/到 生物核磁共振波谱学 NMR in Biological Science 5. 1D NMR Spectra THNMR AN
生物核磁共振波谱学 NMR in Biological Science 5. 1D NMR Spectra THNMR YAN
5.1 1D 1H NMR Spectra Dictional 1/2 Natural abundance=99.985% CH3(C=OCH2CH3 CH3 Magnetogyric ratio= 26 7522 in CDCl3 Receptivity vs. H=1.00 Receptivity vS 3C=5.67x10 Shift range =-25 to +12 ppm CH2 Shift reference: (CH3)4Si TMSI TMS √ chemical shift v spin-spin coupling 化学位移高 >低 integral area 频率高 一>低 磁场弱 >强 THNMR AN
5.1 1D 1H NMR Spectra THNMR YAN chemical shift spin-spin coupling 化学位移 高—————————— integral area >低 频率 高——————————>低 磁场 弱——————————>强 Dictionary: 1H Spin = 1/2 Natural abundance = 99.985% Magnetogyric ratio = 26.7522 Receptivity vs. 1H = 1.00 Receptivity vs.13C = 5.67x103 Shift range = -25 to +12 ppm Shift reference: (CH3 )4Si [TMS]
Chemica/-Shift Reference 非极性溶剂: Dictionary TMS-四甲基硅烷 A chemical-shift reference is used to define the (CH3)4Si positions of the resonances in the spectrum in terms of parts-per-million, or ppm, of frequency. It is a material which is often directly added to the 极性溶剂: sample. For relatively commonly observed DSS nuclides. chemical-shift reference standards have been agreed upon as indicated. In all cases, the (CH3)4Si-CH2-CH2-CH2-SO3-Na shift of this material is defined as d=o. for some more obscure nuclides, no commonly accepted standard exists. Most modern spectrometers can perform frequency referencing operations automatically, but if highly precise chemical shifts are needed. it is still advisable to include the appropriate standard and perform the frequency THMMR referencing manually
THNMR YAN Chemical-Shift Reference Dictionary: A chemical-shift reference is used to define the positions of the resonances in the spectrum in terms of parts-per-million, or ppm, of frequency. It is a material which is often directly added to the sample. For relatively commonly observed nuclides, chemical-shift reference standards have been agreed upon as indicated. In all cases, the shift of this material is defined as d=0. For some more obscure nuclides, no commonly accepted standard exists. Most modern spectrometers can perform frequency referencing operations automatically, but if highly precise chemical shifts are needed, it is still advisable to include the appropriate standard and perform the frequency referencing manually. 非极性溶剂： TMS - 四甲基硅烷 (CH3 )4Si 极性溶剂： DSS (CH3 )4Si-CH2 -CH2 -CH2 -SO3 -Na
屏蔽常数σ和所处的化学环境有关 ototo S an:抗磁屏蔽,与孩外电子有关 7:顺磁屏酸,与接d电子有关 Gn:相獲团各向异性的响 σ:溶痧分质的影响 THMMR
屏蔽常数s 和所处的化学环境有关 s = sd + sp + sa + ss sd : 抗磁屏蔽，与核外s电子有关 sp : 顺磁屏蔽，与核外p,d电子有关 sa : 相邻基团各向异性的影响 ss : 溶剂、介质的影响 THNMR YAN
A.取代基电负性 取代基电负性越强,与取代基连接于同一碳原子上的H的 共振频率移向低场 1-propanol -CDCl3 CH3 CH2 CHa OH 有机官能团的电负性均大于氢原子的电负性,故化学位移 CH>CH2>CH3 THMMR
THNMR YAN A. 取代基电负性 取代基电负性越强，与取代基连接于同一碳原子上的H的 共振频率移向低场 有机官能团的电负性均大于氢原子的电负性，故化学位移 CH > CH2 >CH3
the benzene molecule In some cases. such as the benzene molecule. the circulation of the electrons in the aromatic orbitals creates a magnetic field at the hydrogen nuclei which enhances the b. field This phenomenon is B called deshielding. In this example, the b. field is applied perpendicular to the plane of the molecule. The ring current is traveling clockwise if you look down at the plane THNMR YAN
In some cases, such as the benzene molecule, the circulation of the electrons in the aromatic orbitals creates a magnetic field at the hydrogen nuclei which enhances the Bo field. This phenomenon is called deshielding. In this example, the Bo field is applied perpendicular to the plane of the molecule. The ring current is traveling clockwise if you look down at the plane. the benzene molecule THNMR YAN
B.环状共轭体系的环电流效应 Cyclohexane -CDCl3 CH 12 6432 Benzene-CDCI THMMR
THNMR YAN B. 环状共轭体系的环电流效应 C6H12 C6H6
B.环状共轭体系的环电流效应 Toluene- CDCI CHCH 687654326 Ethyl benzene-CDCl3 C6HS CH2CH 5432 THMMR
THNMR YAN B. 环状共轭体系的环电流效应 C6H5CH3 C6H5CH2CH3
B.环状共轭体系的环电流效应 uridine CDCl3 H-c C-H H-C C-H THMMR
THNMR YAN B. 环状共轭体系的环电流效应
C.相连键的磁各向异性 CH3(C=OCH2CH3 CH3 in cdcl3 CH3 CH2 TMS 2 D.相连碳原子的s亲化 E.溶剂、氢键 ■■■■■■ F.活拨氢 THMMR
THNMR YAN C. 相连键的磁各向异性 D. 相连碳原子的s-p杂化 E. 溶剂、氢键 …… F. 活泼氢
