• Research
• People
• Bio / CV
• Publications
• Funding
• Group meeting

Mail:
Dept. of Chemistry
Ohio State University
100 W. 18th Ave.
Columbus, OH 43210

Office:
412 CBEC

Email:
herbert@
chemistry.ohio-state.edu

Optimized structures for oxalate (C₂O₄), malonate (O₂CCH₂CO₂), and succinate (O₂C(CH₂)₂CO₂) mono- and dianions are computed at the level of second-order Møller-Plesset perturbation theory (MP2). For oxalate, both anions exhibit D_2d and D_2h rotamers, and in addition, for the singly charged species, we find an anionmolecule complex of the form CO₂^–⋅CO₂. For the malonate and succinate anions we examine both keto and enol isomers; the keto structures are characterized by unhindered rotation of the CO₂ moieties about geometries of C₂ symmetry, while the enol isomers are much more rigid as a result of an intramolecular hydrogen bond. In both malonate and succinate, the enol isomer is the more stable form of the monoanion, while the keto isomer is the more stable dianion, although for O₂CCH₂CO₂^2– the estimated isomerization barrier is only about 7 kcal/mol. All of the dianions are adiabatically unbound and the enol dianions are vertically unbound as well. However, vertical detachment energies calculated by electron propagator methods at the partial thirdorder (P3) quasiparticle level with large, highly polarized basis sets suggest that the more stable keto forms of O₂CCH₂CO₂^2– and O₂C(CH₂)₂CO₂^2– are metastable, with vertical detachment barriers of about 0.2 and 0.6 eV, respectively. These results complement recent experimental observations of small dicarboxylate dianions in the gas phase.