Novel physically adapted STO<sup>##</sup>‐3G basis sets. Efficiency for prediction of second‐order electric and magnetic properties of aromatic hydrocarbons

Voronkov, E. O.; Rossikhin, V. V.; Okovytyy, Sergiy I.; Shatckih, A.; Bolshakov, V. I.; Leszczyński, Jerzy

doi:10.1002/qua.23256

Cited by 25 publications

(26 citation statements)

References 22 publications

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“…In the next step, harmonic frequencies were calculated (lack of negative frequencies indicated the presence of energy minima). Single‐point nonrelativistic shielding calculations were performed with VSXC density functional and with modified STO‐3G mag basis set . Both the selected VSXC density functional and Leszczynki's basis set were recently showed advantageous in predicting carbon chemical shifts .…”

Section: Theoretical Calculationsmentioning

confidence: 99%

Halogen effect on structure and ¹³C NMR chemical shift of 3,6‐disubstituted‐N‐alkyl carbazoles

Radula-Janik

Kupka

Ejsmont

et al. 2013

Magnetic Reson in Chemistry

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Structures of selected 3,6-dihalogeno-N-alkyl carbazole derivatives were calculated at the B3LYP/6-311++G(3df,2pd) level of theory, and their (13) C nuclear magnetic resonance (NMR) isotropic shieldings were predicted using density functional theory (DFT). The model compounds contained 9H, N-methyl and N-ethyl derivatives. The relativistic effect of Br and I atoms on nuclear shieldings was modeled using the spin-orbit zeroth-order regular approximation (ZORA) method. Significant heavy atom shielding effects for the carbon atom directly bonded with Br and I were observed (~-10 and ~-30 ppm while the other carbon shifts were practically unaffected). The decreasing electronegativity of the halogen substituent (F, Cl, Br, and I) was reflected in both nonrelativistic and relativistic NMR results as decreased values of chemical shifts of carbon atoms attached to halogen (C3 and C6) leading to a strong sensitivity to halogen atom type at 3 and 6 positions of the carbazole ring. The predicted NMR data correctly reproduce the available experimental data for unsubstituted N-alkylcarbazoles.

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Section: Theoretical Calculationsmentioning

confidence: 99%

Halogen effect on structure and ¹³C NMR chemical shift of 3,6‐disubstituted‐N‐alkyl carbazoles

Radula-Janik

Kupka

Ejsmont

et al. 2013

Magnetic Reson in Chemistry

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“…In particular, basis sets describing electron density close to nuclei are essential for reliable prediction of indirect spin-spin coupling constants (SSCC). 43 Recently, Leszczynski and coworkers 44 proposed modified basis sets STO-3G mag for efficient calculations of NMR shieldings. This basis set was initially developed as practical compromise between the size and accuracy for prediction of very demanding SSCC parameters in case of molecules containing more than a few atoms, as well as for relatively large molecules (using the "locally dense basis set approach").…”

Section: Theoretical Calculationsmentioning

confidence: 99%

Toward engineering efficient peptidomimetics. Screening conformational landscape of two modified dehydroaminoacids

et al. 2013

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Effective peptidomimetics should posses structural rigidity and appropriate interaction pattern leading to potential spatial and electronic matching to the target receptor site. Rational design of such small bioactive molecules could push chemical synthesis and molecular modeling toward faster progress in medicinal chemistry. Conformational properties of N-t-butoxycarbonyl-glycine-(E/Z)-dehydrophenylalanine N',N'-dimethylamides (Boc-Gly-(E/Z)-ΔPhe-NMe2 ) in chloroform were studied by NMR and IR spectroscopy. The experimental findings were supported by extensive calculations at DFT(B3LYP, M06-2X) and MP2 levels of theory and the β-turn tendency for both isomers of the studied dipeptide were determined in vacuum and in solution. The theoretical data and experimental IR results were used as an additional information for the NMR-based determination of the detailed solution conformations of the peptides. The obtained results reveal that N-methylation of C-terminal amide group changes dramatically the conformational properties of studied dehydropeptides. Theoretical conformational analysis reveals that the tendency to adopt β-turn conformations is much weaker for the N-methylated Z isomer (Boc-Gly-(Z)-ΔPhe-NMe2 ), both in vacuum and in polar environment. On the contrary, N-methylated E isomer (Boc-Gly-(E)-ΔPhe-NMe2 ) can easily adopt β-turn conformation, but the backbone torsion angles (φ1, ψ1, φ2, ψ2) are off the limits for common β-turn types.

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“…Our proposal is based on solution of the nonhomogeneous Schrödinger equation for the model problem “one‐electron atom in an external uniform field,” using the closed representation of the Green's function . The efficiency of this approach has been confirmed earlier for construction of basis sets for calculations of nuclear magnetic shielding, spin–spin coupling constants,magnetic susceptibility, polarizability, and vibrational frequencies . The performance of the obtained basis sets on the dynamic hyperpolarizability calculations at DFT levels has been tested here for the series of inorganic and organic molecules.…”

Section: Introductionmentioning

confidence: 94%

Accurate calculations of dynamic first hyperpolarizability: Construction of physically justified slater‐type basis sets

Rossikhin

Voronkov

Okovytyy

et al. 2014

Int J of Quantum Chemistry

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An efficient procedure for construction of physically rationalized Slater‐type basis sets for calculations of dynamic hyperpolarizability is proposed. Their performance is evaluated for the DFT level calculations for model molecules, carried out with a series of functionals. Advantages of new basis sets over standard d‐aug‐cc‐pVTZ and recently developed LPOL‐(FL,FS) Gaussian‐type basis sets are discussed. © 2014 Wiley Periodicals, Inc.

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Novel physically adapted STO^##‐3G basis sets. Efficiency for prediction of second‐order electric and magnetic properties of aromatic hydrocarbons

Cited by 25 publications

References 22 publications

Halogen effect on structure and ¹³C NMR chemical shift of 3,6‐disubstituted‐N‐alkyl carbazoles

Halogen effect on structure and ¹³C NMR chemical shift of 3,6‐disubstituted‐N‐alkyl carbazoles

Toward engineering efficient peptidomimetics. Screening conformational landscape of two modified dehydroaminoacids

Accurate calculations of dynamic first hyperpolarizability: Construction of physically justified slater‐type basis sets

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Novel physically adapted STO##‐3G basis sets. Efficiency for prediction of second‐order electric and magnetic properties of aromatic hydrocarbons

Cited by 25 publications

References 22 publications

Halogen effect on structure and 13C NMR chemical shift of 3,6‐disubstituted‐N‐alkyl carbazoles

Halogen effect on structure and 13C NMR chemical shift of 3,6‐disubstituted‐N‐alkyl carbazoles

Toward engineering efficient peptidomimetics. Screening conformational landscape of two modified dehydroaminoacids

Accurate calculations of dynamic first hyperpolarizability: Construction of physically justified slater‐type basis sets

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Novel physically adapted STO^##‐3G basis sets. Efficiency for prediction of second‐order electric and magnetic properties of aromatic hydrocarbons

Halogen effect on structure and ¹³C NMR chemical shift of 3,6‐disubstituted‐N‐alkyl carbazoles

Halogen effect on structure and ¹³C NMR chemical shift of 3,6‐disubstituted‐N‐alkyl carbazoles