Experimental and theoretical studies of the molecular structure of 1-(2-pyridinylmethyl)-2-methylbenzimidazole

Applications of nuclear shielding

“…4 The 1-carboxymethyl-3-aminopyridinium chloride was studied by B3LYP/6-311G(d,p) calculations and 1 H and 13 C NMR spectroscopies. 5 Correlations between the experimental 1 H and 13 C chemical shifts (d exp ) and the GIAO/B3LYP/6-311G(d,p) calculated magnetic isotropic shielding (s cal ) in DMSO and D 2 O, d exp= a þ b Á s calc , were reported. Chemical shifts d were calculated for the 1 H attached to carbon atoms of sarcosine using DFT and mixing the four functionals B3LYP, PBE, OPBE, PBE0 and the two basis sets 6-311 þ þ G** and pcJ2.…”

“…9 The relative magnitudes of the chemical shift differences in the two diastereomers of menthyl esters of chiral derivatising agents and a-methoxy-a-trifluoromethyl-1-naphthylacetyl analogs were compared and long-range shielding effects in the 1 H NMR Spectra discussed. 10 The seven stationary points of the methane hypersurface were explored and 1 H and 13 C NMR shieldings as well as 1 J(CH) and 2 J(HH) coupling constants were calculated. 11 The relationship between the 1 H and 13 C shieldings was discussed.…”

A systematic theoretical investigation of the relationship between heats of detonation and NBO charges and 15N NMR chemical shifts of nitro groups in nitramines and nitro paraffins

“…Although NMR studies in solution neglect important crystal-lattice interactions affecting some explosive properties, the correlations between impact and electric sparks sensitivities, detonation and thermal decomposition and 13 C and 15 N NMR chemical shifts in nitro compounds have all been demonstrated. In this sense, the measured NMR spectra in combination with calculations of NMR chemical shifts have proven to be useful tools in interpreting experimental data [14][15][16]. 15 N NMR chemical shifts results in Tables 1-3 were calculated by subtracting their isotropic magnetic shielding values from the isotropic shielding calculated for nitromethane, which is used as reference molecule.…”

“…In this sense, the measured NMR spectra in combination with calculations of NMR chemical shifts have proven to be useful tools in interpreting experimental data [14][15][16]. 15 N NMR chemical shifts results in Tables 1-3 were calculated by subtracting their isotropic magnetic shielding values from the isotropic shielding calculated for nitromethane, which is used as reference molecule. The correlation between heat of detonation and the calculated and experimental 15 N Nitro chemical shifts for nitro paraffins and nitramines are shown in Fig.…”

“…On the other hand, the calculated 15 N Nitro NMR chemical shift for nitramines were obtained using a protocol established in our recent work [12] within the continuous sets of gauge transformations (CSGT) method [13]. Ab initio calculations of the NMR chemical shifts for different nuclei have proven to be useful tools in interpreting experimental data in several applications [14][15][16].…”