新穎雙核釩(I)、鉻(I)和錳(I)錯合物的合成及化性研究

Novel Dinuclear V(I), Cr(I) and Mn(I) Complexes Supported by Nitrogen-Containing and Sterically Encumbered Ligand : Syntheses and Reactivity Study

王柏揚(Po-Yang Wang)

指導教授 ： 蔡易州

國立清華大學/理學院/化學系/碩士(2007年)

摘要

雙核皇帝魚式結構的M2[N2N]2錯合物，其中金屬(M)為釩(V)，鉻(Cr)，錳(Mn)或鉬(Mo)，[N2N]為4-methylpyridine(NC6H3-i-Pr2)2或pyridine(NSiMe3)2，已經被製備及完整的鑑定出來。包含了雙核Mn(I)的(K-18-crown-6){Mn2K[N2N]2}錯合物，其中Mn-K-Mn的特殊結構，被認為是一個利用三中心與二電子的鍵結模式。
雙核反三明治結構的(μ-η6:η6-Arene)[M(Nacnac)]錯合物，其中金屬(M)為釩(V)或鉻(Cr)，Nacnac為HC((CMe)NC6H3-i-Pr2)2，已經被製備及完整的鑑定出來。經由單晶X-ray繞射鑑定出雙核錯合物的結構，經由X-ray吸收光譜鑑定出每一個金屬的價數皆為一價。在固態中，錯合物(μ-η6:η6-Arene)[M(Nacnac)]都是利用對稱且六配位的甲苯或苯把左右二邊的[M(Nacnac)]橋接起來。在液態中，錯合物(μ-η6:η6-Arene)[V(Nacnac)]橋接的甲苯會解離開來；當用氘取代的甲苯或苯來置換原來橋接的甲苯時，可利用2H-NMR判斷出錯合物(μ-η6:η6-Arene)[Cr(Nacnac)]中橋接氘取代的甲苯或苯的訊號。儘管以上二種反三明治錯合物在液態時有不同現象，但其原理都是利用二個相同的[M(Nacnac)]來跟加入的基質產生反應及伴隨著中間橋接甲苯的脫去。例如二種錯合物跟有機疊氮化合物反應時都可脫去氮氣而得到bis(imido)的相關錯合物，也都可以藉由打斷azobenzene的N＝N雙鍵而得到imido的相關錯合物。二種反三明治錯合物與其他含氧或含氮的小分子也都有很好的反應性，合成與完整的鑑定出錯合物(μ-η6:η6-Arene)[M(Nacnac)]與O2，N2，N2O，PhCCH和PhCN等小分子反應得到的相關產物。因此，具高活性的二種特殊結構的反三明治錯合物，被認為是具有多電子的還原劑。

關鍵字

反三明治 ； 釩 ； 鉻 ； 錳 ； 三中心二電子 ； 還原斷裂 ； 多電子還原劑 ； 一價

並列摘要

Dinuclear commonsoles M2[N2N]2 where M ＝ V, Cr, Mn or Mo and [N2N] ＝ 4-methylpyridine(NC6H3-i-Pr2)2 or pyridine(NSiMe3)2 were prepared and fully characterized. We also report the isolation and structural characterization of the first complex having an Mn22+ core in (K-18-crown-6){Mn2K[N2N]2}. This Mn-K-Mn type of bonding, involving three atoms and two bonding electrons per bridge, is described as three-center, two-electron bonding.
Dinuclear inverted sandwiches (μ-η6:η6-Arene)[M(Nacnac)], where Arene ＝ toluene or benzene, M ＝ V, Cr, and Nacnac ＝ HC((CMe)NC6H3-i-Pr2)2 were prepared and fully characterized. Their dinuclear nature was confirmed by single crystal X-ray diffraction and the valency of each metal was determined to be I by X-ray absorption spectroscopy. Through arenes bridge two metal centers in a symmetrical η6, η6 fashion in solid state, the bridging arene ligands in (μ-η6:η6-Arene)[V(Nacnac)] tend to dissociate in solution, while the bridging mode of arene ligands in (μ-η6:η6-Arene)[Cr(Nacnac)] can be identified in solution by 2H-NMR spectroscopy when arenes were replaced by deuterated arenes. Despite their different behavior in solutions, both inverted sandwiches act as two [M(Nacnac)] synthetic equivalents when treated with appropriate substrates accompanied by the extrusion of arenes. For example, both complexes react with organic azides to produce bis(imido) complexes with the liberation of N2. They are also able to effect the cleavage of N-N double bonds of azobenzene and engendered the formation of imido complexes. Reaction of both inverted sandwiches with other substrates such as O2, N2, N2O, PhCCH, and PhCN will be covered as well. As a result, both inverted sandwiches behave as multi-electron reductants.

並列關鍵字

inverted sandwich ； vanadium ； chromium ； manganese ； 3c2e ； reductive cleavage ； multi-electron reductant ； univalence