- Synthesis and X-ray structural determination of new aniline derivatives of 2,4,6,8-tetraazabicyclo[3.3.0]octanes; anomeric effect in N-C-N moiety and implications of solvent polarity on 1H-NMR patterns
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The condensation of aniline with glyoxal and formaldehyde in stoichiometric ratio, leads to 2,4,6,8-tetraphenyl-2,4,6,8-tetraazabicyclo[3.3.0]octane (1f) with formic acid as catalyst. Nine substituted derivatives of 1f have been prepared in high yield by this synthetic method. X-ray analysis revealed the existence of an anomeric effect, n(N) → σ*(C-N) in N-C-N moieties manifested by reduction in N-pyramidality and short C-N bond lengths. Moreover, 1H-NMR studies showed the dependency of methylenic protons splitting pattern on solvent polarity.
- Kakanejadifard, Ali,Farnia, S. Morteza F.
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- Spectroscopic study of the complexation of iodine with 2,4,6,8-tetraphenyl-2,4,6,8-tetraazabicyclo[3.3.0]octane
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The charge-transfer complex formation between iodine and 2,4,6.8-tetraphenyl-2,4,6,8-tetraazabicyclo[3.3.0]octane (TPTABO) has been studied spectrophotometrically in chloroform solution. The resulting 2:1 complex is formulated as (TPTABO.I+)I-3 as it is also characterized by IR and NMR spectroscopy. The formation constant was evaluated from the non-linear least-squares fitting of the absorbance-mole ratio data. The enthalpy and entropy of the complex formation reaction were determined from the temperature dependence of the formation constant. The rate constant and activation parameters Ea, ΔH# and ΔS# were also calculated.
- Rouhollahi,Kakanejadifard,Farnia,Shamsipur
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p. 731 - 738
(2007/10/03)
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