乙酰葡萄糖氧代金属卟啉的合成及其对环己烷羟基化反应的催化作用

由吡咯和葡萄糖取代苯甲醛直接缩合制备了两种葡萄糖取代卟吩:四(邻位乙酰葡萄糖氧代苯基)卟吩和四(间位乙酰葡萄糖氧代苯基)卟吩,进一步金属化合成了4种葡萄糖金属卟啉:氯化四(邻位乙酰葡萄糖氧代苯基)卟吩合铁、氯化四(间位乙酰葡萄糖氧代苯基)卟吩合铁、氯化四(邻位四乙酰葡萄糖氧代苯基)卟吩合锰和氯化四(间位乙酰葡萄糖氧代苯基)卟吩合锰.它们的结构由紫外-可见光谱、核磁共振和元素分析证实.研究了这些葡萄糖取代金属卟啉对亚碘酰苯常温常压下氧化环己烷反应的催化作用.研究结果表明,4种糖基金属卟啉催化下的环己烷反应产率和反应速率都比一般金属卟啉高.反应动力学分析表明,在常温常压下,糖基金属卟啉催化下的环己烷氧化反应具有酶催化反应的动力学关系.     

用于光动力治疗的四苯基卟啉衍生物研究进展

四苯基卟啉(TPP)衍生物的重要用途之一是用于光动力治疗(PDT)来破坏肿瘤组织.本文综述了近年来可用于光动力治疗的四苯基卟啉(TPP)衍生物的合成.通过对TPP衍生物进行官能团修饰,可以改善其物理、化学及生物性质,从而合成出可能用于PDT的卟啉衍生物.     

四-(邻氯苯基)卟吩及其金属络合物的制备和光谱研究

卟啉化合物与很多学科有着十分密切的关系。四-(邻氯苯基)卟吩(OCITPP)化合物与实验室常用模拟物四苯基卟吩(TPP)及苯环间、对位取代的四苯基卟吩比较,化学和光谱性质上较为独特,应用上较为优越,且前人做过的工作极少。     

乙酰糖基金属卟啉的合成及其对烷烃温和氧化的选择性催化作用

由吡咯和葡萄糖取代苯甲醛直接缩合制备了两种葡萄糖取代卟吩,四(邻位乙酰葡萄糖氧代苯基)卟吩和四(间位乙酰葡萄糖氧代苯基)卟吩,它们进一步金属化合成了四种葡萄糖金属卟啉,氯化四(邻位乙酰葡萄糖氧代苯基)卟吩合铁、氯化四(间位乙酰葡萄糖氧代苯基)卟吩合铁、氯化四(邻位四乙酰葡萄糖氧代苯基)卟吩合锰和氯化四(间位乙酰葡萄糖氧代苯基)卟吩合锰。它们的结构由紫外-可见光谱、元素分析和核磁共振证实。研究了这些葡萄糖取代金属卟啉对亚碘酰苯常温常压下氧化异戊烷反应的选择性催化作用。研究表明,糖基金属卟啉催化异戊烷端基碳氢键的氧化,对一级碳氢键表现出专一性催化作用。非糖基金属卟啉催化异戊烷二级和三级碳氢键的氧化。与非糖基金属卟啉比较,糖基金属卟啉对烷烃羟基化反应的催化行为更接近细胞色素P-450单充氧酶。     

金属卟吩的给体性质

研究了四-(邻氯苯基)卟吩(OCITPP)和四苯基卟吩(TPP)系列的某些金属络合物在2,4-二硝基氯代苯(DNCB)存在下的可见吸收和荧光光谱, 发现吸收和荧光强度均比金属卟吩单独存在时为低, 表明金属卟吩作为给体, 与π受体DNCB形成分子络合物. OCLTPP系列的金属卟吩, 由于苯环上邻位氯取代降低分子对称性和产生空间阻碍等因素, 使它们与DNCB的络合常数减小, 从而削弱了受体对给体的荧光猝灭作用.     

C-3-吡唑啉基取代的叶绿素类二氢卟吩衍生物的合成

以脱镁叶绿酸-a甲酯为起始原料,通过对E-环、3-位碳碳双键和20-位meso-氢的结构修饰,在二氢卟吩色基上构建和引进不同的官能团,并进一步利用其3-位乙烯基与重氮甲烷的1,3-偶极环加成反应,完成一系列C-3-吡唑啉基取代的叶绿素类二氢卟吩衍生物的合成.同时,讨论了叶绿素衍生物的1,3-偶极环加成反应的的区域选择性与立体选择性.所得新的叶绿素类二氢卟吩衍生物的化学结构均经UV,IR,1H NMR及元素分析得以证实.     

新型meso-四(4-N-n-十二胺基磺酰苯基)四苯并卟啉的合成及其液晶性能

苯乙酸锌和邻苯二甲酰亚胺反应制得meso-四苯基四苯并卟啉锌(1);1酸化得meso-四苯基四苯并卟啉(2);2经氯磺化生成meso-四(4-氯磺基苯基)四苯并卟啉(3);3与n-十二胺反应合成了一种新型的苯并卟啉类化合物--meso-四(4-N-n-十二胺基磺酰苯基)四苯并卟啉(4),其结构经UV-Vis,<'1>H...     

meso-四-(对甲氧基)苯基卟啉和meso-四-(对甲氧基)苯基卟啉的电化学性质

锌卟啉配合物;合成;meso-四-(对甲氧基)苯基卟啉和meso-四-(对甲氧基)苯基卟啉的电化学性质     

焦脱镁叶绿酸-a甲酯的溴化反应

以焦脱镁叶绿酸-a甲酯为起始原料,通过与各种溴化剂的加成和取代反应,在3-位和meso-位上引进溴原子,分别得到单取代、三取代和四取代的溴化卟吩;其3-位乙烯基与溴化氢的加成则分别生成正常溴代产物和水解产物及其酯化产物.用四氧化锇和高碘酸钠将焦脱镁叶绿酸甲酯的3-位乙烯基氧化成醛,进而与四溴化碳和三苯基磷反应,生成3-位偕二溴取代焦脱镁叶绿酸衍生物.所合成的叶绿酸溴代衍生物均经UV, IR, 1H NMR及元素分析证明其结构.     

新型meso-四(4-十四氨基磺酰苯基)卟啉及其配合物的合成与液晶性能

以吡咯和苯甲醛为原料制得meso-四苯基卟啉(1);1经氯磺化得meso-四(4-氯磺苯基)卟啉(2);2与十四胺反应制得meso-四(4-十四氨基磺酰苯基)卟啉(3);3与醋酸镉经配位反应合成了meso-四(4-十四氨基磺酰苯基)镉卟啉(4)。3和4为新化合物,其结构经UV-Vis,1H NMR和IR表征。偏光显微镜和DSC检测结果表明:3和4均具有液晶性能。     

An ESR Study on Singlet Oxygen Photoproduction of the Meso-Tetrakis-(Substituted Phenyl) Porphine Derivatives

The ability of meso-tetrakis- (substituted phenyl) porphine derivatives for photo-generating singlet oxygen (O2) is studied by ESR spectrometry. The results show that the singlet oxygen yields of most of porphine derivatives are higher than that of HPD. It is also exhibited that the nature and structure of the substituent at the meso position are closely related to the photo-sensitizing ability of meso-tetrakis-(substituted phenyl) porphine.     

Aza‐BODIPY Derivatives: Enhanced Quantum Yields of Triplet Excited States and the Generation of Singlet Oxygen and their Role as Facile Sustainable Photooxygenation Catalysts

A new series of aza‐BODIPY derivatives ( 4 a – 4 c , 5 a , c , and 6 b , c ) were synthesized and their excited‐state properties, such as their triplet excited state and the yield of singlet‐oxygen generation, were tuned by substituting with heavy atoms, such as bromine and iodine. The effect of substitution has been studied in detail by varying the position of halogenation. The core‐substituted dyes showed high yields of the triplet excited state and high efficiencies of singlet‐oxygen generation when compared to the peripheral‐substituted systems. The dye 6 c , which was substituted with six iodine atoms on the core and peripheral phenyl ring, showed the highest quantum yields of the triplet excited state (Φ_T=0.86) and of the efficiency of singlet‐oxygen generation (Φ_Δ=0.80). Interestingly, these dyes were highly efficient as photooxygenation catalysts under artificial light, as well as under normal sunlight conditions. The uniqueness of these aza‐BODIPY systems is that they are stable under irradiation conditions, possess strong red‐light absorption (620–680 nm), exhibit high yields of singlet‐oxygen generation, and act as efficient and sustainable catalysts for photooxygenation reactions.     

9,12-Dibenzothiazolylhypericin and 10,11-Dibenzothiazolyl-10,11-didemethylhypericin: Photochemical Properties of Hypericin Derivatives Depending on the Substitution Site

Investigating the properties of similar but regioselectively differently substituted hypericin derivatives, 9,12-dibenzothiazolylhypericin was synthesized and compared with the recently prepared 10,11-analogue. A significant difference in the ability to generate singlet oxygen and/or reactive oxygen species and different absorption spectra of these two derivatives were observed.     

9,12-Dibenzothiazolylhypericin and 10,11-Dibenzothiazolyl-10,11-didemethylhypericin: Photochemical Properties of Hypericin Derivatives Depending on the Substitution Site

Summary. Investigating the properties of similar but regioselectively differently substituted hypericin derivatives, 9,12-dibenzothiazolylhypericin was synthesized and compared with the recently prepared 10,11-analogue. A significant difference in the ability to generate singlet oxygen and/or reactive oxygen species and different absorption spectra of these two derivatives were observed.     

Tuning photosensitized singlet oxygen generation efficiency of novel aza-BODIPY dyes

Novel aza-BODIPY derivatives substituted with heavy atoms such as bromine and iodine were synthesized, and their triplet and singlet oxygen generation efficiencies have been investigated. These derivatives showed absorption in the NIR region with high molar extinction coefficients. The dye substituted with four iodine atoms showed yields of Φ(T) = 0.78 and Φ((1)O(2)) = 0.70, which are the highest values so far obtained for the aza-BODIPY derivatives.     

Substituent and solvent effects on the photosensitized oxygenation of 5,6-dihydro-1,4-oxathiins. Intramolecular oxygen transfer vs normal cleavage of the dioxetane intermediates

The reaction of singlet oxygen with variously substituted oxathiins 1 affords dicarbonyl compounds 4 and/or ketosulfoxides 7 and 8 depending on the nature of the substituent at C3 and on the reaction conditions. The normal fragmentation of dioxetanes 2 to 4 competes with an intramolecular oxygen transfer to ring sulfur, which leads to 7 and 8, presumably via the labile epoxides 5. This new pathway is promoted by electron-withdrawing groups at C3 and, for unsubstituted and monosubstituted amide derivatives 1h and 1i, respectively, by the solvent basicity. Chemical experiments support the intermediacy of epoxides 5 for 7, whereas they are not conclusive for 8. However, the formation of the latter compounds appears to be favored by polar solvents and cation-stabilizing groups at C2 as phenyl or methyl, and these observations may be well accounted for by the suggested pathway from 5 through charged species as E. Direct oxidation by singlet oxygen to sulfur is unsignificant, except for the amide series and for 1g or when the oxygenation is carried out in methanol.     

Quantum-chemical simulation of the elementary step of the oxidation reactions of styrene and its derivatives involving <Superscript>1</Superscript>О<Subscript>2</Subscript> (<Superscript>1</Superscript>Δg)

The results of simulation of the oxidation reaction of styrene and its methyl (two isomers) and phenyl derivatives with molecular oxygen in the excited singlet state (¹Δg) have enabled the conclusion that the reaction can proceed through several mechanisms. For styrene and its phenyl derivative, three reaction channels are possible, and for the methyl derivative, there are four possible channels. For the first two substrates, the major channel is 1,2-addition to form dioxetane; for the methyl derivatives, an extra channel to give a hydroperoxide species is possible in addition to the above channel. The multichannel reaction character revealed by calculations makes it possible to qualitatively understand the reason behind the moderate selectivity (no more than 70%) of such reactions in the case of styrene and its derivatives.     

Oxygen transfer reactions. 4. Reaction of high valent oxoruthenium compounds with sulfides

The oxidation of methoxy substituted benzyl phenyl sulfides can be used to distinguish between oxidants that react by single electron transfer (followed by oxygen rebound) and those which react by direct oxygen atom transfer in a two-electron process. Transfer of a single electron results in the formation of an intermediate radical cation, which can undergo C-S bond cleavage and deprotonation reactions leading to the formation of methoxy substituted benzyl derivatives, methoxy substituted benzaldehydes, and diphenyl disulfide. The oxidation of 4-methoxybenzyl phenyl sulfide and 3,4,5-trimethoxybenzyl phenyl sulfide by oxidants known to participate in single electron transfers (Ce(4+), Mn(3+), and Cr(6+)) results in the formation of the corresponding benzaldehydes, benzyl alcohols, benzyl acetates, and benzyl nitrates in variable yields. However, the only products obtained from the oxidation of the same compounds with RuO(4), RuO(4-), and RuO(4)(2-) are sulfoxides and sulfones. Therefore, it is concluded that the oxidation of sulfides by oxoruthenium compounds likely proceeds by a concerted mechanism.     

Photophysical and photosensitizing properties of brominated porphycenes

A heavy atom, bromine, was directly substituted into the porphycene macrocycle to promote intersystem crossing by way of spin-orbit coupling. The singlet oxygen production ability of the porphycene is dramatically enhanced, and the highest value of 0.95 for the quantum yield of singlet oxygen generation (PhiDelta) was obtained for the dibrominated porphycene by visible light excitation.     

Synthesis of aza-BODIPY dyes bearing the naphthyl groups at 1,7-positions and application for singlet oxygen generation

Near-infrared absorbing aza-BODIPYs with the naphthyl groups at 1,7-positions were prepared for the first time. The singlet oxygen generation of aza-BODIPY with the naphthyl groups at 1,7-positions was more effective than that of the corresponding aza-BODIPY with the phenyl groups at 1,7-positions.