Cyclopentadienyldicarbonyliron Halides as Electrophiles: A Study on the Reactions of CpFe(CO)_2X with PhLi in the Presence of PPh_3 to Produce (PhC_5H_5)Fe(CO)_2(PPh_3) and (C_5H_5)Fe(CO)(PPh_3)C(O)Ph

環戊二烯二羰鐵鹵化物供作親電子基：從1：1CpFe(CO)_2X/PPh_3與PhLi反應生成(PhC_5H_5)Fe(CO)_2(PPh_3)和(C_5H_5)Fe(CO)(PPh_3)C(O)Ph之路徑研究

劉陵崗(Ling-Kang Liu) ； 陸龍翔(Lung-Shiang Luh)

《中央研究院化學研究所集刊》 41期 (1994/03) Pp. 39-50

https://doi.org/10.6522/BICAS.1994.41.6

摘要

在四氫呋喃，-78 °C條件下，相等莫耳數之CpFe(CO)_2X和PPh_3，混合液加入一當量PhLi生成(exo-η^4-PhC_5H_5)Fe(CO)_2(PPh_3)，1，(η^5- C_5H_5)Fe(CO)(PPh_3)C(O)Ph，2，和[(η^5-C_5H_5)Fe(CO)_2]_2，3。根據加入之鹵化物各自結果不相同X = I時產率1:70.9%，2:3.6%，X = Br時，1:59.1%，2:7.8%；X = CI時1:47.2%，2:19.1%。每個反應都產生＜1%之3。在反應系中生成之3咸信為觸媒將CpFe(CO)_2X 和PPh_3，轉化成正離子之中間物[CpFe(CO)_2/PPh_3)]^+其與Ph^-迅速反應使得Ph基加成在Cp環上exo位置產生1。若Ph^-直接攻擊中性之CpFe(CO)_2X上的CO配位子則產生2。對化合物1和2均完成單晶構造解析，結果也證實了1的Cp環上的Ph取代基在exo位置。1的Ph加成至Cp環上，2的Ph加成至CO基上，1與2為同分異構物其相異之處不但在Ph基的位置，更在於環戊二烯基與Fe之鍵結方式。晶體數據：1，C_(31)H_(25)FeO_2P，斜方晶系Pbca，a 10.336(2), b 18.747(3), c 26.94 7(4)Å V = 5222(2) Å^3，Z = 8，R = 0.035, R_w = 0.035，GOF = 1.66使用60個原子，316變數和2732觀測點[I_0 ＞ 2.5σ(I_0)]。2，C_(31)H_(25)FeO_2P，單斜晶系P2_1/n，a 8.054(1), b 18.698(1 ), c 16.445(2) Å，β 95.08(1)°，V = 266.8(5)Å^3，Z = 4, R = 0.032, R_w = 0.037，GOF = 1.76使用60個原子，316變數和2534觀測點[I_0 ＞ 2.5σ(I_0)]。

並列摘要

Treatment of an equi-molar amount of CpFe(CO)_2X and PPh_3 in THF at -78 °C with one molar equivalent of PhLi produces (exo-η^4-PhC_5H_5)Fe(CO)_2(PPh_3) 1, (η^5- C_5H_5)Fe(CO)(PPh_3)C(O)Ph 2, and [(η^5- C_5H_5)Fe(CO)_2]_2 3. The yields of 1-3 depend on halides. When X=I, complex 1 (70.9%) and 2 (3.6%) were isolated. When X=Br, complex 1 (59.1 %) and 2 (7.8%) were isolated. When X=CI, complex 1 (47.2%) and 2 (19.1%) were isolated. In all cases, less than 1% of 3 was isolated. Generated in-situ, 3 is believed to be the catalyst in the conversion of CpFe(CO)_2X and PPh_3 to the cation [CpFe(CO)_2(PPh_3)^+ that is immediately attacked by Ph^- from an exo position at the Cp ring to give 1. Compound 2 probably results from a direct Ph^- attack at one of the CO ligands of the neutral CpFe(CO)_2X complex followed by a PPh_3 substitution of X^-. Both 1 and 2 have been studied with single crystal structure analysis, the results of which confirm the exo-Ph at the Cp ring in 1. As 1 has the Ph group added to the Cp ring and 2 has the Ph group added to the CO site, 1 and 2 are structural isomers, different in not only the positions of Ph group but interestingly Cp-Fe bonding modes. Crystal data: 1, C_(31)H_(25)FeO_2P, Orthorhombic Pbca, a 10.336(2), b 18.747(3), C 26947(4)Å, V = 5222(2)Å^3, Z = 8, R = 0.035, R_w = 0.035, GOF = 1.66 for 60 atoms, 316 parameters and 2732 observations [I_o ＞ 2.5σ(I_o)]. 2, C_(31)H_(25)FeO_2P, Monoclinic P2_1/n, a 8.054(1), b 18.698(1), c 16.445(2)Å, β 95.07(1)°, V = 2466.8(5)Å^3, Z = 4, R = 0.032, R_w = 0.037, GOF = 1.76 for 60 atoms, 316 parameters and 2534 observations [I_o, ＞ 2.5σ(I_o)].