Topological charge stabilization

The “Coloring Problem” in Solids: How It Affects Structure, Composition and Properties

“…white circles are S atoms, black circles are As or N atoms Molecular orbital theory can substantiate this conclusion through the principle of topological charge stabilization. [16] When a Mulliken population analysis [17] is applied to the [ ** ] The German mathematician Möbius is credited with its origination in the form of a puzzle to his students. [11] [ *** ] In terms of graph theory, another statement of the coloring problem is, "Consider a fixed molecule or solid state framework which is then populated with different sorts of atoms or atom groupings.…”

On the possibilities of π-ylides

“…This would open up the possibility that the heterocyclic ring might be transformed into useful functionality after formation of the desired carbocycle. The design of such heterocycles would be facilitated by application of the rule of topological charge stabilization (9) We note that the foregoing discussion could be applied to the side chain of the "T-ylide." In the event that heteroatoms were incorporated into the side chain, the newly constructed ring in the product would be heterocyclic.…”

How far is the pi-electron delocalization of phenanthrene moiety is modified in the aza-analogues and their N-oxides?

“…Tables 1-2 present the local descriptors of π-electron delocalization: HOMA and NICS, and the global ones: the relative energy values (in respect to the lowest-energy isomer), the magnetic susceptibilities and the global values of HOMA (estimated for all bond lengths). Both relative energies and magnetic susceptibilities can serve only as approximate descriptors of aromaticity since they are always perturbed to some extent by additional effects 23 such as strain, topological charge stabilization, 24 heteroatom-heteroatom like anomeric effects, hyperconjugation and other effects which are not related to aromaticity. Neither the replacement of CH moiety by N atom, nor by NO group is associated with dramatic changes in the global descriptors of the π-electron delocalization.…”