作者chicyupin (zzzZZZ)
看板Chemistry
標題[問題]還原力:LiAlH4 >NaBH4 的原因?
時間Fri Apr 11 22:10:51 2008
如題...
請問一下這個小小的問題
不知道這兩個還原劑之間還原力的差別
主要原因是什麼??
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1F：推 buteo:H與B.Al的電負度差應該是主因 (hydride帶的部份負電多寡) 04/11 22:21
2F：→ buteo:可參考2347篇 04/11 22:23
3F：→ chicyupin:嗯 感謝^^ XDDDDDDDDD 04/11 22:35
4F：推 volley:but i do not think the hard-soft consideration could 04/11 22:58
5F：→ volley:explain why LiAlH4 behaves reductant but NaH behaves 04/11 22:59
6F：→ volley:strong base! i think the electronegativity indeed can 04/11 23:00
7F：→ volley:give good explaination about the difference between 04/11 23:01
8F：→ volley:LiAlH4 and NaBH4. 04/11 23:02
9F：→ volley:LiAlH4, which is almost the strongest reductant, is 04/11 23:02
10F：→ volley:due to the coordination of aluminum atom onto reducible 04/11 23:04
11F：→ volley:functional group. then hydride is induced to attack 04/11 23:05
12F：→ volley:that functional group. 04/11 23:05
13F：→ volley:NaH can not form such complex with reducible functional 04/11 23:06
14F：→ volley:groups, thus that hydride can not be a reductant! 04/11 23:07
15F：推 buteo:學長你就打篇文章讓我M一下嘛 ^^ 04/11 23:21
16F：推 jessti:Al-H鍵共價性比Na-H強的多 半徑差異 04/11 23:54
17F：→ chicyupin:So the complex means? 04/12 01:19
18F：推 jessti:Al有能力當lewis acid跟反應物產生complex 增加反應位置的 04/12 03:08
19F：→ jessti:部分正電 讓hydride好攻擊 04/12 03:10
20F：→ chicyupin:所以"主要"的原因是因為產生complex,並非電負度差異囉? 04/12 13:58
21F：→ chicyupin:還有那產生的complex是以什麼型態存在? 結構如何? 04/12 13:59
22F：→ chicyupin:可以麻煩解釋一下嗎? 因為我都查不到相關的資料> < 04/12 13:59
23F：→ chicyupin:只查到下列網址的部份解釋 但我看不大懂所指 04/12 14:01