Phosphine-Exchange Induced Intramolecular Substitution Reaction of [{(η^5-C_5H_5)Fe(CO)_2}_2(μ-η^1: η^1-PPh_2CH_2CH_2PPh_2)^(2+)][PF_6^-]_2

由膦基交換引發之[{(η^5-C_5H_5)Fe(CO)_2}_2(μ-η^1: η^1-PPh_2CH_2CH_2PPh_2)^(2+)][PF_6^-]_2分子內取代反應

彭震(James Peng) ； 劉陵崗(Ling-Kang Liu)

《中央研究院化學研究所集刊》 45期 (1998/03) Pp. 27-43

https://doi.org/10.6522/BICAS.1998.45.3

摘要

利用低溫下17-19e反應路徑可自2：1（η^5-C_5H_5）Fe（CO）_2I／dppe的THF溶液中順利製備出[{(η^5-C_5H_5)Fe(CO)_2}_2(μ-η^1: η^1-dppe)^(2+)][PF_6^-]_2。在固態中，陽離子[{(η^5-C_5H_5)Fe(CO)_2}_2(μ-η^1: η^1-dppe)^(2+)]以PF_6^-鹽或BPh_4^-鹽形式存在時，分子的構型會有差異，前者的兩個Fe中心會在P-C-C-P所鬆散定義的平面同側，後者Fe-P-C-C-P-Fe則完全反式。1：1[{(η^5-C_5H_5)Fe(CO)_2}_2(μ-η^1: η^1-dppe)^(2+)][PF_6^-]_2/dppe的CH_3CN溶液中，利用自由機制在分配，會形成2當量之[{(η^5-C_5H_5)Fe(CO)_2(η^1-dppe)^+][PF_6^-]，不過後續分子內CO解離反應將之全量轉化成為(η^5-C_5H_5)Fe(CO)(η^2-dppe)^+][PF_6^-]。

並列摘要

The preparation of [{η^5-C_5H_5)Fe(CO)_2}_2(μ-η^1: η^1-dppe)2^+][PF_6^-]_2, dppe = PPh_2CH_2CH_2PPh_2, was achieved starting from 2:1 (η^5-C_5H_5)Fe(CO)_2I/dppe in THF at low temperature employing the 17e-19e pathway. In the solid state the conformations for the [{η^5-C_5H_5)Fe(CO)_2}_2(μ-η^1: η^1-dppe)2^+] dication as PF_6^- salt and as BPh_4^- salt are different. In the former the two Fe centers are syn with respect to the loosely defined plane of P-C-C-P skeleton whereas in the latter the Fe-P-C-C-P-Fe skeleton is all trans in conformation. The mixture of 1:1 [{η^5-C_5H_5)Fe(CO)_2}_2(μ-η^1: η^1-dppe)2^+][PF_6^-]_2/dppe in CH_3CN could be made to redistribute towards 2 equiv [{η^5-C_5H_5)Fe(CO)_2(η^1-dppe)^+] [PF_6^-] with the radical mechanism, whereby a second-stage unimolecular CO dissociation follows and results in the quantitative production of [(η^5-C_5H_5)Fe(CO)(η^2-dppe)^+][PF_6^-].