An Objective Alternative to IUPAC's Approach To Assign Oxidation States

Postils, Verònica; Delgado‐Alonso, Carlos; Luis, Josep M.; Salvador, P.

doi:10.1002/anie.201802745

Cited by 52 publications

(42 citation statements)

References 37 publications

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“…Finally, we study how the constituent parts of the compound change upon oxidation of the nanoring. We have performed an effective oxidation state (EOS)[ 48 , 49 ] analysis of three different fragments of the nanoring: the zinc atoms (Zn), the porphyrins (P), and the linkers (L). The carbon shared by the porphyrin and the linkers is assigned to the porphyrin.…”

Section: Resultsmentioning

confidence: 99%

How Aromatic Are Molecular Nanorings? The Case of a Six‐Porphyrin Nanoring**

et al. 2021

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Large conjugated rings give rise to novel promising structures that can sustain persistent currents at low temperatures even in the presence of strong magnetic fields. One of the most interesting such molecules was recently synthesized [Anderson et al., Nature, 2017, 541, 3512] in the form of a six-porphyrin nanoring structure, which, according to the authors, in its +6-oxidation state (c-P66+) sustained an aromatic ring current involving 78π electrons; one of the largest aromatic rings ever produced. In this paper, we have provided compelling evidence that this molecule is not aromatic, as it was incorrectly inferred from computational calculations that suffer from large delocalization errors. A thorough analysis of four oxidation states of the six-porphyrin nanoring re-veals that the main reason behind the poor aromaticity of these nanorings is the low delocalization in the transition from the porphyrins to the bridging butadiyne linkers, which disrupts the overall conjugated circuit. These results highlight the importance of choosing an adequate computational method to study large conjugated molecules and the appropriate aromaticity descriptors to identify the part of the molecule that is responsible for the loss of aromaticity. We believe the strategy here employed will be helpful in designing new large aromatic molecular nanorings. File list (2)download file view on ChemRxiv Nanoring_manuscript.pdf (3.59 MiB) download file view on ChemRxiv SI_nanoring.pdf (7.39 MiB)

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Section: Resultsmentioning

confidence: 99%

How Aromatic Are Molecular Nanorings? The Case of a Six‐Porphyrin Nanoring**

et al. 2021

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“…For instance, the concept of Oxidation State has lacked a clear definition for years, but the problem was not related to any partitioning, but to the rather vague terminology used. After IUPAC has recently revised the concept (albeit not in a fully satisfactory way in my view), new first‐principles schemes (which at the end of the day also make use of a partitioning scheme) can be devised to match with the so‐called chemical intuition. Another illustrative example is that of the “local spin”.…”

Section: Question 3: How Can One Use the Results Of A Partition Schemmentioning

confidence: 99%

Nine questions on energy decomposition analysis

Andrés

Ayers

Boto³

et al. 2019

J Comput Chem

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125

123

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The paper collects the answers of the authors to the following questions: Is the lack of precision in the definition of many chemical concepts one of the reasons for the coexistence of many partition schemes? Does the adoption of a given partition scheme imply a set of more precise definitions of the underlying chemical concepts? How can one use the results of a partition scheme to improve the clarity of definitions of concepts? Are partition schemes subject to scientific Darwinism? If so, what is the influence of a community's sociological pressure in the “natural selection” process? To what extent does/can/should investigated systems influence the choice of a particular partition scheme? Do we need more focused chemical validation of Energy Decomposition Analysis (EDA) methodology and descriptors/terms in general? Is there any interest in developing common benchmarks and test sets for cross‐validation of methods? Is it possible to contemplate a unified partition scheme (let us call it the “standard model” of partitioning), that is proper for all applications in chemistry, in the foreseeable future or even in principle? In the end, science is about experiments and the real world. Can one, therefore, use any experiment or experimental data be used to favor one partition scheme over another? © 2019 Wiley Periodicals, Inc.

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“…We also calculate the localization index, 113,114 which gives a measure of the number of electrons localized in this region. In addition, we performed an effective oxidation state (EOS) analysis 115,116 to assign an integer number of electrons to the NNA basin. Unlike the NNA population, which gives the average number of electrons in the NNA basin, the NNA EOS is an integer number (or, occasionally, a rational number) that is expected to provide a value close to the formal ionic picture 116 of the NNA basin.…”

Section: Methodsmentioning

confidence: 99%

“…In addition, we performed an effective oxidation state (EOS) analysis 115,116 to assign an integer number of electrons to the NNA basin. Unlike the NNA population, which gives the average number of electrons in the NNA basin, the NNA EOS is an integer number (or, occasionally, a rational number) that is expected to provide a value close to the formal ionic picture 116 of the NNA basin. The two values provide important complementary information about the electronic structure of a molecule.…”

Section: Methodsmentioning

confidence: 99%

“…Finally, we will employ the effective oxidation state (EOS) tool developed by Salvador and co-workers. 115,116 Namely, we will calculate the EOS of the NNA basin, which will provide the oxidation state of the NNA basin. In order to calculate the EOS, we must define real-space fragments among which the electrons will be distributed.…”

Section: Which Is the Most Likely Number Of Electrons In Molecular Elmentioning

confidence: 99%

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How Many Electrons Holds a Molecular Electride?

Sitkiewicz¹,

Ramos‐Cordoba²,

Luis³

et al. 2021

Preprint

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<div> <div> <div> <p>Electrides are very peculiar ionic compounds where electrons occupy the anionic positions. In a crystal lattice, these isolated electrons often group forming channels or surfaces, furnishing electrides with a plethora of traits with promising technological applications. Despite their huge potential, thus far, only a few stable electrides have been produced because of the intricate synthesis they entail. Due to the difficulty in assessing the presence of isolated electrons, the characterization of electrides also poses some serious challenges. In fact, their properties are expected to depend on the arrangement of these electrons in the molecule. Among the criteria that we can use to characterize electrides, the presence of a non-nuclear attractor (NNA) of the electron density is both the rarest and the most salient feature. Therefore, a correct description of the NNA is crucial to determine the properties of electrides. In this paper, we analyze the NNA and the surrounding region of nine molecular electrides with the goal of determining the number of isolated electrons that are held in the electride. We have seen that the correct description of a molecular electride hinges on the electronic structure method employed for the analyses. In particular, one should employ a basis set with sufficient flexibility to describe the region close to the NNA and a density functional approximation that does not suffer from large delocalization errors. Finally, we have classified these nine molecular electrides according to the most likely number of electrons that we can find in the NNA. We believe this classification highlights the strength of the electride character and will prove useful in the design of new electrides.</p> </div> </div> </div>

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An Objective Alternative to IUPAC's Approach To Assign Oxidation States

Cited by 52 publications

References 37 publications

How Aromatic Are Molecular Nanorings? The Case of a Six‐Porphyrin Nanoring**

How Aromatic Are Molecular Nanorings? The Case of a Six‐Porphyrin Nanoring**

Nine questions on energy decomposition analysis

How Many Electrons Holds a Molecular Electride?

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