Is triple crossed C28 cyclic polyyne cluster a stable conformation?

Abstract

Polyynes sometimes referred to as oligoynes or carbinoids, and their resonance cumulene form are valuable precursors to a whole series of more complex organic derivatives. Motivated by a series of studies that explore the stabilization of polyynes, in different ways, the possibility of their stabilization through the formation of crossed cycles is explored in this article. It is easy to notice that the cyclic conformations represent a special case, in that they possess an increased symmetry. The stability of the polyene molecule can be enhanced by building cross-clusters. In this article, the molecular modeling tools were employed in order to provide insights about the construction and stability of 3C28 triple crossed C28 cyclic polyyne cluster. It has been shown that C28 and 3C28 triple crossed C28 are very similar energetically. HOMO–LUMO gap suggests a metallic conductivity. The angles between the planes of the molecular rings shows almost an axial alignment of the rings. A symmetry-constrained optimization was conducted using Z-matrix internal coordinates and Gaussian software, and it revealed that the geometrical conformation of C28 polyyne as triple crossed cluster is a stable conformation, since in all investigated scenarios the convergence is assured and it is to nearly optimum local points.