A Cyclotriborane Dianion and the Triboron Cation: “Light Ends” of the Hückel Rule

2016 ◽  
Vol 55 (6) ◽  
pp. 1962-1964 ◽  
Author(s):  
Bernd Wrackmeyer
Keyword(s):  
Hückel Rule

Theory of moments, Hückel rule and stability

1988 ◽  
Vol 53 (8) ◽  
pp. 1607-1612 ◽  
Author(s):  
Štěpán Pick
Keyword(s):  
Wave Function ◽  
Mechanical System ◽  
Present Approach ◽  
Quantum Mechanical ◽  
Quantum Mechanical System ◽  
Conjugated Systems ◽  
And Topology ◽  
Hückel Rule ◽  
Simple Chemical

The connection between moments of the electronic Hamiltonian and topology of a quantum mechanical system is studied. Based on simplifications similar to those usually employed in simple chemical and physical theories, criteria resembling the Hückel rule for cyclic conjugated systems are suggested. Several examples of interest in chemistry and solid physics are discussed. No information on the wave function is necessary in the present approach.

On the Hückel rule in alternant hydrocarbons

1984 ◽  
Vol 107 (3) ◽  
pp. 272-279 ◽  
Author(s):  
Tomislav P. Živković
Keyword(s):  
Hückel Rule ◽  
Alternant Hydrocarbons

On the extension of the Hückel rule to polycyclic non-alternant conjugated hydrocarbons

1976 ◽  
Vol 54 (11) ◽  
pp. 1789-1794 ◽  
Author(s):  
I. Gutman ◽  
N. Trinajstić
Keyword(s):  
Electron System ◽  
The Other ◽  
Conjugated Hydrocarbons ◽  
General Rules ◽  
Stabilizing Effect ◽  
Hückel Rule ◽  
Polycyclic Conjugated Hydrocarbons ◽  
Theoretical Considerations ◽  
Conjugated Molecule

General rules for aromatic stability of non-alternant polycyclic conjugated hydrocarbons are obtained using graph–theoretical considerations. Every pair of odd-membered rings contained in the conjugated molecule has a stabilizing effect if one ring is of the size 4N + 1 and the other of the size 4N + 3. If both rings are of the size 4N + 1 or 4N + 3, a destabilizing effect occurs. This conclusion holds both for fused and disjointed rings. The π-electron System is said to be relatively more stable if the number of (4N + l)-membered rings is equal to the number of (4N + 3)-rings.

Benzene-like N6rings in a Be2N6monolayer: a stable 2D semiconductor with high carrier mobility

2017 ◽  
Vol 5 (44) ◽  
pp. 11515-11521 ◽  
Author(s):  
Feng Li ◽  
Yu Wang ◽  
Hong Wu ◽  
Zhifa Liu ◽  
Urs Aeberhard ◽  
...  
Keyword(s):  
Structural Stability ◽  
Carrier Mobility ◽  
Planar Configuration ◽  
Hückel Rule ◽  
High Carrier Mobility ◽  
High Carrier ◽  
High Structural Stability

Abundant delocalized six-centre–two-electron (6c–2e) π-bonds are responsible for the planar configuration and high structural stability of a Be2N6monolayer, which satisfies the Hückel rule [4n+ 2] (n= 2).

scholarly journals Real space electron delocalization, resonance, and aromaticity in chemistry

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Leonard Reuter ◽  
Arne Lüchow
Keyword(s):  
First Principles ◽  
Valence Bond ◽  
Real Space ◽  
Wave Functions ◽  
High Probability Density ◽  
Hückel Rule ◽  
Bond Theory ◽  
Planar Systems ◽  
The Many ◽  
Lewis Structures

AbstractChemists explaining a molecule’s stability and reactivity often refer to the concepts of delocalization, resonance, and aromaticity. Resonance is commonly discussed within valence bond theory as the stabilizing effect of mixing different Lewis structures. Yet, most computational chemists work with delocalized molecular orbitals, which are also usually employed to explain the concept of aromaticity, a ring delocalization in cyclic planar systems which abide certain number rules. However, all three concepts lack a real space definition, that is not reliant on orbitals or specific wave function expansions. Here, we outline a redefinition from first principles: delocalization means that likely electron arrangements are connected via paths of high probability density in the many-electron real space. In this picture, resonance is the consideration of additional electron arrangements, which offer alternative paths. Most notably, the famous 4n + 2 Hückel rule is generalized and derived from nothing but the antisymmetry of fermionic wave functions.

Proof of the Hückel rule

1977 ◽  
Vol 46 (1) ◽  
pp. 169-171 ◽  
Author(s):  
Ivan Gutman
Keyword(s):  
Hückel Rule

Application of graph theory and topological models for the determination of fundamentals of the aromatic character of pi-conjugated hydrocarbons

2012 ◽  
Vol 84 (4) ◽  
pp. 1069-1088
Author(s):  
Michał K. Cyrański ◽  
Arkadiusz Ciesielski ◽  
Tadeusz M. Krygowski ◽  
Dorota K. Stępień
Keyword(s):  
Graph Theory ◽  
Topological Analysis ◽  
Resonance Energy ◽  
Perturbation Matrix ◽  
Pi Conjugated ◽  
Aromatic Character ◽  
Hückel Rule ◽  
The Individual ◽  
Topological Models

Application of topological analysis and graph theory to benzenoid hydrocarbons leads to the determination of fundamentals of aromaticity: the Hückel rule and the Clar rule. The approach, based on a treatment of the adjacency matrix, allows resonance energy (RE)-like characteristics to be estimated with quite good accuracy, and magnetic aromaticity indices to be derived for both the individual rings and the whole molecules. It also allows an effective approach for interpreting ring current formation in molecules when exposed to an external magnetic field. The transformation of the perturbation matrix into a form describing the canonical structures allows their gradation and determination of their stabilizing/destabilizing character.

Graph theory and molecular orbitals. XV. The Hückel rule

1976 ◽  
Vol 64 (12) ◽  
pp. 4921-4925 ◽  
Author(s):  
I. Gutman ◽  
N. Trinajstić
Keyword(s):  
Graph Theory ◽  
Molecular Orbitals ◽  
Hückel Rule
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