthèse, Analyse et Modélisation (CEISAM), UMR CNRS 6230, Nantes University, 44322 Nantes, France;
| | - Denis Jacquemin
- Chimie et Interdisciplinarités: Synthèse, Analyse et Modélisation (CEISAM), UMR CNRS 6230, Nantes University, 44322 Nantes, France;
- Correspondence: (D.J.); (J.M.)
| | - Gilles Ulrich
- Institut de Chimie et Procédés pour l’Energie, l’Environnement et la Santé (ICPEES), Equipe Chimie Organique pour la Biologie, les Matériaux et l’Optique (COMBO), UMR CNRS 7515, Ecole Européenne de Chimie, Polymères et Matériaux (ECPM), Université de Strasbourg, 25 Rue Becquerel, CEDEX 02, 67087 Strasbourg, France; (T.S.); (T.P.); (G.U.)
| | - Julien Massue
- Institut de Chimie et Procédés pour l’Energie, l’Environnement et la Santé (ICPEES), Equipe Chimie Organique pour la Biologie, les Matériaux et l’Optique (COMBO), UMR CNRS 7515, Ecole Européenne de Chimie, Polymères et Matériaux (ECPM), Université de Strasbourg, 25 Rue Becquerel, CEDEX 02, 67087 Strasbourg, France; (T.S.); (T.P.); (G.U.)
- Correspondence: (D.J.); (J.M.)
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9
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Ma Y, Lv M, Shang F, Zhang C, Liu J, Zhou P. Mechanistic Investigation on the Initial Thermal Decomposition of Energetic Materials FOX-7 and RDX in the Crystal and Gas Phase: An MM/DFT-Based ONIOM Calculation. J Phys Chem A 2022; 126:1666-1673. [PMID: 35258304 DOI: 10.1021/acs.jpca.1c10900] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Interpreting the initial decomposition mechanism is important for evaluating the thermal stability of explosives. In this study, we theoretically investigated the initial thermal decomposition reactions for two typical energetic materials, FOX-7 and RDX, in both the gas phase and crystal phase. Single molecular decomposition pathways in the gas phase are calculated using the density functional theory (DFT) method, and the crystal phase reactions are simulated through the MM/DFT-based ONIOM method. The calculation results indicate that the crystal environment has a significant influence on the initial thermal decomposition mechanism of FOX-7 and RDX. The cage effect induced by the crystal environment greatly confines molecular mobility and diffusion, rendering the generated small molecules to react with the remaining fragment and yield new decomposition channels compared with the gas phase condition. The crystal packing structures and intermolecular interactions (hydrogen bonds/π-π stacking) significantly increase the reaction barriers of FOX-7 and RDX, leading to the crystal phase reactions being more difficult to occur than in the gas phase. Since the practical application of explosives is mostly in the crystal state, it is important to consider the environmental effects on the initial decomposition reactions. The same insight can also be relevant for other energetic materials.
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Affiliation(s)
- Yinhua Ma
- Department of Physics, Dalian Maritime University, Dalian 116026, China
| | - Meiheng Lv
- College of Science, Shenyang University of Chemical Technology, Shenyang 110142, P.R. China
| | - Fangjian Shang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, P.R. China.,University of Chinese Academy of Sciences, Beijing 100049, P.R. China
| | - Chaoyang Zhang
- Institute of Chemical Materials, China Academy of Engineering Physics (CAEP), Mianyang, Sichuan 621900, P.R. China
| | - Jianyong Liu
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, P.R. China.,University of Chinese Academy of Sciences, Beijing 100049, P.R. China
| | - Panwang Zhou
- Institute of Molecular Sciences and Engineering, Institute of Frontier and Interdisciplinary Science, Shandong University, Qingdao 266235, P.R. China
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10
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Emission Quenching in Tetraphenylfuran Crystal: Why This Propeller-Shaped Molecule Does Not Emit in the Condensed Phase. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27020522. [PMID: 35056833 PMCID: PMC8780143 DOI: 10.3390/molecules27020522] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/11/2021] [Revised: 01/06/2022] [Accepted: 01/10/2022] [Indexed: 12/28/2022]
Abstract
Due to their substantial fluorescence quantum yields in the crystalline phase, propeller-shaped molecules have recently gained significant attention as potential emissive materials for optoelectronic applications. For the family of cyclopentadiene derivatives, light-emission is highly dependent on the nature of heteroatomic substitutions. In this paper, we investigate excited state relaxation pathways in the tetraphenyl-furan molecule (TPF), which in contrast with other molecules in the family, shows emission quenching in the solid-state. For the singlet manifold, our calculations show nonradiative pathways associated with C-O elongation are blocked in both vacuum and the solid state. A fraction of the population can be transferred to the triplet manifold and, subsequently, to the ground state in both phases. This process is expected to be relatively slow due to the small spin-orbit couplings between the relevant singlet-triplet states. Emission quenching in crystalline TPF seems to be in line with more efficient exciton hopping rates. Our simulations help clarify the role of conical intersections, population of the triplet states and crystalline structure in the emissive response of propeller-shaped molecules.
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11
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Saunders LK, Pallipurath AR, Gutmann MJ, Nowell H, Zhang N, Allan DR. A quantum crystallographic approach to short hydrogen bonds. CrystEngComm 2021; 23:6180-6190. [PMID: 34588923 PMCID: PMC8436739 DOI: 10.1039/d1ce00355k] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 07/27/2021] [Indexed: 11/21/2022]
Abstract
In this work we use high-resolution synchrotron X-ray diffraction for electron density mapping, in conjunction with ab initio modelling, to study short O-H⋯O and O+-H⋯O- hydrogen bonds whose behaviour is known to be tuneable by temperature. The short hydrogen bonds have donor-acceptor distances in the region of 2.45 Å and are formed in substituted urea and organic acid molecular complexes of N,N'-dimethylurea oxalic acid 2 : 1 (1), N,N-dimethylurea 2,4-dinitrobenzoate 1 : 1 (2) and N,N-dimethylurea 3,5-dinitrobenzoic acid 2 : 2 (3). From the combined analyses, these complexes are found to fall within the salt-cocrystal continuum and exhibit short hydrogen bonds that can be characterised as both strong and electrostatic (1, 3) or very strong with a significant covalent contribution (2). An additional charge assisted component is found to be important in distinguishing the relatively uncommon O-H⋯O pseudo-covalent interaction from a typical strong hydrogen bond. The electron density is found to be sensitive to the extent of static proton transfer, presenting it as a useful parameter in the study of the salt-cocrystal continuum. From complementary calculated hydrogen atom potentials, we attribute changes in proton position to the molecular environment. Calculated potentials also show zero barrier to proton migration, forming an 'energy slide' between the donor and acceptor atoms. The better fundamental understanding of the short hydrogen bond in the 'zone of fluctuation' presented in a salt-cocrystal continuum, enabled by studies like this, provide greater insight into their related properties and can have implications in the regulation of pharmaceutical materials.
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Affiliation(s)
- Lucy K Saunders
- Diamond Light Source, Harwell Science and Innovation Campus Didcot OX11 0DE UK
| | - Anuradha R Pallipurath
- School of Chemical and Process Engineering, University of Leeds Leeds LS2 9JT UK
- Research Complex at Harwell Didcot Oxfordshire OX11 0DE UK
- EPSRC Centre for Innovative Manufacturing in Continuous Manufacturing and Advanced Crystallization, University of Strathclyde G1 1RD UK
| | - Matthias J Gutmann
- ISIS Pulsed Muon and Neutron Source, Rutherford Appleton Laboratory, Harwell Oxford Didcot OX11 0QX UK
| | - Harriott Nowell
- Diamond Light Source, Harwell Science and Innovation Campus Didcot OX11 0DE UK
| | - Ningjin Zhang
- Chemistry, Faculty of Natural and Environmental Sciences, Highfield Campus, University of Southampton Southampton SO17 1HE UK
| | - David R Allan
- Diamond Light Source, Harwell Science and Innovation Campus Didcot OX11 0DE UK
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12
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Rivera M, Stojanović L, Crespo-Otero R. Role of Conical Intersections on the Efficiency of Fluorescent Organic Molecular Crystals. J Phys Chem A 2021; 125:1012-1024. [PMID: 33492964 DOI: 10.1021/acs.jpca.0c11072] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Organic molecular crystals are attractive materials for luminescent applications because of their promised tunability. However, the link between the chemical structure and emissive behavior is poorly understood because of the numerous interconnected factors which are at play in determining radiative and nonradiative behaviors at the solid-state level. In particular, the decay through conical intersection dominates the nonadiabatic regions of the potential energy surface, and thus, their accessibility is a telling indicator of the luminosity of the material. In this study, we investigate the radiative mechanism for five organic molecular crystals which display a solid-state emission, with a focus on the role of conical intersections in their photomechanisms. The objective is to situate the importance of the accessibility of conical intersections with regards to emissive behavior, taking into account other nonradiative decay channels, namely, vibrational decay, and exciton hopping. We begin by giving a brief overview of the structural patterns of the five systems within a larger pool of 13 crystals for a richer comparison. We observe that because of the prevalence of sheet like and herringbone packing in organic molecular crystals, the conformational diversity of crystal dimers is limited. Additionally, similarly spaced dimers have exciton coupling values of a similar order within a 50 meV interval. Next, we focus on three exemplary cases, where we disentangle the role of nonradiative decay mechanisms and show how rotational minimum energy conical intersections in vacuum lead to puckered ones in the crystal, increasing their instability upon crystallization in typical packing motifs. In contrast, molecules with puckered conical intersections in vacuum tend to conserve this trait upon crystallization, and therefore, their quantum yield of fluorescence is determined predominantly by other nonradiative decay mechanisms.
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Affiliation(s)
- Miguel Rivera
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, U.K
| | - Ljiljana Stojanović
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, U.K
| | - Rachel Crespo-Otero
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, U.K
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13
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Aldaz CR, Martinez TJ, Zimmerman PM. The Mechanics of the Bicycle Pedal Photoisomerization in Crystalline cis,cis-1,4-Diphenyl-1,3-butadiene. J Phys Chem A 2020; 124:8897-8906. [PMID: 33064471 DOI: 10.1021/acs.jpca.0c05803] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Direct irradiation of crystalline cis,cis-1,4-diphenyl-1,3-butadiene (cc-DPB) forms trans,trans-1,4-diphenyl-1,3,-butadiene via a concerted two-bond isomerization called the bicycle pedal (BP) mechanism. However, little is known about photoisomerization pathways in the solid state and there has been much debate surrounding the interpretation of volume-conserving isomerization mechanisms. The bicycle pedal photoisomerization is investigated using the quantum mechanics/molecular mechanics complete active space self-consistent field/Amber force-field method. Important details about how the steric environment influences isomerization mechanisms are revealed including how the one-bond flip and hula-twist mechanisms are suppressed by the crystal cavity, the nature of the seam space in steric environments, and the features of the bicycle pedal mechanism. Specifically, in the bicycle pedal, the phenyl rings of cc-DPB are locked in place and the intermolecular packing allows a passageway for rotation of the central diene in a volume-conserving manner. In contrast, the bicycle pedal rotation in the gas phase is not a stable pathway, so single-bond rotation mechanisms become operative instead. Furthermore, the crystal BP mechanism is an activated process that occurs completely on the excited state; the photoproduct can decay to the ground state through radiative and non-radiative pathways. The present models, however, do not capture the quantitative activation barriers, and more work is needed to better model reactions in crystals. Last, the reaction barriers of the different crystalline conformations within the unit cell of cc-DPB are compared to investigate the possibility for conformation-dependent isomerization. Although some difference in reaction barriers is observed, the difference is most likely not responsible for the experimentally observed periods of fast and slow conversion.
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Affiliation(s)
- Cody R Aldaz
- Department of Chemistry, University of Michigan, 930 N University Ave., Ann Arbor, Michigan 48109-1055, United States
| | - Todd J Martinez
- Department of Chemistry and the PULSE Institute, Stanford University, Stanford, California 94305, United States
| | - Paul M Zimmerman
- Department of Chemistry, University of Michigan, 930 N University Ave., Ann Arbor, Michigan 48109-1055, United States
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Rivera M, Dommett M, Sidat A, Rahim W, Crespo-Otero R. fromage: A library for the study of molecular crystal excited states at the aggregate scale. J Comput Chem 2020; 41:1045-1058. [PMID: 31909830 PMCID: PMC7079081 DOI: 10.1002/jcc.26144] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Revised: 11/27/2019] [Accepted: 12/03/2019] [Indexed: 12/31/2022]
Abstract
The study of photoexcitations in molecular aggregates faces the twofold problem of the increased computational cost associated with excited states and the complexity of the interactions among the constituent monomers. A mechanistic investigation of these processes requires the analysis of the intermolecular interactions, the effect of the environment, and 3D arrangements or crystal packing on the excited states. A considerable number of techniques have been tailored to navigate these obstacles; however, they are usually restricted to in‐house codes and thus require a disproportionate effort to adopt by researchers approaching the field. Herein, we present the FRamewOrk for Molecular AGgregate Excitations (fromage), which implements a collection of such techniques in a Python library complemented with ready‐to‐use scripts. The program structure is presented and the principal features available to the user are described: geometrical analysis, exciton characterization, and a variety of ONIOM schemes. Each is illustrated by examples of diverse organic molecules in condensed phase settings. The program is available at https://github.com/Crespo-Otero-group/fromage.
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Affiliation(s)
- Miguel Rivera
- Department of Chemistry, School of Biological and Chemical Sciences, Queen Mary University of London, London, UK
| | - Michael Dommett
- Department of Chemistry, School of Biological and Chemical Sciences, Queen Mary University of London, London, UK
| | - Amir Sidat
- Department of Chemistry, School of Biological and Chemical Sciences, Queen Mary University of London, London, UK
| | - Warda Rahim
- Department of Chemistry, School of Biological and Chemical Sciences, Queen Mary University of London, London, UK
| | - Rachel Crespo-Otero
- Department of Chemistry, School of Biological and Chemical Sciences, Queen Mary University of London, London, UK
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Stojanović L, Crespo‐Otero R. Understanding Aggregation Induced Emission in a Propeller‐Shaped Blue Emitter. CHEMPHOTOCHEM 2019. [DOI: 10.1002/cptc.201900075] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- Ljiljana Stojanović
- School of Biological and Chemical SciencesQueen Mary University of London Mile End Road London E1 4NS UK
| | - Rachel Crespo‐Otero
- School of Biological and Chemical SciencesQueen Mary University of London Mile End Road London E1 4NS UK
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