A Pariser-Parr-Pople-based set of Hueckel molecular orbital parameters

Van-Catledge, F. A.

doi:10.1021/jo01311a060

Cited by 106 publications

(63 citation statements)

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“…Syntaurus calculates on the fly the per-atom delocalization energies (see Ref. [46] and SI, Section S11) of aromatic systems and then uses these values to determine where and which substitutions are allowed (electrophilic and nucleophilic substitutions are allowed if delocalization energy is, respectively,b elow and above certain thresholds).…”

Section: Angewandte Chemiementioning

confidence: 99%

Computer‐Assisted Synthetic Planning: The End of the Beginning

et al. 2016

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Exactly half a century has passed since the launch of the first documented research project (1965 Dendral) on computer-assisted organic synthesis. Many more programs were created in the 1970s and 1980s but the enthusiasm of these pioneering days had largely dissipated by the 2000s, and the challenge of teaching the computer how to plan organic syntheses earned itself the reputation of a "mission impossible". This is quite curious given that, in the meantime, computers have "learned" many other skills that had been considered exclusive domains of human intellect and creativity-for example, machines can nowadays play chess better than human world champions and they can compose classical music pleasant to the human ear. Although there have been no similar feats in organic synthesis, this Review argues that to concede defeat would be premature. Indeed, bringing together the combination of modern computational power and algorithms from graph/network theory, chemical rules (with full stereo- and regiochemistry) coded in appropriate formats, and the elements of quantum mechanics, the machine can finally be "taught" how to plan syntheses of non-trivial organic molecules in a matter of seconds to minutes. The Review begins with an overview of some basic theoretical concepts essential for the big-data analysis of chemical syntheses. It progresses to the problem of optimizing pathways involving known reactions. It culminates with discussion of algorithms that allow for a completely de novo and fully automated design of syntheses leading to relatively complex targets, including those that have not been made before. Of course, there are still things to be improved, but computers are finally becoming relevant and helpful to the practice of organic-synthetic planning. Paraphrasing Churchill's famous words after the Allies' first major victory over the Axis forces in Africa, it is not the end, it is not even the beginning of the end, but it is the end of the beginning for the computer-assisted synthesis planning. The machine is here to stay.

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Section: Angewandte Chemiementioning

confidence: 99%

Computer‐Assisted Synthetic Planning: The End of the Beginning

et al. 2016

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“…Both TRE and BRE are given in units of jbj, where b is the standard resonance integral in H€ uckel theory. Van-Catledge's set of H€ uckel parameters for heteroatoms (29) has been used. In general, aromatic molecules are chemically more stable than less aromatic or antiaromatic molecules.…”

Section: Methods Of Calculationmentioning

confidence: 99%

A Study of the Aromaticity of the Heterofullerene C_24–2nB_nN_n(n= 3 or 6) and C₁₂N₁₂Isomers

Tawar

Kerim

2015

Fullerenes, Nanotubes and Carbon Nanostructures

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The global aromaticity of the heterofullerene C 24-2n B n N n (n D 3 or 6) and C 12 N 12 isomers formed from the initial C 24 fullerene with D 6 symmetry, has been investigated using both the topological resonance energy (TRE) and the percentage topological resonance energy (%TRE) methods. The local aromaticity was studied using the bond resonance energy (BRE) method. Analysis was made of the effects of the types, the numbers, and the arrangements of heteroatoms on the global and local aromaticity of the molecules under consideration. Our results obtained by the TRE and %TRE methods were compared with the nucleus independent chemical shift (NICS (0)) values at the cage center. We found that NICS(0) values were not suitable for estimating the global aromaticity of these compounds. It was expected that the inclusion of heteroatoms would decrease the antiaromaticity relative to the C 24 (D 6 ) cage. Our BRE results show that the antiaromaticity is primarily related to the existence of highly reactive antiaromatic bonds in the molecule. We found that when a local structure within the cage had two nitrogen and one boron atom in the same pentagon ring, it played an important role in the global aromaticity of these compounds. Finally, we predicted the kinetic stability using the minimum BRE method.

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“…3840 We will use, if necessary, the Hückel parameters reported by VanCatledge. 50 We must note that the reference polynomials for a heterocyclic π-system and subsystems are no longer matching polynomials. All matching polynomials in the form of eq 5 must be replaced by the corresponding reference polynomials for the heterocycle and its subsystems, which can be obtained by means of the generalized Sachs formula.…”

Section: 28mentioning

confidence: 99%

Graph Theory of Ring-Current Diamagnetism

Aihara

2017

Bulletin of the Chemical Society of Japan

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Various magnetic criteria of aromaticity have been proposed so far, because they are easily calculated and applicable to a variety of cyclic π-systems. Many researchers, however, are reluctant to accept all or some of them. Our graph theory of ring-current diamagnetism revealed serious flaws in familiar magnetic criteria of aromaticity. Physically meaningful information on aromaticity can nevertheless be extracted from the ring-current diamagnetism. In particular, magnetic resonance energy (MRE), derived from the ring-current diamagnetic susceptibility, is interpretable as a kind of aromatic stabilization energy (ASE) and helps in consistently interpreting energetic and magnetic criteria of aromaticity. MRE and related quantities can be determined without reference to any hypothetical polyene-like structure but with a reasonable assumption that, when a magnetic field is applied to a cyclic π-system, a current is induced in each circuit in proportion to the ASE arising from the circuit. Unlike other conventional magnetic indexes, they are independent of the size and shape of the π-system.

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A Pariser-Parr-Pople-based set of Hueckel molecular orbital parameters

Cited by 106 publications

References 0 publications

Computer‐Assisted Synthetic Planning: The End of the Beginning

Computer‐Assisted Synthetic Planning: The End of the Beginning

A Study of the Aromaticity of the Heterofullerene C_24–2nB_nN_n(n= 3 or 6) and C₁₂N₁₂Isomers

Graph Theory of Ring-Current Diamagnetism

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A Pariser-Parr-Pople-based set of Hueckel molecular orbital parameters

Cited by 106 publications

References 0 publications

Computer‐Assisted Synthetic Planning: The End of the Beginning

Computer‐Assisted Synthetic Planning: The End of the Beginning

A Study of the Aromaticity of the Heterofullerene C24–2nBnNn(n= 3 or 6) and C12N12Isomers

Graph Theory of Ring-Current Diamagnetism

Contact Info

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A Study of the Aromaticity of the Heterofullerene C_24–2nB_nN_n(n= 3 or 6) and C₁₂N₁₂Isomers