雙鉬金屬五重鍵與炔之[2+2+2]環化加成反應及與有機氯化物之碳-氯鍵活化反應研究

Reactions of the Mo-Mo Quintuple Bonded Complex with Alkynes and Chloro Organics: [2+2+2] Cycloaddition and C-Cl Bond Activation

林廷華(Lin, Ting Hua)

指導教授 ： 蔡易州

國立清華大學/理學院/化學系/碩士(2015年)

摘要

本論文著重於研究高立體阻礙的雙氮基脒配基合成出的雙鉬金屬五重鍵Mo2[μ-κ2-HC(N-2,6-iPr2C6H3)2]2 (1)，與炔類分子進行[2+2+2]環化加成反應，得到頭對尾及尾對尾耦合反應之產物，進一步探討其選擇性與反應機制。
錯合物1與末端炔類反應，皆與兩當量的末端炔類試劑反應。錯合物1與對氟苯基乙炔、對甲氧基苯基乙炔、環丙基乙炔及丙炔酸乙酯反應，皆作[2+2+2]環化加成反應得到六員環頭對尾耦合錯合物Mo2[μ-κ2-3,5-R2C4H2][μ-κ2-HC(N-2,6-iPr2C6H3)2]2及尾對尾耦合錯合物Mo2[μ-κ2-3,6-R2C4H2][μ-κ2-HC(N-2,6-iPr2C6H3)2]2 (R=4-FPh (2, 3), 4-MeOPh (4, 5), cyclopropyl (6, 7), COOEt (8))。在錯合物2-5的產率中，可以觀察到對位有推電子基之反應，尾對尾耦合反應之產物明顯較低；反之，對位為拉電子基之反應，會增加尾對尾耦合反應之產率之產率。以此實驗結果可以推測此[2+2+2]環化加成反應之機構與末端炔類上的官能基所產生的電子效應有關。然而，錯合物1與氮-甲基-氮-對甲苯磺醯基-乙炔基胺反應，得到氮硫鍵進行斷裂，形成C4配基與對甲苯磺醯配基的錯合物9，故碳-碳三鍵旁若具有孤對電子，可能會與雙鉬金屬五重鍵反應。此外，錯合物1、內炔與末端炔類反應，也可進行[2+2+2]環化加成反應。錯合物1與二苯基乙炔或苯基丙炔先進行[2+2]環化加成反應，得到四員環C2Mo2錯合物Mo2(μ-κ2-RCCPh)[μ-κ2-HC(N-2,6-iPr2C6H3)2]2 (R=Ph (10), Me (14))。接著，錯合物10及錯合物14分別與1-戊炔、苯乙炔及丙炔酸乙酯反應，皆作[4+2]環化加成反應得到六員環碳-碳耦合錯合物Mo2[μ-κ2-3,4-Ph2-6-RC4H][μ-κ2-HC(N-2,6-iPr2C6H3)2]2 (R=Pr (11), Ph (12), COOEt (13))、Mo2[μ-κ2-3-Ph-4-Me-6-RC4H][μ-κ2-HC(N-2,6-iPr2C6H3)2]2 (R=Pr (15), Ph (16))以及Mo2[μ-κ2-3-R-6-Me-5-PhC4H][μ-κ2-HC(N-2,6-iPr2-C6H3)2]2 (R=Ph (15), COOEt (16))。由錯合物11-13可以得知，末端炔類加成之位向受立體阻礙的影響，而從錯合物15-18可以得知，內炔加成之位向與末端炔類的電子效應有關。簡而言之，錯合物1、內炔與末端炔類[2+2+2]環化加成反應中，內炔的位向受電子效應影響，末端炔的位向受立體效應影響。另外，四員環錯合物10與三甲基乙腈反應，得到二苯乙烯以鄰位配位在鉬金屬上的錯合物Mo2(trans-2-styryl-C6H5)[μ-κ2-HC(N-2,6-iPr2C6H3)(N-2-iPr-6-CH(κ1-CH2)CH3-C6H3)][μ-κ2-HC(N-2,6-iPr2C6H3)2] (21)。錯合物10與苯甲醛反應，可以得到[2+2+2]環化加成反應的六員環錯合物Mo2(H)[μ-κ2-O(PhC)2PhC][μ-κ2-HC(N-2,6-iPr2C6H3)2]2 (22)，由此可知，較富含電子基的二苯乙炔可以對較缺電子基之羰基進行親核加成(nucleophilic addition)。最後，六員環錯合物Mo2[μ-κ2-3,5-Pr2C4H2][μ-κ2-HC(N-2,6-iPr2C6H3)2]2 (24a)與九羰基二鐵或與乙腈反應，會得到一個分子的羰基配位在鉬金屬的錯合物Mo2(CO)[μ-κ2-3,5-Pr2C4H2][μ-κ2-HC(N-2,6-iPr2C6H3)2]2 (24b)，以及兩個分子的乙腈配位在鉬金屬的錯合物Mo2(MeCN)2[μ-κ2-3,5-Pr2C4H2][μ-κ2-HC(N-2,6-iPr2C6H3)2]2 (24c)，此兩個皆為可逆反應，且由X-射線繞射分析中，可以觀察到配基配位在鉬金屬時，d軌域的電子貢獻在配基上，造成貢獻較少於六員環的d，故碳-鉬鍵增長。
另外，錯合物1與四氯乙烯反應，可以得到具彎曲型的亞乙烯配基錯合物Mo2(Cl)2[μ-κ2-HC(N-2,6-iPr2C6H3)2][μ-κ2-HC(N-2,6-iPr2C6H3) (N-2-iPr-6-C(κ1-CCH)(CH3)2C6H3)] (26)，其雙鉬金屬亞乙烯基的反應性是令人感興趣的。

關鍵字

雙鉬金屬五重鍵 ； [2+2+2]環化加成反應

並列摘要

This thesis focus on the study of the [2+2+2] cycloaddition reaction of the low-coordinate and steric hindrance quintuple bonded dimodybedenum complex Mo2[μ-κ2-HC(N-2,6-iPr2C6H3)2]2 (1) with alkynes. It has produced six-membered complexes by head to tail C-C coupling and tail to tail C-C coupling. Further, explore the mechanism and regioseletivity.
The reactions of complex 1 with terminal alkynes othen give products by two terminal alkynes. For example, reaction of complex 1 with 4-fluorophenylacetylene, 4-methoxyphenylacetylene, cyclopropylacetylene, or ethyl propiolate can give six-membered complex of [2+2+2] cycloaddition reaction by head to tail C-C coupling Mo2[μ-κ2-3,5-R2C4H2][μ-κ2-HC(N-2,6-iPr2C6H3)2]2 and tail to tail C-C coupling Mo2[μ-κ2-3,6-R2C4H2][μ-κ2-HC(N-2,6-iPr2C6H3)2]2 (R = 4-FPh (2, 3), 4-MeOPh (4, 5), cyclopropyl (6, 7), COOEt (8)). For Complexes 2-5, low yield by tail to tail coupling is observed reaction of 1 with para is electron donating group phenylacetylene. But, high yield by tail to tail coupling is observed reaction of complex 1 with para is electron withdrawing group phenylacetylene. In addition to experimental evidence, the mechanism of [2+2+2] cycloaddition reaction is affected by electronic effect for fuctional group of terminal alkynes. However, reaction of complex 1 with N-(methyl)-N-(p-toluenesulfonyl)-ethynylamine gives complex 9 which undergoes cleavage of nigrogen-sulfur bond and formed C4 ligand and tosylate ligand. So, if it has lone pair electron next to carbon-carbon triple bond, it can react with dimodybedenum quintuple bonded. However, reactions of complex 1 with internal alkyne and terminal alkyne are [2+2+2] cycloaddition reactions. First, reaction of complex 1 with diphenylacetylene or phenylpropyne gives four-membered complex for [2+2] cycloaddition reaction, Mo2(μ-κ2-RCCPh)[μ-κ2-HC(N-2,6-iPr2C6H3)2]2 (R = Ph (10), Me (14)). Respectively, reactions of complex 10 or complex 14 with 1-pentyne, phenylacetylene, or ethyl propiolate always give six-member complexes, Mo2[μ-κ2-3,4-Ph2-6-RC4H][μ-κ2-HC(N-2,6-iPr2C6H3)2]2 (R = Pr (11), Ph (12), COOEt (13)), Mo2[μ-κ2-3-Ph-4-Me-6-RC4H][μ-κ2-HC(N-2,6-iPr2C6H3)2]2 (R = Pr (15), Ph (16)) and Mo2[μ-κ2-3-R-6-Me-5-PhC4H][μ-κ2-HC(N-2,6-iPr2C6H3)2]2 (R = Ph (15), COOEt (16)). In addition to evidence of complex 11-13, the stereo orientation of terminal alkyne is affented by steric hindrance. In addition to evidence of complex 15-18, the stereo orientation of internal alkyne affected by electronic effect. In short, the electronic effect controls the stereo orientation of first alkyne and the steric effect controls the stereo orientation of second alkyne. In addition, the reaction of complex 10 with pivalonitrile gives complex, Mo2(trans-2-styryl-C6H5)[μ-κ2-HC(N-2,6-iPr2C6H3)(N-2-iPr-6-CH(κ1-CH2)CH3-C6H3)][μ-κ2-HC(N-2,6-iPr2C6H3)2] (21), in which the ortho-activated diphenylethene group coordinates to Mo center. The reaction of complex 10 with benzaldehyde gives six-membered complex, Mo2(H)[μ-κ2-O(PhC)2PhC][μ-κ2-HC(N-2,6-iPr2C6H3)2]2 (22). From this reaction, we can know the electron-rich diphenylacetylene attacks to electron-withdrawing carbon of benzaldehyde by nucleophilic addition. Finally, The reaction of six-membered complex Mo2[μ-κ2-3,5-Pr2C4H2][μ-κ2-HC(N-2,6-iPr2C6H3)2]2 (24a) with Fe2(CO)9 or acetonitrile give two complexes, Mo2(CO)[μ-κ2-3,5-Pr2C4H2][μ-κ2-HC(N-2,6-iPr2C6H3)2]2 (24b), in which a carbon oxide coordinates to Mo center, and Mo2(MeCN)2[μ-κ2-3,5-Pr2C4H2][μ-κ2-HC(N-2,6-iPr2C6H3)2]2 (24c), in which acetonitrile coordinates to Mo centers, respectively. Two reactions are reversible reaction. The molecular structures of complex 24b and complex 24c are determined by X-ray crystallography. The carbon-molybdenum bond is elongated. Because d-orbital electron contributes to back bonding of carbon oxide or acetonitrile, and little contributes to d-electron of six-membered ring.
In addition, the reaction of complex 1 with tetrachloroethylene gives complex, Mo2(Cl)2[μ-κ2-HC(N-2,6-iPr2C6H3)2][μ-κ2-HC(N-2,6-iPr2C6H3) (N-2-iPr-6-C(κ1-CCH)(CH3)2C6H3)] (26), in which bent vinylidene ligand coordinates to a Mo center. We are interested in reactivity of 26.

並列關鍵字

Mo-Mo Quintuple Bonded ； [2+2+2] Cycloaddition

參考文獻

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