Intramolecular Dynamics of Five-coordinate iron Carbonyl Complexes with olefinic ligands as studied by variable-pressure1H-NMR spectroscopy
作者:Jacques Ioset、Lothar Helm、Andr� Merbach、Raymond Roulet、Fabrizia Grepioni、Dario Braga
DOI:10.1002/hlca.19880710609
日期:1988.9.28
Variable-pressure 1H-NMR Spectroscopy has been used to study the fluxionality of some five-coordinated Fe complexes in solution. For [Fe(CO)2 1,3-cyclooctadiene (PPh3)], the CO site exchange is known (by analogy with [Fe(CO)3(1,3-cyclooctadiene)]) to be a non-dissociative process, and an activation volume of ca. 0 cm3.mol−1 was indeed obtained. However, for [Fe(CO2)2,3-η:O-σ-(7,7-dimethoxybicyclo[2
可变压力1 H-NMR光谱已用于研究溶液中某些五配位Fe络合物的通量。对于[Fe(CO)2 1,3-环辛二烯(PPh 3)],已知CO位点交换(类似于[Fe(CO)3(1,3-环辛二烯)])是一种非解离过程并且,确实获得了约0cm 3 .mol -1的活化体积。但是,对于[Fe(CO 2)2,3-η:O - σ-(7,7-二甲氧基双环[2.2.1]庚-2-烯)}(PPh 3)],活化体积为+5 cm 3摩尔-1这表明空前的解离过程是导致CO站点交换的原因。通过单晶X射线衍射法确定[Fe(CO)2(1,3-环辛二烯)(PPh 3)]的分子结构。晶体是三斜晶,空间群P 1,a = 9.606(3),b = 16.795(2),c = 7.743(8)Å,α= 97.83(4),β= 109.63(4),γ= 83.37( 2)°。结构确定表明,该配合物具有四角锥体配位,其中环内CC键和PPh