NMR handout - 13' _ gm am W) U Table I: Typical Absorption...

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Unformatted text preview: 13' _ gm am W) U Table I: Typical Absorption Regions for Variaus Types of Protons 12 11 “ exchanges with D20 Equation: Any substituent directly attached to a methyl has a unique value; there are no additional Bondsfor further consideration. These chemical shifts can be calculated using the equation (1) (1) 6cm 2 0.9 + a, V CH3- on If a methyl group is a part of a longer _ chain with an additional substituent (or ' several substituents) on a b or g position (or both positions), the equation (2) is used to calculate the chemical shift. (2) (San = 0.9 4— 2 (B + y), CH3-C—C— 3 Y In a similar fashion, chemical shifts for methylenes and methines are calculated by the equations (3) and (4). (3) 6cm = 1.2 + 2 (0: + [3 +‘ Y), -CH2-C—C- a B Y (4) 5m = 1.5 + 2 (a + l3 + v), H-C-C-C- ' ' a 0t [3 v --E 7’_ 6 w aromatic heteroaromatic I IIII+ ilk“: I ' conjugated alk'ene - ATNHZ.’ AM"! _ Rs“- TMS now I may. RZNH « 5 .4' =3 "‘2 1 0 / : . 1 Table 1. Estimation of sp3 C—H Chemical Shifts‘ a = directly attached substitutent—u B = once—removed substituem-B y = twice-removed substitutent—y 0‘ ' B aMultiple substituent parameters for protons within three carbons oi consideration. SCH) =5w28 1‘ 25am + ZOE "' Z’l‘yans TABLE 3-3 Substituent Parameters for Aromatic Proton Shifts Substituent 8mm Sm.a Spam CH3 —0.17 —0.09 ~0.18 CHZCH3 —0.15 —0.06 —0.18 NO2 0.95 0.17 0.33 Cl 0.02 -—0.06 —0.04 'Br 0.22 —0.13 ~0.03 _ ‘l 0.40 —0.26 —0.03 CHO 0.58 0.21 0.27 OH —0.50 -O.14 —0.40 NH2 —0.75 ~0.2_4 —-0.63 ON 0.27 0.11 0.30 COZH - 0.80 0.14 0.20 COZCH3, 0.74 0.07 0.20 COCH3 -. 0.64 0.09 0.30 OCH3 —O.43 —0.09 ~0.37 OCOCH3 —0.21 —0.02 —0.13 N(CH3)2 ~0.60 ~0.10 —0.62 _ SCH3 0.37 0.20 0.10 1.00 TABLE 3-2 Substituent Parameters for the Tobey—Simon Rule Substituent 299”, 20,3 Ztrans H. 0.0 0.0 0.0 Alkyl 0.44 —0.26 4 —-0.29 CHZO, CH2l 0.67 ~0.02 —0.07 ' CHz-S ' 0.53 —0.15 . —0.15 . .CHZCI, CHZBr ’ 0.72 0.12 0.07 CH2N 0.66 —0.05 —0.23 C=C 0.50 0.35 / . ' 0.10 CEN 0.23 0.78 0.58,? C=C (isolated) 0.98 ——0.04 —0.21 C=C (conjugated) 1.26. 0.08 —Q.-01 C=O (isolated) 1.10 1.13 0.81 C=O (conjugated) 1.06 1.01 0.95 C02H (isolated) 1.00 1.35 0.74 COZR' (isolated) 0.84 1.15 0.565 CHO . 1.03 0.97 121' OR (R aliphatic) I 1.18 ., —1.06 —1.28/ OCOR ‘ " 2.09 , —o.4o -—0.67 . Aromatic 1.35 0.37 -O.10 Cl' 1.00 0.19 0.03 Br 1.04 0.40 0.55 NFl2 (R aliphatic) . 0.69 ~1.19 —1.31 SR —0.24 ~0.04 6(/’I)=7.677 +1233; Tablev'IIL: Spin-spin interactions. The coupling constants (I) for various relative hydrogen ' V - TABLE E 1 positions which-arise in common organic . ' - ' » molecules are given based on the generalized . molecule illustrated below. ‘ '- Solvent 5 C e Chloroform—al3 l .5 H \ /H O Benzene—d6 . 0.4 /c=c\ I I Acetone—d5 2.75 H - C R ,_ C R u_ C__H Methylene chloride—d2 1.55 . d l - l f Dimethylformamide—d7 , 3.0 ‘ H H - Pyridine—d5 5.0 a b Toluene—d3 , 0. l~0.2 Methanol—d4 4 4.9 . Acetonitrile—al3 . 2. l Jab = 6 - 8 Hz be= l - 3 Hz Dimethyl sulfoxide—ds ‘ 3.35 . Jae = 4 _ 10 HZ Jed : O _ 3 Hz Water—dz _ . 4 ~4.75 (HDO) - . . Jae = 0 ~ 3 HZ Ice = 6 - 12 HZ ‘ , (From Sllverstem et. al., pg. 220) Jad=O-3Hz ' Ide=12-18HZ Jbe = 0 Hz ‘ CI-fC, RS—C ‘(Sulfidesl ' I Saturated al'kanes l racer—21H: l——.—l Aromatics ' HzN—C (Amines) No-9 HO —C (Alcohols) i———l' l—-——l er-c ozw—c [*4 _ l.._"_———_{ RiC=CR—§ \ I _ Ro~c (Ethersl l——____{ }—_—~{ Ar—C RCECH, RCECR l»—-—-——{ |»—-———.-——-l R-C-Q 0 ppm (5) 200 10° Figure 341 Carbon chemical'shift ranges for common structural units. The symbol C represents methyl, methylene, metblne, or qua— ternary carbon; Rf-represents a saturated alkyl group. The indicated ranges are for common fe),(ar'nple's; actual ranges can be larger._ SCCH¢)?-9.Sffm , SCCHid/L): magw A‘(_@./385 TABLE 5.1 13C Atoms Shift (ppm) (A) 0: +9.1 [3 +9.4 7 ~25 8 +0.3 6 +0.1 1° (3°)“ —1.1 1° (4°)“ —3.4 2° (3°)“ ~25 2° (4°) —7.2 3° (2°) ~ —3.7 3° (3°) —9.5 4° (1°) —1.5 4° (2°) ‘ «8.4 “The notations 1° (3°) and 1° (4°) denote a CH, group bound to a R2CH group and to a R3C group, respectively. The notation 2° (3°) denotes a RCHz group bound to a R2CH group, and so on. In general, the terminal =CH2 group (usually a trip- let m an off-resonance decoupled spectrum) absorbs upfield from an internal =CH~ group, and cis —CH=_CH—— signals are upfield from those of cor— responding trans groups. Calculations of approximate shifts can be made from the following parameters where a, B, and y represent substituents on the same end of the double bond as the alkene carbon of interest, and a', B’, and 7’ represent substituents on the far side. 0‘ +10.6 3 + 7.2 7 — 1.5 a' — 7.9 3' — 1.8 7’ — 1.5 Z (cis) correction —— 1_1 l’f’" TABLE 5.3 Terminal Internal 6! [3 7 Y Terminal Internal Terminal Internal CH3 + 9 + 6 +10 + 8 —2 CH=CH2 +20 + 6 ~05 CECH + 4.5 + 5.5 —3.5 COOH +21 +16 + 3 + 2 +2 COO‘ +25 +20 + 5 + 3 —2 COOR +20 +17 + 3 + 2 —-2 COCl +33 +28 + 2 CONHZ +22 + 2.5 —0.5 COR +30 +24 + 1 + 1 —2 CHO +31 0 —-2 Phenyl +23 +17 + 9 + 7 —2 OH +48 +41 +10 + 8 —5 OR +58 +51 + 8 + 5 —4 OCOR +51 +45 + 6 + 5 —3 NH; +29 +24 +11 +10 —5 NH; +26 +24 + 8 + 6 —5 NHR +37 +31 + 8 + 6 —4 NR2 +42 + 6 —3 NR; +31 + 5 —7 N02 +63 +57 + 4 + 4 CN + 4 + 1 + 3 + 3 *3 SH +11 +11 +12 +11 —4 SR +20 + 7 —3 F +68 +63 + 9 + 6 +4 Cl +31 +32 +11 +10 —4 Br +20 +25 +11 _ +10 —3 l — 6 + 4 +11 +12 —1 "Add these increments to the shift values of the appropriate carbon atom in Table 5.2 or to the shift value calculated from Table 5.1. Source: F.W. Wehrli, A.P. Marchand, and S. Wehrli, Interpre- tan‘on of Carbon-13 NMR Specrra. 2nd ed., London: Hayden, 1983. W TABLE 5.9 C-l ' . C of Substituent Su'bstituent (Attachment) C-2 C—3 C-4 (ppm from 'I'MS) W H ' 0.0 0.0 0.0 0.0 CH3 9.3 +0.7 +0.1 —2_-.-9 21.3 CHZCH3 +15.6 —0.5 0.0 —2.6 29.2 (CH2), 15.8 (CH3) CH(CH,)2 +20.1 +2.0 0.0 —2.5 34.4 (CH), 24.1 (CH3) C(CH,)3 +22.2 —3.4 —0.4 —3.1 34.5 (C), 31.4 (CH,) CH=CH2 +9.1 +2.4 +0.2 —0.5 137.1 (CH), 113.3 (CH2) CECH —-5.8 +6.9 +0.1 +0.4 84.0 (C), 77.8 (CH) C611, +12.1 —-l.8 —0.1 —l.6 CH20H - +13.3 —0.8 —0.6 —0.4 64.5 CHZOCCH, +7.7 ~0.0 ~0.0 ~0.0 20.7 (CH,), 66.1 (CH2), ll 170.5 (C=O) 0 OH +26.6 ~12.7 +1.6 ~7.3 OCH3 +31.4 +144 +1.0 -7.7 54.1' OCsH, +290 " 9.4 +1.6 —5.3 fl) _ OCCH, +224 +7.1 ' —0.4 —3.2 23.9 (CH3), 169.7 (C=0) ‘11 CH . +8.2 +1.2 +0.6 +5.8 192.0 ‘1? CCHa +7.8 —0.4 —0.4 +2.8 24.6 (CH3), 1957 (C=O) ‘1’ CC8H5 +9.1 ' +1.5 —0.2 +3.8 196.4 (C=O) 11’ CCF; -5.6 +1.8 +0.7 +6.7 11’ con +2.9 +1.3 +0.4 +4.3 168.0 ‘11’ COCH, +2.0 +1.2 +0.1 +4.8 51.0 (CH,), 166.8 (C=O) C") 168.5 CC] +4.6 +2.9 +0.6 +7.0 CE -16.0 +3.6 +0.6 +4.3 119.5 NH2 +19.2 —12.4 +1.3 —9.5 I, N(CH3)2 +22.4 —15.7 +0.8 —ll.8 40.3 t") NHCCH: +11.1 +9.9 +0.2 —5.6 No2 +19.6 —5.3 +0.9 +6.0 N= =0 +5.7 —3.6 +1.2 —2.8 129.5 F +351 ‘ +143 +0.9 —4.5 C1 +6.4 +0.2 +1.0 —2.0 Br —5.4 +3.4 +2.2 —1.0 1 - —32.2 +9.9 +2.6 —7.3 CF. +2.6 ~3.1 +0.4 . +3.4 SH +2.3 +0.6 +0.2 ~33 SCH, +102 ——l.8 +0.4 —3.6 15.9 SOZNHZ +153 ~29 +0.4 +3.3 Si(CH3); +13.4 +4.4 ~1.1 —1.1 ...
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NMR handout - 13' _ gm am W) U Table I: Typical Absorption...

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