Simultaneous exhibition of positive and negative cooperativity by purely
C-H—O H-bonded (1,3-cyclohexanedione)n (n = 2-6) clusters: A density
functional theoretical investigation
Abstract
Investigation of cooperative effect exhibited by purely C-H—O hydrogen
bonded (H-bonded) networks in linear and cyclic clusters of
(1,3-cyclohexanedione)n (n = 2 to 6) has been carried out using density
functional theoretical calculations. Linear clusters were found to show
anti-cooperative behavior, while the cyclic clusters showed positive
cooperativity. H-bond strengths and binding energies per bimolecular
interaction were found to decrease with increasing cluster size for the
linear clusters whereas their cyclic counterparts showed opposite
trends. The extent of cooperativity has been found to show monotonic
behavior for both linear and cyclic clusters and was found to reach an
asymptotic limit with increasing cluster size. Natural bond orbital
(NBO) analysis and atoms in molecule (AIM) calculations were found to
corroborate the obtained results.