Ab initio Study of Nitrogen-14 Nuclear Quadrupole Coupling and NMR Signal Linewidths in Some Azoles

Jaszuński, Michał; Rizzo, Antonio

doi:10.1515/zna-1998-6-717

Cited by 4 publications

(7 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The active space of RAS SCF is also identical with that we have applied earlier, RAS-A of ref 6. We have 10 inactive orbitals of σ symmetry.…”

Section: Calculationsmentioning

confidence: 99%

“…For the triazoles and tetrazoles, the vacuum NQCC values discussed below are the same as in Table 3 of ref 6.…”

Section: Nuclear Quadrupole Coupling Constants In Vacuummentioning

confidence: 99%

“…In test calculations we have checked that the rotation of the methyl group does not affect the results significantly, as confirmed by the small differences between the values of the studied parameters in 〈1-2-5〉 and 〈1-3-4〉 triazoles. In all the following calculations, performed using the DALTON program, a basis set called H II, taken from Huzinaga's compilation and successfully used in previous similar studies, , was employed. For the C and N atoms, it is a [9s5p1d/5s4p1d] set, whereas for the H atoms, the contraction is [5s1p/3s1p], which, for example, for the triazoles, yields in total 162 CGTO orbitals.…”

Section: Calculationsmentioning

confidence: 99%

“…Note that, for 1-methyl-1-2-5-triazole, the calculated values for N2 and N5 differ only due to the arrangement of the methyl group (and, similarly, for N3 and N4 in 1-methyl-1-3-4-triazole). Previously, in a similar study, following ref , these compounds were called 2-methyl-1-2-3-triazole, and 4-methyl-1-2-4-triazole, respectively, and a different numbering of atoms was used.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

A Study of the Nitrogen NMR Spectra of Azoles and their Solvent Dependence

Jaszuński

Mikkelsen

Rizzo³

2000

J. Phys. Chem. A

Self Cite

View full text Add to dashboard Cite

Ab initio calculated values of the nuclear magnetic shielding constants and nuclear quadrupole coupling constants of nitrogen atoms in azoles are compared with experimental data. The calculations are performed within the multiconfigurational SCF response approach. The solvent dependence of the molecular properties is accounted for, and it is described using solvent response theory. The experimental data for 14 N resonance half-height width are reported for a number of different solvents. For both NMR parameters studied, we find a fair agreement of the measured and calculated values. The analysis of the solvent dependence of the shielding constants and quadrupole coupling constants for all the nitrogen atoms shows that the main experimental trends are well reproduced in the calculations.

show abstract

“…The active space of RAS SCF is also identical with that we have applied earlier, RAS-A of ref 6. We have 10 inactive orbitals of σ symmetry.…”

Section: Calculationsmentioning

confidence: 99%

“…For the triazoles and tetrazoles, the vacuum NQCC values discussed below are the same as in Table 3 of ref 6.…”

Section: Nuclear Quadrupole Coupling Constants In Vacuummentioning

confidence: 99%

Section: Calculationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

A Study of the Nitrogen NMR Spectra of Azoles and their Solvent Dependence

Jaszuński

Mikkelsen

Rizzo³

2000

J. Phys. Chem. A

Self Cite

View full text Add to dashboard Cite

show abstract

“…Most of the theoretical studies concerning tetrazoles involve ground state calculations 12–21. If one wants to study their very rich photochemistry,22, 23 accurate excited state calculations are necessary.…”

Section: Introductionmentioning

confidence: 99%

CASSCF and multireference CI with singles and doubles study of low‐lying valence and Rydberg states of 2H‐tetrazole

Souza¹,

Ventura²,

Araújo³

et al. 2008

J Comput Chem

View full text Add to dashboard Cite

Complete active space self-consistent field (CASSCF) and multireference CI with singles and doubles (MR-CISD) calculations [including extensivity corrections, at MR-CISD+Q and multireference averaged quadratic coupled cluster (MR-AQCC) levels] have been performed to characterize the low-lying valence and the Rydberg states of 2H-tetrazole. The highest level results (MR-AQCC/d'-aug'-cc-pVDZ) indicate the following ordering of the valence singlet excited states: S(1) (n-pi*), 6.06 eV; S(2) (n-pi*), 6.55 eV; S(3) (pi-pi*), 6.55 eV. The MR-CISD+Q/d'-aug'-cc-pVDZ results indicate the same ordering, but at slight higher energies: 6.16, 6.68, and 6.69 eV, respectively. According to our MR-CISD+Q/d'-aug'-cc-pVDZ results, the next two states are Rydberg states, at 7.69 eV (pi-3s) and 7.89 eV (n-3s). The calculated energies of these two states, as well as their proximity, are consistent with the conclusion reached by Palmer and Beveridge (Chem Phys 1987, 111, 249) that the first band of the photoelectron spectrum of 2H-tetrazole is likely to be associated to the first two ionizations processes (of pi and N lone pair electrons), at energies close to 11.3 eV.

show abstract