【作者】 张静；

【导师】 何成； 段春迎；

【作者基本信息】 大连理工大学 ， 精细化工， 2015， 博士

【摘要】 氢键在超分子识别、催化及电子质子传递过程中发挥着重要作用。金属-有机笼状化合物具有特殊的空腔结构,可以选择性包合具有特定尺寸和形状的底物分子。将氢键引入金属-有机笼状化合物将赋予金属-有机笼状化合物丰富的主-客体化学性质,使其在生物分子识别、选择性催化和光致质子还原等方面展现出丰富的用途。本论文通过设计配体,合成含有多种氢键作用位点的金属-有机笼状化合物。通过调控氢键存在模式,调节金属-有机笼状化合物的性质。结合氢键弱作用与金属-有机笼状化合物特殊的空腔结构,实现对特定小分子的识别及对特定反应的高选择性催化。(1)设计合成配体H6TBMN,引入Watson-Crick类型氢键位点、酰胺基团和ONO三齿螯合位点。配体H6TBMN与Ce离子配位自组装得到金属-有机笼状化合物Ce-TBMN。Ce-TBMN上含有12个未配位的Watson-Crick类型氢键作用位点和12个配位的酰胺基团,笼状化合物内部空腔体积为630A3,正交窗口面积为18.0×7.65A2。Ce-TBMN可以在4种RNA核苷分子中选择性识别鸟苷分子。设计合成配体H6TBAS,引入酰胺基团和ONO三齿螯合位点。配体H6TBAS与Ce离子配位自组装得到金属-有机笼状化合物Ce-TBAS。Ce-TBAS上含有12个未配位的酰胺基团和12个配位的酰胺基团,笼状化合物内部空腔体积为1000A3,正交窗口面积为21.0×8.05A2。Ce-TBAS可以在9种天然单糖和二糖分子中选择性识别蔗糖分子。(2)由于存在氢键受体和氢键给体弱作用位点,Ce-TBMN和Ce-TBAS可以作为微反应器选择性催化Knoevenagel缩合反应和氰基硅烷化反应。Ce-TBMN可以高选择性催化2-羟基-3-甲氧基苯甲醛的Knoevenagel缩合反应,3h内转化率大于95%；催化氰基硅烷化反应时,对2-硝基苯甲醛和3-硝基苯甲醛的催化效率较高,1h内转化率大于97%。Ce-TBAS催化Knoevenagel缩合反应时,对尺寸较大的底物分子的催化转化率大于Ce-TBMN;催化氰基硅烷化反应时,对尺寸较大的3-硝基苯甲醛和4-硝基苯甲醛的催化转化率大于尺寸较小的2-硝基苯甲醛。当向催化体系中加入非反应活性的物种时,体系的催化转化率明显降低。Ce-TBMN和Ce-TBAS的催化行为展现出典型的酶催化特点,催化反应发生在笼状化合物空腔内部。当分别用配体H6TBMN和H6TBAS作为催化剂催化Knoevenagel缩合反应时,其催化转化率明显小于相应的配合物的催化转化率。这是因为金属-有机笼状化合物刚性的骨架结构可以固定配体,避免氢键作用位点的自猝灭,提高均相反应中氢键催化效率(3)设计合成配体ZJ,与Co离子配位自组装,得到具有大窗口面积(9.25×9.25A2)和空腔体积(450A3)的三棱柱金属-有机笼状化合物Co-ZJ。Co-ZJ中Co离子配位构型与自然界中维生素B12中C0离子的配位构型相类似,可以催化质子还原产生氢气。当用Co-ZJ作为催化剂,Ru(bpy)3(PF6)2作为光敏剂,抗坏血酸作为电子牺牲剂,光照体系10h可以催化质子还原产生氢气0.09mL (TON=326vs. Co-ZJ)。Co-ZJ具有特殊的空腔体积,可以包合醌氢醌分子,加快体系电子和质子传递过程,提高催化效率。相同实验条件下,可以催化质子还原产生氢气0.92mL (TON=3471vs. Co-ZJ),体系催化效率提高11倍。更多还原

【Abstract】 Hydrogen bonding plays an important role in supramolecular recognition and catalysis, as well as the electron and proton delivery in these systems. Metal-organic polyhedra (MOPs) have shown excellent advantages in the rational building of microenvironments isolated from bulk solution, with size and shape-selective recognition of the substrates. The introducing of hydrogen bonding groups into the well-defined cavities of MOPs would expand their application in the filed such as bio-molecule recognition, size-selective catalysis, electron and proton delivery in light driven proton reduction.In this thesis, through the rational designing of ligands, several metal-organic polyhedra were constructed with the incorporating of different kinds of hydrogen bonding groups into their cavity to enrich the chemical properties of the MOPs. With the cooperation of hydrogen bonding groups and the well-defined cavities of the MOPs, the obtained compounds could achieve the specific recognition and catalysis properties with high efficiency and selectivity.(1) Metal-organic tetrahedrons Ce-TBMN and Ce-TBAS were achieved via self-assembly by incorporating triamine-triazine and amide groups as hydrogen bonding groups into the fragments of the ligands containing three ONO tridentate coordination sites, respectively. The tetrahedron Ce-TBMN has630A3internal cavity,18.0×7.65A2opening windows with totally twelve Watson-Crick type and twelve coordinated amide hydrogen bonding groups, and could selectively recognized guanosine molecule over other ribonucleosides. The tetrahedron Ce-TBAS has1000A3internal cavity and21.0×8.05A2opening windows, with totally twelve uncoordinated and twelve coordinated amide hydrogen bonding groups, could selectively recognize sucrose over other related natural mono-and disaccharides.(2) The presence of hydrogen donor and acceptor in their cavity allowed the Ce-TBMN and Ce-TBAS to act as molecular flasks to prompt the Knoevenagel condensation reactions of salicylaldehyde derivatives and Cyanosilylation reactions of aromatic aldehydes. Ce-TBMN showed remarkable size-selectivity in catalyzing2-hydroxy-3-methoxybenzaldehyde Knoevenagel condensation reaction with95%conversion in3h and2-nitrobenzaldehyde or3-nitrobenzaldehyde Cyanosilylation reaction with97%conversions in1h. Ce-TBAS showed better conversions to the larger size substrates than Ce-TBMN in the promotion of Knoevenagel condensation reaction and greater catalysis ability to the larger-sized3-nitrobenzaldehyde and4-nitrobenzaldehyde Cyanosilylation reaction than the smaller-sized2-nitrobenzaldehyde. Experiments of substrates with different size and shape, as well as competitive experiments using the nonreactive guests as inhibitions demonstrated that the tetrahedrons exhibited enzymatically catalytic behavior and the catalytic reactions were occurred in the "molecular flasks". Control experiments with the ligand H6TMBN or H6TBAS themselves as the catalyst for the Knoevenagel condensation were carried out in the same condition. For the smaller substrates, their conversions catalyzed by the ligands were obviously lower than those catalyzed by Ce-TBMN or Ce-TBAS, respectively, suggesting that metal-organic polyhedra could effectively fix multi hydrogen bonding groups to avoid the "self-quenching" effect, enhancing the catalytic activity of the multi hydrogen bonding groups in homogeneous state.(3) A cobalt-based redox active triangular prism Co-ZJ with the large opening windows (9.25×9.25A2) and internal cavity (450A3) was obtained by the self-assembly of the well-designed ligand ZJ and Co2+. The coordination configurations of cobalt centres in Co-ZJ were similar with that of metalloenzyme VB12, which could work as catalyst for light driven H+reduction in the presence of Ru(bpy)3(PF6)2as photosesitizer and H2A as electron sacrifice during10hours. The volume of the H2was0.09mL and the TON (turnover number) of this system was calculated as326. The Co-ZJ could also encapsulate the hydroquinone/benzoquinone(QHQ) redox couples to accelerate the electron and proton delivery, and improved the catalytic efficiency about11times, with the volume of the H20.92mL and the TON3471.更多还原