Dual Substituent Parameter Modeling of Theoretical, NMR and IR Spectral Data of 5-Substituted Indole-2,3-dionesAuthor(s): Ghazwan F. Fadhil | Hanan A. Radhy | Alexander PerjÃƒÂ©ssy | MÃƒÂ¡ria Ã…Â amalÃƒÂkovÃƒÂ¡ | Erkki Kolehmainen | Walter M.F. Fabian | Katri Laihia | Zora Ã…Â ustekovÃƒÂ¡
Journal: Molecules ISSN 1420-3049
Volume: 7; Issue: 11; Start page: 833; Date: 2002;
Keywords: 5-Substituted indole-2 | 3-diones | AM1 and PM3 theoretical data | IR and NMR data DSP correlations | ÃÂ€-polarization | reverse substituent effect
Correlations of AM1 and PM3 theoretical data, 13C-NMR substituent chemical shifts (13C-SCS) and IR carbonyl group wave numbers [ÃŽÂ½(C3Ã¢Â•ÂO)] were studied using dual substituent parameter (DSP) models for 5-substituted indole-2,3-diones. For the C7 atom a reverse substituent effect attributed to extended ÃÂ€-polarization was observed. On the other hand, the DSP approaches for the C3 atom showed normal substituent effects with some contribution of reverse effect supported strongly by 13C-SCS correlations. In the ÃŽÂ½(C3Ã¢Â•ÂO) and p(C3Ã¢Â•ÂO) DSP correlations the field effect contribution predominates over the resonance effect, which justifies the using of earlier suggested vibrational coupling (V-C) model for 5- and 6-substituted indole-2,3-diones.