Análise de Espectros de Infravermelho e Identificação de Compostos Orgânicos, Resumos de Química

Baixe Análise de Espectros de Infravermelho e Identificação de Compostos Orgânicos e outras Resumos em PDF para Química, somente na Docsity! Reading: 1. Silverstein chapter 2 (IR Spectroscopy). 2. Silverstein chapter 1 (Mass Spectrometry). Problems: 1. Silverstein 7th ed. problems 2.1-2.8. PDF document (2.1-2.8.pdf ). In problem 2.2, note that 1- nitropropane and dioxane are separate compounds. 2. Additional Problems 1-4. PDF document (ExtraProblems1-4.pdf ). 3. 2014 Midterm Exam Part I.1. PDF document (2014-MT-I.1.pdf ). 4. 2015 Midterm Exam Part I.1. PDF document (2015-MT-I.1.pdf ). Modeling: Complete the Molecular modeling with PyMOL assignment (modeling.pdf ). E-mail the final versions of the .pse files for morphine.pse and strychnine.pse to TA James Griffin ([email protected]). STUDENT EXERCISES 2.1 Either benzonitrile or phenylacetonitrile shows a band of medium intensity at 2940 cm
1; the other com- pound shows nothing in the range 3000–2500 cm
1. Explain. 2.2 Select a compound that best fits each of the follow- ing sets of IR bands (in cm
1). Each set corre- sponds to a list of just a few important bands for each compound. Benzamide Diphenyl sulfone Benzoic acid Formic acid Benzonitrile Isobutylamine Biphenyl 1-Nitropropane dioxane a. 3080 (w), nothing 3000–2800, 2230 (s), 1450 (s), 760 (s), 688 (s) b. 3380 (m), 3300 (m), nothing 3200–3000, 2980 (s), 2870 (m), 1610 (m),
900–700 (b) c. 3080 (w), nothing 3000–2800, 1315 (s), 1300 (s), 1155 (s) d. 2955 (s), 2850 (5), 1120 (s) e. 2946 (s), 2930 (m), 1550 (s), 1386 (m) f. 2900 (b, s), 1720 (b, s) g. 3030 (m), 730 (s), 690 (s) h. 3200–2400 (5), 1685 (b, s), 705 (s) i. 3350 (s), 3060 (m), 1635 (s) s  strong, m  medium, w  weak, b  broad For Exercises 2.3–2.6, match the name from each list to the proper IR spectrum. Identify the diagnostic bands in each spectrum. Spectra for Exercises 2.3 to 2.8 can be found on the Wi- ley website at http://www.wiley.com/college/silverstein in PDF format. 2.3 SPECTRA A–D 2.4 SPECTRA E–I 1,3-Cyclohexadiene Butyl acetate Diphenylacetylene Butyramide 1-Octene Isobutylamine 2-Pentene Lauric acid Sodium propionate 2.5 SPECTRA J–M 2.6 SPECTRA N–R Allyl phenyl ether Aniline Benzaldehyde Azobenzene o-Cresol Benzophenone oxime m-Toluic acid Benzylamine Dimethylamine hydrochloride 2.7 Deduce the structure of compound (S) whose formula is C2H3NS from the spectrum below. 2.8 Point out evidence for enol formation of 2,4-pentane- dione (Compound T). Include explanations of the two bands in the 1700–1750 cm
1 range, the 1650 band, and the very broad band with multiple maxima running from 3400–2600 cm
1 (only the peaks at 3000–2900 result from C9H stretching). 2.9 For each of the following IR spectra (A–W) list func- tional groups that a) are present, and b) are absent. The mass spectra of these compounds are in Chapter 1, (Exercise 1.6.) 44913_02_p072-118 11/12/04 3:55 PM Page 110 4000 3000 2000 1000 Wavenumber (cm-1) 70 75 80 85 90 95 100 % T ra ns m it ta nc e 10301134 1373 1462 1712 2877 2962 Problem 2.9 Spectrum A Wavenumbers (cm-1) 114 CHAPTER 2 INFRARED SPECTROMETRY Problem 2.4 Spectrum G Problem 2.4 Spectrum H Problem 2.4 Spectrum I Problem 2.4 PROBLEMS 115 Problem 2.5 Spectrum J Problem 2.5 Spectrum K Problem 2.5 Spectrum L Problem 2.5 116 CHAPTER 2 INFRARED SPECTROMETRY Problem 2.5 Spectrum M Problem 2.6 Spectrum N Problem 2.6 Spectrum O Problems 2.5 and 2.6 3500 3000 2500 2000 1500 1000 0 10 20 30 40 50 60 70 80 90 100 Wavenumbers T r a n s m i t t a n c e 3500 3000 2500 2000 1500 1000 0 10 20 30 40 50 60 70 80 90 100 Wavenumbers T r a n s m i t t a n c e 3500 3000 2500 2000 1500 1000 0 10 20 30 40 50 60 70 80 90 100 Wavenumbers T r a n s m i t t a n c e 3500 3000 2500 2000 1500 1000 0 10 20 30 40 50 60 70 80 90 100 Wavenumbers T r a n s m i t t a n c e 3500 3000 2500 2000 1500 1000 0 10 20 30 40 50 60 70 80 90 100 Wavenumbers T r a n s m i t t a n c e 3500 3000 2500 2000 1500 1000 0 10 20 30 40 50 60 70 80 90 100 Wavenumbers T r a n s m i t t a n c e 3500 3000 2500 2000 1500 1000 0 10 20 30 40 50 60 70 80 90 100 Wavenumbers T r a n s m i t t a n c e 3500 3000 2500 2000 1500 1000 0 10 20 30 40 50 60 70 80 90 100 Wavenumbers T r a n s m i t t a n c e 3500 3000 2500 2000 1500 1000 0 10 20 30 40 50 60 70 80 90 100 Wavenumbers T r a n s m i t t a n c e 3500 3000 2500 2000 1500 1000 0 10 20 30 40 50 60 70 80 90 100 Wavenumbers T r a n s m i t t a n c e FE DC BA G H I J H2O impurity 1. IR spectra are provided for 10 compounds composed only of C, H, and O. Choosing among the following classes of compounds, write the name of the compound class next to the IR spectrum: alkane, alkene, arene (aromatic), alkyne, alcohol, aldehyde, ketone, ester, carboxylic acid, cyclopentanone, γ-lactone, conjugated enone, acid anhydride. 2. Identify the functional group in simple monocompounds A-E from the IR spectra provided. Three of the compounds contain nitrogen-containing functional groups and two do not. Three of the compounds contain oxygen-containing functional groups and two do not. A: _________________________ B: _________________________ C: _________________________ D: _________________________ E: _________________________ 4000 3800 3600 3400 3200 3000 2800 2600 2400 2200 2000 1800 1600 1400 1200 1000 800 600 450 2.5 2.6 2.7 2.8 2.9 3 3.5 4 4.5 5 5.5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 21 22 WAVENUMBERS MICRONS 0 10 20 30 40 50 60 70 80 90 100 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 2.0 .05 % T R A N S M I T T A N C E A B S O R B A N C E NICOLET 20SX FT-IR 4000 3800 3600 3400 3200 3000 2800 2600 2400 2200 2000 1800 1600 1400 1200 1000 800 600 450 2.5 2.6 2.7 2.8 2.9 3 3.5 4 4.5 5 5.5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 21 22 WAVENUMBERS MICRONS 0 10 20 30 40 50 60 70 80 90 100 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 2.0 .05 % T R A N S M I T T A N C E A B S O R B A N C E NICOLET 20SX FT-IR A B 4000 3800 3600 3400 3200 3000 2800 2600 2400 2200 2000 1800 1600 1400 1200 1000 800 600 450 2.5 2.6 2.7 2.8 2.9 3 3.5 4 4.5 5 5.5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 21 22 WAVENUMBERS MICRONS 0 10 20 30 40 50 60 70 80 90 100 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 2.0 .05 % T R A N S M I T T A N C E A B S O R B A N C E NICOLET 20SX FT-IR C D E 4000 3800 3600 3400 3200 3000 2800 2600 2400 2200 2000 1800 1600 1400 1200 1000 800 600 450 2.5 2.6 2.7 2.8 2.9 3 3.5 4 4.5 5 5.5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 21 22 WAVENUMBERS MICRONS 0 10 20 30 40 50 60 70 80 90 100 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 2.0 .05 % T R A N S M I T T A N C E A B S O R B A N C E NICOLET 20SX FT-IR 4000 3800 3600 3400 3200 3000 2800 2600 2400 2200 2000 1800 1600 1400 1200 1000 800 600 450 2.5 2.6 2.7 2.8 2.9 3 3.5 4 4.5 5 5.5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 21 22 WAVENUMBERS MICRONS 0 10 20 30 40 50 60 70 80 90 100 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 2.0 .05 % T R A N S M I T T A N C E A B S O R B A N C E NICOLET 20SX FT-IR 1. Each of the following IR spectra is associated with one of the compounds below. Identify the compound associated with each spectrum. (10 points) CH3O Cl O methyl chloroformate ethyl vinyl ether O O vinyl acetate O O=C=N O O ethyl isocyanatoacetate O O ethyl propiolate Spectrum A _____________________ 0540060080001002100410061008100020022004200620082000300230043006300830004 2.5 2.6 2.7 2.8 2.9 3 3.5 4 4.5 5 5.5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 21 22 WAVENUMBERS MICRONS 0 10 20 30 40 50 60 70 80 90 100 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 2.0 .05 % T R A N S M I T T A N C E A B S O R B A N C E NICOLET 20SX FT-IR Spectrum B _____________________ 0540060080001002100410061008100020022004200620082000300230043006300830004 2.5 2.6 2.7 2.8 2.9 3 3.5 4 4.5 5 5.5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 21 22 WAVENUMBERS MICRONS 0 10 20 30 40 50 60 70 80 90 100 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 2.0 .05 % T R A N S M I T T A N C E A B S O R B A N C E NICOLET 20SX FT-IR This work by Dr. James S. Nowick, Professor of Chemistry, University of California, Irvine, is licensed under a Creative Commons Attribution 4.0 International License. Spectra are from Sigma-Aldrich (www.sigmaaldrich.com) under fair use. Spectrum C _____________________ 0540060080001002100410061008100020022004200620082000300230043006300830004 2.5 2.6 2.7 2.8 2.9 3 3.5 4 4.5 5 5.5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 21 22 WAVENUMBERS MICRONS 0 10 20 30 40 50 60 70 80 90 100 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 2.0 .05 % T R A N S M I T T A N C E A B S O R B A N C E NICOLET 20SX FT-IR Spectrum D _____________________ 0540060080001002100410061008100020022004200620082000300230043006300830004 2.5 2.6 2.7 2.8 2.9 3 3.5 4 4.5 5 5.5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 21 22 WAVENUMBERS MICRONS 0 10 20 30 40 50 60 70 80 90 100 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 2.0 .05 % T R A N S M I T T A N C E A B S O R B A N C E NICOLET 20SX FT-IR Spectrum E _____________________ 0540060080001002100410061008100020022004200620082000300230043006300830004 2.5 2.6 2.7 2.8 2.9 3 3.5 4 4.5 5 5.5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 21 22 WAVENUMBERS MICRONS 0 10 20 30 40 50 60 70 80 90 100 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 2.0 .05 % T R A N S M I T T A N C E A B S O R B A N C E NICOLET 20SX FT-IR This work by Dr. James S. Nowick, Professor of Chemistry, University of California, Irvine, is licensed under a Creative Commons Attribution 4.0 International License. Spectra are from Sigma-Aldrich (www.sigmaaldrich.com) under fair use. This work by Dr. James S. Nowick, Professor of Chemistry, University of California, Irvine, is licensed under a Creative Commons Attribution 4.0 International License. 1. Each of the following IR spectra is associated with one of the compounds below. Identify the compound associated with each spectrum. Use the characteristic C=C stretching and C–H bending frequencies and intensities listed in Appendix C-1 (Silverstein, provided) to aid you in your analysis of the data. (10 points) trans-4-octene1-octene 2-methyl-2-heptene cis-2-pentene2,3,4-trimethyl-2-pentene Spectrum A _____________________ 0540060080001002100410061008100020022004200620082000300230043006300830004 2.5 2.6 2.7 2.8 2.9 3 3.5 4 4.5 5 5.5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 21 22 WAVENUMBERS MICRONS 0 10 20 30 40 50 60 70 80 90 100 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 2.0 .05 % T R A N S M I T T A N C E A B S O R B A N C E NICOLET 20SX FT-IR Organic Spectroscopy Chem 203 Molecular Modeling with PyMOL PyMOL software is distributed at no cost under a license that only permits use by Professor Nowick and his students for research and teaching purposes. Professor Nowick's Chem 203 students are permitted to download and use it only for purposes associated with the Chem 203 class. Use for other purposes or distribution to others is prohibited. You may register and download the software at the following link using my credentials: PyMOL Download: http://www.pymol.org/2/#download FAQ: https://pymol.org/2/support.html#faq Documentation: https://pymol.org/dokuwiki/doku.php Invoice number: 26796 USER: 21jul05 PASSWORD: y3au7nem In addition to the software, you will need to download the license file. After you download this file, you can browse for it when PyMOL asks you to activate it upon starting. PyMOL can perform molecular mechanics calculations to generate realistic molecular models of molecules with common types of atoms and functional groups. Molecular mechanics uses a force field to calculate the steric energy of the molecule and then adjusts the conformation of the molecule to minimize the steric energy. A force field is set of parameters for the bond lengths, angles, torsional parameters, electrostatic properties, van der Waals interactions, etc. PyMOL uses the Merck Molecular Force Field (MMFF), which accurately accommodates a variety of atom types and functional groups. The conformation generated by molecular mechanics is a local minimum. A local minimum is a conformation at the bottom of an energy well (i.e., a conformer). It is not necessarily the lowest energy conformer (i.e., the global minimum). If you start near gauche butane, you will generate gauche butane as a local minimum; if you start near anti butane, you will generate anti butane as a local minimum that is also the global minimum. If you start with a boatlike conformation of cyclohexane, you will end up with a twist-boat conformer; if you start with a chairlike conformation of cyclohexane, you will end up with a chair conformer. The lowest-energy conformer (global minimum) many be identified by various strategies. With simple molecules and small ring sizes, this is often best done by manually adjusting the structure and re-minimizing the structure. Manual adjustments can consist of rotating about bonds (e.g., turning a gauche-like structure to an anti-like structure) or flipping rings (e.g., a ring flip of cyclohexane). The lowest-energy conformer of molecules containing large rings is often best found by automated conformational searching procedures that are implemented in full-featured molecular mechanics programs such as MacroModel. Molecular mechanics calculations are an appropriate method to model molecules containing common structures and functional groups, such as morphine and strychnine. For molecules containing arrangements of atoms and functional groups, reactive intermediates, or transition metals, electronic structure calculations are often more appropriate. Structures such as oxocarbenium ions, organopalladium compounds, or the transition state for an aza-Cope rearrangement best modeled with electronic structure calculations in programs such as Spartan, Gaussian, or TURBOMOLE. Exercise 1, Morphine In this exercise, we are going to build a minimum energy structure of morphine and create a PyMOL file morphine.pse and a .pdb coordinate file morphine.pdb. We are going to build up the structure in a series of steps, making models morph_A, morph_B, and morph_C along the way. A. Use the builder module of PyMOL to make intermediate structure morph_A. First use the cyclohexane template to make a cyclohexane ring. Then use the CH4 template to add a methyl group. Use the pulldown menu (File-Save Session As) to save the structure as morph_A.pse . B. Continue building to make intermediate structure morph_B. Convert the tertiary carbon atom to a nitrogen. Add the axial phenyl group. Rotate about the phenyl group into position using the right mouse button and the control key to pick the torsion bond (PkTB) and then the left mouse button and the control key to rotate the phenyl group (TorF). Use the CH4 template to add an axial methyl group. Use Bonds-Create button to create a bond between the methyl group and the phenyl ring. Use the Model-Clean button to minimize the structure. Use the pulldown menu to save the structure (File-Save Session). C. Continue building to make intermediate structure morph_C. Use the C=C template to add a vinyl group. Use the CH4 template to add the two remaining carbons of the cyclohexene ring. Use Bonds-Create button to close the cyclohexene ring. Use the Model-Clean button to minimize the structure. Use the pulldown menu to save the structure (File-Save Session). D. Complete the construction and minimization of morphine. Add the oxygen atoms. Use Bonds- Create button to close the dihydofuran ring. Use the Model-Clean button to minimize the structure. Use the pulldown menu to save the structure as morphine.pse (File-Save Session As). Use the pulldown menu to export the structure in the .pdb file format as morphine.pdb (File-Save Molecule). Generate a .png image of the molecule as a sticks drawing. Rotate the molecule into an appropriate orientation. Use the side menu (S) to show the molecule as sticks (Show-sticks). Use the pulldown menu hide double bonds (Display- uncheck Show Valences). Use the pulldown N OH Me O OH morphine Me morph_A NMe morph_C NMe morph_B