Solvent Effects on the Nitrogen NMR Shieldings in Oxazole and Oxadiazole Systems

NMR chemical shifts in MNDO approximation: Parameters and results for H, C, N, and O

“…The TNDOr2 method appears to be extensively parameterized, 57 and some promising early results have been reported, 59 but a systematic assessment of the TNDOr2 results is not yet available. Moreover, the method has not yet been defined in the open literature, and the TNDOr2 parameters remain unpublished, so that an independent implementation is impossible.…”

Solvent Effects on Nitrogen Chemical Shifts

“…The δ 14N of the bridgehead, pyrrole-type nitrogen (N4) of indolizine (54), 1-azaindolizine (55), 2-azaindolizine (56), and 3-azaindolizine (57, Fig. 11) [52] experience rather limited solvent effects, up to 2 ppm, as compared to their pyridine-type nitrogen (N1 to N3) that alters its chemical shift up to 30 ppm upon changing the solvent (Table 3), similar to pyridine (44).…”

Synthesis, Characterization and Biological Activity Studies on Novel 4-Chloro-2- [(1-Phenyl-1H-Tetrazol-5-Ylimino)-Methyl] Phenol and Its Metal Complexes

“…The eigen values for molecular orbitals were computed for the geometry optimized molecule of Cl-PTMP using hyperchem 7.5 tools [8]- [12] As minus eigen values correspond to binding energies of electrons, the computed data is informative to understand electron donating properties of a molecule. The frontier molecular orbital energies (i.e., E HOMO and E LUMO ) are significant parameters for the prediction of the reactivity of a chemical compound ( Figure 5 and Figure 6).…”