Lab Report 2-2 PDF

Preview

Summary

Lab report...

Description

Experiment 2: Hydroboration of Indene - NMR Determination of Regioselectivity Analysis The purpose of this lab was to perform a hydroboration reaction of indene and to use 13C NMR to determine the structure of the resulting product. However the final result obtained did not match the hypothesis, the product was mostly all water. Error The final product weighed 1.0495g, but when the NMR was taken it showed that it was mostly water. This could have happened because when the washing of the product with ether was being done, water was added in order to see the separation of the organic layer. This could have been the reason why the final product ended up having mostly water. Postlab: 1.

2. The indene product when compared with the Product in IR spectroscopy will have a broad peak in the 3550 - 3200 cm-1 region corresponding to the O-H stretching frequency. 3. IR can’t distinguish between the two products that are shown because they are only different by symmetry which IR can’t distinguish and it’s specific to functional groups and both have the same functional group. 4. a. Benzene one peaks in 13C NMR as all the carbon atoms are similar b. 13C NMR will have 4 peaks since there is a centre of symmetric along the NC and the para position of the aromatic unit the C-NH will give one peak. The ortho carbons will give 1 peak, the meta carbons 1 peak and the p-CH will give one peak. c. This compound will give 3 13C NMR peaks as the centre of symmetry runs between the two carbons containing the Cl atom. one peak for the C-Cl carbon, one peak for the two CH carbons next to the C-Cl and one peak for the carbons next to this. d. This compound should show 6 signal in the 13 C NMR as this molecule has no symmetry. Each carbon C-Cl, C-Br the CH next to C-Br, the CH next to C-Cl and the next set of CH carbons will appear at different positions. 5. The given 13C NMR shows five peaks. There are peaks present in aromatic region-one for two carbon atoms. There are two peaks for aliphatic region-one for two equivalent carbons and one for C-OH carbon. 6. This is only possible for the structure shown on attached image.

7. Go back to the mechanism of reaction you wrote in Q1. Explain the observed regioselectivity of the reaction, i.e. in chemical terms, why do you get the isomer from Q6?...