含鈣及鐿之雙鉻金屬錯合物之反應性研究

Preparation and Reactivity Study of Ca- and Yb-Containing Heterotrinuclear Complexes with a Cr-Cr Quintuple Bond

張雅惠(Ya-Hui Chang)

指導教授 ： 蔡易州

國立清華大學/理學院/化學系/碩士(2014年)

摘要

本論文利用[N2Ndipp](N2Ndipp = 4-methyl-2,6-(NDipp)2pyridine)(Dipp = iPr2-C6H3)作為配基，將錯合物 [(OEt2)KCr(κ1:κ2-N2Ndipp)]2 (1)與碘化鈣反應，合成出含鈣的鉻-鉻五重鍵錯合物，{Ca(THF)2Cr2[μ3-κ1:κ2-(N2Ndipp)2]} (2)，我們將2與小分子反應，可得到許多新穎的化合物。將2與多種有機疊氮小分子進行反應，其中，與對甲基苯疊氮反應，得到{Ca[Cr(p-tolylN)(μ-p-tolylN)]2[μ3-κ1:κ2-(N2Ndipp)2]} (4)，分別有兩分子的對甲基苯亞胺基以橋接及端點的方式配位於雙鉻金屬上；與三甲基矽烷疊氮反應，則得到{(μ-THF)[Cr2Ca(μ-TMSN)2][μ3-κ1:κ2-(N2Ndipp)2]} (5)，有兩分子的三甲基矽基亞胺基以橋接的方式鍵結於雙鉻金屬上；與1-金剛烷疊氮反應，則得到{Ca(1AdN)Cr(μ-1AdN)2Cr[μ3-κ1:κ2-(N2Ndipp)2]} (6)，為兩分子的1-金剛烷亞胺基橋接於雙鉻金屬上，另有一分子的亞胺基配位於一鉻金屬上。之後，我們將1與YbI2(THF)2反應，得到{Yb(THF)2Cr2[μ3-κ1:κ2-(N2Ndipp)2]} (3)，並且將此與三甲基矽烷疊氮反應，得到{[YbCr2(μ-TMSN)3][μ3-κ1:κ2-(N2Ndipp)2]} (7)，此結構與錯合物5類似，且三金屬皆經由三甲基矽基亞胺基的氮原子橋接於一起。而後，將2與二苯基鋅反應，得到{(THF)Ca[Cr(η1-C6H5)]2[μ3-κ1:κ2-(N2Ndipp)2]} (8)，為二苯基鋅的兩片苯環以端點的方式配位於雙鉻金屬上，與碳-碳多重鍵於有機合成反應常進行的碳-鋅加成反應不同。
將Li2[N2Nmes](mes = 2,4,6-(CH3)3C6H2)作為配基與氯化亞鉻進行反應，可以得到Cr2[μ3-κ1:κ2-(N2Nmes)2]3 (9)，為三片配基橋接於雙鉻金屬上的結構。試圖將9進行還原，無法分離出逆磁性的產物，故我們將Li2[N2Nmes]與氯化鉻反應，得到{[(Cl)Cr(μ-Cl)Cr(THF)][μ3-κ1:κ2-(N2Nmes)2]} (10)，為兩片配基橋接於雙鉻金屬上，其中，雙鉻金屬間有一氯原子橋接其中，另有一氯原子以端點方式鍵結於鉻金屬上。然而，我們將10進行還原，發現會先經過一橘色中間物，再經過9，最後得到褐色的產物，亦無法分離出可能為五重鍵的產物。

關鍵字

金屬五重鍵 ； 雙鉻五重鍵

並列摘要

The low-valent and low-coordinate quintuply-bonded dichromium complex, [(OEt2)KCr(κ1:κ2-N2Ndipp)]2 (1) was supported by the sterically hindered three-nitrogen donor ligand, Li2[N2Ndipp](N2Ndipp= 4-methyl-2,6-(NDipp)2pyridine) (Dipp = 2, 6-iPr2-C6H3). Treatment of 1 with 1 equiv of CaI2 leads to the formation of the hetereotrinuclear metal complex, {Ca(THF)2Cr2[μ3-κ1:κ2-(N2Ndipp)2]} (2), with the Cr-Cr quintuple bond retained. Treatment of 2 with organic azides gives Cr imido complexes. Reaction of 2 with p-tolyl azide gives {Ca[Cr(p-tolylN)(μ-p-tolylN)]2[μ3-κ1:κ2-(N2Ndipp)2]} (4), in which two imido groups bridge and two imido groups chelate to chromium atoms. Treatment of 2 with trimethylsilyl azide produces the complex, {(μ-THF)[Cr2Ca(μ-TMSN)2][μ3-κ1:κ2-(N2Ndipp)2]} (5). Reaction of 2 with 1-adamantyl azide generates the complex, {Ca(1AdN)Cr(μ-1AdN)2Cr[μ3-κ1:κ2-(N2Ndipp)2]} (6). For comparison, we carry out the reaction of 1 with YbI2(THF)2 to give rise to the formation of {Yb(THF)2Cr2[μ3-κ1:κ2-(N2Ndipp)2]} (3), which is confirmed by the 1H NMR spectroscopy. Treatment of 3 with trimethylsilyl azide leads to the isolation of {[YbCr2(μ-TMSN)3][μ3-κ1:κ2-(N2Ndipp)2]} (7), which is structurally similar to 5. The three metal centers of 5 and 7 are bound via the nitrogen atom of a trimethylsilyl imido group. Moreover, the bonding fashion of N2Ndipp in its product is transformed from bridging to chelating. In addition, treatment of 2 with diphenylzinc generates the complex, {(THF)Ca[Cr(η1-C6H5)]2[μ3-κ1:κ2-(N2Ndipp)2]} (8), in which both phenyl rings are terminally coordinated to chromium atoms. The result is different from the carbozincation of alkynes and alkenes.
In the second part of this thesis, treatment of Li2[N2Nmes](Mes = 2,4,6-CH3C6H2) with CrCl3 leads to the formation of Cr2[μ3-κ1:κ2-(N2Nmes)2]3 (9), where two Cr atoms are spanned by three N2Nmes ligands. However, we could not obtain the diamagnetic product upon reduction of 9. Afterwards, treatment of Li2[N2Nmes] with CrCl2 generates the complex, {[(Cl)Cr(μ-Cl)Cr(THF)][μ3-κ1:κ2-(N2Nmes)2]} (10), in which two Cr atoms are ligated bridged by two N2Nmes ligands. Nevertheless, stepwise reduction of 10 generates orange intermediate, and then leads to the formation of 9. The isolation of the diamagnetic product is still not achieved.

並列關鍵字

Cr-Cr quintuple bond

參考文獻

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