1
00:00:00,430 --> 00:00:01,280
這集

2
00:00:01,300 --> 00:00:02,970
我們就來觀察一對兒分子

3
00:00:02,990 --> 00:00:04,420
看看這兩個分子

4
00:00:04,440 --> 00:00:07,360
是不是明裏暗裏有點聯係

5
00:00:07,380 --> 00:00:09,770
第一對兒分子在這兒呢

6
00:00:09,780 --> 00:00:10,720
看上去這兩個是

7
00:00:10,740 --> 00:00:12,310
完全不同的兩種分子

8
00:00:12,330 --> 00:00:13,770
所以你第一感覺就是

9
00:00:13,790 --> 00:00:16,280
這兩個分子根本不一樣

10
00:00:16,300 --> 00:00:17,860
但是其實不完全是這樣的

11
00:00:17,890 --> 00:00:19,460
我們再來仔細觀察一下這兩個

12
00:00:19,480 --> 00:00:21,170
就會發現 左邊的這個分子

13
00:00:21,190 --> 00:00:24,680
有1 2 3 4個碳

14
00:00:24,700 --> 00:00:25,970
右邊這個分子也是

15
00:00:25,990 --> 00:00:28,850
它有1 2 3 4個碳

16
00:00:28,870 --> 00:00:29,960
左邊的分子有

17
00:00:29,970 --> 00:00:34,110
2 3 6 7 8個氫

18
00:00:34,130 --> 00:00:35,030
右邊的分子

19
00:00:35,050 --> 00:00:37,870
也是2 4 6 8個氫

20
00:00:37,890 --> 00:00:39,660
這兩個分子都有1個氧

21
00:00:39,680 --> 00:00:41,120
所以這兩個分子的結構式都是

22
00:00:41,140 --> 00:00:43,320
所以這兩個分子的結構式都是

23
00:00:43,340 --> 00:00:47,390
4個碳 8個氫 1個氧

24
00:00:47,410 --> 00:00:50,340
它們都是C4H8O

25
00:00:50,360 --> 00:00:52,360
它們的結構式一樣

26
00:00:52,380 --> 00:00:53,960
它們的組成都一樣的

27
00:00:53,980 --> 00:00:55,680
所以這兩個分子就叫同分異構物

28
00:00:55,700 --> 00:00:57,560
它們是同分異構物

29
00:00:57,580 --> 00:00:59,380
這對是個特殊的同分異構物

30
00:00:59,400 --> 00:01:02,660
它們的化學鍵是不同的

31
00:01:02,690 --> 00:01:04,480
組成是相同的

32
00:01:04,510 --> 00:01:07,120
但是化學鍵 原子和原子的相連是不一樣的

33
00:01:07,140 --> 00:01:17,590
我們把這樣的叫做結構異構物

34
00:01:17,610 --> 00:01:21,340
分子的組成相同

35
00:01:21,360 --> 00:01:24,300
但是其實這是兩種不同的分子

36
00:01:24,320 --> 00:01:26,400
這兩種分子大大的不同

37
00:01:26,420 --> 00:01:29,610
下面我們來看看這對兒分子

38
00:01:29,630 --> 00:01:32,350
我們來觀察一下這個分子

39
00:01:32,400 --> 00:01:36,650
貌似這個碳有手性哦

40
00:01:36,670 --> 00:01:38,890
這是個不對稱碳原子

41
00:01:38,910 --> 00:01:41,140
它連接4個不同的基團

42
00:01:41,150 --> 00:01:44,830
有氟 溴 氫 還有個甲基

43
00:01:44,850 --> 00:01:46,610
這個分子也是

44
00:01:46,630 --> 00:01:49,250
這兩個分子的組成是一樣的

45
00:01:49,270 --> 00:01:50,060
這個碳…

46
00:01:50,080 --> 00:01:52,040
它們不但組成一樣

47
00:01:52,060 --> 00:01:53,550
而且化學鍵也一樣

48
00:01:53,570 --> 00:01:56,270
碳氟 碳氟

49
00:01:56,290 --> 00:01:58,350
碳溴 碳溴

50
00:01:58,370 --> 00:02:00,040
然後都有碳氫鍵

51
00:02:00,060 --> 00:02:02,340
然後也都有碳甲基鍵

52
00:02:02,370 --> 00:02:04,700
但是這兩個分子長的不太一樣

53
00:02:04,730 --> 00:02:06,290
它們互呈鏡像嘛？

54
00:02:06,300 --> 00:02:06,620
好吧 不是

55
00:02:06,650 --> 00:02:07,860
這個分子的鏡像應該是

56
00:02:07,880 --> 00:02:09,980
氟從這裡伸出來

57
00:02:10,010 --> 00:02:13,190
然後氫從這裡伸進去的

58
00:02:13,210 --> 00:02:16,670
然後溴應該是從這邊支出來

59
00:02:16,680 --> 00:02:17,690
我們現在來看看我能不能

60
00:02:17,720 --> 00:02:19,570
把這個分子變成這個分子

61
00:02:19,590 --> 00:02:22,370
我先翻轉一下這個分子 我先…

62
00:02:22,390 --> 00:02:27,980
最好先把分子翻轉過來

63
00:02:28,000 --> 00:02:33,450
看我能迅雷不及掩耳就變過來了

64
00:02:33,470 --> 00:02:35,200
我這樣 把分子翻轉過來

65
00:02:35,220 --> 00:02:37,600
我要把它翻轉出紙面 想象一下

66
00:02:37,620 --> 00:02:39,060
這樣翻轉

67
00:02:39,080 --> 00:02:41,400
我抓住這個甲基

68
00:02:41,410 --> 00:02:42,660
然後把它翻到右邊來

69
00:02:42,680 --> 00:02:43,890
想象一下 我要把它轉過來

70
00:02:43,910 --> 00:02:46,780
這樣它先從紙面中出來 然後再落回去

71
00:02:46,800 --> 00:02:48,590
翻轉之後 分子變什麽樣兒了？

72
00:02:48,600 --> 00:02:51,140
分子中還有碳 就是這個碳

73
00:02:51,160 --> 00:02:53,760
然後甲基就跑到這邊來了

74
00:02:53,770 --> 00:02:56,010
翻轉之後呢

75
00:02:56,040 --> 00:02:58,370
溴還是在紙面上

76
00:02:58,390 --> 00:03:01,230
它仍然在紙面上

77
00:03:01,260 --> 00:03:04,710
但是因爲我把分子翻過來了 這個氫

78
00:03:04,730 --> 00:03:08,070
之前後面的氫 就跑到前面來了

79
00:03:08,080 --> 00:03:10,970
現在氫是在紙面外了

80
00:03:10,990 --> 00:03:13,950
氟在紙面裏面

81
00:03:13,970 --> 00:03:15,070
因爲我把分子給翻轉了

82
00:03:15,070 --> 00:03:20,090
氟在後面了

83
00:03:20,110 --> 00:03:22,410
那麽對比一下 會發現什麽呢？

84
00:03:22,440 --> 00:03:24,640
看看能不能變成這個分子

85
00:03:24,660 --> 00:03:26,660
好啦 如果我把這個氟

86
00:03:26,680 --> 00:03:28,350
旋轉到氫的位置上

87
00:03:28,370 --> 00:03:30,720
然後把這個氫旋轉到…

88
00:03:30,740 --> 00:03:32,100
當然這兩個都是同時進行的啦…

89
00:03:32,120 --> 00:03:33,430
把它轉到溴這兒來

90
00:03:33,450 --> 00:03:35,490
然後溴轉到氟這兒來

91
00:03:35,510 --> 00:03:36,530
就變出這個分子啦

92
00:03:36,580 --> 00:03:38,450
先把分子翻轉一下

93
00:03:38,470 --> 00:03:43,030
然後再以這個鍵爲軸旋轉

94
00:03:43,050 --> 00:03:44,650
最後就得到這個分子啦

95
00:03:44,680 --> 00:03:45,970
所以雖然這兩個分子看上去不太一樣

96
00:03:45,990 --> 00:03:47,220
翻轉一下 再旋轉一下

97
00:03:47,240 --> 00:03:54,380
大家就會發現 是同一個分子

98
00:03:54,400 --> 00:03:56,130
下一個登場

99
00:03:56,160 --> 00:03:57,890
大家看看 這兩個分子是什麽情況呢？

100
00:03:57,910 --> 00:03:59,480
我換個顏色哦

101
00:03:59,490 --> 00:04:01,000
先看這個

102
00:04:01,030 --> 00:04:04,040
兩個分子的這個部分都一樣

103
00:04:04,060 --> 00:04:06,320
每個分子上都有這個碳

104
00:04:06,340 --> 00:04:08,560
這個碳呢 有點像手性中心

105
00:04:08,570 --> 00:04:11,920
這個碳連著1 2 3個不同的基團

106
00:04:11,940 --> 00:04:13,770
你可能要說 你看這是2個碳

107
00:04:13,790 --> 00:04:14,850
但是其實這個是甲基

108
00:04:14,860 --> 00:04:16,820
這邊的碳有這麽一堆東西連著

109
00:04:16,840 --> 00:04:18,380
所以這肯定是個手性中心啦

110
00:04:18,400 --> 00:04:20,570
這邊也是一樣的

111
00:04:20,590 --> 00:04:22,150
這是個手性碳

112
00:04:22,170 --> 00:04:23,640
這個也是手性的

113
00:04:23,660 --> 00:04:25,260
這個碳連著4個不同基團

114
00:04:25,270 --> 00:04:28,330
所以每個分子都有2個手性碳

115
00:04:28,350 --> 00:04:31,310
而且貌似它們的組成也一樣

116
00:04:31,330 --> 00:04:33,980
不僅兩個分子的組成一樣

117
00:04:34,000 --> 00:04:39,110
而且化學鍵也都是一樣的

118
00:04:39,130 --> 00:04:42,700
這個碳連著1個氫和1個氟

119
00:04:42,720 --> 00:04:44,600
另外2個碳也是一樣的

120
00:04:44,620 --> 00:04:45,950
有1個氫和1個氟

121
00:04:45,970 --> 00:04:48,850
這個碳就跟氫一樣

122
00:04:48,870 --> 00:04:51,830
這個碳連著一個氫和一個氯

123
00:04:51,850 --> 00:04:54,470
它們的組成元素都是一樣的

124
00:04:54,490 --> 00:04:56,500
成鍵方式也是一樣的

125
00:04:56,520 --> 00:04:59,330
貌似…

126
00:04:59,340 --> 00:05:01,960
成鍵方式有一點點的不同

127
00:05:01,980 --> 00:05:03,520
左邊的這個分子

128
00:05:03,540 --> 00:05:05,470
這個氫是向後面的

129
00:05:05,500 --> 00:05:07,330
這邊這個呢 氫是向外的

130
00:05:07,350 --> 00:05:09,830
這邊的這個氯來裏面

131
00:05:09,850 --> 00:05:11,350
而這邊的氯指在外面

132
00:05:11,380 --> 00:05:18,420
這兩個很像立體異構物诶

133
00:05:18,440 --> 00:05:20,120
前面我們看到了

134
00:05:20,140 --> 00:05:21,400
看到了結構異構物

135
00:05:21,420 --> 00:05:23,130
它們組成的元素相同

136
00:05:23,150 --> 00:05:24,510
但是原子之間的連接方式不同

137
00:05:24,530 --> 00:05:27,530
而立體異構物呢 它們不但組成相同

138
00:05:27,550 --> 00:05:29,170
原子之間的連接方式也相同

139
00:05:29,190 --> 00:05:31,400
但是兩個分子的立體結構

140
00:05:31,430 --> 00:05:32,680
有一點點不同

141
00:05:32,710 --> 00:05:34,450
比如說 這個碳

142
00:05:34,470 --> 00:05:36,490
和這個碳連的取代基都是一樣的

143
00:05:36,500 --> 00:05:37,230
但是注意

144
00:05:37,260 --> 00:05:39,870
這個氟在裏面 這裡…

145
00:05:39,880 --> 00:05:41,490
這兒 氟在前面

146
00:05:41,510 --> 00:05:43,280
但是這裡 這個氟在後面

147
00:05:43,310 --> 00:05:44,510
氯也一樣

148
00:05:44,530 --> 00:05:46,250
一個向內 一個向外

149
00:05:46,270 --> 00:05:48,540
現在我們來看看

150
00:05:48,570 --> 00:05:51,180
這兩個分子有沒有什麽微妙的聯係

151
00:05:51,200 --> 00:05:54,880
大家可以想象在分子後面放一面鏡子

152
00:05:54,890 --> 00:05:56,930
我覺得這個思路最好了

153
00:05:56,950 --> 00:05:59,910
想象這個分子後面有一面鏡子

154
00:05:59,930 --> 00:06:02,280
如果後面有個鏡子

155
00:06:02,300 --> 00:06:04,160
那鏡子裏面的分子是什麽樣的呢？

156
00:06:04,180 --> 00:06:05,930
如果放個鏡子

157
00:06:05,950 --> 00:06:09,100
在鏡子裏面呢 這個氫

158
00:06:09,130 --> 00:06:11,380
因爲鏡子是在分子後面的

159
00:06:11,400 --> 00:06:13,300
這個氫距離鏡子最近

160
00:06:13,310 --> 00:06:14,970
所以鏡子裏

161
00:06:14,990 --> 00:06:17,060
這個氫指向外面

162
00:06:17,080 --> 00:06:18,810
然後連個碳

163
00:06:18,830 --> 00:06:22,610
然後這個氟指向更裏面

164
00:06:22,630 --> 00:06:24,650
這邊的也一樣啦

165
00:06:24,650 --> 00:06:27,210
這個氯離我們更近一點點

166
00:06:27,230 --> 00:06:28,680
因爲氯指向紙面內

167
00:06:28,700 --> 00:06:29,800
距離鏡子更近一點

168
00:06:29,820 --> 00:06:30,610
然後呢

169
00:06:30,640 --> 00:06:33,050
這個氫這樣伸出來

170
00:06:33,070 --> 00:06:34,970
顯然啦 這個分子剩下的部分

171
00:06:34,990 --> 00:06:38,910
鏡子裏面和外面都是一樣的

172
00:06:38,920 --> 00:06:40,190
所以這個

173
00:06:40,210 --> 00:06:42,040
我用白色畫出來的鏡像

174
00:06:42,060 --> 00:06:44,440
就和這個分子一樣

175
00:06:44,450 --> 00:06:50,070
氫指向外面

176
00:06:50,090 --> 00:06:53,090
你可能又要說了 你看 這個氫在右邊

177
00:06:53,110 --> 00:06:53,710
而這個在左邊

178
00:06:53,730 --> 00:06:54,110
這個無所謂啦

179
00:06:54,130 --> 00:06:54,760
這兩個都是

180
00:06:54,790 --> 00:06:56,270
氫指向外面

181
00:06:56,300 --> 00:06:57,640
氯指向裏面

182
00:06:57,660 --> 00:06:59,270
氫向外 氟向內

183
00:06:59,300 --> 00:07:03,870
氯向外 氫向內

184
00:07:03,890 --> 00:07:05,550
所以這兩個互爲鏡像

185
00:07:05,570 --> 00:07:08,120
但是這兩個不像以前

186
00:07:08,140 --> 00:07:08,740
那些那麽簡單了

187
00:07:08,760 --> 00:07:11,280
以前鏡子都在這兩個分子之間

188
00:07:11,300 --> 00:07:15,290
這個是把鏡子放到

189
00:07:15,310 --> 00:07:18,390
一個分子上面或者後面形成的

190
00:07:18,410 --> 00:07:20,100
所以這也是一種立體異構物

191
00:07:20,120 --> 00:07:22,080
這個詞之前我們碰過了

192
00:07:22,100 --> 00:07:25,980
也叫對映體

193
00:07:26,000 --> 00:07:28,270
這兩個都是對映體

194
00:07:28,290 --> 00:07:30,580
是彼此的對映體

195
00:07:30,600 --> 00:07:32,110
還是立體異構物

196
00:07:32,130 --> 00:07:33,940
組成這兩個分子的原子都一樣

197
00:07:33,950 --> 00:07:36,850
也就是說分子的組成相同

198
00:07:36,870 --> 00:07:39,520
原子之間的連接方式也是一樣的

199
00:07:39,540 --> 00:07:41,130
不僅僅它們有相同的連接方式

200
00:07:41,150 --> 00:07:43,090
也就是說不僅僅是立體異構物

201
00:07:43,110 --> 00:07:45,170
還是特殊的立體異構物

202
00:07:45,180 --> 00:07:46,030
即對映體

203
00:07:46,060 --> 00:07:49,760
也就是說它們互爲鏡像

204
00:07:49,780 --> 00:07:53,590
那麽這個藍色的分子是什麽呢？

205
00:07:53,620 --> 00:07:55,020
就像這個一樣

206
00:07:55,030 --> 00:07:57,420
看起來它們的組成也是一樣的

207
00:07:57,440 --> 00:07:59,280
這裡有碳 這個也有

208
00:07:59,300 --> 00:08:01,090
這個有了碳 還有氫

209
00:08:01,100 --> 00:08:02,130
它也一樣

210
00:08:02,190 --> 00:08:04,910
這邊是氫溴 這邊也是氫溴

211
00:08:04,930 --> 00:08:07,100
氫和氯 這兒也是氫和氯

212
00:08:07,120 --> 00:08:09,130
氫和氯 氫和氯

213
00:08:09,150 --> 00:08:10,520
所以這兩個分子的組成相同

214
00:08:10,540 --> 00:08:12,680
原子之間的連接也相同

215
00:08:12,700 --> 00:08:15,440
所以它們一定互爲立體異構物啦

216
00:08:15,450 --> 00:08:17,090
好啦 我們先要確定…

217
00:08:17,110 --> 00:08:19,430
我們先確定它們不一樣

218
00:08:19,460 --> 00:08:21,270
這裡 氫指向外

219
00:08:21,300 --> 00:08:23,580
這裡的氫指向內

220
00:08:23,600 --> 00:08:25,780
這裡 氫指向內

221
00:08:25,800 --> 00:08:26,820
而這裡氫指向外

222
00:08:26,860 --> 00:08:28,280
所以這兩個不是同一個分子

223
00:08:28,300 --> 00:08:31,090
雖然組成原子的連接方式是一樣的

224
00:08:31,110 --> 00:08:33,990
但是立體構型不一樣

225
00:08:34,010 --> 00:08:43,610
所以它們是立體異構物

226
00:08:43,620 --> 00:08:45,970
我們再來看看是不是對映體

227
00:08:45,980 --> 00:08:49,260
仔細觀察一下 如果在這裡放面鏡子

228
00:08:49,280 --> 00:08:50,720
沒辦法得到這個分子

229
00:08:50,740 --> 00:08:51,140
那樣的話

230
00:08:51,170 --> 00:08:52,760
氯指向內 然後氫在前面

231
00:08:52,790 --> 00:08:54,830
所以鏡子放這裡不行

232
00:08:54,850 --> 00:08:58,470
但如果和上一對用同樣的方法

233
00:08:58,490 --> 00:09:02,660
也就是在這個分子後面放個鏡子

234
00:09:02,680 --> 00:09:03,460
我現在只關注

235
00:09:03,480 --> 00:09:05,020
後面和前面的原子

236
00:09:05,040 --> 00:09:06,380
因爲如果鏡子在後面

237
00:09:06,400 --> 00:09:08,940
只有前後原子會變化

238
00:09:08,960 --> 00:09:10,900
所以如果鏡子在分子後面的話

239
00:09:10,920 --> 00:09:13,330
那麽這個溴

240
00:09:13,350 --> 00:09:15,560
會比這個氫離鏡子更近

241
00:09:15,590 --> 00:09:18,850
所以溴是向外的

242
00:09:18,870 --> 00:09:21,270
氫向內

243
00:09:21,290 --> 00:09:22,780
這個氫是指向裏面的

244
00:09:22,810 --> 00:09:25,420
這樣可能有點難理解

245
00:09:25,430 --> 00:09:27,000
其實我就是在畫一個鏡像

246
00:09:27,020 --> 00:09:29,440
剩下的這些都是一樣的

247
00:09:29,460 --> 00:09:33,370
這個氯指向外

248
00:09:33,390 --> 00:09:35,050
在鏡像中

249
00:09:35,070 --> 00:09:37,840
這個氫指向內

250
00:09:37,850 --> 00:09:39,000
如果你能想象到

251
00:09:39,010 --> 00:09:40,320
然後再來一個

252
00:09:40,340 --> 00:09:42,940
這個氯距離鏡子更近一點

253
00:09:42,960 --> 00:09:44,300
它緊挨著鏡子的

254
00:09:44,320 --> 00:09:47,100
所以在鏡像中 它是指向外的

255
00:09:47,120 --> 00:09:49,360
這個氫指向內

256
00:09:49,380 --> 00:09:50,110
現在大家看看

257
00:09:50,130 --> 00:09:52,010
這個鏡像和這個分子是一樣的嘛？

258
00:09:52,030 --> 00:09:53,370
在這個鏡像中

259
00:09:53,390 --> 00:09:55,420
溴是指向外的

260
00:09:55,440 --> 00:09:56,920
氫是指向內的

261
00:09:56,940 --> 00:10:00,560
然後氫 在鏡像中

262
00:10:00,580 --> 00:10:02,230
這個氫指向內 氯指向外

263
00:10:02,250 --> 00:10:02,880
這邊一樣

264
00:10:02,900 --> 00:10:05,210
目前看來還挺像鏡像的

265
00:10:05,230 --> 00:10:07,730
然後最後這個碳

266
00:10:07,750 --> 00:10:09,670
氯指向外 然後氫指向內

267
00:10:09,690 --> 00:10:11,590
但是這裡呢 這個氯指向內

268
00:10:11,610 --> 00:10:12,450
而是氫指向外的

269
00:10:12,470 --> 00:10:15,790
大家可以這樣想 這部分呢

270
00:10:15,810 --> 00:10:18,630
這部分是這部分的鏡像

271
00:10:18,640 --> 00:10:21,200
然後這部分也是這部分的鏡像

272
00:10:21,220 --> 00:10:24,290
而這部分卻不是那部分的鏡像

273
00:10:24,310 --> 00:10:28,390
所以如果立體異構物不是鏡像的話

274
00:10:28,420 --> 00:10:29,660
兩個立體異構的分子

275
00:10:29,680 --> 00:10:31,780
不互爲鏡像的話

276
00:10:31,800 --> 00:10:34,340
我們就把它們叫做非對映體

277
00:10:34,360 --> 00:10:35,740
真拗口

278
00:10:35,760 --> 00:10:36,370
我寫下來

279
00:10:36,380 --> 00:10:44,470
它們是 非對映體

280
00:10:44,490 --> 00:10:45,490
也就是說

281
00:10:45,510 --> 00:10:47,940
它們是立體異構物 但不對映

282
00:10:47,960 --> 00:10:49,240
就是：

283
00:10:49,260 --> 00:10:50,890
是立體異構物 但不是對映體

284
00:10:50,910 --> 00:10:52,390
立體異構物除了對映體

285
00:10:52,410 --> 00:10:54,110
就是非對映體

286
00:10:54,130 --> 00:10:56,660
我們現在來看最後一組

287
00:10:56,690 --> 00:10:58,850
這裡有2個…

288
00:10:58,860 --> 00:11:02,830
這有個環己烷

289
00:11:02,840 --> 00:11:03,860
它們的1號和2號碳上都有個溴取代

290
00:11:03,930 --> 00:11:06,200
它們的1號和2號碳上都有個溴取代

291
00:11:06,220 --> 00:11:07,380
這兩個碳編號就隨你啦

292
00:11:07,400 --> 00:11:10,580
它們貌似互爲鏡像

293
00:11:10,600 --> 00:11:14,300
我們可以在這裡放個鏡子

294
00:11:14,320 --> 00:11:16,420
它們確實像鏡面對映

295
00:11:16,440 --> 00:11:18,400
這是個手性碳

296
00:11:18,420 --> 00:11:19,940
這個碳連了一個碳鏈

297
00:11:19,960 --> 00:11:21,490
並且這個碳鏈和這個碳鏈不同

298
00:11:21,510 --> 00:11:23,020
這個碳鏈上有個溴

299
00:11:23,040 --> 00:11:24,130
而這個沒有

300
00:11:24,140 --> 00:11:25,350
這個上面倒是有一堆氫

301
00:11:25,370 --> 00:11:26,760
如果你這麽看的話

302
00:11:26,780 --> 00:11:28,990
這是個氫 這是個溴

303
00:11:29,010 --> 00:11:30,280
這是個手性的

304
00:11:30,300 --> 00:11:33,350
同樣 這個也是手性

305
00:11:33,370 --> 00:11:35,500
顯然這個是手性的 這個也是手性的

306
00:11:35,520 --> 00:11:37,150
但是大家仔細想想

307
00:11:37,180 --> 00:11:39,120
它們確實互爲鏡像

308
00:11:39,140 --> 00:11:42,530
每個分子都有2個手性中心

309
00:11:42,550 --> 00:11:43,780
2個手性碳

310
00:11:43,800 --> 00:11:45,460
仔細想想

311
00:11:45,480 --> 00:11:48,350
如果你把它翻轉過來

312
00:11:48,370 --> 00:11:49,990
就得到了這個分子

313
00:11:50,010 --> 00:11:51,420
所以其實它們是相同的分子

314
00:11:51,440 --> 00:11:55,260
所以它們是同一分子

315
00:11:55,280 --> 00:11:57,360
這個有意思是吧

316
00:11:57,380 --> 00:12:00,180
我們剛講到手性的時候就遇過這個

317
00:12:00,200 --> 00:12:02,830
雖然這裡有2個手性中心

318
00:12:02,850 --> 00:12:04,650
這也不是手性分子

319
00:12:04,680 --> 00:12:06,870
分子本身和它的鏡像是一樣的

320
00:12:06,890 --> 00:12:23,670
它本身和它鏡像完全重合

321
00:12:23,700 --> 00:12:26,370
所以雖然分子中有手性碳

322
00:12:26,390 --> 00:12:29,130
它也不是手性分子

323
00:12:29,150 --> 00:12:34,470
我們把這類化合物叫內消旋體

324
00:12:34,490 --> 00:12:35,810
箭頭就指向一個就行了

325
00:12:35,830 --> 00:12:37,660
因爲它們其實是一樣的化合物

326
00:12:37,680 --> 00:12:41,650
這是內消旋體

327
00:12:41,670 --> 00:12:43,560
它確實有手性中心

328
00:12:43,580 --> 00:12:45,910
你確實可以說 它具有手性碳

329
00:12:45,930 --> 00:12:48,450
但是它卻不是手性化合物

330
00:12:48,470 --> 00:12:50,320
最直接的判斷方法是看

331
00:12:50,340 --> 00:12:51,670
化合物有手性中心

332
00:12:51,680 --> 00:12:53,960
但是這裡有個對稱軸

333
00:12:53,990 --> 00:12:56,000
有個對稱軸哦

334
00:12:56,020 --> 00:12:58,850
化合物的這兩邊

335
00:12:58,870 --> 00:13:00,270
互爲鏡像

336
00:13:00,300 --> 00:13:03,630
但是 如果我把這個和這個

337
00:13:03,650 --> 00:13:06,900
都改成氟

338
00:13:06,930 --> 00:13:09,170
它們就不是同一個分子啦

339
00:13:09,190 --> 00:13:11,600
改了之後 分子就沒有對稱軸了

340
00:13:11,620 --> 00:13:13,540
這兩個還是互爲鏡像

341
00:13:13,550 --> 00:13:15,110
但是它們無法完全重合了

342
00:13:15,130 --> 00:13:16,190
所以如果這是氟的話

343
00:13:16,200 --> 00:13:18,820
這兩個分子就成了對映體了

344
00:13:18,840 --> 00:13:21,360
這就不是一個內消旋體

345
00:13:21,390 --> 00:13:23,380
而是兩個對映體了

346
00:13:23,400 --> 00:13:28,550
如果我們要用前幾集中

347
00:13:28,570 --> 00:13:30,280
學到的命名法來命名的話

348
00:13:30,310 --> 00:13:32,620
那麽其中一個的開頭就是R

349
00:13:32,650 --> 00:13:34,710
另一個是S