介孔Ag2S固载锰卟啉催化氧化环己烷性能研究

摘要：为了充分发挥5,10,15,20-四(4-吡啶基)锰卟啉(Mn TPyP)的催化活性和效率，将介孔硫化银对Mn TPyP进行轴向配位，形成了介孔硫化银固载5,10,15,20-四(4-吡啶基)锰卟啉(Mn TPyP/mp-Ag2S)纳米孔仿生催化材料,用多种光谱技术对其进行表征。本催化材料中S2-与阳离子Mn3+之间有很强的轴向配位作用，这使得催化材料催化氧化环己烷的活性大幅提高，环己烷转化率和醇酮产率分别提高了46.9%和29.6%。催化材料使用了5次后，其催化性能几乎没有下降，这归因于催化材料中强的轴向配位作用和纳米空腔结构功能作用的结果。     

5,10,15,20-(2-吡啶基)卟啉及其锰(Ⅲ)配合物的合成

在微波辐射下合成了5,10,15,20-(2-吡啶基)卟啉(TPyP)及其锰(Ⅲ)配合物[Mn(Ⅲ)TPyP]。找到了较好的分离和提纯Mn(Ⅲ)TPyP的方法。     

镧系乙酰丙酮-5,10,15,20-四(4-吡啶基 )卟啉配合物

制备了乙酰丙酮-5,10,15,20-四(4-吡啶基)卟啉稀土配合物Ln(TPyP)acac[In:Dy,Ho,Yb,Lu;H~2TPyP:5,10,15,20-四(4-吡啶基)卟啉;Hacac:乙酰丙酮].配合物由一 个中心稀土离子,一个乙酰丙酮和一个四(4-吡啶基)卟啉组成,乙酰丙酮以氧双卤配位,卟啉以氮四卤配位,因此配合物有六配位的结构.     

混杂[2, 3, 9, 10, 16, 17, 23, 24-八(庚基)酞菁][四(4-吡啶 基)卟啉]合钇 (III)二层配合物的合成及其谱学和电化学性质

用四(4-吡啶基)卟啉(H~2TPyP)与乙酰丙酮钇(III)[Y(acac)~3.H~2O]反应,生成单层配合物Y(TPyP)(acac)。将其与4,5-二(庚基)二氰基苯混和,后者在DBU催化下发生四聚反应,生成混杂[2,3,9,10,16,17,23,24-八(庚基)酞菁][四(4-吡啶基)卟啉]合钇(III)二层配合物Y(TPyP)[Pc(C~7H~1~5)~8]。该化合物用紫外-可见、近红外、红外及质谱等进行了表征,并用循环伏安法(CV)和差示脉冲法(DP)研究了其电化学性质。     

混杂[2, 3, 9, 10, 16, 17, 23, 24-八(庚基)酞菁][四(4-吡啶 基)卟啉]合钇 (III)二层配合物的合成及其谱学和电化学性质

用四(4-吡啶基)卟啉(H~2TPyP)与乙酰丙酮钇(III)[Y(acac)~3.H~2O]反应,生成单层配合物Y(TPyP)(acac)。将其与4,5-二(庚基)二氰基苯混和,后者在DBU催化下发生四聚反应,生成混杂[2,3,9,10,16,17,23,24-八(庚基)酞菁][四(4-吡啶基)卟啉]合钇(III)二层配合物Y(TPyP)[Pc(C~7H~1~5)~8]。该化合物用紫外-可见、近红外、红外及质谱等进行了表征,并用循环伏安法(CV)和差示脉冲法(DP)研究了其电化学性质。     

5,10,15,20-四(4′-氯乙酸乙酯基吡啶基)卟啉配合物的合成与表征

5,10,15,20-四(4-吡啶基)卟啉与氯乙酸乙酯反应得到5,10,15,20-四(4′-氯乙酸乙酯基吡啶基)卟啉(产率78．4％),后者与过量的醋酸锌发生络合反应得到新化合物5,10,15,20-四(4′-氯化乙酸乙酯基吡啶基)卟啉络锌(产率88．4％)。其结构经UV—vis,^1HNMR,IR和元素分析表征。     

水溶性卟啉催化氧化1,5-萘二酚

合成并表征了系列水溶性卟啉配体[H2TPPS: 5,10,15,20-四-(4-磺酸基苯基)-21H,23H-卟啉, H2TMPyP: 5,10,15,20-四(4-吡啶基)-21H,23H-卟啉, H2TCPP: 5,10,15,20-四-(4-羧基苯基)-21H,23H-卟啉]及相应的铁、锌及钴配合物. 将水溶性卟啉作为光敏剂, 用于1,5-萘二酚的光催化反应, 产物为5-羟基-1,4萘醌. 利用UV-Vis方法对卟啉催化1,5-萘二酚的反应过程进行了监测, 探索了水相和水/二氯甲烷双相催化体系, 确定了较为理想的反应条件. 探讨了不同取代基和不同金属离子对卟啉催化性能的影响, 初步讨论了催化机理. 结果表明, 具有磺酸根阴离子取代基的水溶性卟啉具有最好的催化活性; 卟啉的催化活性与其在反应体系中的稳定性密切相关; 铁卟啉在反应初期呈现很高的催化活性, 但在光照条件下容易发生光解而导致催化活性的降低; 无金属的磺酸卟啉在催化体系中的催化活性和稳定性最好.     

环己烷并卟啉的合成及光谱和电化学性质研究

合成了三种在中位上具有不同取代苯基的环己烷并卟啉:5,10,15,20-四(4-甲苯基)环己烷并卟啉,5,10,15,20-四苯基环己烷并卟啉和5,10,15,20-四(4-氯苯基)环己烷并卟啉。利用核磁共振及质谱对它们进行了结构表征,研究了它们在二氯甲烷和吡啶溶剂中的紫外-可见光谱和电化学性质,探讨了卟啉大环周边的取代基和溶剂对化合物的光谱和氧化还原电位的影响,发现β-位上的环己烷取代基对化合物的光谱和电化学性质具有显著的影响。     

高分子键联金属卟啉的合成及催化性能的研究

本文合成了一种新型大环网状高分子聚苯乙烯键联的四(4-吡啶基)卟啉和四(4-氨基苯基)卟啉的金属配合物。考察了它们在正己烷羟基化反应中的催化性能。结果表明: 四(4-吡啶基)卟啉锰和高分子键联后稳定性增加, 且活性有所提高。     

新型2-氢醌-多羟基卟啉的合成及其抗菌活性研究

为寻找新的光动力治疗光敏剂,首次利用电中性的对苯二酚与2-硝基-5,10,15,20-四芳基卟啉直接反应,制备了一系列新型2-氢醌-5,10,15,20-四(4-羟基苯基)卟啉,分离产率达90%以上.用青霉素钠做对照,首次研究了2-氢醌-5,10,15,20-四(4-羟基苯基)卟啉及其Ni(Ⅱ),Zn(Ⅱ)配合物对金黄色葡萄球菌(Staphylococcus aureus,ATCC 25923)和大肠杆菌(Escherichia coli,ATCC 25922)的抑菌活性,显示其浓度为80μmol/L时,就能完全抑制金黄色葡萄球菌的生长(而相应的青霉素钠的浓度为320μmol/L),但对大肠杆菌的作用不明显.结果表明,2-氢醌-5,10,15,20-四(4-羟基苯基)卟啉及其金属配合物在杀灭金黄色葡萄球菌等方面具有很好的应用前景.     

Synthesis and Solution Studies of Silver(I)‐Assembled Porphyrin Coordination Cages

The synthesis and the characterization of two porphyrin coordination cages are reported. The design of the cage formation is based on the coordination of silver(I) ions to the pyridyl units of 3‐pyridyl appended porphyrins. ¹H/¹⁰⁹Ag NMR spectroscopy, and diffusion‐ordered spectroscopy (DOSY) experiments demonstrate that both the free base porphyrin 2H‐TPyP and the Zn‐porphyrin Zn‐TPyP form the closed cages, [ Ag₄(2H‐TPyP)₂ ]⁴⁺ and [ Ag₄(Zn‐TPyP)₂ ]⁴⁺, respectively, upon addition of two equivalents of Ag⁺. The complexation processes are characterized in details by means of absorption and emission spectroscopy in diluted CH₂Cl₂ solutions. The data are discussed in the frame of the point‐dipole exciton coupling theory; the two porphyrin monomers, in fact, experience a rigid face‐to‐face geometry in the cages and a weak inter‐porphyrin exciton coupling. An intermediate species is observed, for Zn‐TPyP , in a porphyrin/Ag⁺ stoichiometric ratio of about 1:0.5 and is tentatively ascribed to an oblique open form. The occurrence of a photoinduced electron‐transfer reaction within the cages is excluded on the basis of the experimental outcomes and thermodynamic evaluations. Photophysical experiments evidence different reactivities of singlet and triplet excited states in the assemblies. A lower fluorescence quantum yield and triplet formation is discussed in relation to the constrained geometry of the complexes. Unusually long triplet excited state lifetimes are measured for the assemblies.     

Heteromolecular grids of free-base and zinc-tetra(4-pyridyl)porphyrins with benzenetetracarboxylic acid

This study describes the formation of hetero-molecular networks involving the 1,2,4,5-benzenetetracarboxylic acid (BTCA) and either the free-base or zinc-metallated tetra(4-pyridyl)porphyrin (TPyP or Zn–TPyP, respectively), taking advantage of the complementary tetradentate H-atom donor and H-atom acceptor capacity of the component species. The reaction of BTCA with TPyP yields flat square-grid-type hydrogen bonded arrays, wherein every BTCA moiety interacts with four different porphyrin units and each one of the latter links laterally to four different tetraacid molecules. Replacement of TPyP by Zn–TPyP adds axial coordination capacity to the porphyrin unit and changes the intermolecular interaction pattern. In this case, the supramolecular self-assembly involves trans-axial coordination of BTCA to Zn–TPyP, into a 2:1 complex of the two species, as well as extended hydrogen bonding in four lateral directions between the (BTCA)₂(Zn–TPyP) units thus formed. The hydrogen-bond networking takes place between the four N(pyridyl)-sites of the porphyrin scaffold and the axial tetracid ligands of four neighboring complexes. In the two crystals, the open hydrogen bonded molecular networks stack in an offset manner, incorporating molecules of the 1,1,2,2-tetrachloroethane solvent within channel zones that penetrate through the layered structure. Application of the TPyP scaffold in the formation of hydrogen-bonded (rather than coordination-driven) assemblies has not been explored prior to our work on this subject.     

Highly Active Catalysis of Cobalt Tetrakis(pentafluorophenyl)porphyrin Promoted by Chitosan for Cyclohexane Oxidation in Response-Surface-Methodology-Optimized Reaction Conditions

We aimed at elevating catalytic performances of cobalt tetrakis(pentafluorophenyl)porphyrin (Co TPFPP) through axial coordination, nanocavities, and covalently grafting action. The Co TPFPP was immobilized onto nanoporous and nonporous chitosan, forming Co TPFPP/np- and nonp-CTS catalysts, respectively. The catalysts were characterized by various spectroscopic techniques. The catalytic performances of these catalysts for cyclohexane oxidation under response-surface-methodology-optimized oxidation reaction conditions were estimated and compared. Co TPFPP/np-CTS was an excellent catalyst at aspect of catalytic activity, exhibiting the considerable potential reusability, 24.2 mol % yields (KA oil : cyclohexanone and cyclohexanol) in average, and total turnover frequencies (TOFs) of 3.25×10⁶ h⁻¹. This is attributed to the structural characteristics of the Co TPFPP/np-CTS catalyst: the cobalt porphyrin molecules could be highly scattered on CTS, forming the independent active sites, and were not leached. The axial coordination exerted the most important effect on the catalytic activity, and the covalent grafting action had a decisive effect on the increase of the total TOFs and on the reusability of the catalyst.     

Hydrophobic Modification of Pd/SiO2@Single‐Site Mesoporous Silicas by Triethoxyfluorosilane: Enhanced Catalytic Activity and Selectivity for One‐Pot Oxidation

To enhance the catalytic activity in a selective one‐pot oxidation using in‐situ generated H₂O₂, a hydrophobically modified core–shell catalyst was synthesized by means of a simple silylation reaction using the fluorine‐containing silylation agent triethoxyfluorosilane (TEFS, SiF(OEt)₃). The catalyst consisted of a Pd‐supported silica nanosphere and a mesoporous silica shell containing isolated Ti^IV and F ions bonded with silicon (Si?F bond). Structural analyses using XRD and N₂ adsorption–desorption suggested that the mesoporous structure and large surface area of the mesoporous shells were retained even after the modification. During the one‐pot oxidation of sulfide, catalytic activity was enhanced significantly by increasing the amount of fluorine in the shell. A hydrophobic surface enhanced adsorption of the hydrophobic reactant into the mesopore, while the less hydrophobic oxygenated products efficiently diffused into the outside of the shell, which improved the catalytic activity and selectivity. In addition, the present methodology can be used to enhance the catalytic activity and selectivity in the one‐pot oxidation of cyclohexane by using an Fe‐based core–shell catalytic system.     

Encapsulation of Metalloporphyrins in a Self‐Assembled Cubic M8L6 Cage: A New Molecular Flask for Cobalt–Porphyrin‐Catalysed Radical‐Type Reactions

The synthesis of a new, cubic M₈L₆ cage is described. This new assembly was characterised by using NMR spectroscopy, DOSY, TGA, MS, and molecular modelling techniques. Interestingly, the enlarged cavity size of this new supramolecular assembly allows the selective encapsulation of tetra(4‐pyridyl)metalloporphyrins (M^II(TPyP), M=Zn, Co). The obtained encapsulated cobalt–porphyrin embedded in the cubic zinc–porphyrin assembly is the first example of a catalytically active encapsulated transition‐metal complex in a cubic M₈L₆ cage. The substrate accessibility of this system was demonstrated through radical‐trapping experiments, and its catalytic activity was demonstrated in two different radical‐type transformations. The reactivity of the encapsulated Co^II(TPyP) complex is significantly increased compared to free Co^II(TPyP) and other cobalt–porphyrin complexes. The reactions catalysed by this system are the first examples of cobalt–porphyrin‐catalysed radical‐type transformations involving diazo compounds which occur inside a supramolecular cage.     

Disproportionation of hydrogen peroxide in the presence of Mn(III) complexes with various porphyrins and acid anions

The kinetics of homogeneous decomposition of H₂O₂ in the presence of Mn(III) complexes with octaethylporphine or meso-phenyloctaethylporphines and acid anions Cl^?, AcO^?, and SCN^? was studied by volumetry. The ionic-molecular mechanism of the transformation, involving reversible coordination of the H₂O₂ molecule, its irreversible decomposition with the release of H₂O and removal of two electrons from the metal porphyrin, reversible coordination of the second peroxide molecule in the form of HO ₂ ^? , and slow irreversible reduction of the catalyst with the release of O₂ and H₂O was substantiated by electronic absorption spectra. The catalytic activity of Mn(III) porphyrin complexes is independent of the acid anion present as extra ligand, but depends on the structure of the porphyrin ligand, which can be used for controlling the catalytic activity. Unsymmetrical (chloro)(monophenyloctaethylporphinato)managanese(III) is the most active; it increases the rate of O₂ evolution by a factor of 2 at the peroxide: catalyst molar ratio of (3 × 10⁵): 1.     

Synthesis and characterization of Cr-MSU-1 and its catalytic application for oxidation of styrene

Chromium-containing mesoporous silica material Cr-MSU-1 was synthesized using lauryl alcohol-polyoxyethylene (23) ether as templating agent under the neutral pH condition by two-step method. The sample was characterized by XRD, TEM, FT-IR, UV-Vis, ESR, ICP-AES and N₂ adsorption. Its catalytic performance for oxidation of styrene was studied. Effects of the solvent used, the styrene/H₂O₂ mole ratio and the reaction temperature and time on the oxidation of styrene over the Cr-MSU-1 catalyst were examined. The results indicate that Cr ions have been successfully incorporated into the framework of MSU-1 and the Cr-MSU-1 material has a uniform worm-like holes mesoporous structure. After Cr-MSU-1 is calcined, most of Cr³⁺ is oxidized to Cr⁵⁺ and Cr⁶⁺ in tetrahedral coordination and no extra-framework Cr₂O₃ is formed. The Cr-MSU-1 catalyst is highly active for the selective oxidation of styrene and the main reaction products over Cr-MSU-1 are benzaldehyde and phenylacetaldehyde. Its catalytic performance remains stable within five repeated runs and no leaching is noticed for this chromium-based catalyst.     

1D and 2D solid-state metallosupramolecular arrays of freebase 5,10,15,20-tetra(4-pyridyl)porphyrin, peripherally linked by zinc and manganese ions

Freebase 5,10,15,20-tetra(4-pyridyl)porphyrin (TPyP) is able to assemble into crystalline rigid 1D and 2D metallosupramolecular arrrays via exocyclic coordination with tetracoordinate and hexacoordinate metal ions, respectively. In this contribution we report on two coordination polymers of μ ⁴-bridging freebase TPyP with zinc and manganese halide moieties. The structure of [(ZnBr₂)₂TPyP] · 6 TCE (2) (TCE = 1,1,2,2-tetrachloroethane) consists of 1D polymeric chains. The topology of [(MnCl₂)TPyP] · 6 TCE (3) is the (4,4) square grid type. The crystal structure of the known compound [(HgI₂)₂TPyP] · 4 TCE (1) was redetermined by X-ray crystallography.     

Unusual Photoinduced Electron Transfer from a Zinc Porphyrin to a Tetrapyridyl Free‐Base Porphyrin in a Noncovalent Multiporphyrin Array

Excitation of the peripheral Zn porphyrin units in a noncovalent five‐porphyrin array, formed by gable‐like zinc(II) bisporphyrins and a central free‐base meso‐tetrakis(4‐pyridyl)porphyrin in a 2:1 ratio, ( ZnP₂ )₂? ( TPyP ), does not lead to a quantitative sensitization of the luminescence of the free‐base porphyrin acceptor, even though there is an effective energy transfer. Time resolution of the luminescence evidences a quenching of TPyP upon sensitization by the peripheral ZnP₂ . The time evolution of the TPyP fluorescence in the complex can be described by a bi‐exponential fitting with a major component of 180 ps and a minor one of 5 ns, compared to an isolated TPyP lifetime of 9.4 ns. The two quenched lifetimes are shown to be correlated to the presence of 2:1 and 1:1 complexes, respectively. No quenching of TPyP fluorescence occurs in ( ZnP₂ )₂?( TPyP ) at 77 K in a rigid solvent for which only an energy‐transfer process (τ=150±10 ps) from peripheral ZnP₂ to the central TPyP is observed. An unusual HOMO–HOMO electron‐transfer reaction from ZnP₂ to the excited TPyP units, responsible for the observed phenomena, is detected. The resulting charge‐separated state, ( ZnP₂ )⁺₂?( TPyP )^? is found to recombine to the ground state with a lifetime of 11 ns.     

A Porphyrin‐Based Porous rtl Metal–Organic Framework as an Efficient Catalyst for the Cycloaddition of CO2 to Epoxides

A porous rtl metal–organic framework (MOF) [Mn₅L(H₂O)₆?(DMA)₂]?5DMA?4C₂H₅OH ( 1? Mn) (H₁₀L=5,10,15,20‐tetra(4‐(3,5‐dicarboxylphenoxy)phenyl)porphyrin; DMA=N,N′‐dimethylacetamide) was synthesized by employing a new porphyrin‐based octacarboxylic acid ligand. 1? Mn exhibits high Mn^II density in the porous framework, providing it great Lewis‐acid heterogeneous catalytic capability for the cycloaddition of CO₂ with epoxides. Strikingly, 1? Mn features excellent catalytic activity to the cycloaddition of CO₂ to epoxides, with a remarkable initial turnover frequency 400 per mole of catalyst per hour at 20 atm. As‐synthesized 1? Mn also exhibits size selectivity to different epoxide substrates on account of their steric hindrance. The high catalytic activity, size selectivity, and stability toward the epoxides on catalytic cycloaddition of CO₂ make 1? Mn a promising heterogeneous catalyst for fixation and utilization of CO₂.