雙鎢金屬多重鍵化合物之合成及其反應性研究

Synthesis and Reactivity of Multiply-Bonded Ditungsten Complexes

林展民

指導教授 ： 蔡易州

國立清華大學/理學院/化學系/碩士(2013年)

https://doi.org/10.6843/NTHU.2013.00389

摘要

化合物[Li(THF)4]{W2Cl4[μ-η2-HC(N-2,6-iPr2C6H3)2]2} (1a)與碘化鉀及18-crown-6 ether (冠狀醚)進行陽離子交換可得到化合物
[K(18-c-6)]{W2Cl4[μ-η2-HC(N-2,6-iPr2C6H3)2]2} (2)，將化合物2以KC8進一步還原可得一進行甲基的碳-氫鍵氧化加成反應且有兩個鉀原子橋接在雙鎢(II)間的金屬四重鍵化合物W2H2[μ-K(OEt2)]2[μ-η2-HC(N-
2,6-iPr2C6H3)(N-2-iPr2-6-CH(1-CH2)CH3-C6H3)]2 (3)。將化合物3與四氫呋喃反應可得到同樣進行甲基的碳-氫鍵氧化加成反應且有兩個氫原子橋接在雙鎢(III)間的金屬三重鍵化合物W2(μ-H)2(THF)[μ-η2-HC
(N-2,6-iPr2C6H3)(N-2-iPr2-6-CH(1-CH2)CH3-C6H3)]2 (1e)。而用KC8可將化合物1e還原成化合物3，兩者間為可逆的。
化合物1e和3與兩當量的2,4,6-三甲基苯甲腈反應，皆可得到W2(μ-H)2[1-NC(Mes)]2[μ-η2-HC(N-2,6-iPr2C6H3)(N-2-iPr2-6-CH(1-CH2)CH3-C6H3)]2 (4)，其苯甲腈以氮原子配位至鎢金屬上。化合物1e和3與兩當量的二苯基鋅反應，皆可得到W2H2[μ-ZnC6H5]2[μ-η2-HC(N-
2,6-iPr2C6H3)(N-2-iPr2-6-CH(1-CH2)CH3-C6H3)]2 (5)，其苯基鋅以架橋形式配位至雙鎢金屬間。化合物3與二乙基氯化鋁反應，可得到
[K(OEt2)4]W2H2(μ-AlEt2)[μ-η2-HC(N-2,6-iPr2C6H3)(N-2-iPr2-6-CH(1-
CH2)CH3-C6H3)]2 (6)，其二乙基鋁與鉀進行陽離子置換，以架橋形式配位至雙鎢金屬間。
將WCl4(DME)與兩當量雙氮基脒配基Li[HC(N-2,6-Et2C6H3)2]反應不同時間，可得到順磁性鎢(IV)化合物W[η3-Cl2Li(OEt2)N(2,6-Et2C6
H3)C(H)N(2,6-Et2C6H3)]2 (7)及順磁性鎢(IV)化合物WCl2[η2-HC(N-
2,6-Et2C6H3)2]2 (8)，化合物7脫去兩分子的LiCl，而形成化合物8。將化合物8與一當量的WCl4(DME)反應，可得到順磁性鎢(V)化合物WCl3[η2-HC(N-2,6-Et2C6H3)2]2 (9)。將WCl3(DME)與一當量雙氮基脒配基Li[HC(N-2,6-Et2C6H3)2]2反應，可得到一具有氧原子橋接在雙鎢金屬間的W2Cl2(μ-O)(μ-Cl) [η2-ClLi(OEt2)2Cl][η2-HC(N-2,6-Et2C6H3)2]
[μ-η2-HC(N-2,6-Et2C6H3)2] (10)，將化合物10進一步還原可得到W2(μ-Cl)(μ-CH)(1-N-2,6-Et2C6H3)2[η2-HC(N-2,6-Et2C6H3)2]2 (11)及W4(μ-Cl)4[μ-η2-HC(N-2,6-Et2C6H3)2]4 (12)，化合物11將一分子的雙氮基脒配基進行三原子六電子的切割反應，methylidyne橋接於雙鎢金屬間，兩個imido以terminal的形式配位至鎢金屬上。化合物12為四個鎢(II)金屬以四個氯原子橋接的四重鍵化合物。將化合物10與一當量的雙氮基脒配基Li[HC(N-2,6-Et2C6H3)2]2反應，可得到W2Cl2
(μ-O)(μ-Cl)[η2-HC(N-2,6-Et2C6H3)2]2[μ-η2-HC(N-2,6-Et2C6H3)2] (13)，將化合物13進一步還原可得W2[μ-O(KOEt2)](μ-CH)(1-N-2,6-Et2C6H3)2
[η2-HC(N-2,6-Et2C6H3)2]2 (14)，化合物14與化合物11同樣將雙氮基脒配基進行三原子六電子的切割反應，形成methylidyne的化合物。

關鍵字

雙鎢金屬多重鍵

並列摘要

The cation exchange between [Li(THF)4]{W2Cl4[μ-η2-HC(N-2,6-iPr2
C6H3)2]2} (1a) and KI in the presence of 18-crown-6 ether affords [K(18-c-6)]{W2Cl4[μ-η2-HC(N-2,6-iPr2C6H3)2]2} (2). Subsequent reduction of 2 gives the quadruply-bonded ditungsten(II) complex W2H2[μ-K(OEt2)]2[μ-η2-HC(N-2,6-iPr2C6H3)(N-2-iPr2-6-CH(1-CH2)CH3-C6H3)]2 (3), which is arisen from double intramolecular C-H bond activation and features two potassium counter-cations. Dissolution of 2 in THF affords W2(μ-H)2(THF)[μ-η2-HC(N-2,6-iPr2C6H3)(N-2-iPr2-6-CH(1
-CH2)CH3-C6H3)]2 (1e), which displays a gem conformation with two hydrido ligands unsymmetrically bridging two tungsten centers. Complexes 1e and 3 are chemically interconvertible. Reduction of 1e by KC8 gives back to 3.
Treatment of 1e or 3 with 2 equiv of mesityl nitrile yields W2(μ-H)2 [1-NC(Mes)]2[μ-η2-HC(N-2,6-iPr2C6H3)(N-2-iPr2-6-CH(1-CH2)CH3
-C6H3)]2 (4), where the nitrogen donor atom of mesityl nitrile coordinates tungsten centers. Reaction of 1e or 3 with 2 equiv of diphenylzinc generates the hetero tetranuclear complex W2H2[μ-ZnC6H5]2[μ-η2-HC(N-
2,6-iPr2C6H3)(N-2-iPr2-6-CH(1-CH2)CH3-C6H3)]2 (5), whereby phenyl zinc bridges two tungsten atoms. Addition of 1 equiv of AlEt2Cl to 3 yields [K(OEt2)4]W2H2(μ-AlEt2)[μ-η2-HC(N-2,6-iPr2C6H3)(N-2-iPr2-6-CH
(1-CH2)CH3-C6H3)]2 (6), whereby diethyl aluminum group bridges two tungsten centers.
Reactions of WCl4(DME) with 2 equiv of lithiated amidinate Li[HC(N-2,6-Et2C6H3)2] in different time periods afford two mononuclear complexes W[η3-Cl2Li(OEt2)N(2,6-Et2C6H3)C(H)N(2,6-
Et2C6H3)]2 (7) and WCl2[η2-HC(N-2,6-Et2C6H3)2]2 (8). Complex 8 can be thought of LiCl extrusion from 7. Upon treatment of 8 with 1 equiv of WCl4(DME), the mononuclear penta-valent tungsten complex WCl3[η2-
HC(N-2,6-Et2C6H3)2]2 (9) is obtained.
On the other hand, the reaction of WCl3(DME) with 1 equiv of Li[HC(N-2,6-Et2C6H3)2] affords the dinuclear “-ate” complex W2Cl2
(μ-O)(μ-Cl)[η2-ClLi(OEt2)2Cl][η2-HC(N-2,6-Et2C6H3)2] [μ-η2-HC(N-
2,6-Et2C6H3)2] (10), which features an oxygen atom bridging two tungsten centers. Subsequent reduction of 10 gives the methylidyne complex W2(μ-Cl)(μ-CH)(1-N-2,6-Et2C6H3)2[η2-HC(N-2,6-Et2C6H3)2]2
(11) and the tetranuclear complex W4(μ-Cl)4[μ-η2-HC(N-2,6-Et2C6H3)2]4 (12). Complex 11 is formed through a three-atom 6e reductive cleavage of the amidinate to give a bis-terminal imido and bridging methylidyne ditungsten complex. Complex 12 is the quadruply-bonded complex, which has four tungsten(II) centers with four chloride atoms bridging to the tungsten centers. Further reaction of 10 with 1 equiv of Li[HC(N-2,6-Et2C6H3)2] affords W2Cl2(μ-O)(μ-Cl)[η2-HC(N-2,6-Et2C6
H3)2]2[μ-η2-HC(N-2,6-Et2C6H3)2] (13). Subsequent reduction of 13 also induces the cleavage of the amidinato ligand to give the methylidyne complex W2[μ-O(KOEt2)](μ-CH)(1-N-2,6-Et2C6H3)2[η2-HC(N-2,6-Et2
C6H3)2]2 (14).

並列關鍵字

Multiply-Bonded Ditungsten Complexes

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