Search results
Results From The WOW.Com Content Network
The Hückel method or Hückel molecular orbital theory, proposed by Erich Hückel in 1930, is a simple method for calculating molecular orbitals as linear combinations of atomic orbitals. The theory predicts the molecular orbitals for π-electrons in π-delocalized molecules , such as ethylene , benzene , butadiene , and pyridine .
Möbius (left) and Hückel (right) orbital arrays. The two orbital arrays in Figure 3 are just examples and do not correspond to real systems. In inspecting the Möbius one on the left, plus–minus overlaps are seen between orbital pairs 2-3, 3-4, 4-5, 5-6, and 6-1, corresponding to an odd number (5), as required by a Möbius system.
Hückel is most famous for developing the Hückel method of approximate molecular orbital (MO) calculations on π electron systems, a simplified quantum-mechanical method to deal with planar unsaturated organic molecules. In 1930 he proposed a σ/π separation theory to explain the restricted rotation of alkenes (compounds containing a C=C ...
In contrast to the rarity of Möbius aromatic ground state molecular systems, there are many examples of pericyclic transition states that exhibit Möbius aromaticity. The classification of a pericyclic transition state as either Möbius or Hückel topology determines whether 4N or 4N + 2 electrons are required to make the transition state aromatic or antiaromatic, and therefore, allowed or ...
A program for the extended Hückel method is YAeHMOP which stands for "yet another extended Hückel molecular orbital package". [10] YAeHMOP has also been merged with the Avogadro open-source molecular editor and visualizer to enable calculations directly from the Avogadro graphical user interface for materials that are periodic in one, two, or ...
Hückel or Huckel may refer to: Erich Hückel (1896-1980), German physicist and chemist Debye–Hückel equation (named after Peter Debye and Erich Hückel), in chemistry, a method of calculating activity coefficients; Hückel method (named after Erich Hückel), a method for the determination of energies of molecular orbitals
Benzene, the most widely recognized aromatic compound with six delocalized π-electrons (4n + 2, for n = 1).. In organic chemistry, Hückel's rule predicts that a planar ring molecule will have aromatic properties if it has 4n + 2 π-electrons, where n is a non-negative integer.
The picture of the day (POTD) is a section on the English Wikipedia's Main Page that is automatically updated every day with one or more featured pictures, accompanied by a blurb. Although it is generally scheduled and edited by a small group of regular editors, anyone can contribute.