【作者】 于淼；

【导师】 李斐；

【作者基本信息】 大连理工大学 ， 精细化工， 2011， 硕士

【摘要】 人工模拟光合作用系统,是将太阳能转化为化学能的重要手段。实现太阳能到氢能转变的一条潜在途径是基于人工模拟光合作用体系建立光电化学电池(PEC),其燃料可以是水,也可以是有机物。因此,以水为氧源的光致有机底物选择性氧化,对于建立PEC和实现利用太阳能的绿色氧化工艺具有深刻的意义。目前基于分子水平催化剂光催化氧化有机底物的研究刚刚兴起,仍然存在底物范围狭窄和反应效率低下等缺点,这对于太阳能的实际应用来说依旧是很大的障碍。为了进一步推动光致有机底物氧化反应的研究,本论文设计合成了[Ru(dmp)2 (H2O)2](PF6)2(Rul, dmp=2,9-二甲基-1,10-菲咯啉)、[Ru(tpy)(bpy)(OH2)](C104)2 (Ru2,tpy=2,2’,6’,2”-三吡啶,bpy=2,2’-联吡啶)和Ru(pda)(mpy)(bpy) (Ru3, pda=2,6-吡啶二甲酸,mpy=4-甲基吡啶)三种单核金属钌催化剂,在水作为溶剂和氧源的情况下,用Ce(NH4)2(NO3)6 (CeⅣ)作为氧化剂,催化氧化有机底物。结果表明,Rul和Ru2可实现硫醚、烯烃、烷烃等多种底物的高效选择性氧化,选择性几乎高达100%。我们成功将这两种催化剂进一步应用于光敏剂/电子牺牲受体/催化剂三组分光驱动氧化体系中,对苄醇及硫醚类底物表现出出色的催化效果,其中对硫醚氧化为亚砜的转化率高达88%,选择性达到100%。此外通过电化学、紫外可见光谱等手段揭示了通过逐步质子偶合电子转移形成的高价金属-氧中间体在有机底物氧化进程中具有重要的作用,表明通过精心设计的三组分体系对光合作用体系实施了有效的功能模拟,这对于发展全新的光催化体系意义重大。基于以上的科研成果,本论文还设计合成出了锰催化剂Mn(dmp)2(CF3SO3)2 (Mnl)、Mn(bpy)2(CF3SO3)2(Mn2)和Q3Mn (Mn3, HQ=5-C1-7-I-8-OH-喹啉),铁催化剂Fe(pda)(imz)3 (Fel, pda=2,6-吡啶二甲酸,imz=咪唑),以及[((phen)2(H2O)FeⅢ)2(μ-O)] (C1O4)4 (Fe2)和[Fe(dmp)2(H2O)2](CF3SO3)2 (Fe3),并考察了这两类非贵金属催化剂在以水为氧源的有机底物氧化反应中的催化活性。更多还原

【Abstract】 Artificial photosynthesis system plays an crucial role in solar energy conversion into clean and renewable fuel. With this respect, development of photoelectrochemical (PEC) cells based on artificial photosynthesis system is a promising approach for sunlight transfer to hydrogen. In principle, both water and organic substrates are available fuels for such devices. Although much effort has been devoted to photo-induced water oxidation, photo-induced organic substrates oxidation using molecular catalyst is relatively rare. Narrow substrate scope as well as low selectivity and conversion are main drawbacks for practical application of this photocatalysis system in viable PEC cells.To develop efficient photocatalytic hydrocarbon oxidation system, in this research, three ruthenium complexes [Ru(dmp)2(H2O)2](PF6)2 (Rul, dmp= 2,9-dimethyl-1,10-phenanthroline),[Ru(tpy)(bpy)(OH2)](ClO4)2 (Ru2, tpy= 2,2’,6’,2"-terpyridine, bpy= 2,2’-bipyridine) and Ru(pda)(mpy)(bpy) (Ru3, pda= 2,6-pyridinedicarboxylic acid, mpy= 4-picoline) were prepared and characterized. Their catalytic properties on alkene’s selective oxidation were investigated by using Ce(NH4)2(NO3)6 (CeⅣ) as an oxidant and water as an oxygen source. Our results showed that Rul and Ru2 could catalytically oxidize various alkenes with highly selectivities. It was also found that Rul and Ru2 are higly efficient catalysts in a three components homogeneous photocatalysis system consisting of photosensitizer,.sacrificial electron acceptor and catalyst. In particular, remarkable yield and 100%selectivity were obtained in the conversion of sulfide to sulfoxide. Cyclic voltammetry and UV-Vis spectrometry reveals the possible catalytic active species in photocatalysis system is high-valent metal-oxo intermediate.Nonprecious metal cataylsts including manganese catalysts Mn(dmp)2(CF3SO3)2 (Mnl), Mn(bpy)2(CF3SO3)2 (Mn2) and Q3Mn(HQ= 5-C1-7-I-8-OH-quinoline, Mn3) and iron cayalysts Fe(pda)(imz)3 (Fel, pda= 2,6-Pyridine dicarboxylic acid, imz= imidazole), [((phen)2(H20)FeⅢ)2(μ-O)](C104)4 (Fe2) and [Fe(dmp)2(H2O)2] (CF3SO3)2 (Fe3) were prepared as a replacement for ruthenium based catalysts. Their catalytic properties with water as an oxidant were studied, which show an inferior catalysis capability in comparison with the ruthenium complexes.更多还原