当前位置:首页 >> 学科竞赛 >>

波谱分析 第6章 综合解析再编2


第六章 波谱综合解析

照射质子4,2与4的远程 偶合消失,4变成单峰,1 与2偶合符合n+1规则

选择性 去偶谱 :双共 振去偶

照射质子2,2与1的偶合、2与4的 偶合消失,均变成单峰 照射质子1,1与2的偶合消失,但 仍保留2与4的远程偶合,故4仍为 三重峰,2由六重峰变为双峰

常规谱

(B)

AA’

BB’

C

Hx

HM

HA

d H BrH 2C a

b H H c

烯烃上取代基不同对于烯氢的化学位 移的影响是不同的。见P114~P115计算 公式和表3-7

(C)

9 8

10

4

3 2 1

6 7 11 5

(C)

3

4

5

8

9 8

10

4

3 2 1

6 7 11 5

9

11

2

1 5 3 4 8 9 2

11 1

3 4

8 9 2 11 5

1 1

9 8

10

4

3 2 1

6 5
11

7

5 8

2 9

11

4 3

9

10

4

3 2 1

6 5
11

8 7

11 1 9 85 2 3 4 10 6 7

3 4

5

8 92 11

1

1 11 2 5 8 9

4
3

7
9 8 7 11

10
6

4

3 2 1 6 10

5

34

11 8 9 2 5

1

2,3 2,4

1,2
5,11

5,3 5,4

1 11 2 5 8 9 4

3
7 9 10 6 5 7 11 4 3 2 1 6 10

8

(D)

HMQC spectrum

HMBC spectrum

13C

satellites of intense proton peaks, especially methyl groups. If we trace parallel to the proton axis (F2) at about 23 pprn on the carbon axis (Fl), we find a cross peak at about 0.93 pprn (proton), which is real. On either side, we find two "cross peaks" that do not line up (correlate) with any protons in F2. These are 13C satellites and should be ignored. The other methyl carbon resonance shows the same phenomenon; the satellite peaks are marked with arrows in the figure.

8

A

C

B

C (1H,7.4ppm,t)

n+m+1规则

B

N

B (2H,6.9ppm,d) A (6H,2.5ppm,s)

d e c

a
b

d

c
N

b a

e

d

b

a

c

e c d b
N

e

a

b
a c

c
N

b a

1.某化合物A,分子式C13H18O2,其谱图 如下,请确定其结构。

DMSO-d6

H H COSY spectrum

HMQC spectrum

2.某化合物B,分子式C8H6O3,其谱图如 下,请确定其结构。

1H

NMR in CDCl3

HMQC spectrum

HMBC spectrum(C-H远程偶合)

Interpretation of HMBC's requires a degree of flexibility because we do not always find what we expect to find. In particular, depending on the hybridization of carbon and other factors, some of the two-bond correlations (2JCH) or three-bond (3JCH) correlations are occasionally absent. To add to the confusion, infrequently we find four-bond (4JCH) correlations! The variations in correlations that we find are due to the variations in the magnitude of 2JCH, 3JCH, and 4JCH coupling constants.

3.某化合物C,分子式C8H14O,其谱图如 下,请确定其结构。

HMQC spectrum

HMBC spectrum(C-H远程偶合)



相关文章:
更多相关标签: