0.144 Iculate the HMO energy levels and atomic orbital coefficients for 1,3 buta
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Question
0.144 Iculate the HMO energy levels and atomic orbital coefficients for 1,3 butadiene Estimate the dication C,H4 from HMO theory Estima VIS absorption of 1,3,5.7-octatetraene. Does it appear at a longer or shorter wavelength than the corresponding absorption in 1,3,5-hexatriene? 1.17 a. Ca te the delocalization energy, in units of , of the cyclobutadienyl b. ate, in units of , the energy associated with the longest-wavelength UV- Spio pentane has unusual strain and hybridization. Consider the following facets of its structure. a. The strain energy of spiropentane (62.5 kcal/mol) is considerably more than b. The structure of spiropentane has been determined by X-ray crystallography twice that of cyclopropane (27.5 kcal/mol). Suggest an explanation. The endocyclic angles at the spiro carbon are about 62e, and the bond angles between C-C bonds in the adjacent rings are about 137°. How would you relate the strain to the hybridization of each carbon in spirocyclopentane based on these bond angles? The fractional s character in a C-C bond can be estimated from C-C coupling constants using the equation where K is a constant = 550 Hz and s is the fractional s character of each atom. In spiropentane, the J for coupling between C(1) and C(3) is 20.2 The J between C(2) and C(3) is about 7.5 Hz. Calculate the s character of the C(1)-C(3) and C(2)-C(3) bonds. 3 62° 4 1370 2 spiropentane
Explanation / Answer
for question 1.18 c.
If JCi-Cj = K (si)(sj) and K = 550 Hz; JC1-C3 = 20.2 Hz; JC2-C3 = 7.5 Hz
then solving for s:
(si)(sj) = JCi-Cj / K
s1s3 = 20.2 Hz/550 Hz = 0.0367
s2s3 = 7.5 Hz/550 Hz = 0.0136
Question 1.20
a) in the case of this reaction, I think that reaction a) would occur faster basically because the Ag+ is acting as a catalyst of the reaction. And in a reaction, one fo the factors that have some effect in the speed of the reaction is the effect of the catalyst. In this case, Ag+ acts as a catalyst and the reaction would go faster thant the other one that do not have it.
b) the first reaction would be more complete, basically because it has a better inductive and resonating effect by the phenile groups that in the second. Once the first reaction is complete, that compound becames in a nucleofile, and the charge is stabilized by resonating with the phenile groups better than in the second reaction. That compound is not a better nucleofile basically, because of the steric effect of all the compounds around the charge. That's why the first reaction is faster and more complete.
The last question, I would like to answer it for you, but please post it in another question, right now I have some doubts about the answer of that one. So post it in another question, while I'm looking the answer por it.
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