Theoretical studies the structure and properties of bicyclic and tricyclic hydrogen peroxide clusters (H2O2)n, n = 8–21: MP2 and DFT calculations

Abstract

DFT calculations of bicyclic and tricyclic hydrogen peroxide (HP) clusters Pn up to n = 21 in the gas phase have been performed for the first time. Three main types of coupling of two or more ring clusters P4-P7 (tetramer, pentamer, hexamer, heptamer) into a cyclic structure have been studied. The first, type A, involves the reorientation of hydrogen bonds and a change in the chirality of several HP molecules. The second, type B, consists in the formation of bridges between two HP molecules without changing the chirality. The third way in which two clusters can be connected is by forming nested structures in which the smaller cluster is inside the larger one. Thermodynamic parameters of the coupling of P4-P7 clusters with the formation of cyclic structures have been calculated. In the gas phase, heterochiral structures of type A are lower in energy than homochiral structures of type B with the same number of HP molecules. In low energy clusters, the largest number of hydrogen bonds (2n) is more favourable.