Exam 12: Structure Determination: Mass Spectrometry and Infrared Spectroscopy

Exhibit 12-5 Refer to the mass spectrum of 2-methylbutane shown below to answer the following question(s). Spectrum obtained from: SDBSWeb: http://www.aist.go.jp/RIODB/SDBS/ -Refer to Exhibit 12-5.Which peak represents the parent peak?

Exhibit 12-1 Select the most reasonable formula for the compounds with the following mass spectral data. -Refer to Exhibit 12-1.M⁺ at m/z = 101 with a minor M+1 peak

Exhibit 12-2 Use the data below to answer the following question(s). Loratidine is the active ingredient in the antihistamine Claritin .Mass spectral analysis of loratidine shows M⁺ at m/z = 382 and M⁺ at m/z = 384 in an approximate ratio of 3:1 in intensity. -Refer to Exhibit 12-2.The mass spectral data indicates that loratidine contains:

Exhibit 12-3 For each compound below,what are the masses of the charged fragments produced by the indicated cleavage pathways? -Refer to Exhibit 12-3.Alpha cleavage of

Exhibit 12-6 MATCH each of the following groups of bond-types to the region of the infrared spectrum in which their absorptions occur.Place the letter of the region in the blank to the left of the bond-type. -_____ triple bond stretching vibrations.

Mass spectrometry and infrared spectroscopy are complementary techniques because:

In which of the following regions of the electromagnetic spectrum is the frequency lower than in the IR region?

Predict the m/z position of the parent peak,the peak due to dehydration of the alcohol and α-cleavage of the carbonyl in the mass spectrum of the compound shown below.

Which of the following regions of the electromagnetic spectrum would have insufficient energy to produce the following energy transition?

Exhibit 12-3 For each compound below,what are the masses of the charged fragments produced by the indicated cleavage pathways? -Refer to Exhibit 12-3.Alpha cleavage and dehydration of

Exhibit 12-4 The following question(s) refer to the mass spectrum shown below. Spectrum obtained from: SDBSWeb: http://www.aist.go.jp/RIODB/SDBS/ -Refer to Exhibit 12-4.This compound contains C,H,and one other atom.Identify the other atom from the mass spectrum and explain your reasoning.

Exhibit 12-5 Refer to the mass spectrum of 2-methylbutane shown below to answer the following question(s). Spectrum obtained from: SDBSWeb: http://www.aist.go.jp/RIODB/SDBS/ -Refer to Exhibit 12-5.What peak represents M⁺?

Exhibit 12-4 The following question(s) refer to the mass spectrum shown below. Spectrum obtained from: SDBSWeb: http://www.aist.go.jp/RIODB/SDBS/ -Refer to Exhibit 12-4.Propose a structure for this compound.

The amount of energy in infrared light corresponds to:

When 2-bromopropane reacts with ethoxide ion,two products are formed;one is the product of S_N2 substitution and the other is the product of E2 elimination.Write the structures of both products,and tell how they could be distinguished using IR spectroscopy.

Exhibit 12-6 MATCH each of the following groups of bond-types to the region of the infrared spectrum in which their absorptions occur.Place the letter of the region in the blank to the left of the bond-type. -_____ C=O,C=N,and C=C bond absorptions.

​What are the charged fragments produced if 4,5-dimethylhex-1-en-3-ol undergoes alpha cleavage?

​Ethyl acetate and 2-butene-1,4-diol both have the molecular formula C₄H₈O₂.How would you use infrared spectroscopy to distinguish between the two?

Which of the following regions of the IR spectrum would be significantly different for the following two substances?

​Both methylcycloheptane and ethylcyclohexane have the same molecular mass.Explain how it is possible to distinguish between the two compounds by studying and comparing both their mass spectra.