Bonds p orbital

As the following resonance structures indicate, enamines are electronically similar to enolate ions. Overlap of the nitrogen lone-pair orbital with the double-bond p orbitals leads to an increase in electron density on the a carbon atom, making that carbon nucleophilic. An electrostatic potential map of N,N-6imethyl-aminoethvlene shows this shift of electron density (red) toward the a position. 

Isolated F-atom Molecular orbitals Isolated P-atom orbitals of three-center bond p orbitals... 

The polydiacetylene crystals (1-4) most strikingly corroborate these conjectures. Along this line of thought is also shown that this electron-phonon interaction is intimately interwoven with the polymerisation process in these materials and plays a profound role there. We make the conjecture that this occurs through the motion of an unpaired electron in a non-bonding p-orbital dressed with a bending mode and guided by a classical intermolecular mode. Such a polaron type diffusion combined with the theory of non radiative transitions explains the essentials of the spectral characteristics of the materials as well as their polymerisation dynamics. ... 

Separate values of the parameters were deduced for ortho, meta and para substituents. These values are listed in Table 6. As most chemists would have anticipated the standard deviation of the predicted frequency for the orf/w-substituted iodobenzenes is much higher than for the meta or para derivatives. Likewise, of these two last series it is the /wra-substituted compounds that exhibit the greatest sensitivity to asymmetry parameter. This is probably due to steric factors that may deform the shape of the filled non-bonding p-orbitals on the iodine atom and it is unlikely that in this case the asymmetry parameter can be used as a measure of the -character of the carbon-iodine bond. The meta and para are certainly better candidates for study in this respect, but even here no clear picture of the carbon-iodine 7i-bond arises. 

An electrocyclic reaction is an intramolecular reaction in which a new a (sigma) bond is formed between the ends of a conjugated tt (pi) system. To form this new a bond, p orbitals at the ends of the conjugated system rotate so they... 

Here the shaded and unshaded circles denote positive and negative atomic orbitals, respectively. Also, and most importantly, only the signs of the upper lobes of the jr-bonding p orbitals are shown. Make use of the Dih character table to determine the irreducible representation of each of the 12 molecular orbitals. Show your reasoning clearly,... 

The 71 system of a molecule consists of its % bonds, p orbitals, and all electrons in those bonds/orbitals. 

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