2016/02/25 by V. Gineitytė, Viktorija Gineityte, Gineityte, Viktorija
Chemistry · Physics and Astronomy · #Advanced Physical and Chemical Molecular Interactions #Chemical Physics (physics.chem-ph) #FOS: Physical sciences #Fullerene Chemistry and Applications #Synthesis and Properties of Aromatic Compounds #physics.chem-ph
paper · pdf · doi:10.48550/arxiv.1602.07904
arxiv created 2016/02/25 · openalex publication_date 2016/02/25 · arxiv updated 2016/02/26 · openalex created_date 2022/10/02 · openalex updated_date 2026/07/28
Individual Kekule valence structures of biphenylene and related hydrocarbons are comparatively studied in respect of their total pi-electron energies and thereby relative stabilities. These structures are modeled as sets of weakly-interacting initially-double (C=C) bonds. The relevant total energies are represented in the form of power series, wherein the averaged resonance parameter of initially-single (C-C) bonds underlies the expansion. To rationalize the resulting distinctions in total energies, interrelations are sought between separate members of the series, on the one hand, and presence of definite substructures in the given Kekule valence structure, on the other hand. It is shown that monocycles S1 and S2 correspondingly containing two and four exocyclic methylene groups (like 3,4-dimethylene cyclobutene and [4]radialene) participate in the formation of energy corrections of the relevant Kekule valence structures along with the usual conjugated circuits of the 4n+2 and 4n series (Rn and Qn, n=1,2,3...). Thus, the cycles S1 and S2 are deductively predicted to play the role of supplementary conjugated circuits for biphenylene-like hydrocarbons. Moreover, the S2- and S1- containing structures are shown to be the most stable ones among all Kekule valence structures of the given hydrocarbon. Meanwhile, the lowest stability is predicted for structures in which either the neighboring hexagonal rings are connected by two C=C bonds or two exocyclic C=C bonds are attached to the same hexagonal ring.