NMR有机氟谱

19F核磁共振刘金涛（一）19FNMR的特点（二）19FNMR的基本规律（三）含氟脂肪族化合物19FNMR（四）含氟芳香族化合物19FNMR（五）实例分析主要内容（一）19FNMR的特点①19F核特性核自旋量子数相对灵敏度天然丰度V(MHz)1H1/210099.9860.O13C1/21.591.1115.119F1/283.310056.4②化学位移区间大（一般300ppm）F2O2NOFCF3OFCFCl3HFCH3F8654761400-192-276（ppm）③操作方便，任何不含氟的溶剂都可以使用，便于反应跟踪（二）19FNMR的基本规律化学位移偶合常数化学位移①标准：一般用CFCl3(F11)为标准，高场为负CFCl3=CF3CO2H-77ppm=PhCF3-63ppm=C6F6-163ppm=F2+430ppmF2CFCl3PhCF3CF3CO2HC6F64300-63-77-163（ppm）③影响值的因素电负性：与C、F连接的基团电负性增大，移向低场：CF3CF2CFNF3CF4BF3ClF3PF3SiF4：142-64-12983-37-172电负性：3.02.52.03.02.11.8位阻效应：位阻增大，向低场移动CF4CF3ClCF2Cl2CFCl3-64-40-160CF2I＞CF2Br＞CF2Cl＞CF3NNCF2RfCF2RfNCF2RfNCF2Rf-113.4-108.6-104.5-97.5CF2RfCF2RfCF2RfFFFClFBrFI-106.5-105.8-99.0-132-109-100-87溶剂效应F---SF4---N==SF2DMSO76.284.546.7DMF75.884.247.5MeCN73.184.049.5Neat70.383.752.7C6H671.783.952.8F11370.083.653.3n-C6H1469.783.553.6Rf-CF2-INeat-57.7n-C5H12-58.0CCl4-59.3CHCl3-59.6Me2CO-64.1EtOH-65.2DMF-67.5偶合常数①同碳19F、19F和19F、1H间的偶合(n+1)环状化合物同碳JFF随环增大而增大，JFH变化不明显FFFFFFFF157187244297环上JFF较烯烃JFF大FF15730-80FFJFH较JFF小FHHFFHCF2H4952-5754.6HFHHHFHF84.772.7②相邻碳上19F、19F和19F、1H间的偶合脂肪链偶合常数较小一般反式偶合常数较顺式大1.4FClClFFClFClCF3CF2CO2HHFFHHHFFJHF=0.1JFF=19.4JHF=5.2JFF=16.437.5129.6FFFH~206~10③长距离偶合（≥4键）CF2CF2CFCO2HFFJ=9.9HzCF3FFF1324J14=22HzJ24=8HzJ34=13HzCH3HHFJ=3.3HzFFFFHH5–186–8～2FH3CFCH3FF8.30170④空间偶合H2FC-CF2-CF2-CF2HFAFMCF2CF2HFX（三）含氟脂肪族化合物19FNMR3-1直链含氟烃化学位移差别大偶合复杂CF3-CF2-CF2-CF2-CF2-CF2-I-81.6-126.6-123.1-121.4-113.3-59.3CF3-CF2-(CF2CF2CF2CF2)-CF2-CF2-CBr=CHBr-81.2-126.6-121.5～-122.5-120.4-105.93-1-1与氟直接键合的原子或基团的影响-C-F-140～-240-COF20～30-SO2F40～503-1-2在C-F同一碳上基团的影响同一碳上卤原子增多，向低场移动同一碳上连接O、N、S等原子，移向低场CF4CF3HCF2H2CFH3-63-81.2-143.9-273CF3（CF2）nCF2X(高场为正)X（ppm）M55-58I58-60Br62-64Cl68-70F80-84OF92-94C=CH98-100CH=100-103CN108CH2110-115CO2H117-120COCH2124-126H135-140溶剂效应只影响α位一般小于2ppm，X=I时例外RFCF2INEAT-57.7n-C5H12-58.0CCl4-59.3CHCl3-59.6(CH3)2CO-64.1EtOH-65.2MeCN-62.8DMF-67.53-1-3C-F相邻基团的影响α碳上卤原子增多，向高场移动β碳上卤原子增多，向低场移动CF3CH3CF3CFH2CF3CF2HCF3-61.7-78.5-86.8-CH2CF2CH2--CFHCF2CFH--CF2CF2CF2-CF2-91-116-120利用该规律可通过19FNMR推断聚偏氟乙烯的结构情况①CF2+CH2=CF2+CH2=CF2→-CF2CH2CF2CH2CF2-(0/4)-91.6②CH2+CH2=CF2+CH2=CF2→-CH2CH2CF2CH2CF2-(0/2)-94.8③CF2+CH2=CF2+CF2=CH2→-CF2CH2CF2CF2CH2-(2/2)-113.6④CH2+CH2=CF2+CF2=CH2→-CH2CH2CF2CF2CH2-(2/0)-115.93-1-4AB峰CF2在环上与不对称碳相邻或中间隔一个氧原子脂肪链自由旋转受阻ν4ν3ν2ν1JAB=ν4-ν3=ν2-ν1J值一般较氢谱大3-1-5远距离偶合4JFF＞3JFFCF3CF2CF2OF17.02.92.94.5CF2CF2CFCO2HFFJ=9.9HzCF3FFF1324J14=22HzJ24=8HzJ34=13HzCH3HHFJ=3.3Hz3-2含氟脂环化合物Fδ=-133ppm低温时为AB峰，δe-F高场（18ppm）FXCFXZ在高场CF2为AB峰，J：280～300Hz全氟萘烷具有顺反式结构，反式谱图教复杂FF峰编号（ppm）AB峰归属（ppm)1.-119.52.-123.01256-127.03.-124.53478-135.04.-127.75.-131.21278-132.06.-134.53456-129.57.-142.28.-145.7顺式:-126,-1353-3含氟烯烃F1F2F3low(-70)high(-220)⑴末端烯烃F3最高场且变化范围大,高场可达-220ppm,碳上连接金属原子时较高场,连接卤素和氧原子时稍低;F1低场.当双键上只有一个氟时化学位移变化更大,低场可达-53ppm.规律性较差,分析谱图时尽可能与类似结构的谱图比较.F-F偶合3J反式＞2J＞3J顺式～120～80～40F1F2F3CF24CF2(CF2)nCF2CF3-92-193-108-121-127-129-83J23=117,J12=82,J13=40J24=28,J34=14,J14=6F-H偶合2J＞3J反式＞3J顺式～9012～521～20⑵1,2-二氟烯烃偶合常数可以按经验式估算[JCS(CC),1996,703]取代基HIBrClFCF3N(CF3)2Jcis-7.912.517.518.839.01.618.1Jtrans67.378.471.464.551.469.762.9FClHFFClFHJFF=67.3+64.5=131.8(Hz)JFF=18.8-7.9=10.9(Hz)⑶复杂含氟烯烃尽量利用已知的结构数据信息（四）含氟芳香族化合物19FNMR1.多氟取代的芳香族化合物2.少氟取代的芳香族化合物1.多氟取代的芳香族化合物lowhighFFX-162.9-132～-174X=OH,NH2,NHMe,NHNH2时,对位F最高场化学位移估算(加和规律):=C6H6+取代基影响参数(苯环上氟原子越多越准确,取代基多误差大)取代基邻位间位对位H23.70.28.4Cl21.61.06.2Br30.31.77.7I43.23.0-10.0F1F2F3F4IHF1=-162.9+23.7+43.2=-96.0F2=-162.9+8.4+43.2=-111.3F3=-162.9+0.2+3.0=-159.7F4=-162.9+23.7-10.0=-149.2偶合常数:Jo＞Jp＞Jm19～240～150～8计算实测F2=-162.9+23.7+30.3=-108.9-109.6F4=-162.9+30.3+8.4=-124.8-124.8F5=-162.9+0.2+1.7=-161.0-161.2F6=-162.9+23.7+7.7=-132.2-132.2F2F4F5F6Br3H1J56=J54=19.6HzJ24=J26=5.3HzJ25=9.7HzJ15=5.0HzJ12=9.0HzJ16=9.7HzCH3FFFFFo=-162.9+18.8=-144.1m=-162.9-1.5=-164.4p=-162.9+3.2=-159.7mJFF=01HNMR:t-d峰ClClNH2NH2+B(A)NH3FF3=-162.9+0.1×2+1.0=-161.75=-162.9+0.1+1.0-11=-172.86=-162.9+21.6–2.6×2=-146.5ClNH2NH2123546FClNH2NH2123546F①化学位移相近A:-149.8-161.9-176.4B:-147.2-164.5-178.8取代基邻位间位对位H23.70.28.4Cl21.61.06.2Br30.31.77.7I43.23.0-10.0②化合物B裂分较化合物A复杂③化合物B的HNMR在5.86处有H信号HNH2NH2FHNH2NH2F565165616336312.少氟取代的芳香族化合物=-113.8+取代基影响参数(CD3COCD3)-112.6+取代基影响参数(DMSO-d6)(苯环上氟原子越少越准确)取代基邻位间位对位F-25.93.2-6.3NH2-22.5-1.9-15.9OCH3-22.31.2-11.4CHO-8.61.29.5CO2H3.80.56.6CF3-2.02.45.8Br5.72.9-1.8Cl-2.52.6-2.4I19.42.9-1.1OH-24.30.6-13.0CH3-4.6-1.1-5.4FClCF3OHFF=-113.8-2.5+5.8=-110.5(-111.2)2=-113.8–24.3+3.2=-134.9(-113.4)4=-113.8–13.0+3.2=-123.6(-124.4)在其它领域应用实例:F-和(HF)n间氢键研究Bu4N+F-/HFinCDF3/CDF2Cl(110K)F-+nHF→[FHF]-+[F(HF)2]-+[F(HF)3]-+···[F·····H·····F]-氢键最强,键长最短.n数增加,氢键减弱.FHFFHHFFFHHFFHF