請用此 Handle URI 來引用此文件:
http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/27639
標題: | 含吡啶基或末端烯基之釕金屬亞乙烯基化合物的合成及相關反應 Synthesis and Related Reactions of Ruthenium Vinylidene Complexes Containing a Pyridyl or a Terminal Vinyl Group |
作者: | Hsien-Hsin Chou 周憲辛 |
指導教授: | 林英智(Ying-Chih Lin) |
關鍵字: | 亞乙烯基,釕,重排反應,密度泛函理論, vinylidene,ruthenium,rearrangement,density functional theory, |
出版年 : | 2007 |
學位: | 博士 |
摘要: | 在本篇論文中,我們研究了含吡啶基或末端烯基的半三明治釕金屬炔基錯合物與亞乙烯基錯合物的反應性。我們製備了一系列含吡啶官能基的釕金屬炔基錯合物。其中炔基錯合物Cp(PPh3)2RuC≡C(C5H3RN)(R=H,1a;Me,1b)可以進行質子化與烷基化反應或與路易士酸作用而得到吡啶基亞乙烯基錯合物{Cp(PPh3)2Ru=C=C(H)(C5H3RNH)}+ ( 4a 、4b ) 與吡啶基炔基錯合物Cp(PPh3)2RuC≡C(C5H3RN)→R’(R’=BF3、BH3,3a-3c;R’=烷基,8a-8k)。在溶液狀態中, 化合物3 與4 會自發性的轉換成烷氧基碳烯錯合物{Cp(PPh3)2Ru=C(O)CH2(C5H4N→BF2)}+(6)。很明顯地,來自溶液或空氣中少量的水導致了這樣的轉換反應。密度泛函理論計算顯示出在模擬系統中這類的轉換是一個放熱反應(-23.09 仟卡�莫耳)。另外,有部份的吡啶基炔基錯合物{Cp(PPh3)2RuC≡C(C5H4NCH2R)}+(R=CO2Me,8d;R=Ph,8i)可進一步進行質子化反應而得到吡啶基亞乙烯基錯合物{Cp(PPh3)2Ru=C=C(H)(C5H4NCH2R)2+ ( 9d 、9i )。而化合物8g ( R =trans-CH=C(H)CO2Me)在空氣中,可以對乙炔基的β 碳與烷基上的碳-碳雙鍵進行偶合反應而得到{Cp(PPh3)2Ru=C=C(C5H4N)CH2CH CH2CO2Me}2+(10a)。
在KPF6 的存在下,當Cp*(PPh3)2RuCl 與鄰-乙炔基吡啶或鄰-氰基吡啶反應會分別得到釕五元環的化合物{Cp*(PPh3)Ru(κ2-C,N-C(H)=C(PPh3)(C5H4N))}PF6 (11a)與{Cp*(PPh3)Ru(κ2-C,N-N(H)=C(OMe)(C5H4N))}PF6(11b)。在雙電子配位基的存在下,對中性的亞乙烯基錯合物Cp*(PPh3)(Cl)Ru=C=C(H)R(12a,R=Ph)進行去質子化會得到炔基錯合物Cp*(PPh3)(L)RuC≡CPh(13a-13c,L=CO、PEt3、CNtBu)。另一方面,在鹵烷基的存在下對中性的亞乙烯基 錯合物12a 與12b(R=nBu)去質子化則得到不對稱的中性亞乙烯基錯合物Cp*(PPh3)(X)Ru=C=C(R)CH2R’(14a-14g,R=Ph、nBu;X=Cl、Br;R’=Ph,C6F5 、C6H4-p-CN 、CH=C(Me)2 ) 。而不對稱的離子性亞乙烯基錯合物{Cp*(PPh3)(L)Ru=C=C(R)CH2R’}X (15a-15g,L=PEt3、CNtBu;R=Ph、nBu;R’=Ph、C6F5、C6H4-p-CN、CH=C(Me)2)可以藉由炔基錯合物13b 或13c 與鹵烷基反應而得到。 我們也製備了一系列的五甲基茂基( Cp* ) 釕金屬亞乙烯基錯合物Cp*(L)2Ru=C=C(H)C(Ar)2CH2R}BF4(20a-20l,L=PPh3、dppe;2Ar=2Ph、2,2’-芴基、2(C6H4-p-OMe);R=CH=CH2、C(Me)=CH2、C≡CH、CH2CH2CH=CH2)。在室溫或是高溫的氯甲烷中, 含末端炔基的化合物{Cp*(PPh3)2Ru=C=C(H)C(Ph)2CH2CH=CH2}+ ( 20a ) 會緩慢轉變成化合物{Cp*(PPh3)RuC(H)=C(PPh3)C(Ph)2CH2(η2-CH=CH2)}+(25a)。進一步由二維核磁共振光譜COSY 的HSQC 技術鑑定發現,在這樣的轉變過程中產生一個中間物{Cp*(PPh3)Ru(η2-HC≡C)C(Ph)2CH2(η2-CH=CH2)}+(25a)。在含25a 的溶液中加入亞磷酸三苯酯會得到24a 與另一釕環化合物{Cp*(P(OPh)3)RuC(H)=C(PPh3)C (Ph)2CH2(η2-CH=CH2)}+(25c)的混合物以1:1.5 的比例存在。然而,含甲基的衍生物20b 與20h 並沒有類似的反應。在室溫的丙酮溶液中,化合物{Cp*(dppe)Ru=C=C(H)C(Ph)2C(Me)=CH2}+(20h)會轉變成含環狀丙二烯基官能基配位的化合物{Cp*(dppe)Ru(η2-C(H)MeC(H)=C=C(H)C(Ph)2CH2)}+(27a)。在雙電子配位基如亞磷酸三苯酯、第三丁基氰、乙氰或一氧化碳的存在下, 化合物{Cp*(PPh3)2Ru=C=C(H)C(Ph)2CH2C(R)=CH2}+(R=H,20a;Me,20b)會反應產生{Cp*(PPh3)RuLL’} BF4(22a-22d,L、L’=P(OPh)3、CNtBu、NCMe、CO)與1,5-烯炔化合物。這類化合物中,五甲基茂基的立體效應可能對磷配位基的離去與加成扮演著重要的角色,這是在茂基釕化合物(Cp(PR3)2Ru)的系統中所未見到的。 另一方面,將化合物{Cp*(dppe)Ru=C=C(H)C(Ar)2CH2CH=CH2}+(20j,Ar = C6H4-p-OMe ) 在四氫啉呋喃中加熱至沸騰會得到骨架重排的產物{Cp*(dppe)Ru=C=C(H)CH2C(Ar)2CH=CH2}+(28b)。這樣的骨架重排反應先前已在茂基二磷基釕化合物(Cp(PR3)2Ru)的系統中被發現。密度泛函理論的計算顯示這類的重排反應在模擬系統中放熱了1.55 仟卡�莫耳,並且可能經過一個含二環[2.1.1]己烷的釕金屬中間產物(Ibcl)。同時我們也檢視了另一種牽涉到含環己烯官能基(Icy、Icy’)或連環官能基(I35、I35’)的中間產物的反應機構的可能性。將亞乙烯基錯合物( 28a - 28b ) 進行去質子化會產生炔基錯合物Cp*(dppe)RuC≡CCH2C(Ar)2CH=CH(Ar=Ph,29a;Ar=C6H4-p-OMe,29b)。進一步對此類炔基錯合物進行甲基化反應則得到另一類的亞乙烯基錯合物{Cp*(dppe)Ru=C=C(Me)C(Ar)2CH=CH2}OTf(Ar=Ph,30a)。化合物30a 相當的穩定,即便是在高溫下我們也沒有觀察到重排反應的產物的生成。 In this thesis, we investigated versatile reactivities of the half-sandwiched ruthenium acetylides, vinylidenes containing pyridyl or terminal vinyl group. We have prepared a series of ruthenium acetylides and vinylidenes containing pyridyl functional group. The ruthenium acetylides Cp(PPh3)2RuC≡C(C5H3RN) (R = H, 1a; Me, 1b) can undergo protonation, Lewis-acid interaction and alkylation to give the corresponding pyridiniumvinylidenes {Cp(PPh3)2Ru=C=C(H)(C5H3RNH)}+ (4a-4b) and pyridiniumacetylides Cp(PPh3)2RuC≡C(C5H3RN)→R’ (R’ = BF3 or BH3, 3a-3c; R’ = alkyl groups, 8a-8k), respectively. Both solution states of 3 and 4 will spontaneously decompose into the cationic alkoxycarbene complexes {Cp(PPh3)2Ru=C(O)CH2(C5H4N→BF2)}+ (6). These processes possibly involve an intermediate {Cp(PPh3)2Ru=C=C(H)(C5H3RN→BF2OH)}+ (5), which then undergo thermal rearrangement to yield alkoxycarbene complexes 6. The trace water in the solvent or in the ambient atmosphere appears to cause this decomposition. DFT calculations show that this transformation is a highly exothermic process (-23.09 kcal/mol). Some of the pyridiniumacetylides {Cp(PPh3)2RuC≡C(C5H3RNCH2R’)}+ (R = Me, R’= CO2Me, 8d; R = Me, R = Ph, 8i) can undergo further protonation to give pyridiniumvinylidene complexes {Cp(PPh3)2Ru=C=C(H)(C5H3RNCH2R’)2+ (9d, 9i). While complex 8g (R = Me, R’ = trans-CH=C(H)CO2Me) can undergo C-C coupling reaction of the acetylic β-carbon with alkylated olefin C=C double bond to give {Cp(PPh3)2Ru=C=C(C5H3RN)CH2CHCH2CO2Me}2+ (10a) in the air. Reactions of Cp*(PPh3)2RuCl with 2-ethynylpyridine or 2-cyanopyridine in the presence of KPF6 lead to formation of five-membered ruthenacyclic products Cp*(PPh3)Ru(κ2-C,N-C(H)=C(PPh3)(C5H4N))}PF6- (11a) and Cp*(PPh3)Ru(κ2-C,NNH)=C(OMe)(C5H4N))}PF6 (11b), respectively. Deprotonation of neutral vinylidenes Cp*(PPh3)(Cl)Ru=C=C(H)R (12a, R = Ph) in the presence of 2-electron donors give the neutral acetylides Cp*(PPh3)(L)RuC≡CPh (13a-13c, L = CO, PEt3, CNtBu). On the other hand, deprotonation of neutral vinylidenes 12a and 12b (R = nBu) in the presence of alkyl halides gives the asymmetric neutral vinylidenes Cp*(PPh3)(X)Ru=C=C(R)CH2R’ (14a-14g, R = Ph, nBu; X = Cl, Br; R’ = Ph, C6F5, C6H4-p-CN, CH=C(Me)2). The asymmetric cationic vinylidenes can be achieved via reaction of acetylides 13b and 13c with alkyl halides to give {Cp*(PPh3)(L)Ru=C=C(R)CH2R’}X (15a-15g, L = PEt3, CNtBu; R = Ph, nBu; R’= Ph, C6F5, C6H4-p-CN, CH=C(Me)2). A series of (pentamethylcyclopentadienyl)ruthenium vinylidene complexes {Cp*(L)2Ru=C=C(H)C(Ar)2CH2R}BF4 (20a-20l, L= PPh3, dppe; 2Ar = 2Ph, 2,2'-fluorenyl, 2(C6H4-p-OMe); R = CH=CH2, C(Me)=CH2, C≡CH, CH2CH2CH=CH2) was prepared. In chloroform complex {Cp*(PPh3)2Ru=C=C(H)C(Ph)2CH2CH=CH2}+ (20a) containing terminal vinyl group gradually transforms into {Cp*(PPh3)RuC(H)=C(PPh3)C(Ph)2CH2(η2-CH=CH2)}+ (25a) either at room or elevated temperature. Further monitoring indicates this transformation proceeds via formation of an intermediate {Cp*(PPh3)Ru(η2-HC≡C)C(Ph)2CH2(η2-CH=CH2)}+ (25a), which has been characterized by 2D NMR COSY and HSQC determination at 0oC. Addition of P(OPh)3 into solution of 25a give a mixture of 24a and another ruthenacyclic product {Cp*(P(OPh)3)RuC(H)=C(PPh3)C(Ph)2CH2(η2-CH=CH2)}+ (25c) in a ratio of 1:1.5. However, the methyl derivative 20a and 20h does not follow the same route. At room temperature the acetone solution of {Cp*(dppe)Ru=C=C(H)C(Ph)2CH2C(Me)=CH2}+ (20h) spontaneously transform into complex {Cp*(dppe)Ru(η2-C(H)MeC(H)=C=C(H)C(Ph)2CH2)}+ (27a) which containing coordinated cylic allene. In the presence of two-electron donors, such as P(OPh)3, CNtBu, acetonitrile or CO, complexes {Cp*(PPh3)2Ru=C=C(H)C(Ph)2CH2C(R)=CH2}+ (R = H, 20a; Me, 20b) in solution leads extrusion of 1,5-enyne ligands and {Cp*(PPh3)RuLL’}BF4 (22a-22d, L, L’ = P(OPh)3, CNtBu, NCMe, CO) were obtained. The more steric demanding Cp* ligand of these complexes probably plays important role in this phosphine dissociation-addition process, which was absent in the corresponding (cyclopentadienyl)ruthenium system. On the other hand, heating a THF solution of {Cp*(dppe)Ru=C=C(H)C(Ar)2CH2 CH=CH2}+ (20j, Ar = C6H4-p-OMe) at reflux give the skeletal rearrangement product {Cp*(dppe)Ru=C=C(H)CH2C(Ar)2CH=CH2}+ (28b). Deprotonation of the vinylidene complexes (28a-28b) causes acetylide complexes Cp*(dppe)RuC≡CCH2C(Ar)2CH=CH (Ar = Ph, 29a; Ar = C6H4-p-OMe, 29b). Further methylation of these acetylides give another vinylidene complexes {Cp*(dppe)Ru=C=C(Me)C(Ar)2CH=CH2}OTf (Ar = Ph, 30a). However, the vinylidene complex 30a is sufficiently stable toward rearrangement to give other products even under elevated temperature. Similar rearrangement process has earlier been experimentally observed in the Cp(PR3)2Ru system. Here we intend to theoretically analyze this rearrangement. DFT calculations show that this rearrangement is slightly exothermic for -1.55 kcal/mol, which possibly involves an ruthenium bicyclo[2.1.1]hexan-5-ylidene intermediate (Ibcl). Alternatively, another mechanism which involves formation of intermediates containing cyclohexenyl (Icy, Icy’) or fused-ring ligands (I35, I35’) has also been examined. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/27639 |
全文授權: | 有償授權 |
顯示於系所單位: | 化學系 |
文件中的檔案:
檔案 | 大小 | 格式 | |
---|---|---|---|
ntu-96-1.pdf 目前未授權公開取用 | 16.75 MB | Adobe PDF |
系統中的文件,除了特別指名其著作權條款之外,均受到著作權保護,並且保留所有的權利。