【作者】 张光菊；

【导师】 康振辉；

【作者基本信息】 苏州大学 ， 无机化学， 2014， 博士

【摘要】 随着人类社会的日新月异，能源短缺和环境污染已经成为人类健康、生态平衡和社会经济发展面临的最大挑战。当今社会的大部分物质都是通过催化反应而生产的，因此，发展新型的催化材料是实现可持续发展的有效途径。利用可见光进行光催化，绿色又环保，不仅反应效率高，速度快，而且对多种有机污染物降解效果显著。同时在化学工业上，高效的氧化反应催化剂是人们梦寐以求的。因此，制备新型的环境友好、高效的催化剂是具有广泛基础研究价值和应用前景的重要研究课题。本论文中利用简便的化学方法，设计、制备具有一定尺寸和形貌的多孔MOFs手性及非手性材料，并将其应用于环辛烯的选择性催化氧化、电化学催化和镜像选择识别、氧还原反应（ORR）以及生物酶的固定等方面的研究。(1)采用水热法，由次黄嘌呤和Co(OAc)24H2O按照一定的比例最终合成一个3D钴基多孔非手性MOFs，通过单晶X射线衍射确定分子式为([Co3(2-OH)4(I)2]·2H2O， I=次黄嘌呤，化合物1)。进一步结构分析表明3D结构中同时包含了两种类型的1D孔道，尺寸大小分别为11.2×11.2和8.5×8.5。在77K和195K温度下，对1进行N2，CO2气体吸附脱附研究。在1atm下N2，CO2的吸附量分别为237.4和160.4cm3g-1，所获得的吸附曲线为典型的Ⅰ类曲线，由此可证明化合物1为典型的多微孔材料。通过对其磁性方面的探究，化合物1具有罕见的变磁性行为。为进一步探究其在催化方面的性能，将所合成的化合物1作为催化剂，空气作为氧化剂，进行环辛烯的选择性催化氧化实验。最终得出环辛烯的转化率为34.84%，环氧环辛烷的选择性达到了87.71%。由此可见，化合物1在环辛烯的选择性催化氧化方面有很好的催化性能。(2)采用水热法，由手性小分子L/D-酒石酸为手性配体，与4,4’-联吡啶、Co(OAc)24H2O按照一定的比例最终合成了一对纯手性多孔MOFs材料[Co2F2(bpy)2(L-tart)]·7H2O (2)和[Co2F2(bpy)2(D-tart)]·5.5H2O(3)。在77K和195K温度下，对所合成的多孔MOFs材料进行N2，CO2气体吸附脱附研究。在1atm下N2，CO2的吸附量分别为237.4和160.4cm3g-1，所获得的吸附曲线为典型的Ⅰ类曲线，由此可证明所合成的2和3为典型的多微孔材料。另外通过圆二色谱的进一步分析证实，2和3确实为左右手对应的一对对映体。(3)采用水热法，由手性小分子酒石酸的衍生物二苯甲酰-L/D-酒石酸(LL/D-DBTA)为手性源，与4,4’-联吡啶和Co(OAc)24H2O按照一定的比例最终合成了一对纯手性非孔MOFs材料[Cu(H2O)(bpy)(L-DBTA)]·H2O(4)和[Cu(H2O)(bpy)(D-DBTA)]·H2O(5)。结构分析表明4,4’-联吡啶与Cu相互连接形成一条1D链，L-DBTA配体作为二齿配体将相邻的1D链连接在一起形成了一个2D波浪层，其中L-DBTA配体中没配位的苯酰基作为手臂悬挂在2D层的两侧。相邻2D波浪层采用ABAB的方式排列堆积，最终形成3D非孔手性栅栏结构。另外通过圆二色谱的进一步分析证实，4和5确实为左右手对应的一对对映体。(4)采用电化学方法，通过线性伏安和交流阻抗实验进一步探究一对钴基纯手性多孔MOFs材料(2和3)和一对铜基纯手性非孔MOFs材料(4和5)对手性小分子L/D-酒石酸和L/D-苹果酸在选择性识别和电化学催化活性方面的性能研究。由交流阻抗曲线可以看出，L型MOFs材料制得的碳糊电极对L-酒石酸/苹果酸有很明显的镜像选择识别能力，而对D-酒石酸/苹果酸没有识别能力。同样的，D型MOFs材料对D-酒石酸/苹果酸有很明显的镜像选择识别能力，而对L-酒石酸/苹果酸没有识别能力。另外，从线性伏安图可以看出，L型MOFs材料对L-酒石酸/苹果酸的电化学催化活性比对D-酒石酸/苹果酸电化学催化活性强，而同样的D型MOFs材料对D型手性小分子的电化学催化活性要比L型的强。由一系列的电化学实验可以看出，化合物2和3，4和5具有非常好的电化学催化和镜像识别性能，这为MOFs材料在手性方面的应用开辟了新的道路，为手性识别等领域提供了新的思路。(5)采用煅烧方法，由已合成的嘌呤类钴基MOFs材料(化合物1)为原料，成功合成出一种Co3O4@N-C纳米复合材料。通过TEM和HRTEM图可以很清晰的看出所获得的Co3O4@N-C纳米复合材料具有核壳结构，其中Co3O4为核结构(直径大约为15nm)，氮掺杂的石墨烯结构充当外层的壳结构(其厚度大约为5nm)。通过对氧还原催化性能的研究来进一步检验所制备的Co3O4@N-C纳米复合材料的催化活性。循环伏安曲线可看出样品的起峰电位和还原峰电位分别为0.95V，0.80V(与标准氢电极对比)，与商用Pt/C电极很接近(1.03V，0.82V)。另外，通过在旋转圆盘电极不同扫速下测得线性伏安曲线，最终计算出此氧化还原反应的转移电子数为4。通过进一步抗甲醇实验的探究，可以直观的看出Co3O4@N-C纳米复合材料比商用Pt/C电极具有更好的抗甲醇性。(6)由已合成的嘌呤类钴基MOFs材料(化合物1)为原料，在一定条件下与猪胰腺脂肪酶（PPL）成功结合，最终得到MOF-PPL复合物。由于酶的活性位点一般都包裹于其结构的内部，通过与MOFs复合，减少了PPL结构中的α-螺旋，使得包裹在酶内部的活性中心裸露出来，从而进一步增强了酶的活化性能。我们分别在不同温度，不同PH的条件下对MOF-PPL复合物的催化活性进行了探究，最终得到MOF-PPL复合物催化活性最高时的最佳温度为311K，最佳PH为7.0。另外还进行了稳定性测试，结果表明MOF-PPL复合物的稳定性比单纯PPL的稳定性高，并且随着时间的延长其催化活性的降幅不大。实验表明通过将MOF与PPL复合，进一步提高了酶的活性，这为MOFs在生物医学方面的应用开辟了新的道路。更多还原

【Abstract】 Over the last at least three decades, the science of porous solid materials hasbecome one of the most intense areas of study for chemists, physicists, and materialsscientists. These materials have found a large number of applications in many felds,such as adsorption, separation and purifcation, as well as catalysis. Porous solids actingas adsorbents or membrane fllers are playing key roles in separations and purifcationsof various chemicals that we encounter in our daily activities, directly or indirectly.Explorations of advanced porous materials for these applications are therefore anintense subject of scientifc research.In this thesis, we used the simplest chemical method for the preparation of porousMOFs in the selective oxidation of cis-cyclooctene, enantioselective recognition andelectrocatalysis of chiral molecule, catalytic ability for oxygen reduction reaction (ORR)and porcine pancreatic lipase (PPL) catalyst which can be control by the size andmorphology.(1) Here we report a3D PCP, namely [Co3(μ2-OH)4(I)2]·2H2O (compound1, I=hypoxanthine), exhibiting an unprecedented3D porous framework containing two typesof1D channels running along c axis. the typical regular square (type-A and type-B)channels exhibit the sizes of11.2×11.2and8.5×8.5, respectively. In order to testifythe porous structure of1, the N2and CO2sorption isotherms were performed at77and195K on the activated samples, respectively. The activated sample1adsorbs N2andCO2of237.4and160.4cm3g1at1atm, respectively. The adsorption isotherms of N2and CO2display a steep rise at the low relative pressure region, and the isotherms canbe categorized as type I, indicating a typical physisorption process of a microporousmaterial. The catalytic experiments showed that compound1, directly used asheterogeneous catalyst without any supports, indeed possesses excellent catalytic abilityfor the selective oxidation of cis-cyclooctene (34.84%conversion based oncis-cyclooctene and87.71%selectivity for epoxycyclooctane). (2) We have demonstrated a facile chemical etching method for the fabrication ofmesoporous black TiO2nanocrystals. Here we report the synthesis of two3Dhomochiral porous coordination polymers, namely [Co2F2(bpy)2(L-tart)]7H2O (2) and[Co2F2(bpy)2(D-tart)]5.5H2O (3) from cobalt salt with4,4’-bpy, L-and/or D-tart. Both2and3exhibit a unique3D chiral porous framework containing three types of1D chiralchannels running along a, b and c axes, respectively. In order to confirm the porousstructure of2and3, theN2and CO2sorption isotherms were performed at77and195Kon the activated samples, respectively. The adsorption isotherm of CO2at195Kdisplays a steep rise at the low relative pressure region, with a small hysteresis betweensorption–desorption curves, and the isotherm can be categorized as type I, indicating atypical physisorption process of a microporous material. Further close observationreveals that the circular dichroism spectra are mirror images of one another, whichconclusively demonstrates that2and3are enantiomers. This phenomena indicated thatthe chiral information was transferred from chiral tartaric acid ligand to the metal centreand finally to the whole framework.(3) Here we report two nonporous homochiral coordination polymers, namely[Cu(H2O)(bpy)(L-DBTA)]·H2O (4) and [Cu(H2O)(bpy)(D-DBTA)]·H2O (5) assembledfrom copper salt with4,4′-bpy, L-and/or D-DBTA. Both compounds4and5exhibit3Dnonporous chiral interdigitated architectures. Further close observation reveals that thecircular dichroism spectra are mirror images of one another, which conclusivelydemonstrates that4and5are enantiomers. This phenomena indicated that the chiralinformation was transferred from chiral tartaric acid ligand to the metal centre andfinally to the whole framework.(4) The chiral porous materials (compounds2-5), possesses excellentenantioselective recognition and electrocatalytic ability towards L/D-tart and L/D-malic,respectively. The enantioselective recognition abilities of2-5were analyzed byelectrochemical impedance spectroscopy (EIS). The EIS of L-CPE in Na2SO4solutionwith L-tart showed a large semicircle in the high-frequency region, indicating aninterfacial electron transfer process on the L-CPE surface. However, the spectrum ofL-CPE for D-tart in Na2SO4solution is not observed. Similarly, in the D-CPE system,the EIS of D-CPE in Na2SO4solution with D-tart also showed a typical interfacialelectron transfer behavior on the D-CPE surface, while that for L-tart is not observed.Linear sweep voltammograms are shown for the oxidation of L-and D-tart on L-CPE and D-CPE, respectively. As shown, the L-CPE is more active for the oxidation of theL-tart, and the D-CPE is more active for the oxidation of the D-tart. In controlexperiments (using the bare CPE instead of L-and D-CPE), bare CPE shows noenantioselective recognition and electrocatalytic abilities of the enantiomers. The linearsweep voltammogram results for the different catalytic processes of L-and D-CPE werein good agreement with that of impedance experiments, which confirms theenantioselective recognition and electrocatalytic abilities of the chiral porous materials.（5）we report a facile and simple one–step approach for the synthesis of hybridcore–shell nanocomposites using compound1as precursors. The TEM image furtherconfrms the Co3O4particle with size about15nm was encapsulated into the carbonshell. The further electrochemical experiments indicated that Co3O4@N-Cnanocomposites exhibits an excellent electrocatalytic performance for a four-electronORR, and longer-term stability and higher methanol tolerance than the commercial Pt/Ccatalysts in alkaline medium.（6）Exploring porous MOFs materials performances for applications in biology isattracting intense interest of researchers working in the felds of biological chemistry.we reported an effcient method to attain highly active immobilized pig pancreatic lipase(PPL) by using the compound1as precursors. Furthermore, we demonstrated that theoptimal pH of free PPL and MOF-PPL was7.0,8.0, respectively. Free PPL activityfluctuated within a narrow pH range. The MOF-PPL system maintained high activitywas in7.0~9.0. The experimental dates revealed that the highest hydrolysis activity ofMOF-PPL was5100U g-1, whereas the activity of free PPL was3850U g-1. Meanwhile,we demonstrated that the optimal reaction temperature of free PPL and MOF-PPL was311K,318K, respectively.更多还原