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Ośmiałowski B, Petrusevich EF, Antoniak MA, Grela I, Bin Jassar MA, Nyk M, Luis JM, Jędrzejewska B, Zaleśny R, Jacquemin D. Controlling Two-Photon Action Cross Section by Changing a Single Heteroatom Position in Fluorescent Dyes. J Phys Chem Lett 2020; 11:5920-5925. [PMID: 32628024 PMCID: PMC7460565 DOI: 10.1021/acs.jpclett.0c01438] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
The optimization of nonlinear optical properties for "real-life" applications remains a key challenge for both experimental and theoretical approaches. In particular, for two-photon processes, maximizing the two-photon action cross section (TPACS), the figure of merit for two-photon bioimaging spectroscopy, requires simultaneously controlling all its components. In the present Letter, a series of difluoroborates presenting various heterocyclic rings as an electron acceptor have been synthesized and their absorption, fluorescence, photoisomerization, and two-photon absorption features have been analyzed using both experimental and theoretical approaches. Our results demonstrate that the TPACS values can be fine-tuned by changing the position of a single heteroatom, which alters the fluorescence quantum yields without changing the intrinsic two-photon absorption cross section. This approach offers a new strategy for optimizing TPACS.
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Medved' M, Iglesias-Reguant A, Reis H, Góra RW, Luis JM, Zaleśny R. Partitioning of interaction-induced nonlinear optical properties of molecular complexes. II. Halogen-bonded systems. Phys Chem Chem Phys 2020; 22:4225-4234. [PMID: 32043097 DOI: 10.1039/c9cp06620a] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Following our study on hydrogen-bonded (HB) complexes [Phys. Chem. Chem. Phys., 2018, 20, 19841], the physical nature of interaction-induced (non)linear optical properties of another important class of molecular complexes, namely halogen-bonded (XB) systems, was analyzed in this study. The excess electronic and nuclear relaxation (hyper)polarizabilities of nine representative XB complexes covering a wide range of halogen-bond strengths were computed. The partitioning of the excess properties into individual interaction-energy components (electrostatic, exchange, induction, dispersion) was performed by using the variational-perturbational energy decomposition scheme at the MP2/aug-cc-pVTZ level of theory and further supported by calculations with the SCS-MP2 method. In the case of the electronic interaction-induced properties, the physical composition of Δαel and Δγel was found to be very similar for the two types of bonding, despite the different nature of the binding. For Δβel, the XB complexes exhibit a more systematic interplay of interaction-energy contributions compared to the HB systems studied in the previous work. Our analysis revealed that the patterns of interaction-energy contributions to the interaction-induced nuclear-relaxation contributions to the linear polarizability and the first hyperpolarizability are very similar. For both properties the exchange repulsion term is canceled out by the electrostatic and delocalization terms. The physical composition of these contributions is analogous to those observed for the HB complexes.
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Besalú-Sala P, Sitkiewicz SP, Salvador P, Matito E, Luis JM. A new tuned range-separated density functional for the accurate calculation of second hyperpolarizabilities. Phys Chem Chem Phys 2020; 22:11871-11880. [DOI: 10.1039/d0cp01291b] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Among the nine functionals benchmarked, the most accurate γ are obtained by Tα-LC-BLYP, reducing about half the errors of LC-BLYP.
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Fernández S, Franco F, Casadevall C, Martin-Diaconescu V, Luis JM, Lloret-Fillol J. A Unified Electro- and Photocatalytic CO2 to CO Reduction Mechanism with Aminopyridine Cobalt Complexes. J Am Chem Soc 2019; 142:120-133. [DOI: 10.1021/jacs.9b06633] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Capdevila L, Meyer TH, Roldán-Gómez S, Luis JM, Ackermann L, Ribas X. Chemodivergent Nickel(0)-Catalyzed Arene C–F Activation with Alkynes: Unprecedented C–F/C–H Double Insertion. ACS Catal 2019. [DOI: 10.1021/acscatal.9b03620] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Zaleśny R, Medved' M, Sitkiewicz SP, Matito E, Luis JM. Can Density Functional Theory Be Trusted for High-Order Electric Properties? The Case of Hydrogen-Bonded Complexes. J Chem Theory Comput 2019; 15:3570-3579. [PMID: 31082215 DOI: 10.1021/acs.jctc.9b00139] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
This work reports on an extensive assessment of the performance of a wide palette of density functional approximations in predicting the (high-order) electric properties of hydrogen-bonded complexes. To this end, we compute the electronic and vibrational contributions to the electric polarizability and the first and second hyperpolarizabilities, using the CCSD(T)/aug-cc-pVTZ level of theory as reference. For all the studied properties, the average absolute errors below 20% can only be obtained using the CAM-B3LYP functional, while LC-BLYP and MN15 are shown to be only slightly less accurate (average absolute errors not exceeding 30%). Among Minnesota density functionals, i.e., M06, M06-2X, and MN15, we only recommend the latter one, which quite accurately predicts the electronic and vibrational (hyper)polarizabilities. We also analyze the optimal tuning of the range-separation parameter μ for the LC-BLYP functional, finding that this approach does not bring any systematic improvement in the predictions of electronic and vibrational (hyper)polarizabilities and the accuracy of computed properties is largely system-dependent. Finally, we report huge errors in predicting the vibrational second hyperpolarizability by ωB97X, M06, and M06-2X functionals. Based on the explicit evaluation of anharmonic terms contributing to the second hyperpolarizability, this failure is traced down to a poor determination of third- and fourth-order energy derivatives with respect to normal modes. These results reveal serious flaws of some density functional approximations and suggest caution in selecting the appropriate functional to calculate not only electronic and vibrational (hyper)polarizabilities but also other molecular properties that contain vibrational anharmonic contributions.
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Sitkiewicz SP, Rodríguez-Mayorga M, Luis JM, Matito E. Partition of optical properties into orbital contributions. Phys Chem Chem Phys 2019; 21:15380-15391. [DOI: 10.1039/c9cp02662b] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
A new tool to analyze the response property through the partition of nonlinear optical properties in terms of orbital contributions (PNOC), valuable in the assessment of the electronic structure methods in the NLOPs computations, is presented.
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Codolà Z, Gamba I, Acuña-Parés F, Casadevall C, Clémancey M, Latour JM, Luis JM, Lloret-Fillol J, Costas M. Design of Iron Coordination Complexes as Highly Active Homogenous Water Oxidation Catalysts by Deuteration of Oxidation-Sensitive Sites. J Am Chem Soc 2018; 141:323-333. [PMID: 30497265 DOI: 10.1021/jacs.8b10211] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The nature of the oxidizing species in water oxidation reactions with chemical oxidants catalyzed by α-[Fe(OTf)2(mcp)] (1α; mcp = N, N'-dimethyl- N, N'-bis(pyridin-2-ylmethyl)cyclohexane-1,2-diamine, OTf = trifluoromethanesulfonate anion) and β-[Fe(OTf)2(mcp)] (1β) has been investigated. Mössbauer spectroscopy provides definitive evidence that 1α and 1β generate oxoiron(IV) species as the resting state. Decomposition paths of the catalysts have been investigated by identifying and quantifying ligand fragments that form upon degradation. This analysis correlates the water oxidation activity of 1α and 1β with stability against oxidative damage of the ligand via aliphatic C-H oxidation. The site of degradation and the relative stability against oxidative degradation are shown to be dependent on the topology of the catalyst. Furthermore, the mechanisms of catalyst degradation have been rationalized by computational analyses, which also explain why the topology of the catalyst enforces different oxidation-sensitive sites. This information has served in creating catalysts where sensitive C-H bonds have been replaced by C-D bonds. The deuterated analogues D4-α-[Fe(OTf)2(mcp)] (D4-1α), D4-β-[Fe(OTf)2(mcp)] (D4-1β), and D6-β-[Fe(OTf)2(mcp)] (D6-1β) were prepared, and their catalytic activity has been studied. D4-1α proves to be an extraordinarily active and efficient catalyst (up to 91% of O2 yield); it exhibits initial reaction rates identical with those of its protio analogue, but it is substantially more robust toward oxidative degradation and yields more than 3400 TON ( n(O2)/ n(Fe)). Altogether this evidences that the water oxidation catalytic activity is performed by a well-defined coordination complex and not by iron oxides formed after oxidative degradation of the ligands.
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Postils V, Delgado‐Alonso C, Luis JM, Salvador P. An Objective Alternative to IUPAC's Approach To Assign Oxidation States. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201802745] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Planas O, Roldán-Gómez S, Martin-Diaconescu V, Luis JM, Company A, Ribas X. Mechanistic insights into the S N2-type reactivity of aryl-Co(iii) masked-carbenes for C-C bond forming transformations. Chem Sci 2018; 9:5736-5746. [PMID: 30079183 PMCID: PMC6050605 DOI: 10.1039/c8sc00851e] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Accepted: 05/28/2018] [Indexed: 12/14/2022] Open
Abstract
Herein we describe the synthesis and characterization of a family of C-metalated aryl-Co(iii) enolates, which can be considered as masked-carbenes, using diazoacetates as coupling partners. These species have been proved to be necessary intermediates in the C(sp2)-C(sp3) bond forming event to obtain cyclic amides, taming the elusive Co(iii)-carbene species. The scope of diazoacetates has been exhaustively examined, varying the nature of the ester and the α-substitution, and a clear preference for electron-poor carbene precursors is observed. Exhaustive experimental and theoretical studies indicate that an unprecedented intramolecular SN2-type process governs the formation of the newly formed C-C bond. Furthermore, the key role of several Lewis acids as carboxylate-activating reagents is further explored by DFT calculations.
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Postils V, Saint-André M, Timmins A, Li XX, Wang Y, Luis JM, Solà M, de Visser SP. Quantum Mechanics/Molecular Mechanics Studies on the Relative Reactivities of Compound I and II in Cytochrome P450 Enzymes. Int J Mol Sci 2018; 19:E1974. [PMID: 29986417 PMCID: PMC6073316 DOI: 10.3390/ijms19071974] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Revised: 06/28/2018] [Accepted: 07/02/2018] [Indexed: 02/03/2023] Open
Abstract
The cytochromes P450 are drug metabolizing enzymes in the body that typically react with substrates through a monoxygenation reaction. During the catalytic cycle two reduction and protonation steps generate a high-valent iron (IV)-oxo heme cation radical species called Compound I. However, with sufficient reduction equivalents present, the catalytic cycle should be able to continue to the reduced species of Compound I, called Compound II, rather than a reaction of Compound I with substrate. In particular, since electron transfer is usually on faster timescales than atom transfer, we considered this process feasible and decided to investigate the reaction computationally. In this work we present a computational study using density functional theory methods on active site model complexes alongside quantum mechanics/molecular mechanics calculations on full enzyme structures of cytochrome P450 enzymes. Specifically, we focus on the relative reactivity of Compound I and II with a model substrate for O⁻H bond activation. We show that generally the barrier heights for hydrogen atom abstraction are higher in energy for Compound II than Compound I for O⁻H bond activation. Nevertheless, for the activation of such bonds, Compound II should still be an active oxidant under enzymatic conditions. As such, our computational modelling predicts that under high-reduction environments the cytochromes P450 can react with substrates via Compound II but the rates will be much slower.
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Postils V, Delgado-Alonso C, Luis JM, Salvador P. An Objective Alternative to IUPAC's Approach To Assign Oxidation States. Angew Chem Int Ed Engl 2018; 57:10525-10529. [PMID: 29787636 DOI: 10.1002/anie.201802745] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 04/25/2018] [Indexed: 11/11/2022]
Abstract
The IUPAC has recently clarified the term oxidation state (OS), and provided algorithms for its determination based on the ionic approximation (IA) of the bonds supported by atomic electronegativities (EN). Unfortunately, there are a number of exceptions and ambiguities in IUPAC's algorithms when it comes to practical applications. Our comprehensive study reveals the critical role of the chemical environment on establishing the OS, which cannot always be properly predicted using fix atomic EN values. By identifying what we define here as subsystems of enhanced stability within the molecular system, the OS can be safely assigned in many cases without invoking exceptions. New insights about the effect of local aromaticity upon OS are revealed. Moreover, we prove that there are intrinsic limitations of the IA that cannot be overcome. In this context, the effective oxidation state (EOS) analysis arises as a robust and general scheme to derive an OS without any external guidance.
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El Bakouri O, Postils V, Garcia-Borràs M, Duran M, Luis JM, Calvello S, Soncini A, Matito E, Feixas F, Solà M. Metal Cluster Electrides: A New Type of Molecular Electride with Delocalised Polyattractor Character. Chemistry 2018; 24:9853-9859. [DOI: 10.1002/chem.201800878] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Revised: 04/16/2018] [Indexed: 11/06/2022]
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Postils V, Rodríguez M, Sabenya G, Conde A, Díaz-Requejo MM, Pérez PJ, Costas M, Solà M, Luis JM. Mechanism of the Selective Fe-Catalyzed Arene Carbon–Hydrogen Bond Functionalization. ACS Catal 2018. [DOI: 10.1021/acscatal.7b03935] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Serrano-Plana J, Acuña-Parés F, Dantignana V, Oloo WN, Castillo E, Draksharapu A, Whiteoak CJ, Martin-Diaconescu V, Basallote MG, Luis JM, Que L, Costas M, Company A. Acid-Triggered O-O Bond Heterolysis of a Nonheme Fe III (OOH) Species for the Stereospecific Hydroxylation of Strong C-H Bonds. Chemistry 2018; 24:5331-5340. [PMID: 29193378 DOI: 10.1002/chem.201704851] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Indexed: 12/11/2022]
Abstract
A novel hydroperoxoiron(III) species [FeIII (OOH)(MeCN)(PyNMe3 )]2+ (3) has been generated by reaction of its ferrous precursor [FeII (CF3 SO3 )2 (PyNMe3 )] (1) with hydrogen peroxide at low temperatures. This species has been characterized by several spectroscopic techniques and cryospray mass spectrometry. Similar to most of the previously described low-spin hydroperoxoiron(III) compounds, 3 behaves as a sluggish oxidant and it is not kinetically competent for breaking weak C-H bonds. However, triflic acid addition to 3 causes its transformation into a much more reactive compound towards organic substrates that is capable of oxidizing unactivated C-H bonds with high stereospecificity. Stopped-flow kinetic analyses and theoretical studies provide a rationale for the observed chemistry, a triflic-acid-assisted heterolytic cleavage of the O-O bond to form a putative strongly oxidizing oxoiron(V) species. This mechanism is reminiscent to that observed in heme systems, where protonation of the hydroperoxo intermediate leads to the formation of the high-valent [(Porph. )FeIV (O)] (Compound I).
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Zaleśny R, Medved’ M, Góra RW, Reis H, Luis JM. Partitioning of interaction-induced nonlinear optical properties of molecular complexes. I. Hydrogen-bonded systems. Phys Chem Chem Phys 2018; 20:19841-19849. [DOI: 10.1039/c8cp02967a] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Interaction-induced electronic and vibrational (hyper)polarizabilities were decomposed into different interaction types (electrostatic, exchange, induction and dispersion).
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Call A, Franco F, Kandoth N, Fernández S, González-Béjar M, Pérez-Prieto J, Luis JM, Lloret-Fillol J. Understanding light-driven H 2 evolution through the electronic tuning of aminopyridine cobalt complexes. Chem Sci 2017; 9:2609-2619. [PMID: 29675253 PMCID: PMC5892349 DOI: 10.1039/c7sc04328g] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Accepted: 12/18/2017] [Indexed: 11/25/2022] Open
Abstract
Electronic effects provide a general mechanistic scenario for rationalizing photocatalytic water reduction activity with aminopyridine cobalt complexes.
A new family of cobalt complexes with the general formula [CoII(OTf)2(Y,XPyMetacn)] (1R, Y,XPyMetacn = 1-[(4-X-3,5-Y-2-pyridyl)methyl]-4,7-dimethyl-1,4,7-triazacyclononane, (X = CN (1CN), CO2Et (1CO2Et), Cl (1Cl), H (1H), NMe2 (1NMe2)) where (Y = H, and X = OMe when Y = Me (1DMM)) is reported. We found that the electronic tuning of the Y,XPyMetacn ligand not only has an impact on the electronic and structural properties of the metal center, but also allows for a systematic water-reduction-catalytic control. In particular, the increase of the electron-withdrawing character of the pyridine moiety promotes a 20-fold enhancement of the catalytic outcome. By UV-Vis spectroscopy, luminescence quenching studies and Transient Absorption Spectroscopy (TAS), we have studied the direct reaction of the photogenerated [IrIII(ppy)2(bpy˙–)] (PSIr) species to form the elusive CoI intermediates. In particular, our attention is focused on the effect of the ligand architecture in this elemental step of the catalytic mechanism. Finally, kinetic isotopic experiments together with DFT calculations provide complementary information about the rate-determining step of the catalytic cycle.
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Planas O, Roldán-Gómez S, Martin-Diaconescu V, Parella T, Luis JM, Company A, Ribas X. Carboxylate-Assisted Formation of Aryl-Co(III) Masked-Carbenes in Cobalt-Catalyzed C–H Functionalization with Diazo Esters. J Am Chem Soc 2017; 139:14649-14655. [DOI: 10.1021/jacs.7b07880] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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Torrent-Sucarrat M, Navarro S, Cossío FP, Anglada JM, Luis JM. Relevance of the DFT method to study expanded porphyrins with different topologies. J Comput Chem 2017; 38:2819-2828. [DOI: 10.1002/jcc.25074] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Revised: 08/03/2017] [Accepted: 09/07/2017] [Indexed: 12/14/2022]
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Zaleśny R, Chołuj M, Kozłowska J, Bartkowiak W, Luis JM. Vibrational nonlinear optical properties of spatially confined weakly bound complexes. Phys Chem Chem Phys 2017; 19:24276-24283. [PMID: 28848981 DOI: 10.1039/c7cp04259k] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This study focuses on the theoretical description of the influence of spatial confinement on the electronic and vibrational contributions to (hyper)polarizabilities of two dimeric hydrogen bonded systems, namely HCNHCN and HCNHNC. A two-dimensional analytical potential is employed to render the confining environment (e.g. carbon nanotube). Based on the results of the state-of-the-art calculations, performed at the CCSD(T)/aug-cc-pVTZ level of theory, we established that: (i) the influence of spatial confinement increases with increasing order of the electrical properties, (ii) the effect of spatial confinement is much larger in the case of the electronic than vibrational contribution (this holds for each order of the electrical properties) and (iii) the decrease in the static nuclear relaxation first hyperpolarizability upon the increase of confinement strength is mainly due to changes in the harmonic term, however, in the case of nuclear relaxation second hyperpolarizability the anharmonic terms contribute more to the drop of this property.
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Rovira M, Roldán-Gómez S, Martin-Diaconescu V, Whiteoak CJ, Company A, Luis JM, Ribas X. Trifluoromethylation of a Well-Defined Square-Planar Aryl-Ni II Complex involving Ni III /CF 3. and Ni IV -CF 3 Intermediate Species. Chemistry 2017; 23:11662-11668. [PMID: 28685908 DOI: 10.1002/chem.201702168] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Indexed: 11/11/2022]
Abstract
Ni-mediated trifluoromethylation of an aryl-Br bond in model macrocyclic ligands (Ln -Br) has been thoroughly studied, starting with an oxidative addition at Ni0 to obtain well-defined aryl-NiII -Br complexes ([Ln -NiII ]Br). Abstraction of the halide with AgX (X=OTf- or ClO4- ) thereafter provides [Ln -NiII ](OTf). The nitrate analogue has been obtained through a direct C-H activation of an aryl-H bond using NiII salts, and this route has been studied by X-ray absorption spectroscopy (XAS). Crystallographic XRD and XAS characterization has shown a tight macrocyclic coordination in the aryl-NiII complex, which may hamper direct reaction with nucleophiles. On the contrary, enhanced reactivity is observed with oxidants, and the reaction of [Ln -NiII ](OTf) with CF3+ sources afforded Ln -CF3 products in quantitative yield. A combined experimental and theoretical mechanistic study provides new insights into the operative mechanism for this transformation. Computational analysis indicates the occurrence of an initial single electron transfer (SET) to 5-(trifluoromethyl)dibenzothiophenium triflate (TDTT), producing a transient L1 -NiIII /CF3. adduct, which rapidly recombines to form a [L1 -NiIV -CF3 ](X)2 intermediate species. A final facile reductive elimination affords L1 -CF3 . The well-defined square-planar model system studied here permits to gain fundamental knowledge on the rich redox chemistry of nickel, which is sought to facilitate the development of new Ni-based trifluoromethylation methodologies.
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Garcia-Borràs M, Osuna S, Luis JM, Solà M. Rationalizing the relative abundances of trimetallic nitride template-based endohedral metallofullerenes from aromaticity measures. Chem Commun (Camb) 2017; 53:4140-4143. [PMID: 28352903 PMCID: PMC5436040 DOI: 10.1039/c7cc01750b] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Accepted: 03/20/2017] [Indexed: 11/25/2022]
Abstract
The synthesis of endohedral metallofullerenes (EMFs) from a carbon soot sample of an arc discharge leads to a variety of EMFs that are obtained in different relative abundances. In the present work, we show that these abundances can be predicted from aromaticity calculations. In particular, we use the normalized Additive Local Aromaticity (ALAN) index. Our results show that the most abundant Sc3N-based and Y3N-based EMFs in fullerene soot are the most aromatic. This study reinforces the idea that aromaticity plays a key role in determining the stability of EMFs.
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Rovira M, Jašíková L, Andris E, Acuña-Parés F, Soler M, Güell I, Wang MZ, Gómez L, Luis JM, Roithová J, Ribas X. A CuI/CuIII prototypical organometallic mechanism for the deactivation of an active pincer-like CuI catalyst in Ullmann-type couplings. Chem Commun (Camb) 2017; 53:8786-8789. [DOI: 10.1039/c7cc04491g] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Decomposition pathways in Ullmann C–O couplings have been studied by helium tagging IRPD and DFT studies, supporting aryl–CuIII intermediate species.
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Planas O, Whiteoak CJ, Martin-Diaconescu V, Gamba I, Luis JM, Parella T, Company A, Ribas X. Isolation of Key Organometallic Aryl-Co(III) Intermediates in Cobalt-Catalyzed C(sp2)–H Functionalizations and New Insights into Alkyne Annulation Reaction Mechanisms. J Am Chem Soc 2016; 138:14388-14397. [DOI: 10.1021/jacs.6b08593] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Zaleśny R, Garcia-Borràs M, Góra RW, Medved' M, Luis JM. On the physical origins of interaction-induced vibrational (hyper)polarizabilities. Phys Chem Chem Phys 2016; 18:22467-77. [PMID: 27465257 DOI: 10.1039/c6cp02500e] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This paper presents the results of a pioneering exploration of the physical origins of vibrational contributions to the interaction-induced electric properties of molecular complexes. In order to analyze the excess nuclear relaxation (hyper)polarizabilities, a new scheme was proposed which relies on the computationally efficient Bishop-Hasan-Kirtman method for determining the nuclear relaxation contributions to electric properties. The extension presented herein is general and can be used with any interaction-energy partitioning method. As an example, in this study we employed the variational-perturbational interaction-energy decomposition scheme (at the MP2/aug-cc-pVQZ level) and the extended transition state method by employing three exchange-correlation functionals (BLYP, LC-BLYP, and LC-BLYP-dDsC) to study the excess properties of the HCN dimer. It was observed that the first-order electrostatic contribution to the excess nuclear relaxation polarizability cancels with the negative exchange repulsion term out to a large extent, resulting in a positive value of Δα(nr) due to the contributions from the delocalization and the dispersion terms. In the case of the excess nuclear relaxation first hyperpolarizability, the pattern of interaction contributions is very similar to that for Δα(nr), both in terms of their sign as well as relative magnitude. Finally, our results show that the LC-BLYP and LC-BLYP-dDsC functionals, which yield smaller values of the orbital relaxation term than BLYP, are more successful in predicting excess properties.
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