interações de orbitais e seus efeitos nos acoplamentos jch em 1,3,5 ...

More documents

Recommendations

Info

A análise conjunta dos dados teóricos e experimentais para 1,3,5-tritianos monosubstituídos mostrou a influência dos átomos eletronegativos, flúor, cloro e bromo, no valor da constante de acoplamento 1 JCHax no carbono 6 através do efeito eletrostático. As constantes de acoplamento 1 JCHax e 1 JCHeq , no carbono 2, sofrem influência direta do substituinte eletronegativo. A presença do grupo metila não mostrou nenhum efeito nos valores das constantes de acoplamento estudadas. xvi
Abstract: Orbital Interactions and their effects on 2 JHH e 1 JCH Coupling Constants in 1,3,5-trioxane, 1,3,5-trithiane and 2-substituted 1,3,5 –trithianes: Experimental and Theoretical Study Keywords: hyperconjugative interactions, coupling constants The present work reports the NMR data and theoretical calculations of orbital interactions and their effects on 2 JHH e 1 JCH coupling constants in 1,3,5-trioxane, 1,3,5- trithiane and 2-substituted 1,3,5-trithianes, where the substitutents are fluorine, chlorine, bromine and methyl. The calculations were carried out with the Gaussian 98 and 03 package of programs. The aug-cc-pVTZ basis sets were employed for geometries optimizations at level MP2. The energies of hyperconjugative interactions were calculated with the NBO program. The coupling constants were evaluated within the CP-DFT perturbative approach. The 1 H and 13 C spectra were recorded for all compounds at room and low temperature, for obtained the determination of coupling constants. The experimental results and those from theoretical calculations showed the influence of hyperconjugative interactions nx→σ*C–Heq, nx→σ*C–Hax e nx→σ*C–X, where X is oxygen or sulfur atoms, on 1 JCHax, 1 JCheq and 2 JHH coupling constants in 1,3,5-trioxane and 1,3,5-trithiane. The experimental results and those from theoretical calculations showed the influence of electrostatic effects for 1 JCHax coupling constant in 2-substituted 1,3,5- xvii
Page 1: UNIVERSIDADE ESTADUAL DE CAMPINAS I
Page 4 and 5: Ao meu Pai Oscar, à minha mãe Jo
Page 6 and 7: AGRADECIMENTOS • Agradeço a Deus
Page 8 and 9: 4. Tormena, C.F.; Vilcachagua, J.D.
Page 12 and 13: trithianes with electronegative ato
Page 14 and 15: 3.3.3. Preparação das Amostras pa
Page 16 and 17: Interações de Orbitais e seus Efe
Page 60 and 61:
Interações de Orbitais e seus Efe
Page 62 and 63:
Page 64 and 65:
Page 66:
Page 69 and 70:
Page 71 and 72:
Page 73 and 74:
Page 75 and 76:
Page 92:
show all

interações de orbitais e seus efeitos nos acoplamentos jch em 1,3,5 ...

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?