碳核磁共振谱.讲课资料.ppt

第四讲：核磁共振碳谱 Carbon-13 Nuclear Magnetic Resonance Spectroscopy 庞文民 2013年12月 ;13C NMR概述;核磁共振碳谱特点;13C NMR;13C NMR化学位移;13C NMR化学位移;13C NMR化学位移;化学位移;影响化学位移的因素;诱导效应;诱导效应;空间效应;共轭效应和超共轭效应;缺电子效应;电场效应;取代程度;邻近基团的各向异性效应 ;构型;介质效应;易离解的化合物在溶液稀释时会使化学位移有少许的变化。当化合物中含有—COOH、—OH、—NH2、SH 等基团时，pH 的改变会使化学位移发生明显变化。如，羧基碳原子在 pH 增大时受到屏蔽作用而使化学位移移向高场。;温度效应;顺磁离子效应;烯烃及取代烯烃的化学位移;炔碳的化学位移;苯环碳的化学位移;羰基化合物的碳化学位移;氢键对碳化学位移的影响;耦合裂分及耦合常数;sepet, 2J = 5.7 Hz;耦合常数的典型值;13C-X的偶合及偶合常数;13C-X的偶合及偶合常数;耦合常数的应用;某化合物 C18H18N3O3F3含下列结构片段，13C 质子噪声去耦谱如上图 所示，请标识 C（1）和 C（2）所对应的谱线。;质子噪声去耦谱（proton noise decoupling）;反转门控去耦谱（inverse gated decoupling）;偏共振去偶谱 ;偏共振去偶谱;质子非去偶谱;无NOE去偶谱;选择性质子去偶谱;选择性质子去偶谱;DEPT（Distortionless Enhancement by Polarization Transfer）谱;DEPT 谱;P(CH)=B;纵向弛豫时间T1测定及其意义;纵向弛豫时间T1测定及其意义;碳谱的解析步骤;碳谱的解析步骤;碳谱的解析步骤;Two isomeric hydrocarbons, A and B, of C5H10 were separated by GC and gave the following 13C data: A: 13 (q), 17 (q), 26 (q), 118 (d), and 132 (s) ppm B: 13 (q), 22 (q), 31 (t), 108 (t), and 147 (s) ppm;A compound gives a molecular ion in its EI spectrum at m/z 80. This value is unchanged when the compound is introduced into the mass spectrometer in the presence of D2O. A high resolution measurement establishes the molecular formula as C5H6N2. The compound gives the following 13C NMR spectrum: 16 (t), 22 (t), 119 (s) ppm. Deduce its structure.;Three compounds of molecular formula C4H8O have the following 13C spectra, and the described features in their IR spectra. Compound 1: IR: 1730 cm-1, 13C NMR: 13.3, 15.7, 45.7, 201.6 ppm. Compound 2: IR: 3200 (broad) cm-1, 13C NMR: 36.9, 61.3, 117.2, 134.7 ppm. Compound 3: IR: no peaks except CH and fingerprint, 13C NMR: 25.8 and 67.9 ppm. Suggest a structure for each compound, and then see whether your suggestions are compatible with the following information. Compound 1 react with NaBH4 to give compound 4, C4H10O, IR 3200 (broad) cm-1 and 13C NMR 15.2, 20.3, 36.0, and 62.9 ppm. Compound 2 reacts with hydrogen over a palladium catalyst to give the same