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各种的化学位移值经验计算方法及常见氢核的化学位移1.烷烃和取代烷烃中1H的化学位移(1)可从表4-6直接查得取代基碳上的质子化学位移值。取代基对碳上的质子化学位移也有一定影响,在计算碳上的质子化学位移值时,应将表4-7中位的各种取代基影响值加到表4-6中的化学位移值上。表4-6不同取代基时CH3X、CH2X和CHX的质子化学位移(/ppm)XCH3XCH2XCHX-R0.91.31.5-CH=CH21.71.92.6-CH=CH-CH=CH21.8CH2=CH-C=CH22.02.22.3-CH=N-2.0---CCH2.02.2--COOR,-COOAr2.02.12.2-CN2.02.52.7-CONH2,-CONR22.02.02.1-COOH2.12.32.6-COR2.12.42.5-SH,-SR2.12.42.5-I2.23.14.2-NH2,-NR22.12.52.9-CHO2.22.22.4-Ph2.32.62.9-Br2.63.34.1-NHCOR,-NRCOR2.93.33.5-Cl3.03.44.0-OCOR3.64.15.0-OR3.33.33.8-N+R33.33.43.5-OH3.43.63.8-OAr3.73.94.0-OCOAr3.94.25.1-NO24.34.44.6注:表中R表示烷基,Ar表示芳香基。表4-7取代基X对位CH3、CH2、CH质子化学位移值的影响XCH3-C-XCH2-C-XCH-C-XXCH3-C-XCH2-C-XCH-C-X-C=C-0.10.10.1-Br0.80.60.25-COOH,-COOR0.20.20.2-NHCOR0.10.10.1-CN0.50.40.4-Cl0.60.40-CONH20.250.20.2-OH,-OR0.30.20.2-COR,-CHO0.30.20.2-OCOR0.40.30.3-SH,-SR0.450.30.2-OPh0.40.350.3HRRR顺反同-NH2,-NHR,-NR20.10.10.1-F0.20.40.1-I1.00.50.4-NO20.60.80.8-Ph0.350.30.3注:此表必须与表4-6一起使用。将此表中查得的数据与表4-6中查得的相关数据相加。(2)烷烃和取代烷烃中质子化学位移还可以用经验公式来计算,常用的有舒里公式:H=0.23+(4-21)表4-8舒里公式中各取代基的值取代基值取代基值取代基值-H0.17R-CC-CC1.65-OR2.36-CH30.47-CONR21.59-NO22.46-CH2R0.67-SR1.64-Cl2.53-CF31.14-CN1.70-OH2.56-C=C-1.32-COR1.70-N=C=S2.86R-CC1.44-I1.82-OCOR3.13-COOR1.55-Ph1.85―OPh3.23Ar-CC1.65-S-CN2.30-F3.60-NR21.57-Br2.332.烯氢的化学位移值烯烃的结构通式可以表示如下,其中双键碳原子上的质子化学位移值可用公式(4-22)计算。C=C-H=5.28+S(4-22)式中,5.28是乙烯质子的值,S是乙烯基上各取代基R同、R顺和R反对烯氢化学位移影响之和。R同、R顺和R反的值见表4-9。表4-9取代基对烯氢化学位移值的影响取代基R同、R顺R反取代基R同R顺R反-H000-COOH1.001.350.74烃0.44-0.26-0.29-COOH(共轭)0.690.970.39环烃0.71-0.33-0.30-COOR0.841.150.56-CH2O0.67-0.02-0.07-COOR(共轭)0.681.020.33-CH2I0.67-0.02-0.07-CHO1.030.971.21-CH2S0.53-0.15-0.15-CON1.370.930.35-CH2Cl0.720.120.07-COCl1.101.410.99-CH2Br0.720.120.07―OR1.18-1.06-1.28-CH2N0.66-0.05-0.23-OCOR2.09-0.40-0.67-CC-0.500.350.10-Ph1.350.37-0.10-CN0.230.780.58-Br1.040.400.55―C=C-0.98-0.04-0.21-Cl1.000.190.03-C=C-(共轭)1.260.08-0.01-F1.03-0.89-1.19-C=O1.101.130.81-NR20.69-1.19-1.31-C=O(共轭)1.061.010.95-SR1.00-0.24-0.043.苯环上质子的化学位移值与烯氢化学位移值的计算类似,苯环上质子的化学位移值可用以下公式计算:=7.26+Zi(4-23)式中,7.26是没有取代的苯环上质子的值,Zi是取代基对苯环上的剩余质子化学位移影响之和,Zi不仅与取代基的种类有关,而且与取代基的相对位置有关。各种取代基的Zi值列入表4-10中。表4-10取代基对苯环上质子化学位移值的影响取代基Z2Z3Z4取代基Z2Z3Z4-H000-NHCH3-0.80-0.22-0.68-CH3-0.20-0.12-0.22-N(CH3)2-0.66-0.18-0.67-CH2CH3-0.14-0.06-0.17-NHNH2-0.60-0.08-0.55-CH(CH3)2-0.13-0.08-0.18-N=N-Ph0.670.200.20-C(CH3)30.02-0.08-0.21-NO0.580.310.37-CF30.320.140.20-NO20.950.260.38-CCl30.640.130.10-SH-0.08-0.16-0.22-CHCl2000-SCH3-0.08-0.10-0.24-CH2OH-0.07-0.07-0.07-S-Ph0.06-0.09-0.15-CH=CH20.06-0.03-0.10-SO3CH30.600.260.33-CH=CH-Ph0.15-0.01-0.16-SO2Cl0.760.350.45-CCH0.15-0.02-0.01-CHO0.560.220.29-CC-Ph0.190.020-COCH30.620.140.21-Ph0.370.200.10-COC(CH3)30.440.050.05-F-0.260-0.20-CO-Ph0.470.130.22-Cl0.03-0.02-0.09-COOH0.850.180.27-Br0.18-0.08-0.04-COOCH30.710.110.21-I0.39-0.210-COO-Ph0.900.170.27-OH-0.56-0.12-0.45-CONH20.610.100.17-OCH3-0.48-0.09-0.44-COCl0.840.220.36-O-Ph-0.29-0.05-0.23-COBr0.800.210.37-OCOCH3-0.250.03-0.13-CH=N-Ph~0.6~0.2~0.2-OCO-Ph-0.090.09-0.08-CN0.360.180.28-OSO2CH3-0.050.07-0.01-Si(CH3)30.22-0.02-0.02-NH2-0.75-0.25-0.65-PO(OCH3)20.480.160.24
本文标题:各种的化学位移值经验计算方法及常见氢核的化学位移
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