Charge Density Analysis of Ferulic Acid: Robustness of a Trifurcated C–H···O Hydrogen Bond

The
toplogical features of a sporadic trifurcated C–H···O
interaction region, where an oxygen atom acts as an acceptor of three
weak hydrogen bonds, has been investigated by experimental and theoretical
charge density analysis of ferulic acid. The interaction energy of
the asymmetric molecular dimer formed by the trifurcated C–H···O
motif, based on the multipolar model, is shown to be greater than
the corresponding asymmetric O–H···O dimer in
this crystal structure. Further, the hydrogen bond energies associated
with these interaction motifs have been estimated from the local kinetic
and potential energy densities at the bond critical points. The trends
suggest that the interaction energy of the trifurcated C–H···O
region is comparable to that of a single O–H···O
hydrogen bond.