Description:
Both the intermolecular interaction energies and the geometries for
M
⋯
thiophene,
M
⋯
pyrrole,
M
n
+
⋯
thiophene, and
M
n
+
⋯
pyrrole (with
M
=
Li
, Na, K, Ca, and Mg; and
M
n
+
=
Li
+
,
Na
+
,
K
+
,
Ca
2
+
, and
Mg
2
+
) have been estimated using four commonly used density functional theory (DFT) methods: B3LYP, B3PW91, PBE, and MPW1PW91. Results have been compared to those provided by HF, MP2, and MP4 conventional ab initio methods. The PBE and MPW1PW91 are the only DFT methods able to provide a reasonable description of the
M
⋯
π
complexes. Regarding
M
n
+
⋯
π
complexes, the four DFT methods have been proven to be adequate in the prediction of these electrostatically stabilized systems, even though they tend to overestimate the interaction energies.