Intramolecular Hydrogen Bonding and Molecular Structure of
2,5-Dihydroxyterephthalaldehyde and 4,6-Dihydroxyisophthalaldehyde: A Gas-Phase
Electron Diffraction and ab Initio Molecular Orbital Study
posted on 1996-12-12, 00:00authored byKonstantin B. Borisenko, Károly Zauer, István Hargittai
The molecular structure of 2,5-dihydroxyterephthalaldehyde has
been determined from a joint electron
diffraction/ab initio investigation, and the molecular structure of
4,6-dihydroxyisophthalaldehyde has been
obtained from ab initio calculations at the MP2/6-31G* level.
There is considerable intramolecular hydrogen
bonding in these structures manifested by the O···H and
O···O distances as well as by the structural changes
in the rest of the molecule. These changes are consistent with the
notion of resonance-assisted hydrogen
bonding. The hydrogen bonding is somewhat stronger in
4,6-dihydroxyisophthalaldehyde than in 2,5-dihydroxyterephthalaldehyde, and this difference may be linked to the
difference in the mutual positioning of
the interacting formyl and hydroxy groups in these
molecules.