Overlap principle of maximum

Localized bonding orbitals are then constructed from a linear combination of the orbital on each of the paired atoms. To do this we use the principle of maximum overlap, which states... 

Six-Membered Ring (endo-Cyclic). All the previous discussion of stereo-attack is based on steric hindrance, but in the case of a six-membered ring (endo-cyclic) enolate, the direction is affected simultaneously by stereo-electronic effects (Scheme 2-4).10 In the transition state, the attacking electrophiles must obey the principle of maximum overlap of participating orbitals by perpendicularly approaching the plane of atoms that constitute the enolate functional group. Electrophile attacks take place on the two diastereotopic... 

Due to the simplicity and the ability to explain the spectroscopic and excited state properties, the MO theory in addition to easy adaptability for modern computers has gained tremendous popularity among chemists. The concept of directed valence, based on the principle of maximum overlap and valence shell electron pair repulsion theory (VSEPR), has successfully explained the molecular geometries and bonding in polyatomic molecules. 

As we have pointed out many times previously, the columns of the standard tableaux functions are antisymmetrized, and the orbitals in a column may be replaced by any linear combination of them with no more than a change of an unimportant overall constant. In this case, consider a linear combination that has two hybrid orbitals that point directly at the H atoms in accord with Pauling s principle of maximum overlap. Using the parameter

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This effect has been reproduced in ab initio calculations40 and rationalized.41 The principle of maximum overlap states that the preferred trajectory corresponds to the best molecular overlap between the reaction partners (rule 4). If the nucleophile adopts a perpendicular trajectory, the atomic overlap with the carbon will be maximized. However, a competing out-of-phase overlap between the nucleophile HOMO and the carbonyl LUMO (shown by the wavy line) reduces the overall frontier orbital interaction. If the nucleophile is displaced laterally (arrow), the small diminution in the overlap with C is outweighed by the reduction in the antibonding interaction with O. This increase in the overall overlap explains the preference for attack from an obtuse angle... 

The main factors that determine the steric coordination of molecules and crystal lattices (accepting that the positions of chemical bonds between atoms in lattice obey the same laws of electron density distribution that are actual for molecules) is the direction and the principle of maximum overlapping. The strongest chemical bonds are formed in the direction of maximum overlapping between the orbitals ofbinding electrons. 

The principle of maximum overlap, first stated in 1931 by Linus Pauling (at the California Institute of Technology), has been ranked only slightly below the exclusion principle in importance to the understanding of molecular structure. 

The structure in space of polyatomic molecules depends on the stereochemistry of their chemical bonds through the principle of maximum overlap (Magnasco, 2005). 

Neglecting hybridization, as we did so far, the angle between p and pi is 26 = 90°, so that the resulting O—H bonds will be bent outwards, since the experimentally observed valence angle is about 26 = 105° (Herzberg, 1956). This is contrary to the principle of maximum overlap... 

The hybridization parameter < >, arbitrary so far, is best chosen so as the bond hybrids bi and b2 point in the direction of the two O—H bonds, giving in this way strongest bonding with His orbitals and satisfying the principle of maximum overlap. According to Equation (2.214), 26 = 105° gives o)Ki 40°, and we obtain the set (Figure 2.21) ... 

This is what we expect in absence of hybridization, the resulting N—H bonds being strongly bent outwards, and so very far from the principle of maximum overlap. 

Magnasco, V. (2005) On the principle of maximum overlap in molecular orbital theory. Chem. Phys.Lett., 407, 213-216. 

For the formation of a chemical bond between atoms, two main conditions have to be fulfilled. The principle of maximum overlap, 091 states that strongest bonds will be formed when the atomic orbital energies do not differ too much and the atomic orbitals have the correct symmetry to give nonvanishing values for the overlap integral SAB (2). 

These represent equal concentrations of density along four symmetrically directed spatial axes. Accordingly, if the principle of maximum overlapping is valid, methane, for example, will possess a tetrahedral structure—as of course it has to do. 

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