Patterns in localized chemical bonds

It is well known that crystal and electronic structures are interdependent and define the reactivity of chemical substances. In Section 1.4.2, it was noted that copper-porphyrin complex gives cation-radicals with significant reactivity at the molecular periphery. This reactivity appears to be that of nucleophilic attack on this cation-radical, which belongs to n-type. The literature sources note, however, some differences in the reactivity of individual positions. A frequently observed feature in these n-cation derivatives is the appearance of an alternating bond distance pattern in the inner ring of porphyrin consistent with a localized structure rather than the delocalized structure usually ascribed to cation-radical. A pseudo Jahn-Teller distortion has been named as a possible cause of this alternation, and it was revealed by X-ray diffraction method (Scheidt 2001). 

The mean-field approximation of this chapter offers us the orbital model of the electronic structure of molecules within the RHF approach. In this picture, the electrons are described by the doubly occupied molecular orbitals. Localization of the orbitals gives flie doubly occupied inner shell, lone pair, and bond MOs. The first and second are sitting on atoms, and the third on chemical bonds. Not all atoms are bound with all, but instead die molecule has a pattern of chemical bonds. 

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