【作者】 王良骍；

【导师】 胡青眉；

【作者基本信息】 南开大学 ， 有机化学， 2009， 博士

【摘要】 由于[铁铁]-氢化酶具有极高的催化制氢反应活性,对其活性中心的结构和功能模拟研究已成为生物金属有机化学领域的研究热点。通过人工方法合成具有催化制氢功能的[铁铁]-氢化酶模型物不但可以帮助人们深入理解天然氢化酶活性中心的结构和催化机理,还为人们设计合成新型高效廉价的制氢催化剂开辟了新的方向,对解决人类面临的日益严重的能源危机和环境污染等问题具有重要的理论意义和潜在的应用前景。因此,为了丰富和发展[铁铁]-氢化酶的化学模拟研究工作,本论文设计合成了一系列结构新颖的含卟啉或锌卟啉光敏剂的[铁铁]-氢化酶活性中心模型物,并系统、深入的研究了它们的结构、性质及催化功能,取得了创新性成果:1.本论文共合成了7个含卟啉或锌卟啉的[铁铁]-氢化酶活性中心模型物,3个含有[2Fe2S]结构单元的前体模型物和3个不含金属的有机前体化合物,这13个新化合物的结构通过元素分析、红外光谱、¹H NMR、³¹P NMR和¹³C NMR表征,并用X-射线衍射技术测定了其中6个化合物的单晶分子结构。此外,本论文还研究了部分化合物的电化学、紫外-可见光谱和荧光光谱的性质,并研究了6个含卟啉或锌卟啉模型物的光照催化制氢功能。2.首次合成了一个同时含有三苯基膦配体和卟啉的氮杂丙撑二硫桥[铁铁]-氢化酶模型物5-{p-C₆H₄N（CH₂S-μ）₂]Fe₂（CO）₅PPh₃},10,15,20-Ph₃PorphH₂（1）,并首次合成了两个含卟啉或锌卟啉的氮杂丙撑二硫桥[铁铁]-氢化酶模型物5-{[（C₆H₄-p）NC（O）（μ-SCH₂）₂]Fe₂（CO）₆},10,15,20-Ph₃PorphH₂（3）、5-{[（C₆H₄-p）NC（O）（μ-SCH₂）₂]Fe₂（CO）₆},10,15,20-Ph₃PorphZn（4）以及一个它们的前体模型物[（CHOC₆H₄-p）NC（O）（μ-SCH₂）₂]Fe₂（CO）₆（2）。对模型物2和4的单晶进行了X-射线衍射分析,进一步确定了它们的结构。通过荧光光谱和Rehm-weller方程研究了模型物1、3和4在光照下发生从卟啉到[2Fe2S]基团电子转移的可能性,并以模型物3为代表在水溶性胶束体系内进行光照制氢实验,系统的研究了光照时间、表面活性剂、pH值和催化剂浓度对体系制氢量的影响,并通过对比1和4的光照制氢结果研究了此类模型物结构对光照制氢性质的作用。首次对已知化合物5-[p-{Fe₂（CO）₆（μ-SCH₂）₂NC₆H₄]-10,15,20-Ph₃PorphH₂在以二氯甲烷为溶剂的光照制氢均相体系中进行了光照制氢实验,实现了此类含有卟啉的[2Fe2S]模型物在均相体系内的光照制氢,结果优于胶束体系,并提出了此类卟啉光敏剂与[2Fe2S]催化剂一体化模型物的光照催化制氢机理。3.首次合成了两个新颖的以铁膦配位键连接了卟啉大环的碳丙撑和氮杂丙撑二硫桥[铁铁]-氢化酶模型物5-{[μ-S₂（CH₂）₃]Fe₂（CO）₅PPh₂（C₆H₄-p）},10,15,20-Ph₃PorphH₂（3）和5-{[（μ-SCH₂）₂NC₆H₄CO₂CH₃-p]Fe₂（CO）₅PPh₂（C₆H₄-p）},10,15,20-Ph₃PorphH₂（4）以及它们的两个前体模型物[μ-S₂（CH₂）₃]Fe₂（CO）₅PPh₂（C₆H₄CHO-p）（1）和[（μ-SCH₂）₂NC₆H₄CO₂CH₃-p]Fe₂（CO）₅PPh₂（C₆H₄CHO-p）（2）。对模型物1、3和4的单晶进行了X-射线衍射分析,进一步确定了它们的结构。通过对3和4的荧光光谱和Rehm-weller方程研究发现它们在光照下可以通过铁膦配位键发生从卟啉到[2Fe2S]基团的电子转移。对代表性模型物4进行了不同溶剂中均相体系的光照制氢研究,成功的实现了其在二氯甲烷和四氢呋喃溶液中光照制氢,并证明了由铁膦配位键进行电子转移是一种比从双硫桥进行电子转移更有效的方式。通过对体系中缺少电子供体时发生的反常光照制氢现象的研究,提出了一种在光照制氢均相体系中普遍存在的单电子还原制氢的可能机理。4.首次合成了一个新颖的通过铁硫键将卟啉大环与蝶状[2Fe2S]簇连接的[铁铁]-氢化酶模型物5-{[（μ-SCH₂）₂NC₂H₄C₆H₄-p-SFe₂（CO）₅},10,15,20-Ph₃PorphH₂（5）,它的合成是以常见的HSC₂H₄NH₂·HCl为起始原料,通过六步反应完成的;其中的四个前体化合物BOC-N（H）C₂H₄SC₆H₄CHO-p（1）、5-[BOC-N（H）C₂H₄SC₆H₄-p],10,15,20-Ph₃PorphH₂（2）、5-[H₂NC₂H₄SC₆H₄-p],10,15,20-Ph₃PorphH₂（3）和5-{[（μ-SCH₂）₂NC₂H₄C₆H₄S-p)]Fe₂（CO）₆},10,15,20-Ph₃PorphH₂（4）是首次合成。以X-射线衍射分析确定了前体化合物4的结构。通过电化学、Uv-vis光谱、荧光光谱研究了模型物4和5性质,并通过对这两个化合物光照制氢结果的比较以及和本论文其他制氢结果的比较,详尽分析了卟啉与[2Fe2S]的连接方式以及[2Fe2S]的取代基可能对光照制氢产生的影响,为进一步设计、改进此类含有光敏剂卟啉的[铁铁]-氢化酶模型物提供了帮助与借鉴。更多还原

【Abstract】 Because of the extremely high activity of [FeFe]-hydrogenase for catalytic production of molecular hydrogen, the synthetic, structural and functional studies on [FeFe]-hydrogenase models have received great attention in bioorganometallic chemistry. The artificial models of [FeFe]-hydrogenase with the ability of hydrogen production provide not only insight into structure and catalytic mechanism of its active center, but also a route for solving the increasing problems of energy crisis and environmental pollutions. In order to develop biomimetic chemistry of [FeFe]-hydrogenase, we carried out our studies on the synthesis, structure and catalytic function of a series of new light-driven model compounds containing porphyrin or porphyrinozinc moieties. Also, a series of new precursor compounds of these light-driven models were synthesized and structurally characterized. The main results described in this thesis are as follows:1. A total of 13 new compounds were successfully synthesized, including 7 [FeFe]-hydrogenase active center model compunds containing porphyrin or porphyrinozinc moieties, 3 precursors containing [2Fe2S] moieties and 3 precursors without metal. The structures for all these new compounds were fully characterized by elemental analysis, IR , ¹H NMR, ³¹P NMR and ¹³C NMR spectroscopies, as well as for 6 of them by single-crystal X-ray diffraction methods. Part of these compounds were investigated by electrochemistry, Uv-vis and fluorescence spectra, and 6 model compounds containing porphyrin or porphyrinozinc moieties were studied by photoinduced hydrogen production experiments.2.A new [FeFe]-hydrogenase model compound 5-{p-C₆H₄N（CH₂S-μ）₂] Fe₂（CO）₅PPh₃},10,15,20-Ph₃PorphH₂ （1） containing PPh₃ ligand and porphyrin moiety was synthesized. Two new model compounds 5-{[（C₆H₄-p）NC（O）（μ-SCH₂）₂] Fe₂（CO）₆},10,15,20-Ph₃PorphH₂ （3） and 5-{[（C₆H₄-p）NC（O）（μ-SCH₂）₂]Fe₂（CO）₆}, 10,15,20-Ph₃PorphZn （4） in which porphyrin or porphyrinozinc moiety was covalently bonded to the N atom of a diiron-ADT moiety also synthesized. A new compound [（CHOC₆H₄-p）NC（O）（μ-SCH₂）₂]Fe₂（CO）₆ （2） as the precursor of 3 and 4 was synthesized . The molecular structures of 2 and 4 were confirmed by X-ray diffraction techniques. The possibilities of intramolecular electron transfer of 1,3 and 4 from porphyrin to diiron moiety were studied by fluorescence spectra and Rehm-weller equation. In water soluble micelle system the influences of the hydrogen-producing ability of representative model 3 upon irradiation time, surfactant, pH value and concentration of 3 were systematically studied. In addition, the structural factors of 1, 3 and 4 were discussed by comparing their hydrogen-producing abilities in micelle system. Furthermore, a homogeneous system of photoinduced hydrogen production catalyzed by known model 5-[p-{Fe₂（CO）₆（μ-SCH₂）₂NC₆H₄]-10,15,20- Ph₃PorphH₂ was first carried out. It proved that this system is better than the micelle system for the porphyrin-containing model compounds. A possible mechanism of photoinduced catalytic cycle of hydrogen production for this kind of models was proposed.3.Two new [FeFe]-hydrogenase model compounds 5-{[μ-S₂（CH₂）₃] Fe₂（CO）₅PPh₂（C₆H₄-p）},10,15,20-Ph₃PorphH₂ （3） and 5-{[（μ-SCH₂）₂NC₆H₄CO₂ CH₃-p]Fe₂（CO）₅PPh₂（C₆H₄-p）},10,15,20-Ph₃PorphH₂ （4） in which the porphyrin macrocycle is attached to diiron-PDT or -ADT moiety through a Fe-P coordination bond were synthesized.Two new compounds [μ-S₂（CH₂）₃]Fe₂（CO）₅PPh₂（C₆H₄CHO-p） （1） and [（μ-SCH₂）₂NC₆H₄CO₂CH₃-p]Fe₂（CO）₅PPh₂（C₆H₄CHO-p） （2） as the precursors of 3 and 4 were also synthesized. The molecular structures of 1, 3 and 4 were confirmed by X-ray diffraction techniques. The intramolecular electron transfer through the Fe-P bond in 3 and 4 were studied by fluorescence spectra and Rehm-weller equation. Studies of photoinduced catalytic hydrogen production of the homogeneous system containing representative model 4 were carried out successfully in CH₂Cl₂ and THF. It proved that the electron transfer via the Fe-P coordination bond is more efficient than via the dithiolate bridge. A possible mechanism for the abnormally hydrogen production in the absence of electron donor was proposed.4. A new [FeFe]-hydrogenase model compound 5-{[（μ-SCH₂）₂NC₂H₄C₆H₄-p-SFe₂（CO）₅},10,15,20-Ph₃PorphH₂ （5） in which the porphyrin moiety is attached to diiron-ADT moiety through a Fe-S coordination bond was synthesized. The synthetic route involves six steps and started from a simple material HSC₂H₄NH₂·HCl Four new compounds as precursors of 5, namely BOC-N（H）C₂H₄SC₆H₄CHO-p （1）, 5-[BOC-N（H）C₂H₄SC₆H₄-p],10,15,20-Ph3PorphH2（2）,5-[H₂NC₂H₄SC₆H₄-p],10,15,20 -Ph₃PorphH₂（3） and 5-{[（μ-SCH₂）₂NC₂H₄C₆H₄S-p)]Fe₂（CO）₆},10,15,20-Ph₃PorphH₂ （4） were synthesized. The molecular structure of precursor compound 4 was confirmed by X-ray diffraction techniques. The influences of the linking mode between porphyrin and diiron moieties, as well as the substituents attached to diiron moiety on electron transfer and photoinduced H₂ evolution were investigated by using electrochemistry, Uv-vis spectra, fluorescence spectra and homogeneous photoinduced hydrogen production experiment of 4 and 5. The properties and H₂ evolution abilitily of 4 and 5 were compared with those of the other model compounds previously reported by our group. All of the aforementioned studies would be helpful for designing and modifying the light-driven [FeFe]-hydrogenase models in the future.更多还原