溶剂的化学位移(碳谱和氢谱)

NMR Chemical Shifts of Common Laboratory Solvents as Trace Impurities Hugo E.Gottlieb,*Vadim Kotlyar,and

Abraham Nudelman*

Department of Chemistry,Bar-Ilan University,

Ramat-Gan52900,Israel

Received June27,1997

In the course of the routine use of NMR as an aid for organic chemistry,a day-to-day problem is the identifica-tion of signals deriving from common contaminants (water,solvents,stabilizers,oils)in less-than-analyti-cally-pure samples.This data may be available in the literature,but the time involved in searching for it may be considerable.Another issue is the concentration dependence of chemical shifts(especially1H);results obtained two or three decades ago usually refer to much more concentrated samples,and run at lower magnetic fields,than today’s practice.

We therefore decided to collect1H and13C chemical shifts of what are,in our experience,the most popular “extra peaks”in a variety of commonly used NMR solvents,in the hope that this will be of assistance to the practicing chemist.

Experimental Section

NMR spectra were taken in a Bruker DPX-300instrument (300.1and75.5MHz for1H and13C,respectively).Unless otherwise indicated,all were run at room temperature(24(1°C).For the experiments in the last section of this paper,probe temperatures were measured with a calibrated Eurotherm840/T digital thermometer,connected to a thermocouple which was introduced into an NMR tube filled with mineral oil to ap-proximately the same level as a typical sample.At each temperature,the D2O samples were left to equilibrate for at least 10min before the data were collected.

In order to avoid having to obtain hundreds of spectra,we prepared seven stock solutions containing approximately equal amounts of several of our entries,chosen in such a way as to prevent intermolecular interactions and possible ambiguities in assignment.Solution1:acetone,tert-butyl methyl ether,di-methylformamide,ethanol,toluene.Solution2:benzene,di-methyl sulfoxide,ethyl acetate,methanol.Solution3:acetic acid,chloroform,diethyl ether,2-propanol,tetrahydrofuran. Solution4:acetonitrile,dichloromethane,dioxane,n-hexane, HMPA.Solution5:1,2-dichloroethane,ethyl methyl ketone, n-pentane,pyridine.Solution6:tert-butyl alcohol,BHT,cyclo-hexane,1,2-dimethoxyethane,nitromethane,silicone grease, triethylamine.Solution7:diglyme,dimethylacetamide,ethyl-ene glycol,“grease”(engine oil).For D2O.Solution1:acetone, tert-butyl methyl ether,dimethylformamide,ethanol,2-propanol. Solution2:dimethyl sulfoxide,ethyl acetate,ethylene glycol, methanol.Solution3:acetonitrile,diglyme,dioxane,HMPA, pyridine.Solution4:1,2-dimethoxyethane,dimethylacetamide, ethyl methyl ketone,triethylamine.Solution5:acetic acid,tert-butyl alcohol,diethyl ether,tetrahydrofuran.In D2O and CD3OD nitromethane was run separately,as the protons exchanged with deuterium in presence of triethylamine.

Results

Proton Spectra(Table1).A sample of0.6mL of the solvent,containing1μL of TMS,1was first run on its own.From this spectrum we determined the chemical shifts of the solvent residual peak2and the water peak. It should be noted that the latter is quite temperature-dependent(vide infra).Also,any potential hydrogen-bond acceptor will tend to shift the water signal down-field;this is particularly true for nonpolar solvents.In contrast,in e.g.DMSO the water is already strongly hydrogen-bonded to the solvent,and solutes have only a negligible effect on its chemical shift.This is also true for D2O;the chemical shift of the residual HDO is very temperature-dependent(vide infra)but,maybe counter-intuitively,remarkably solute(and pH)independent. We then added3μL of one of our stock solutions to the NMR tube.The chemical shifts were read and are presented in Table 1.Except where indicated,the coupling constants,and therefore the peak shapes,are essentially solvent-independent and are presented only once.

For D2O as a solvent,the accepted reference peak(δ)0)is the methyl signal of the sodium salt of3-(trimeth-ylsilyl)propanesulfonic acid;one crystal of this was added to each NMR tube.This material has several disadvan-tages,however:it is not volatile,so it cannot be readily eliminated if the sample has to be recovered.In addition, unless one purchases it in the relatively expensive deuterated form,it adds three more signals to the spectrum(methylenes1,2,and3appear at2.91,1.76, and0.63ppm,respectively).We suggest that the re-sidual HDO peak be used as a secondary reference;we find that if the effects of temperature are taken into account(vide infra),this is very reproducible.For D2O, we used a different set of stock solutions,since many of the less polar substrates are not significantly water-soluble(see Table1).We also ran sodium acetate and sodium formate(chemical shifts: 1.90and8.44ppm, respectively).

Carbon Spectra(Table2).To each tube,50μL of the stock solution and3μL of TMS1were added.The solvent chemical shifts3were obtained from the spectra containing the solutes,and the ranges of chemical shifts

(1)For recommendations on the publication of NMR data,see: IUPAC Commission on Molecular Structure and Spectroscopy.Pure Appl.Chem.1972,29,627;1976,45,217.

(2)I.e.,the signal of the proton for the isotopomer with one less deuterium than the perdeuterated material,e.g.,C H Cl3in CDCl3or C6D5H in C6D6.Except for CHCl3,the splitting due to J HD is typically observed(to a good approximation,it is1/6.5of the value of the corresponding J HH).For CHD2groups(deuterated acetone,DMSO, acetonitrile),this signal is a1:2:3:2:1quintet with a splitting of ca.2 Hz.

(3)In contrast to what was said in note2,in the13C spectra the solvent signal is due to the perdeuterated isotopomer,and the one-bond couplings to deuterium are always observable(ca.20-30Hz). Figure1.Chemical shift of H DO as a function of tempera-ture.

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show their degree of variability.Occasionally,in order to distinguish between peaks whose assignment was ambiguous,a further1-2μL of a specific substrate were added and the spectra run again.

Table1.1H NMR Data

proton mult CDCl3(CD3)2CO(CD3)2SO C6D6CD3CN CD3OD D2O solvent residual peak7.26 2.05 2.507.16 1.94 3.31 4.79 H2O s 1.56 2.84a 3.33a0.40 2.13 4.87

acetic acid CH3s 2.10 1.96 1.91 1.55 1.96 1.99 2.08 acetone CH3s 2.17 2.09 2.09 1.55 2.08 2.15 2.22 acetonitrile CH3s 2.10 2.05 2.07 1.55 1.96 2.03 2.06 benzene CH s7.367.367.377.157.377.33

tert-butyl alcohol CH3s 1.28 1.18 1.11 1.05 1.16 1.40 1.24 OH c s 4.19 1.55 2.18

tert-butyl methyl ether CCH3s 1.19 1.13 1.11 1.07 1.14 1.15 1.21 OCH3s 3.22 3.13 3.08 3.04 3.13 3.20 3.22 BHT b ArH s 6.98 6.96 6.877.05 6.97 6.92

OH c s 5.01 6.65 4.79 5.20

ArCH3s 2.27 2.22 2.18 2.24 2.22 2.21

ArC(CH3)3s 1.43 1.41 1.36 1.38 1.39 1.40

chloroform CH s7.268.028.32 6.157.587.90 cyclohexane CH2s 1.43 1.43 1.40 1.40 1.44 1.45

1,2-dichloroethane CH2s 3.73 3.87 3.90 2.90 3.81 3.78 dichloromethane CH2s 5.30 5.63 5.76 4.27 5.44 5.49

diethyl ether CH3t,7 1.21 1.11 1.09 1.11 1.12 1.18 1.17 CH2q,7 3.48 3.41 3.38 3.26 3.42 3.49 3.56 diglyme CH2m 3.65 3.56 3.51 3.46 3.53 3.61 3.67 CH2m 3.57 3.47 3.38 3.34 3.45 3.58 3.61

OCH3s 3.39 3.28 3.24 3.11 3.29 3.35 3.37 1,2-dimethoxyethane CH3s 3.40 3.28 3.24 3.12 3.28 3.35 3.37 CH2s 3.55 3.46 3.43 3.33 3.45 3.52 3.60 dimethylacetamide CH3CO s 2.09 1.97 1.96 1.60 1.97 2.07 2.08 NCH3s 3.02 3.00 2.94 2.57 2.96 3.31 3.06

NCH3s 2.94 2.83 2.78 2.05 2.83 2.92 2.90 dimethylformamide CH s8.027.967.957.637.927.977.92 CH3s 2.96 2.94 2.89 2.36 2.89 2.99 3.01

CH3s 2.88 2.78 2.73 1.86 2.77 2.86 2.85 dimethyl sulfoxide CH3s 2.62 2.52 2.54 1.68 2.50 2.65 2.71 dioxane CH2s 3.71 3.59 3.57 3.35 3.60 3.66 3.75 ethanol CH3t,7 1.25 1.12 1.060.96 1.12 1.19 1.17 CH2q,7d 3.72 3.57 3.44 3.34 3.54 3.60 3.65

OH s c,d 1.32 3.39 4.63 2.47

ethyl acetate CH3CO s 2.05 1.97 1.99 1.65 1.97 2.01 2.07

C H2CH3q,7 4.12 4.05 4.03 3.89 4.06 4.09 4.14

CH2C H3t,7 1.26 1.20 1.170.92 1.20 1.24 1.24 ethyl methyl ketone CH3CO s 2.14 2.07 2.07 1.58 2.06 2.12 2.19

C H2CH3q,7 2.46 2.45 2.43 1.81 2.43 2.50 3.18

CH2C H3t,7 1.060.960.910.850.96 1.01 1.26 ethylene glycol CH s e 3.76 3.28 3.34 3.41 3.51 3.59 3.65“grease”f CH3m0.860.870.920.860.88

CH2br s 1.26 1.29 1.36 1.27 1.29

n-hexane CH3t0.880.880.860.890.890.90

CH2m 1.26 1.28 1.25 1.24 1.28 1.29

HMPA g CH3d,9.5 2.65 2.59 2.53 2.40 2.57 2.64 2.61 methanol CH3s h 3.49 3.31 3.16 3.07 3.28 3.34 3.34 OH s c,h 1.09 3.12 4.01 2.16

nitromethane CH3s 4.33 4.43 4.42 2.94 4.31 4.34 4.40 n-pentane CH3t,70.880.880.860.870.890.90

CH2m 1.27 1.27 1.27 1.23 1.29 1.29

2-propanol CH3d,6 1.22 1.10 1.040.95 1.09 1.50 1.17 CH sep,6 4.04 3.90 3.78 3.67 3.87 3.92 4.02 pyridine CH(2)m8.628.588.588.538.578.538.52 CH(3)m7.297.357.39 6.667.337.447.45

CH(4)m7.687.767.79 6.987.737.857.87 silicone grease i CH3s0.070.130.290.080.10 tetrahydrofuran CH2m 1.85 1.79 1.76 1.40 1.80 1.87 1.88 CH2O m 3.76 3.63 3.60 3.57 3.64 3.71 3.74 toluene CH3s 2.36 2.32 2.30 2.11 2.33 2.32

CH(o/p)m7.177.1-7.27.187.027.1-7.37.16

CH(m)m7.257.1-7.27.257.137.1-7.37.16 triethylamine CH3t,7 1.030.960.930.960.96 1.050.99 CH2q,7 2.53 2.45 2.43 2.40 2.45 2.58 2.57

a In these solvents the intermolecular rate of exchange is slow enough that a peak due to HDO is usually also observed;it appears at

2.81and

3.30ppm in acetone and DMSO,respectively.In the former solvent,it is often seen as a1:1:1triplet,with2J H,D)1Hz. b2,6-Dimethyl-4-tert-butylphenol.c The signals from exchangeable protons were not always identified.d In some cases(see note a),the coupling interaction between the CH2and the OH protons may be observed(J)5Hz).e In CD3CN,the OH proton was seen as a multiplet atδ2.69,and extra coupling was also apparent on the methylene peak.f Long-chain,linear aliphatic hydrocarbons.Their solubility in DMSO was too low to give visible peaks.g Hexamethylphosphoramide.h In some cases(see notes a,d),the coupling interaction between the CH3and the OH protons may be observed(J)5.5Hz).i Poly(dimethylsiloxane).Its solubility in DMSO was too low to give visible peaks.

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Table2.13C NMR Data a

CDCl3(CD3)2CO(CD3)2SO C6D6CD3CN CD3OD D2O solvent signals77.16(0.0629.84(0.0139.52(0.06128.06(0.02 1.32(0.0249.00(0.01

206.26(0.13118.26(0.02

acetic acid CO175.99172.31171.93175.82173.21175.11177.21 CH320.8120.5120.9520.3720.7320.5621.03 acetone CO207.07205.87206.31204.43207.43209.67215.94 CH330.9230.6030.5630.1430.9130.6730.89 acetonitrile CN116.43117.60117.91116.02118.26118.06119.68 CH3 1.89 1.12 1.030.20 1.790.85 1.47 benzene CH128.37129.15128.30128.62129.32129.34

tert-butyl alcohol C69.1568.1366.8868.1968.7469.4070.36 CH331.2530.7230.3830.4730.6830.9130.29 tert-butyl methyl ether OCH349.4549.3548.7049.1949.5249.6649.37 C72.8772.8172.0472.4073.1774.3275.62

C C H326.9927.2426.7927.0927.2827.2226.60 BHT C(1)151.55152.51151.47152.05152.42152.85

C(2)135.87138.19139.12136.08138.13139.09

CH(3)125.55129.05127.97128.52129.61129.49

C(4)128.27126.03124.85125.83126.38126.11

CH3Ar21.2021.3120.9721.4021.2321.38

C H3C30.3331.6131.2531.3431.5031.15

C34.2535.0034.3334.3535.0535.36

chloroform CH77.3679.1979.1677.7979.1779.44

cyclohexane CH226.9427.5126.3327.2327.6327.96

1,2-dichloroethane CH243.5045.2545.0243.5945.5445.11 dichloromethane CH253.5254.9554.8453.4655.3254.78

diethyl ether CH315.2015.7815.1215.4615.6315.4614.77 CH265.9166.1262.0565.9466.3266.8866.42 diglyme CH359.0158.7757.9858.6658.9059.0658.67 CH270.5171.0369.5470.8770.9971.3370.05

CH271.9072.6371.2572.3572.6372.9271.63 1,2-dimethoxyethane CH359.0858.4558.0158.6858.8959.0658.67 CH271.8472.4717.0772.2172.4772.7271.49 dimethylacetamide CH321.5321.5121.2921.1621.7621.3221.09 CO171.07170.61169.54169.95171.31173.32174.57

NCH335.2834.8937.3834.6735.1735.5035.03

NCH338.1337.9234.4237.0338.2638.4338.76 dimethylformamide CH162.62162.79162.29162.13163.31164.73165.53 CH336.5036.1535.7335.2536.5736.8937.54

CH331.4531.0330.7330.7231.3231.6132.03 dimethyl sulfoxide CH340.7641.2340.4540.0341.3140.4539.39 dioxane CH267.1467.6066.3667.1667.7268.1167.19 ethanol CH318.4118.8918.5118.7218.8018.4017.47 CH258.2857.7256.0757.8657.9658.2658.05 ethyl acetate C H3CO21.0420.8320.6820.5621.1620.8821.15 CO171.36170.96170.31170.44171.68172.89175.26

CH260.4960.5659.7460.2160.9861.5062.32

CH314.1914.5014.4014.1914.5414.4913.92 ethyl methyl ketone C H3CO29.4929.3029.2628.5629.6029.3929.49 CO209.56208.30208.72206.55209.88212.16218.43

C H2CH336.8936.7535.8336.3637.0937.3437.27

CH2C H37.868.037.617.918.148.097.87 ethylene glycol CH263.7964.2662.7664.3464.2264.3063.17“grease”CH229.7630.7329.2030.2130.8631.29

n-hexane CH314.1414.3413.8814.3214.4314.45

CH2(2)22.7023.2822.0523.0423.4023.68

CH2(3)31.6432.3030.9531.9632.3632.73

HMPA b CH336.8737.0436.4236.8837.1037.0036.46 methanol CH350.4149.7748.5949.9749.9049.8649.50c nitromethane CH362.5063.2163.2861.1663.6663.0863.22 n-pentane CH314.0814.2913.2814.2514.3714.39

CH2(2)22.3822.9821.7022.7223.0823.38

CH2(3)34.1634.8333.4834.4534.8935.30

2-propanol CH325.1425.6725.4325.1825.5525.2724.38 CH64.5063.8564.9264.2364.3064.7164.88 pyridine CH(2)149.90150.67149.58150.27150.76150.07149.18 CH(3)123.75124.57123.84123.58127.76125.53125.12

CH(4)135.96136.56136.05135.28136.89138.35138.27 silicone grease CH3 1.04 1.40 1.38 2.10 tetrahydrofuran CH225.6226.1525.1425.7226.2726.4825.67 CH2O67.9768.0767.0367.8068.3368.8368.68 toluene CH321.4621.4620.9921.1021.5021.50

C(i)137.89138.48137.35137.91138.90138.85

CH(o)129.07129.76128.88129.33129.94129.91

CH(m)128.26129.03128.18128.56129.23129.20

CH(p)125.33126.12125.29125.68126.28126.29

triethylamine CH311.6112.4911.7412.3512.3811.099.07 CH246.2547.0745.7446.7747.1046.9647.19

a See footnotes for Table1.b2J PC)3Hz.c Reference material;see text.

For D2O solutions there is no accepted reference for carbon chemical shifts.We suggest the addition of a drop of methanol,and the position of its signal to be defined as49.50ppm;on this basis,the entries in Table2were recorded.The chemical shifts thus obtained are,on the whole,very similar to those for the other solvents. Alternatively,we suggest the use of dioxane when the methanol peak is expected to fall in a crowded area of the spectrum.We also report the chemical shifts of sodium formate(171.67ppm),sodium acetate(182.02and 23.97ppm),sodium carbonate(168.88ppm),sodium bicarbonate(161.08ppm),and sodium3-(trimethylsilyl)-propanesulfonate[54.90,19.66,15.56(methylenes1,2, and3,respectively),and-2.04ppm(methyls)],in D2O. Temperature Dependence of HDO Chemical Shifts.We recorded the1H spectrum of a sample of D2O, containing a crystal of sodium3-(trimethylsilyl)propane-sulfonate as reference,as a function of temperature.The data are shown in Figure1.The solid line connecting the experimental points corresponds to the equation which reproduces the measured values to better than1 ppb.For the0-50o C range,the simpler

gives values correct to10ppb.For both equations,T is the temperature in°C.

Acknowledgment.Generous support for this work by the Minerva Foundation and the Otto Mayerhoff Center for the Study of Drug-Receptor Interactions at Bar-Ilan University is gratefully acknowledged.

JO971176V

δ)5.060-0.0122T+(2.11×10-5)T2(1)

δ)5.051-0.0111T(2)

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核磁常见杂质化学位移表

proton mult CDC13 (CD 3)2CO (CD 3)2SO C 6D 6 CD 3CN CD 3OD D 2O solvent residual peak 7.26 2.05 2.50 7.16 1.94 3.31 4.79 H 2O s 1.56 2.84 3.33 0.40 2.13 4.87 acetic acid CH 3 s 2.10 1.96 1.91 1.55 1.96 1.99 2.08 acetone CH 3 s 2.17 2.09 2.09 1.55 2.08 2.15 2.22 acetonitrile CH 3 s 2.10 2.05 2.07 1.55 1.96 2.03 2.06 benzene CH s 7.36 7.36 7.37 7.15 7.37 7.33 tert -butyl alcohol CH 3 s 1.28 1.18 1.11 1.05 1.16 1.40 1.24 OH s 4.19 1.55 2.18 chloroform CH s 7.26 8.02 8.32 6.15 7.58 7.90 cyclohexane CH 2 s 1.43 1.43 1.40 1.40 1.44 1.45 1,2-dichlorbethane CH 2 s 3.73 3.87 3.90 2.90 3.81 3.78 dichloromethane CH 2 s 5.30 5.63 5.76 4.27 5.44 5.49 diethyl ether CH 3 t, 7 1.21 1.11 1.09 1.11 1.12 1.18 1.17 CH 2 q, 7 3.48 3.41 3.38 3.26 3.42 3.49 3.56 1,2-dimethoxyethane CH 3 s 3.40 3.28 3.24 3.12 3.28 3.35 3.37 CH 2 s 3.55 3.46 3.43 3.33 3.45 3.52 3.60 dimethylformamide CH s 8.02 7.96 7.95 7.63 7.92 7.97 7.92 CH 3 d 2.96 2.94 2.89 2.36 2.89 2.99 3.01 CH 3 s 2.88 2.78 2.73 1.86 2.77 2.86 2.85 dimethyl sulfoxide CH 3 s 2.62 2.52 2.54 1.68 2.50 2.65 2.71 dioxane CH 2 s 3.71 3.59 3.57 3.35 3.60 3.66 3.75 ethanol CH 3 t, 7 1.25 1.12 1.06 0.96 1.12 1.19 1.17 CH 2 q, 7 3.72 3.57 3.44 3.34 3.54 3.60 3.65 OH s 1.32 3.39 4.63 2.47 ethyl acetate CH 3CO s 2.05 1.97 1.99 1.65 1.97 2.01 2.07 CH 2CH 3 q, 7 4.12 4.05 4.03 3.89 4.06 4.09 4.14 CH 2CH 3 t, 7 1.26 1.20 1.17 0.92 1.20 1.24 1.24 ethylene glycol CH s 3.76 3.28 3.34 3.41 3.51 3.59 3.65 “grease” CH 3 m 0.86 0.87 0.92 0.86 0.88 CH 2 br, s 1.26 1.29 1.36 1.27 1.29 n -hexane CH 3 t 0.88 0.88 0.86 0.89 0.89 0.90 CH 2 m 1.26 1.28 1.25 1.24 1.28 1.29 HMPA CH 3 d, 9.5 2.65 2.59 2.53 2.40 2.57 2.64 2.61 methanol CH 3 s 3.49 3.31 3.16 3.07 3.28 3.34 3.34 OH s 1.09 3.12 4.01 2.16 nitromethane CH 3 s 4.33 4.43 4.42 2.94 4.31 4.34 4.40 n -pentane CH 3 t, 7 0.88 0.88 0.86 0.87 0.89 0.90 CH 2 m 1.27 1.27 1.27 1.23 1.29 1.29 2-propanol CH 3 d, 6 1.22 1.10 1.04 0.95 1.09 1.50 1.17 CH sep, 6 4.04 3.90 3.78 3.67 3.87 3.92 4.02 pyridine CH(2) m 8.62 8.58 8.58 8.53 8.57 8.53 8.52 CH(3) m 7.29 7.35 7.39 6.66 7.33 7.44 7.45 CH(4) m 7.68 7.76 7.79 6.98 7.73 7.85 7.87 silicone grease CH 3 s 0.07 0.13 0.29 0.08 0.10 tetrahydrofuran CH 2 m 1.85 1.79 1.76 1.40 1.80 1.87 1.88 CH 2O m 3.76 3.63 3.60 3.57 3.64 3.71 3.74 toluene CH 3 s 2.36 2.32 2.30 2.11 2.33 2.32 CH(o /p ) m 7.17 7.1-7.2 7.18 7.02 7.1-7.3 7.16 CH(m ) m 7.25 7.1-7.2 7.25 7.13 7.1-7.3 7.16 triethylamine CH 3 t,7 1.03 0.96 0.93 0.96 0.96 1.05 0.99 CH 2 q, 7 2.53 2.45 2.43 2.40 2.45 2.58 2.57 丙酮三乙胺

核磁共振氢谱(1H-NMR)

第二章核磁共振氢谱(1H-NMR) §1 概述 基本情况 1H 天然丰度：99.9844%, I=1/2， γ=26.752(107radT-1S-1) 共振频率：42.577 MHz/T δ: 0～20ppm §2 化学位移 1.影响δ值的因素 A.电子效应 (1)诱导效应 a电负性 电负性强的取代基使氢核外电子云密度降低，其共振吸收向低场位移，δ值增大 b.多取代有加和性 c.诱导效应通过成键电子传递，随着与电负性取代基距离的增大，诱导效应的影响逐渐减弱，通常相隔3个以上碳的影响可以忽略不计 （2）.共轭效应 氮、氧等杂原子可与双键、苯环共轭。 苯环上的氢被推电子基取代，由于p-π共轭,使苯环电子云密度增大, δ值向高场移动苯环上的氢被吸电子基取代，由于p-π共轭或π-π共轭,使苯环电子云密度降低, δ值向低场移动 (3). 场效应 在某些刚性结构中,一些带杂原子的官能团可通过其电场对邻近氢核施加影响,使其化学

位移发生变化.这些通过电场发挥的作用称为场效应 (4). 范德华(Van der Waals)效应 在某些刚性结构中,当两个氢核在空间上非常接近，其外层电子云互相排斥使核外电子云不能很好地包围氢核，相当于核外电子云密度降低，δ值向低场移动 B.邻近基团的磁各向异性 某些化学键和基团可对空间不同空间位置上的质子施加不同的影响，即它们的屏蔽作用是有方向性的。磁各向异性产生的屏蔽作用通过空间传递，是远程的。 （1）芳环 在苯环的外周区域感应磁场的方向与外加磁场的方向相同（顺磁屏蔽），苯环质子处于此去屏蔽区，其所受磁场强度为外加磁场和感应磁场之和，δ值向低场移动。 （2）双键 >C=O, >C=C<的屏蔽作用与苯环类似。在其平面的上、下方各有一个锥形屏蔽区 （“+”），其它区域为去屏蔽区。 （3）三键 互相垂直的两个π键轨道电子绕σ键产生环电流，在外加磁场作用下产生与三键平行但方向与外加磁场相反的感应磁场。三键的两端位于屏蔽区（“+”），上、下方为去锥形屏蔽区（“-”）δ值比烯氢小。 （4）单键和环己烷 单键各向异性方向与双键相似，直立键质子的化学位移一般比平伏键小0.05-0.8 C.氢键 氢键的缔合作用减少了质子周围的电子云密度, δ值向低场移动。 氢键质子的δ值变化范围大，与缔合程度密切相关。 分子内氢键，质子的δ值与浓度无关 分子间氢键，质子的δ值与浓度有关，浓度大，缔合程度密切。 D.非结构因素 1.介质因素 2.浓度 3.温度 2.各类质子的化学位移 (1).sp3杂化(饱和烷烃) a.化学位移的范围 δ<-CH3 < CH2 < CH, 0-2ppm 与同碳上有强电子基团(O,N,CL,Br)相连, 或邻位有各项异性基团(=,=O,Ph),δ值上升,<5ppm b.化学位移的计算 1）-CH2- δ(CH2R1R2) =1.25+Σσ δ(CHR1R2R3) =1.50+Σσ

第四章 核磁共振碳谱 习题2

第四章核磁共振碳谱 一、判断题 [1]自由衰减信号(FID)是频率域信号。（） [2]碳谱的化学位移范围范围较宽(0-200)，所以碳谱的灵敏度高于氢谱。（） [3]在宽带去耦碳谱中，不同类型的碳核产生的裂分峰数目不同。（） [4]氢质子在二甲基亚砜中的化学位移比在氯仿中要小。（） [5]在13C NMR谱中，由于13C-13C相连的概率很低，所以通常不考虑13C核只见到耦合。 （） [6]含19F的化合物，可观测到19F对13C核的耦合裂分，且谱带裂分数符合n+1规律。（） [7]但在固相核磁共振波谱中，分子运动受到限制，由于磁各向异性作用将是谱线带变宽， 分辨率大大下降。（） [8]在碳谱中，13C-1H会发生耦合作用，但是13C-1H的耦合常数远比1H-1H之间的耦合常 数小.（） [9]在135°DEPT试验中，CH、CH2和CH3均出正峰，季碳原子不出现谱峰。（） [10]在APT实验中，CH和CH3均出正峰，CH2出负峰，季碳原子不出现谱峰。（） 二、选择题（单项选择） [1] 下列原子核没有自旋角动量的是哪一种？（）。 A. 14N7 B. 12C6 C. 31P15 D. 13C6 [2] 在13C NMR波谱中在化学位移125-140产生两个信号的化合物是（）。 A. 1,2,3,-三氯苯； B. 1,2,4,-三氯苯； C. 1,3,5,-三氯苯 [3] 在13C NMR波谱中在化学位移125-140产生六个信号的化合物是（）。 A. 1,2,3,-三氯苯； B. 1,2,4,-三氯苯； C. 1,3,5,-三氯苯 [4] 在13C NMR波谱中在化学位移125-140产生三个信号的化合物是（）。 A. 对二氯苯； B. 邻二氯苯； C. 间二氯苯。 [5] 在13C NMR中在化学位移0-60产生3个信号；在1H NMR中在化学位移0-5产生3个信号（最低场信号为多重峰）的化合物是（）。 A. 1,1-二氯丙烷； B. 1,2二氯丙烷； C. 2,2-二氯丙烷； D. 1,3二氯丙烷。 [6] 在13C NMR中在化学位移0-70产生2个信号；在1H NMR中在化学位移0-5产生2个信号（最低场信号为三重峰）的化合物是（）。 A. 1,1-二氯丙烷； B. 1,2二氯丙烷； C. 2,2-二氯丙烷； D. 1,3二氯丙烷。 [7]下面原子核发生核磁共振时，如果外磁场强度相同，哪种核将需要最大照射频率（）。 A. 19F9； B. 13C6; C.1H1; D. 14N7 [8]碳谱如果不采用标识技术很难解析的原因是（）。 A. 碳谱灵敏度较低； B. 碳核之间有耦合裂分； C. 碳谱分辨率高； D. 碳核与氢核之间有耦合裂分。 [9]下列各类化合物中碳核化学位移最大的是（）。 A. 苯环上的碳； B. 酸酯羟基碳； C. 醛酮羟基碳； D. 与氧相连的饱和碳。 [10]在13C谱中，常看到溶剂的多重峰，如DMSO-d6在化学位移39.5ppm附近的七重峰，溶

溶剂的化学位移(氢谱)

show their degree of variability.Occasionally,in order to distinguish between peaks whose assignment was ambiguous,a further 1-2μL of a specific substrate were added and the spectra run again. Table 1. 1H NMR Data 2acetic acid CH 3s 2.10 1.96 1.91 1.55 1.96 1.99 2.08acetone CH 3s 2.17 2.09 2.09 1.55 2.08 2.15 2.22acetonitrile CH 3s 2.10 2.05 2.07 1.55 1.96 2.03 2.06benzene CH s 7.367.367.377.157.377.33tert -butyl alcohol CH 3s 1.28 1.18 1.11 1.05 1.16 1.40 1.24OH c s 4.19 1.55 2.18tert -butyl methyl ether CCH 3s 1.19 1.13 1.11 1.07 1.14 1.15 1.21OCH 3s 3.22 3.13 3.08 3.04 3.13 3.20 3.22 BHT b ArH s 6.98 6.96 6.877.05 6.97 6.92OH c s 5.01 6.65 4.79 5.20ArCH 3 s 2.27 2.22 2.18 2.24 2.22 2.21ArC(CH 3)3s 1.43 1.41 1.36 1.38 1.39 1.40chloroform CH s 7.268.028.32 6.157.587.90cyclohexane CH 2s 1.43 1.43 1.40 1.40 1.44 1.451,2-dichloroethane CH 2s 3.73 3.87 3.90 2.90 3.81 3.78dichloromethane CH 2s 5.30 5.63 5.76 4.27 5.44 5.49diethyl ether CH 3t,7 1.21 1.11 1.09 1.11 1.12 1.18 1.17CH 2q,7 3.48 3.41 3.38 3.26 3.42 3.49 3.56diglyme CH 2m 3.65 3.56 3.51 3.46 3.53 3.61 3.67CH 2m 3.57 3.47 3.38 3.34 3.45 3.58 3.61OCH 3s 3.39 3.28 3.24 3.11 3.29 3.35 3.371,2-dimethoxyethane CH 3s 3.40 3.28 3.24 3.12 3.28 3.35 3.37CH 2 s 3.55 3.46 3.43 3.33 3.45 3.52 3.60dimethylacetamide CH 3CO s 2.09 1.97 1.96 1.60 1.97 2.07 2.08NCH 3s 3.02 3.00 2.94 2.57 2.96 3.31 3.06NCH 3s 2.94 2.83 2.78 2.05 2.83 2.92 2.90dimethylformamide CH s 8.027.967.957.637.927.977.92CH 3s 2.96 2.94 2.89 2.36 2.89 2.99 3.01CH 3s 2.88 2.78 2.73 1.86 2.77 2.86 2.85dimethyl sulfoxide CH 3s 2.62 2.52 2.54 1.68 2.50 2.65 2.71dioxane CH 2s 3.71 3.59 3.57 3.35 3.60 3.66 3.75ethanol CH 3t,7 1.25 1.12 1.060.96 1.12 1.19 1.17CH 2q,7d 3.72 3.57 3.44 3.34 3.54 3.60 3.65OH s c,d 1.32 3.39 4.63 2.47ethyl acetate CH 3CO s 2.05 1.97 1.99 1.65 1.97 2.01 2.07C H 2CH 3q,7 4.12 4.05 4.03 3.89 4.06 4.09 4.14CH 2C H 3t,7 1.26 1.20 1.170.92 1.20 1.24 1.24ethyl methyl ketone CH 3CO s 2.14 2.07 2.07 1.58 2.06 2.12 2.19C H 2CH 3q,7 2.46 2.45 2.43 1.81 2.43 2.50 3.18CH 2C H 3t,7 1.060.960.910.850.96 1.01 1.26ethylene glycol CH s e 3.76 3.28 3.34 3.41 3.51 3.59 3.65 “grease”f CH 3m 0.860.870.920.860.88CH 2br s 1.26 1.29 1.36 1.27 1.29n -hexane CH 3t 0.880.880.860.890.890.90CH 2m 1.26 1.28 1.25 1.24 1.28 1.29HMPA g CH 3d,9.5 2.65 2.59 2.53 2.40 2.57 2.64 2.61methanol CH 3s h 3.49 3.31 3.16 3.07 3.28 3.34 3.34OH s c,h 1.09 3.12 4.01 2.16nitromethane CH 3s 4.33 4.43 4.42 2.94 4.31 4.34 4.40n -pentane CH 3t,70.880.880.860.870.890.90CH 2m 1.27 1.27 1.27 1.23 1.29 1.292-propanol CH 3d,6 1.22 1.10 1.040.95 1.09 1.50 1.17CH sep,6 4.04 3.90 3.78 3.67 3.87 3.92 4.02pyridine CH(2)m 8.628.588.588.538.578.538.52CH(3)m 7.297.357.39 6.667.337.447.45CH(4)m 7.687.767.79 6.987.737.857.87silicone grease i CH 3s 0.070.130.290.080.10tetrahydrofuran CH 2m 1.85 1.79 1.76 1.40 1.80 1.87 1.88CH 2O m 3.76 3.63 3.60 3.57 3.64 3.71 3.74 toluene CH 3 s 2.36 2.32 2.30 2.11 2.33 2.32CH(o/p )m 7.177.1-7.27.187.027.1-7.37.16CH(m )m 7.257.1-7.27.257.137.1-7.37.16triethylamine CH 3t,7 1.030.960.930.960.96 1.050.99CH 2 q,7 2.53 2.45 2.43 2.40 2.45 2.58 2.57 a In these solvents the intermolecular rate of exchange is slow enough that a peak due to HDO is usually also observed;it appears at 2.81and 3.30ppm in acetone and DMSO,respectively.In the former solvent,it is often seen as a 1:1:1triplet,with 2J H,D )1Hz.b 2,6-Dimethyl-4-tert -butylphenol.c The signals from exchangeable protons were not always identified.d In some cases (see note a ),the coupling interaction between the CH 2and the OH protons may be observed (J )5Hz).e In CD 3CN,the OH proton was seen as a multiplet at δ2.69,and extra coupling was also apparent on the methylene peak.f Long-chain,linear aliphatic hydrocarbons.Their solubility in DMSO was too low to give visible peaks.g Hexamethylphosphoramide.h In some cases (see notes a ,d ),the coupling interaction between the CH 3and the OH protons may be observed (J )5.5Hz).i Poly(dimethylsiloxane).Its solubility in DMSO was too low to give visible peaks. Notes https://www.wendangku.net/doc/ae15957360.html,.Chem.,Vol.62,No.21,19977513 乙酸丙酮乙腈叔丁醇 叔丁基醚氯仿二氯甲烷DMF 三乙胺 硅脂四氢呋喃 DMSO 乙醚甲醇

氢谱中各种基团的化学位移

1.化学位移能够提供的信息？ 化学位移可以提示质子所处化学环境，氢谱中各种基团的化学位移变化很大，不易记忆，但只要牢记几个典型基团的化学位移就可以解决很多问题。如：甲基0.8～1.2ppm，连苯环的甲基2ppm附近，乙酰基上的甲基2ppm附近，甲氧基和氮甲基3～4ppm，双键5～7ppm，苯环7～8ppm，醛基8～10ppm，不连氧的亚甲基1～2ppm，连氧的亚甲基3～4ppm。 2.偶合常数可以给出哪些结构信息？ 可以从偶合常数看出基团间的关系，邻位偶合常数较大，远程偶合常数较小。还可以利用Kapulus公式计算邻位氢的二面角。对于有双键的化合物，顺式的氢之间偶合常数为6～10Hz，反式的氢之间偶合常数为12～16Hz。 3.质子偏共振去偶可以用来确定碳的类型，为什么现在常用DEPT谱，而不同质子偏共振去偶谱？ 质子偏共振去偶区分伯、仲、叔、季碳的方法是根据裂分成四重、三重、二重和单峰，如果峰离得近会产生重叠，不容易解析，而DEPT区分伯、仲、叔、季碳的方法是根据峰向上或向下，峰不会重叠，并且质子偏共振去偶的灵敏度比DEPT法的灵敏度低得多，所以现在常用DEPT谱区分碳的类型。 5.解析合成化合物的谱、植物中提取化合物的谱和未知化合物的谱，思路有什么不同？ 合成化合物的结果是已知的，只要用谱和结构对照就可以知道化合物和预定的结构是否一致。对于植物中提取化合物的谱，首先应看是哪一类化合物，然后用已知的文献数据对照，看是否为已知物，如果文献中没有这个数据则继续测DEPT谱和二维谱，推出结构。对于一个全未知的化合物，除测核磁共振外，还要结合质谱、红外、紫外和元素分析，一步步推测结构。

核磁共振碳谱

核磁共振碳谱(13C-NMR) Produced by Jiwu Wen

?核磁共振碳谱的特点： 1. 化学位移范围宽。 碳谱(13C-NMR)的化学位移δC通常在0～220 ppm之间(对于碳正可达330 ppm)。 离子δ C 比较：1H-NMR的化学位移δ通常在0～10 ppm之间。Example:

2. 13C-NMR给出不与氢相连的碳的共振吸收峰。 核磁共振碳谱(13C-NMR)可以给出季碳，羰基碳，氰基碳，以及不含氢原子的烯碳和炔碳的特征吸收峰。 3. 13C-NMR的偶合情况复杂，偶合常数大。 核磁共振碳谱(13C-NMR)中偶合情况比较复杂，除了1H-1H偶合，还有1H-13C以及1H，13C与其它自旋核之间的偶合。1H-13C的偶合常数通常在125-250 Hz。因此在谱图测定过程中，通常采用一些去偶技术。 4. 13C-NMR的灵敏度低。

?核磁共振碳谱的去偶技术 1. 质子宽带去偶(也称为质子噪声去偶)。质子宽带去偶是一种双共振去偶技术，实验方法是：用一相当宽的频率(包括样品中所有氢核的共振频率)照射样品，消除13C-1H 之间的偶合，使每种碳原子只给出一条谱线。 2. 偏共振去偶(也称不完全去偶)。 这种去偶技术的实验方法是：采用一个频率范围很小、比质子宽带去偶功率弱很多的射频场(B 2)，其频率略高于待测样品中所有氢核的共振吸收频率，使1H 与13C 之间在一定程度上去偶，不仅消除2J ～4J 的弱偶合，而且使1J 减小到J r (表观偶合常数)。J r 和1J 之间的关系如下： r 12J J B /2?ν λπ =

溶剂的化学位移(碳谱和氢谱)

NMR Chemical Shifts of Common Laboratory Solvents as Trace Impurities Hugo E.Gottlieb,*Vadim Kotlyar,and Abraham Nudelman* Department of Chemistry,Bar-Ilan University, Ramat-Gan52900,Israel Received June27,1997 In the course of the routine use of NMR as an aid for organic chemistry,a day-to-day problem is the identifica-tion of signals deriving from common contaminants (water,solvents,stabilizers,oils)in less-than-analyti-cally-pure samples.This data may be available in the literature,but the time involved in searching for it may be considerable.Another issue is the concentration dependence of chemical shifts(especially1H);results obtained two or three decades ago usually refer to much more concentrated samples,and run at lower magnetic fields,than today’s practice. We therefore decided to collect1H and13C chemical shifts of what are,in our experience,the most popular “extra peaks”in a variety of commonly used NMR solvents,in the hope that this will be of assistance to the practicing chemist. Experimental Section NMR spectra were taken in a Bruker DPX-300instrument (300.1and75.5MHz for1H and13C,respectively).Unless otherwise indicated,all were run at room temperature(24(1°C).For the experiments in the last section of this paper,probe temperatures were measured with a calibrated Eurotherm840/T digital thermometer,connected to a thermocouple which was introduced into an NMR tube filled with mineral oil to ap-proximately the same level as a typical sample.At each temperature,the D2O samples were left to equilibrate for at least 10min before the data were collected. In order to avoid having to obtain hundreds of spectra,we prepared seven stock solutions containing approximately equal amounts of several of our entries,chosen in such a way as to prevent intermolecular interactions and possible ambiguities in assignment.Solution1:acetone,tert-butyl methyl ether,di-methylformamide,ethanol,toluene.Solution2:benzene,di-methyl sulfoxide,ethyl acetate,methanol.Solution3:acetic acid,chloroform,diethyl ether,2-propanol,tetrahydrofuran. Solution4:acetonitrile,dichloromethane,dioxane,n-hexane, HMPA.Solution5:1,2-dichloroethane,ethyl methyl ketone, n-pentane,pyridine.Solution6:tert-butyl alcohol,BHT,cyclo-hexane,1,2-dimethoxyethane,nitromethane,silicone grease, triethylamine.Solution7:diglyme,dimethylacetamide,ethyl-ene glycol,“grease”(engine oil).For D2O.Solution1:acetone, tert-butyl methyl ether,dimethylformamide,ethanol,2-propanol. Solution2:dimethyl sulfoxide,ethyl acetate,ethylene glycol, methanol.Solution3:acetonitrile,diglyme,dioxane,HMPA, pyridine.Solution4:1,2-dimethoxyethane,dimethylacetamide, ethyl methyl ketone,triethylamine.Solution5:acetic acid,tert-butyl alcohol,diethyl ether,tetrahydrofuran.In D2O and CD3OD nitromethane was run separately,as the protons exchanged with deuterium in presence of triethylamine. Results Proton Spectra(Table1).A sample of0.6mL of the solvent,containing1μL of TMS,1was first run on its own.From this spectrum we determined the chemical shifts of the solvent residual peak2and the water peak. It should be noted that the latter is quite temperature-dependent(vide infra).Also,any potential hydrogen-bond acceptor will tend to shift the water signal down-field;this is particularly true for nonpolar solvents.In contrast,in e.g.DMSO the water is already strongly hydrogen-bonded to the solvent,and solutes have only a negligible effect on its chemical shift.This is also true for D2O;the chemical shift of the residual HDO is very temperature-dependent(vide infra)but,maybe counter-intuitively,remarkably solute(and pH)independent. We then added3μL of one of our stock solutions to the NMR tube.The chemical shifts were read and are presented in Table 1.Except where indicated,the coupling constants,and therefore the peak shapes,are essentially solvent-independent and are presented only once. For D2O as a solvent,the accepted reference peak(δ)0)is the methyl signal of the sodium salt of3-(trimeth-ylsilyl)propanesulfonic acid;one crystal of this was added to each NMR tube.This material has several disadvan-tages,however:it is not volatile,so it cannot be readily eliminated if the sample has to be recovered.In addition, unless one purchases it in the relatively expensive deuterated form,it adds three more signals to the spectrum(methylenes1,2,and3appear at2.91,1.76, and0.63ppm,respectively).We suggest that the re-sidual HDO peak be used as a secondary reference;we find that if the effects of temperature are taken into account(vide infra),this is very reproducible.For D2O, we used a different set of stock solutions,since many of the less polar substrates are not significantly water-soluble(see Table1).We also ran sodium acetate and sodium formate(chemical shifts: 1.90and8.44ppm, respectively). Carbon Spectra(Table2).To each tube,50μL of the stock solution and3μL of TMS1were added.The solvent chemical shifts3were obtained from the spectra containing the solutes,and the ranges of chemical shifts (1)For recommendations on the publication of NMR data,see: IUPAC Commission on Molecular Structure and Spectroscopy.Pure Appl.Chem.1972,29,627;1976,45,217. (2)I.e.,the signal of the proton for the isotopomer with one less deuterium than the perdeuterated material,e.g.,C H Cl3in CDCl3or C6D5H in C6D6.Except for CHCl3,the splitting due to J HD is typically observed(to a good approximation,it is1/6.5of the value of the corresponding J HH).For CHD2groups(deuterated acetone,DMSO, acetonitrile),this signal is a1:2:3:2:1quintet with a splitting of ca.2 Hz. (3)In contrast to what was said in note2,in the13C spectra the solvent signal is due to the perdeuterated isotopomer,and the one-bond couplings to deuterium are always observable(ca.20-30Hz). Figure1.Chemical shift of H DO as a function of tempera-ture. https://www.wendangku.net/doc/ae15957360.html,.Chem.1997,62,7512-7515 S0022-3263(97)01176-6CCC:$14.00?1997American Chemical Society

氢谱中影响化学位移的因素

氢谱中影响化学位移的因素 1. 取代基电负性越强，δ 越移向低场 aí3-5 óèCH 3á??óoùí?(X)μ?μ?·1D??????ê?óoˉ?§?oò?μ?ó??ì化合物CH 3X CH 3F CH 3OH CH 3Cl CH 3Br CH 3I CH 4 (CH 3)4Si 元素X F O Cl Br I H Si X 的电负性 4.0 3.5 3.1 2.8 2.5 2.1 1.8 化学位移δ 4.26 3.40 3.05 2.68 2.16 0.23 0 τ 5.74 6.60 6.95 7.32 7.84 9.77 10 图3-18 取代基电负性对质子化学位移的影响 表3-6 取代效应 CHCl 3 CH 2Cl 2 CH 3Cl -CH 2Br -CH 2-CH 2Br -CH 2-CH 2CH 2Br δ 7.27 5.30 3.05 3.30 1.69 1.25 τ 2.73 4.70 6.95 6.70 8.31 8.75 多取代效应强于单取代取代效应随着键距的延长而急剧降低 去屏蔽效应（deshield ） 2. 相连碳原子的sp 杂化轨道的s 成分越多， δ 越移向低场 “sp 3”质子 0-2δ 321C C C C H C C H C H C C H H H H H 0 |? 1 2 ??????o o o ??á|o? > >>

“sp 2”质子 4.5-7δ “sp ”质子 2-3δ 3. 酸性质子 10-12δ R R C O O 作用和O 电负性拉电子效应的双重影响 氢键的影响和可交换质子 能够形成氢键的质子（-OH ，-NH2）化学位移可变 aí3-7 ?éa?oˉ?§?oò?μ??ê?ó Acids RCOOH 10.5-12.0δ Phenols ArOH 4.0-7.0 Alcohols ROH 0.5-5.0 Amines RNH 2 0.5-5.0 Amides RCONH 2 5.0-8.0 Enols CH=CH-OH ≥15 形成氢键的数目越多，质子的去屏蔽效应越强 氢键数目通常是浓度和温度的函数 R O O H δ 游离羟基（稀溶液）0.5-1.0δ 形成氢键（浓溶液）4-5δ 可交换质子（活泼氢） H H R O H a + R' O H b R O H b + R' O H a R O +R O H + H SOLV SOLV R O +SOLV SOLV H R O + 3. 共轭效应

溶剂的化学位移(碳谱)

https://www.wendangku.net/doc/ae15957360.html,.Chem.,Vol.62,No.21,1997Notes Table2.13C NMR Data a CDCl3(CD3)2CO(CD3)2SO C6D6CD3CN CD3OD D2O solvent signals77.16(0.0629.84(0.0139.52(0.06128.06(0.02 1.32(0.0249.00(0.01 206.26(0.13118.26(0.02 acetic acid CO175.99172.31171.93175.82173.21175.11177.21 CH320.8120.5120.9520.3720.7320.5621.03 acetone CO207.07205.87206.31204.43207.43209.67215.94 CH330.9230.6030.5630.1430.9130.6730.89 acetonitrile CN116.43117.60117.91116.02118.26118.06119.68 CH3 1.89 1.12 1.030.20 1.790.85 1.47 benzene CH128.37129.15128.30128.62129.32129.34 tert-butyl alcohol C69.1568.1366.8868.1968.7469.4070.36 CH331.2530.7230.3830.4730.6830.9130.29 tert-butyl methyl ether OCH349.4549.3548.7049.1949.5249.6649.37 C72.8772.8172.0472.4073.1774.3275.62 C C H326.9927.2426.7927.0927.2827.2226.60 BHT C(1)151.55152.51151.47152.05152.42152.85 C(2)135.87138.19139.12136.08138.13139.09 CH(3)125.55129.05127.97128.52129.61129.49 C(4)128.27126.03124.85125.83126.38126.11 CH3Ar21.2021.3120.9721.4021.2321.38 C H3C30.3331.6131.2531.3431.5031.15 C34.2535.0034.3334.3535.0535.36 chloroform CH77.3679.1979.1677.7979.1779.44 cyclohexane CH226.9427.5126.3327.2327.6327.96 1,2-dichloroethane CH243.5045.2545.0243.5945.5445.11 dichloromethane CH253.5254.9554.8453.4655.3254.78 diethyl ether CH315.2015.7815.1215.4615.6315.4614.77 CH265.9166.1262.0565.9466.3266.8866.42 diglyme CH359.0158.7757.9858.6658.9059.0658.67 CH270.5171.0369.5470.8770.9971.3370.05 CH271.9072.6371.2572.3572.6372.9271.63 1,2-dimethoxyethane CH359.0858.4558.0158.6858.8959.0658.67 CH271.8472.4717.0772.2172.4772.7271.49 dimethylacetamide CH321.5321.5121.2921.1621.7621.3221.09 CO171.07170.61169.54169.95171.31173.32174.57 NCH335.2834.8937.3834.6735.1735.5035.03 NCH338.1337.9234.4237.0338.2638.4338.76 dimethylformamide CH162.62162.79162.29162.13163.31164.73165.53 CH336.5036.1535.7335.2536.5736.8937.54 CH331.4531.0330.7330.7231.3231.6132.03 dimethyl sulfoxide CH340.7641.2340.4540.0341.3140.4539.39 dioxane CH267.1467.6066.3667.1667.7268.1167.19 ethanol CH318.4118.8918.5118.7218.8018.4017.47 CH258.2857.7256.0757.8657.9658.2658.05 ethyl acetate C H3CO21.0420.8320.6820.5621.1620.8821.15 CO171.36170.96170.31170.44171.68172.89175.26 CH260.4960.5659.7460.2160.9861.5062.32 CH314.1914.5014.4014.1914.5414.4913.92 ethyl methyl ketone C H3CO29.4929.3029.2628.5629.6029.3929.49 CO209.56208.30208.72206.55209.88212.16218.43 C H2CH336.8936.7535.8336.3637.0937.3437.27 CH2C H37.868.037.617.918.148.097.87 ethylene glycol CH263.7964.2662.7664.3464.2264.3063.17“grease”CH229.7630.7329.2030.2130.8631.29 n-hexane CH314.1414.3413.8814.3214.4314.45 CH2(2)22.7023.2822.0523.0423.4023.68 CH2(3)31.6432.3030.9531.9632.3632.73 HMPA b CH336.8737.0436.4236.8837.1037.0036.46 methanol CH350.4149.7748.5949.9749.9049.8649.50c nitromethane CH362.5063.2163.2861.1663.6663.0863.22 n-pentane CH314.0814.2913.2814.2514.3714.39 CH2(2)22.3822.9821.7022.7223.0823.38 CH2(3)34.1634.8333.4834.4534.8935.30 2-propanol CH325.1425.6725.4325.1825.5525.2724.38 CH64.5063.8564.9264.2364.3064.7164.88 pyridine CH(2)149.90150.67149.58150.27150.76150.07149.18 CH(3)123.75124.57123.84123.58127.76125.53125.12 CH(4)135.96136.56136.05135.28136.89138.35138.27 silicone grease CH3 1.04 1.40 1.38 2.10 tetrahydrofuran CH225.6226.1525.1425.7226.2726.4825.67 CH2O67.9768.0767.0367.8068.3368.8368.68 toluene CH321.4621.4620.9921.1021.5021.50 C(i)137.89138.48137.35137.91138.90138.85 CH(o)129.07129.76128.88129.33129.94129.91 CH(m)128.26129.03128.18128.56129.23129.20 CH(p)125.33126.12125.29125.68126.28126.29 triethylamine CH311.6112.4911.7412.3512.3811.099.07 CH246.2547.0745.7446.7747.1046.9647.19 a See footnotes for Table1.b2J PC)3Hz.c Reference material;see text.