15N-1H HMBC

14,000,000 Leading Edge Experts on the ideXlab platform

Scan Science and Technology

Contact Leading Edge Experts & Companies

Scan Science and Technology

Contact Leading Edge Experts & Companies

The Experts below are selected from a list of 30 Experts worldwide ranked by ideXlab platform

Kenneth K. Laali - One of the best experts on this subject based on the ideXlab platform.

  • Experimental and GIAO 15N NMR Study of Substituent Effects in 1H-Tetrazoles
    Journal of Organic Chemistry, 2012
    Co-Authors: Gopalakrishnan Aridoss, Gabriela L. Borosky, Chunqing Zhao, Kenneth K. Laali
    Abstract:

    A series of 1-aryl/alkyl-1H-1,2,3,4-tetrazoles, 5-substituted 1H-tetrazoles, and 1,5- and 2,5-disubstituted 1H-tetrazoles were studied by a combination of experimental NMR (natural abundance 15N, 15N/1H HMBC, and 13C) and computational GIAO-NMR techniques to explore substituent effects on 15N (and 13C) NMR chemical shifts in the tetrazole (TA) moiety. Computed 15N chemical shifts via GIAO-B3LYP/6-311+G(2d,p) calculations gave satisfactory results in comparison with experimental data. Whereas N-alkylation leads to large 15N chemical shift changes, changes in the N1-aryl derivatives bearing diverse substituent(s) are generally small except for polar ortho-substituents (COOH, NO2). Large Δδ15N values were computed in N1-aryl derivatives for p-COH2+ and p-OMeH+ as extreme examples of electron-withdrawing substituents on a TA moiety.

Gopalakrishnan Aridoss - One of the best experts on this subject based on the ideXlab platform.

  • Experimental and GIAO 15N NMR Study of Substituent Effects in 1H-Tetrazoles
    Journal of Organic Chemistry, 2012
    Co-Authors: Gopalakrishnan Aridoss, Gabriela L. Borosky, Chunqing Zhao, Kenneth K. Laali
    Abstract:

    A series of 1-aryl/alkyl-1H-1,2,3,4-tetrazoles, 5-substituted 1H-tetrazoles, and 1,5- and 2,5-disubstituted 1H-tetrazoles were studied by a combination of experimental NMR (natural abundance 15N, 15N/1H HMBC, and 13C) and computational GIAO-NMR techniques to explore substituent effects on 15N (and 13C) NMR chemical shifts in the tetrazole (TA) moiety. Computed 15N chemical shifts via GIAO-B3LYP/6-311+G(2d,p) calculations gave satisfactory results in comparison with experimental data. Whereas N-alkylation leads to large 15N chemical shift changes, changes in the N1-aryl derivatives bearing diverse substituent(s) are generally small except for polar ortho-substituents (COOH, NO2). Large Δδ15N values were computed in N1-aryl derivatives for p-COH2+ and p-OMeH+ as extreme examples of electron-withdrawing substituents on a TA moiety.

Paresh L Dhepe - One of the best experts on this subject based on the ideXlab platform.

  • understanding interactions between lignin and ionic liquids with experimental and theoretical studies during catalytic depolymerisation
    Catalysis Today, 2017
    Co-Authors: Sandip K Singh, Subhrashis Banerjee, Kumar Vanka, Paresh L Dhepe
    Abstract:

    Abstract Compared to H2SO4, Bronsted acidic ionic liquid (BAIL, [C3SO3HMIM][HSO4]) catalyzed depolymerization of lignin yielded higher concentration of low molecular weight products under mild conditions (120 °C) as proven by GC and GC–MS. To comprehend this disparity in catalytic activity among H2SO4 and BAIL (at similar H+ concentration), experimental techniques [1D(1H) NMR, 2D(15N/1H HMBC) NMR and RAMAN] have been employed. Based on these studies, it has been proven that the transfer of electron density from substrate to the electron deficient imidazolium ring via formation of hydrogen bond between OH/OCH3 (substrate) and N1C2H2N3− (cation) is possible, while the anion plays an important role. Further, density functional theory (DFT) calculations also corroborated this fact by showing a change in the bond angle and decrease in bond length (C2 H2 in imidazole), due to the presence of weak and strong hydrogen bonding between the substrate and IL.

Gabriela L. Borosky - One of the best experts on this subject based on the ideXlab platform.

  • Experimental and GIAO 15N NMR Study of Substituent Effects in 1H-Tetrazoles
    Journal of Organic Chemistry, 2012
    Co-Authors: Gopalakrishnan Aridoss, Gabriela L. Borosky, Chunqing Zhao, Kenneth K. Laali
    Abstract:

    A series of 1-aryl/alkyl-1H-1,2,3,4-tetrazoles, 5-substituted 1H-tetrazoles, and 1,5- and 2,5-disubstituted 1H-tetrazoles were studied by a combination of experimental NMR (natural abundance 15N, 15N/1H HMBC, and 13C) and computational GIAO-NMR techniques to explore substituent effects on 15N (and 13C) NMR chemical shifts in the tetrazole (TA) moiety. Computed 15N chemical shifts via GIAO-B3LYP/6-311+G(2d,p) calculations gave satisfactory results in comparison with experimental data. Whereas N-alkylation leads to large 15N chemical shift changes, changes in the N1-aryl derivatives bearing diverse substituent(s) are generally small except for polar ortho-substituents (COOH, NO2). Large Δδ15N values were computed in N1-aryl derivatives for p-COH2+ and p-OMeH+ as extreme examples of electron-withdrawing substituents on a TA moiety.

Chunqing Zhao - One of the best experts on this subject based on the ideXlab platform.

  • Experimental and GIAO 15N NMR Study of Substituent Effects in 1H-Tetrazoles
    Journal of Organic Chemistry, 2012
    Co-Authors: Gopalakrishnan Aridoss, Gabriela L. Borosky, Chunqing Zhao, Kenneth K. Laali
    Abstract:

    A series of 1-aryl/alkyl-1H-1,2,3,4-tetrazoles, 5-substituted 1H-tetrazoles, and 1,5- and 2,5-disubstituted 1H-tetrazoles were studied by a combination of experimental NMR (natural abundance 15N, 15N/1H HMBC, and 13C) and computational GIAO-NMR techniques to explore substituent effects on 15N (and 13C) NMR chemical shifts in the tetrazole (TA) moiety. Computed 15N chemical shifts via GIAO-B3LYP/6-311+G(2d,p) calculations gave satisfactory results in comparison with experimental data. Whereas N-alkylation leads to large 15N chemical shift changes, changes in the N1-aryl derivatives bearing diverse substituent(s) are generally small except for polar ortho-substituents (COOH, NO2). Large Δδ15N values were computed in N1-aryl derivatives for p-COH2+ and p-OMeH+ as extreme examples of electron-withdrawing substituents on a TA moiety.