Quantum Chemical Exploration of Intermolecular Reactions of Acetylene

Quantum chemical explorations of potential energy surfaces showed that acetylene produces various products starting from molecular arrays in short distances of 1.3-2.5 Å. Arrays of (C₂ H₂ )₂ gave cyclobutadiene, tetrahedrane, and acetylene dimers. Arrays of (C₂ H₂ )₃ gave benzene, prismane, benzvalene, Dewar benzene, and acetylene trimers. Arrays of (C₂ H₂ )₄ gave cubane, cyclooctatetranene, and acetylene tetramers. Different forms of initial arrays yielded different sets of products; a parallel array of two monomers gave cyclobutadiene, whereas a cross array gave tetrahedrane. Initial molecular arrays with unusually close contacts were estimated to require local forces of 1-9 × 10^-8  N. © 2019 Wiley Periodicals, Inc.