Espectroscopia Infravermelho, RMN e massas, Exercícios de Química Orgânica

Baixe Espectroscopia Infravermelho, RMN e massas e outras Exercícios em PDF para Química Orgânica, somente na Docsity! PROBLEMS Bach of lhe following compounds is characterized by a TE NMR spectrum Lhat consists 13.31 of only a single peak having the chemical shift indicated, Tdentify each compound. (a) Coll 3 09 (f) CoLCIs; 827 (Db) CH: & 1.5 (e) (e) Coll 5 5.8 (hm) € (d) CiHBr; é 1.8 (id CiHaBr,; d 2.6 (o) CHCh; 837 13.32 spectra and molecular formulas: (0) Coy 8 1.2 (triple, 3H) 8 2.6 (quartet, 2H) (8) CH: (1 CHCh; Deduce the structure of each of the [ollowing compounds on the basis of their TE NMR 8 3.9 (doublet, 4H) 3 4.6 (triplet, 2H) 8 2.2 (singlei, 2H) (b) Ciolg: 8 13 (Singlet, 9H) 84.1 (doubler, 21) 8 70 to 75 (multipler, 5H) 3 57 (triplet, 1H) (6) CH: 8 0.8 (doublet, 12H) (8) CAH;CIO: 8 2.0 (quintet, 2H) 8 14 (septer, 21D) 309 (triple, 3H) 81.6 Ginglet, 317) 8 2.8 (singlet, 1) 8 27 (triplet, 2H) & 3.8 dlriplet, 217) 8 17 (singlet, 3H) (h) CiHy: 829 (Singlet, 4H) 8 2.0 (quimer, 2H) 8 71 (broad singlet, 10H) 85.1 (triplet, 18) 13.33. lirom among the isomeric compounds of molecular formula C.H,CI, choose the one having a “1 NMR spectrum that (a) Contains only a single peak (b) Has several peaks including a doublet at à 3.4 (c) Has several peaks including a triplet at 5 3.5 (d) Has several peaks including two distinct three-proton signals, one of them a triplet at à LO and the other a doublet ar ô 1.5 13.34 Identify the C,HsBr isomers on the basis of the following information: (a) Isomer A has the !'H NMR spectrum shown in Figure 1346. (b) Isomer B has three peaks in its “C NMR spectrum: 3 32.6 (CH): 18.8 (CI); and 134.2 (CID. (c) Isomer C has two peaks in its C NMR spectrum: 3 12.0 (CH.) and 16.8 (CH), The peak at lower field is only half as intense as the one at higher field. 3 Figure 13.46 The 200-MHz !H NMR spectrum of isomer A (Problem 13.344) 1 Lu. 0 90 E 70 60 E 10 30 20 0 qo Chemical shift (6, nom)  Pheny vinyl sulfoxide Figure 13.47 13.35 Identify each of the C,H,O isomers on the basis of their “C NMR spectra: (a) 8 18,9 (CH;) (two carbons) 8 30.8 (CH) (one carbon) 5 69,4 (CH,) (one carbon) (b) 8 10.0 (CH) 3227 (CH;) 8 22.0 (CH,) 5 69.2 (CH) (c) 8 31.2 (CH,) (three carbons) 8 68.9 (C) (one carbon) 13.36 A compound (C;ILCIO,) exhibited three peaks in its PC NMR spectrum at à 46.8 (CIL,), 5 63.5 (CIL), and 8 72.0 (CIT). Excluding compounds that have Cl and OII on the same carbon, which are unstable. what is the most reasonable structure for this compound? 13.37 Label nonequivalent carbons in the following compounds. OCH. CH. + Ss, HC HC ON . ON SEA SENA 4 LOCA N Vc MON po MON po nã Ac; À OCH; OCH; CHs (a) 0) (9) (a) 13.38 The 'H NMR spectrum of Nuorene has signals at 3 3.8 amd 3 7.2-7.7 in a 1:4 rulio. Alter heating with NaOCH, in CH,OD at reflux for 15 minutes the signals at 3 727.7 remuined, but the one at 3 3.8 had disappeared. Suggest an explanation and write à mechanism for lhis observation q » ( S, Wo 4 VA AL Tluorene 13.39. The vinyl proton region of the !H NMR specirum of phenyl vinyl sulfoxide is shown in Figure 13.47. Construct a splitting diagram similar to the one in Pigure 13.21 and label cach of the coupling constants 4, Jp. and Jo 1856.7 1760.6 1751.0 18403 NAN A Var pr perros 1 poa 66 64 E) su 58 Chemical shift (à. ppm) pectrum of phenyl vinyl sulfoxide. Vinyl proton region of the 300-MHz H NMR spectrum of pheny! vinyl sulfoxide.  100 + 80 +) E 607 40 À 20 + od 3500 3000 2500 2000 1500 1000 500 Wavenumbers, em”! (a) 5 CoHoO | 3 M 0 48 1 1.60 (ppm) (ppra) 1 o 100 90 80 70 60 50 40 30 20 TO 00 Chemical shift (5, ppm) th) Figure 13.51 (a) IR and (b) 200-MHz !H NMR spectra of a compcund CaHha0 (Problem 13.43), 13.43 A compound (C,H,,O) has the IR and 'H NMR spectra presented in Figure 13.51. What is its structure? 13.47 Which would you predict to be more shielded, the inner or outer protons of [B4Jannulene? 13.48 "F is the only isotope of fluorine that occurs naturally, and it has a nuclear spin of ss. (a) Into how many peaks will the proton signal in the !H NMR spectrum of methyl fluoride be split? (b) Into how many pcaks will the fluorinc signal in the !ºF NMR spectrum of methyl fluoride be split? (c) The chemical shift of the protons in methyl fluoride is 8 4.3. Given that the geminal !H—F coupling constant is 45 Hz, specify the 8 values at which peaks are observed in the proton spectrum of this compound at 200 MHz. 15.9 Foreach of the following IR spectra, identify whether it is consistent with the structure of an alcohol, a carboxylic acid, or neither. 100. 100 so. — so ) a A Dani | ) s £% | 5 e E E é Ê 5 E so E 1 s 8 20. 20 o. o ADO 3500 3000 2500 2000 1500 1000 AUU0 SU0 JUDO 2500 2000 1500 ICOU (a) Wavenumber (cm) (b) Wavenumber (cm=!) 100 100 su eu pre Bel > É o proa E N |, Eco E E Eu N (O Eu É N É 8 Y 8 20 20 u o 4000 3500 2000 2500 2000 1500 1000 4000 3500 3000 2500 2000 1500 1000 (e) Wavenumber (cm-1) (d) Wavenumber (cm-!) 100 100 DI e — sol 8 RA au 8 N TT A ) Eco / ER A! 2 5 Es Ú Es x 8 20 20 o º ano 3500 3000 2500 2000 1500 1000 4000 3500 3000 2500 2000 1500 1000 (e) Wavenumber (cm!) (1 Wavenumber (cm!) e PRACTICE the skill 15.12 Match each compound with the appropriate IR spectrum: o O O EM Dm A nha AAA i E | O meo que aa e K | a nf TAS à Vo NO ps | y | Po g A PM | 5 h | Ê | Mn j o |! E my ) M | o | ê | | ã | 2 E Êo | i = É Los s i a a CE 0 0 HO 0 Im GG BE So MM ao 16 Nm Wiavenumber (em ) by Wavenumber (cm !) o 1º 8 Yf ê ê | Ê E E i Ee | | E o | E i E a Ea 2 | Ê | R | x i ” ) a | I o Wavenumber (cm) td) Wavenumber tom!) | q . i 4 8 ] ê ) É Eu N (| E : E vo | ç . Ê NR ED Ê Ro a] E ! E (| Hi E i É HAI 4 É os CER £ º m || | ; yu “o Wavenumber (cm”") E) wavenumber (cm!) 16.23 Propose a structure that is consistent with each of the following 'H NMR spectra. In each case, the molecular formula is provided. Proton NMR CoHqgO ] | Vol Ay | SL ) No 35 30 25 20 15 1.0 ppm E — a (b) Integration Values 108 65.7 Proton NM CaHçOo | | | ql | ) JA PAN 50 45 40 35 20 25 20 15 ppm —— 1 18.02 Integration Values 19.F7 (cl) 19.46 Proton NMR CoHy20 | À H dy Ju AM JA MU ASSIS OD ASSESSORA 30 28 26 24 22 20 18 146 14 142 40 08 06 04 ppm a + a Da (f) Integration Values 13.6 27.8 845 41.9 10 16.62 Deduce the structure of a compound with molecular formula CsH,40» that exhibits the following IR, 'H NMR, and Be NMR spectra. 100 e o co o Õ o 1 1 1 % Transmittance ho o 1 0 T T T T T T 4000 3500 3000 2500 2000 1500 1000 Wavenumber (cm — 1) Proton NMR E 1 22 45 40 35 30 25 20 15 10 05 Chemical Shift (ppm) Carbon NMR o 10 Bo CO 4 20º 0 Chemical Shift (ppm) 11 15.46 Match each compound with the appropriate spectrum. TOCO ta) 100 Relative Intensity e O o o o o l l l ha S L 9 ) dl 1 ql] d rum RI] 10 20 30 40 50 60 70 80 ao mz Relative Intensity 8 8 & | | l [o] So Ii 9 À ) da ; ati, 10 20 30 40 So 60 70 80 90 100 110 mz 12