Boaz Galdino de Oliveira* and Mário Luiz Araújo de Almeida Vasconcellos
Departamento de Química, Universidade Federal da Paraíba, 58059-900, Joa o
Pessoa, Paraíba – Brazil
* Corresponding author: E-mail: boazgaldino@gmail.com
Abstract
The optimized geometries and infrared spectra of the 2-pyridone···ammonia and
2-hydroxypyridine···ammonia hydrogen-
bonded complexes were examined using the B3LYP/6-311++G(d,p) level of theory. By
taking into account the tautomerism
in the 2-pyridone and 2-hydroxypyridine molecules, the ammonia functions as
donor and acceptor of proton
in each hydrogen-bonded complex. Thereby, some classic aspects of hydrogen bonds
can be observed, such as the redshift
(bathochromic) effects in the N–H(ammonia), N–H(2-pyridone), and
O–H(2-hydroxypyridine) bonds. In this insight,
a theoretical investigation of these frequencies was performed not only by the
B3LYP/6-311++G(d,p) calculations,
but also by means of charge density integrations ruled by protocol of the theory
of atoms in molecules (AIM), by
which some molecular operators were computed, such as the electronic density
centers ( ρ) and Laplacian fields (V2 ρ).
Keywords: Tautomerism; 2-hydroxypyridine; 2-pyridone; B3LYP; AIM.