Investigating cyclic cooperativity in ring stabilization of (HCN)n and (HNC)n: n = 3–11 clusters

Abstract The cooperativity effect in cyclic molecular clusters of hydrogen cyanide (HCN) and its isomeric form hydrogen isocyanide (HNC) is studied in the present work. The cyclic ring stabilization and molecular cooperativity of the (HCN)n and (HNC)n clusters n = 3 to 11 are studied as example with DFT method at B3LYP/6-31G(d,p) level of theory. The observed cyclic cooperativity increases with clusters size. Remarkable correlation between cyclic cooperativity energy (CCE) and hydrogen bond density critical point value (ρBCP) of the clusters is observed with molecular electron density (MED) topography. Higher cooperativity is observed in (HCN)n clusters than the respective (HNC)n ones.