Theoretical characterization of intramolecular proton transfer in the ground and the lowest-lying triplet excited states of 1-amino-3-propenal: a methodological comparison

✍ Scribed by For�s, Marta; Duran, Miquel; Sol�, Miquel; Adamowicz, Ludwik

• Publisher: John Wiley and Sons
• Year: 2000
• Tongue: English
• Weight: 511 KB
• Volume: 21
• Category: Article
• ISSN: 0192-8651
• DOI: 10.1002/(sici)1096-987x(200003)21:4<257::aid-jcc2>3.0.co;2-f

✦ Synopsis

Several theoretical methods are employed to characterize the intramolecular proton transfer in the ground state and in the lowest-lying 3 nπ * and 3 ππ * excited states of 1-amino-3-propenal. The geometrical parameters, the relative energy of the two tautomeric forms, the energy barrier for the proton transfer, and the energy difference between the ground and the excited states predicted by the different methods are compared. It was found that: (1) the CASPT2 results are in good agreement with those obtained using the CCSD(T) method; (2) the CIS method and the CASSCF method with a medium-sized active space yield poor geometries and overestimate the adiabatic energy excitations and the energy barriers for the proton transfer; and (3) the B3LYP method provides good adiabatic excitation energies, although B3LYP energy barriers are