Assessment of dispersion-corrected DFT functionals to predict conformational behaviors of aza-asparagine-containing tripeptides

Model azapeptides, Ac-Pro-azaAsn-NHMe (PAN-a) and Piv-Pro-azaAsn(Me)-NH-iPr (PAN-b). 34 conformers of PAN-a and 5 conformers of PAN-b were characterized using DFT functionals. Methods: 11 DFT functionals with and without dispersion correction (D3). - BP86(BP86-D3), BPBE(BPBE-D3), TPSSTPSS (TPSSTPSS-D3), B3LYP (B3LYP-D3), B3PW91 (B3PW91-D3), PBE1PBE (PBE1PBE-D3), M06 (M06-D3), M06-2X (M06-2X-D3), BMK (BMK-D3), CAM-B3LYP (CAM-B3LYP-D3), and LCgau-BOP (LCgau-BOP+LRD). Gaussian 09/16 programs were employed. Basis Set: 6-311++G(d,p) used.