Crystal structure, 1H and 13C NMR spectral studies of 1,2,4,5-oxadiazaborole derivatives

Abstract

Substituent effects on 1H and 13C NMR chemical shifts of 5-substituted phenyl-3-phenyl-4,5-dihydro-1,2,4,5-oxadiazaboroles (1a-r) were studied respectively. Single and duel substituent parameters were used for the correlation analysis of substituent-induced chemical shifts with σ, F and R constants. The calculations have shown the polar and resonance substituent effects on N-H proton and C=N carbon atoms. The ρ value was found positive for compounds (1a-r), which means that the substituent effect is normal. Additionally, crystal structure of compound (1i) was also studied. Density functional theory (DFT) calculations were carried out to calculate the theoretical chemical shifts, bond distances and bond angles. 

Keywords

• 1H and 13C chemical shifts
• GIAO-DFT calculations
• Oxadiazaboroles
• Substituent effect
• X-ray structure

References

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