Ring-Opening Reaction of Phosphorus-Bridged [1]Ferrocenophane via Ring Slippage from η5- to η1-Cp
Ring-Opening Reaction of Phosphorus-Bridged [1]Ferrocenophane via Ring Slippage from η5- to η1-Cp
复制标题
磷桥[1]二茂铁通过从 η5- 到 η1-Cp 的环滑移进行开环反应
DOI：
10.1021/ja029297m
复制
发表时间：
2003
影响因子：
15
通讯作者：
K. Miyoshi
中科院分区：
文献类型：
--
作者：
Tsutomu Mizuta;Y. Imamura;K. Miyoshi
研究了Rp(E)桥联[1]二茂铁的开环反应机理，其中Rp(E)=Ph(S)(3a)、Ph(3b)和MeSP(3c)(Mes=2，4，6-三甲基苯基)。在过量P(OMe)(3)存在下的UV-Vis光照射下，3a转变为[Fe(PhP(S)(eta(5)-C(5)H(4))(eta(1)-C(5)H(4)))(P(OMe)(3))(2)](4a)，其中两个环戊二烯(CP)环中的一个由Eta(5)转变为Eta(1)，从而在铁中心形成的空位被两个P(OMe)(3)配体占据。通过X-射线分析确定了4a的分子结构，其中ETA(1)-CP采用1-Fe-2-P-1，3-环戊二烯结构。在相同的反应条件下，3b和3c也分别得到了相似的滑环产物4b和4c。用更强的配位Pme(3)取代P(OMe)(3)对3a进行光解，使Cp配体从铁中心完全解离，生成[Fe(PhP(S)(eta(5)-C(5)H(4))(C(5)H(4)))(PMe(3))(3)](5)。3光解产物的滑环和解离产物的形成有力地支持了3的光解开环聚合是通过一种前所未有的Fe-CP键断裂机制进行的观点。
A reaction mechanism was investigated for a ring-opening reaction of RP(E)-bridged [1]ferrocenophane, where RP(E) = PhP(S) (3a), PhP (3b), and MesP (3c) (Mes = 2,4,6-trimethylphenyl). Irradiation of UV-vis light in the presence of an excess amount of P(OMe)(3) transformed 3a to [Fe(PhP(S)(eta(5)-C(5)H(4))(eta(1)-C(5)H(4)))(P(OMe)(3))(2)] (4a), in which one of the two cyclopentadienyl (Cp) rings of 3a changed its coordination mode from eta(5) to eta(1) and vacant coordination sites thus formed on the iron center were occupied by two P(OMe)(3) ligands. The molecular structure of 4a was determined by X-ray analysis, in which eta(1)-Cp adopted a 1-Fe-2-P-1,3-cyclopentadiene structure. Under the same reaction conditions, 3b and 3c also gave similar ring-slipped products 4b and 4c, respectively. Photolysis of 3a using more strongly coordinating PMe(3) in place of P(OMe)(3) led to complete dissociation of a Cp ligand from the iron center to form [Fe(PhP(S)(eta(5)-C(5)H(4))(C(5)H(4)))(PMe(3))(3)] (5). The formation of the ring-slipped and -dissociated products on the photolysis of 3 strongly supports the view that photolytic ring-opening polymerization of 3 proceeds via an unprecedented Fe-Cp bond cleavage mechanism.