0000000000236345
AUTHOR
Zora ŠUsteková
showing 2 related works from this author
Dual Substituent Parameter Modeling of Theoretical, NMR and IR Spectral Data of 5-Substituted Indole-2,3-diones
2002
Correlations of AM1 and PM3 theoretical data, 13C-NMR substituent chemical shifts (13C-SCS) and IR carbonyl group wave numbers [ν(C3â•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 À-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 ν(C3â•ÂO) and p(C3â•ÂO) DSP correlations the field effect contribution predominates over the resonance effect, which justifies the using of earlier suggested vibrational cou…
A correlative IR, MS, 1H, 13C and 15N NMR and theoretical study of 4-arylthiazol-2(3H)-onesElectronic supplementary information (ESI) available: NMR …
2002
Sixteen 4-arylthiazol-2(3H)-ones (3) were synthesised by cyclisation of α-thiocyanatoacetophenones (1) in acid solution. They appear to prefer greatly the oxo tautomeric forms. In CCl4 solution an equilibrium between the free CO bond and a “dimeric” hydrogen-bonded form exists in which the latter predominates. Several IR and NMR (1H, 13C and 15N) spectral properties are shown to correlate with Hammett σ-values and/or atomic Mulliken charges and bond orders, the latter being estimated by PM3 or AM1 semiempirical methods. The electron-impact mass spectra were also recorded and the fragmentation mechanisms interpreted in terms of the energetics of the ionic species. In addition, the geometric …