Li Ping, Wang Mei, Pan Jingxi, Chen Lin, Wang Ning, Sun Licheng
State Key Laboratory of Fine Chemicals, DUT-KTH Joint Education and Research Center on Molecular Devices, Dalian University of Technology (DUT), Dalian 116012, China.
J Inorg Biochem. 2008 Apr;102(4):952-9. doi: 10.1016/j.jinorgbio.2007.12.018. Epub 2007 Dec 25.
Three diiron dithiolate complexes containing rigid and conjugated bridges, [mu-SC(6)H(4)-2-(CO)S-mu]Fe(2)(CO)(6) (1), [2-mu-SC(5)H(3)N-3-(CO)S-mu]Fe(2)(CO)(6) (2), and the PPh(3)-monosubstituted complex [mu-SC(6)H(4)-2-(CO)S-mu]Fe(2)(CO)(5)(PPh(3)) (1-P), were prepared as biomimetic models for the [FeFe]-hydrogenase active site. The structures of complexes 1 and 2 were determined by single crystal X-ray analysis, which shows that each complex features a rigid coplanar dithiolate bridge with a 2-3 degrees deviation from the bisect plane of the molecule. The influence of the rigid bridge on the reduction potentials of complexes 1, 2 and 1-P was investigated by electrochemistry. The cyclic voltammograms of complexes 1 and 2 display large positive shifts for the primary reduction potentials, that is, 380-480mV in comparison to that of the pdt-bridged (pdt=propane-1,3-dithiolato) complex (mu-pdt)Fe(2)(CO)(6) and 160-260mV to that of the bdt-bridged (bdt=benzene-1,2-dithiolato) analogue (mu-bdt)Fe(2)(CO)(6).
合成了三种含有刚性共轭桥联的二铁二硫醇盐配合物，即[μ-SC(6)H(4)-2-(CO)S-μ]Fe(2)(CO)(6) (1)、[2-μ-SC(5)H(3)N-3-(CO)S-μ]Fe(2)(CO)(6) (2) 以及膦单取代配合物[μ-SC(6)H(4)-2-(CO)S-μ]Fe(2)(CO)(5)(PPh(3)) (1-P)，作为[FeFe]-氢化酶活性位点的仿生模型。配合物1和2的结构通过单晶X射线分析确定，结果表明每个配合物均具有刚性共面的二硫醇盐桥联，与分子的平分面存在2 - 3度的偏差。通过电化学方法研究了刚性桥联对配合物1、2和1-P还原电位的影响。配合物1和2的循环伏安图显示其初级还原电位有较大的正向偏移，即与pdt桥联（pdt = 丙烷-1,3-二硫醇盐）配合物(μ-pdt)Fe(2)(CO)(6)相比，正向偏移380 - 480 mV，与bdt桥联（bdt = 苯-1,2-二硫醇盐）类似物(μ-bdt)Fe(2)(CO)(6)相比，正向偏移160 - 260 mV。
