Synthesis and spectral properties of N4, N3S, and N2S2 porphyrins containing one, two, three, and four meso-furyl groups

Porphyrins with N₄, N₃S, and N₂S₂ cores having one, two, three, and four furyl groups at the meso-positions were synthesized by following various methodologies and characterized by using mass spectrometry, NMR spectroscopy, elemental analysis, absorption, and fluorescence spectroscopic techniques. NMR studies indicated that by replacing the meso-aryl groups with meso-furyl groups, the β-pyrrole and β-thiophene protons of porphyrins experienced considerable downfield shifts, supporting the alteration of π-delocalization of porphyrins on the introduction of meso-furyl groups. The absorption and emission bands of porphyrins experienced red shifts on the introduction of meso-furyl groups and the magnitude of red shifts vary linearly with the number of meso-furyl groups. Thus, the spectral studies supported a systematic alteration in spectral properties on successive introduction of meso-furyl groups.     

Synthesis of mono meso-pyridyl 21,23-dithiaporphyrins and unsymmetrical non-covalent porphyrin dimers

A new method has been developed to synthesize 21,23-dithiaporphyrins having one pyridyl group at the meso position. The method required easily available unknown precursors and the condensation resulted in mono meso-pyridyl 21,23-dithiaporphyrins as single products in 8-11% yield. Two of the three mono meso-pyridyl N₂S₂ porphyrins were used to synthesize non-covalent unsymmetrical porphyrin dimers containing one N₂S₂ and one N₄ porphyrin cores.     

meso-Multi(iodophenyl) porphyrins: synthesis, isolation, and identification

We report on a simple method for identification of a series of six meso-substituted porphyrins by ¹H NMR spectroscopy. The meso-substituted porphyrins are synthesized by a simple mixed-aldehyde condensation approach [3,5-di-tert-butylstyrylbenzaldehyde (A) and 4-iodobenzaldehyde (B)] to give the two parent porphyrins (A₄, B₄) and four hybrid porphyrins (A₃B, cis-A₂B₂, trans-A₂B₂, AB₃) which are isolated and characterized.     

Synthesis of meso-tetraarylporphyrins using SeO2 as oxidant

The oxidative step of the two-step, one-flask synthesis of meso-tetraarylporphyrins is herein conducted with heterogeneous oxidant SeO₂ instead of the usual quinones DDQ or p-chloranil. Evaluation of BF₃O(Et)₂ or I₂ amount for the condensation of the first step combined with the excess of SeO₂ defined porphyrin synthesis conditions employing benzaldehydes and pyrrole (or 5-phenyldipyrromethane) as starting materials. The simplicity of the workup, allied with reaction mild conditions, makes this method a good option for the synthesis of this kind of compound.     

Palladium-catalyzed meso-amination and amidation of porphyrins: marked acceleration with the Ni(II) central metal ion

The preparation of meso-amino and meso-amido substituted porphyrins was easily accomplished by palladium-mediated cross-coupling reactions of meso-brominated porphyrins with amines and amides. Ni(II) introduced as a central metal ion into the substrate porphyrin markedly accelerated the cross-coupling.     

An unprecedented regioselective lithiation of dipyrromethanes. Synthesis of meso-functionalized dipyrromethanes

Functionalization of meso-positions of dipyrromethanes, gives valuable intermediates through a highly regioselective lithiation-substitution sequence.     

Synthesis of highly substituted meso-tetraarylporphyrins

meso-Tetraphenylporphyrin (and its derivatives), in the reaction with fuming yellow nitric acid (d=1.53), form either 5-(4-nitroaryl)-10,15,20-triarylporphyrin, 5,10-bis(4-nitroaryl)-15,20-diarylporphyrin, or 5,10,15-tris(4-nitroaryl)-20-arylporphyrin, depending on the reaction temperature (0-20 °C), amounts of the acid used, and reaction time. The above nitroporphyrins react, in the presence of a base (t-BuOK) at 0 °C, with carbanions (which bear nucleophugal groups at the carbanionic center: ⁻CH(Cl)SO₂Tol, ⁻CH(Br)SO₂Tol, and ⁻CH(Cl)SO₂NMe₂), leading to the nucleophilic substitution of hydrogen in one or more of the meso-nitroaryl rings. By this route, the preparation of the highly substituted ‘synthetic’ porphyrins (bearing up to ten O-, N-, Cl-, or C-substituents) was demonstrated.     

Synthesis of α,β-unsaturated dioxanes, dioxolanes and dioxepanes by trans-acetalisation of dimethylacetals with meso or C2-symmetrical 1,2-, 1,3- and 1,4-diols

Several o-dibenzylic diols were prepared reacting organometallics with o-phthalaldehyde at room temperature in ether. The identity of the meso and C₂-symmetrical (d,l) isomers as well as their ratio were determined by chiral gas chromatography. The meso and C₂ (racemic) stereoisomeric diols were easily separated by flash chromatography on silica gel. A set of 18 α,β-unsaturated acetals were then prepared reacting those, as well as commercially available 1,2, 1,3 and 1,4 diols, with the corresponding methylacetals in acidic medium. A trans-acetalisation procedure adapted to the cases of fragile allylic alcohols or unfavorable 1,6 diols-derived dioxonanes based on a Dean-Stark trapping of methanol was also employed.     

Synthesis and characterizations of meso-disubstituted asymmetric porphycenes

A post-synthetic method has been developed to synthesize novel asymmetric porphycenes bearing two different substituents on the meso-positions. Nitration of 9-acetoxy-2,7,12,17-tetra-n-propylporphycene with AgNO₃ in CH₃COOH/CH₂Cl₂ occurs regioselectively at the 19-position of the macrocycle to give 9-acetoxy-19-nitro-2,7,12,17-tetra-n-propylporphycene (3a) which was readily converted to 9-acetoxy-19-amino-2,7,12,17-tetra-n-propylporphycene (4a) by the reduction with SnCl₂ in pyridine.     

中位-四(对烷氧苯基 )卟啉 Co2+、Cu2+、Zn2+、Pb2+配合物的合成与表征

Synthesis of fourteen new complexes of meso-tetrakis(4-alkoxyphenyl) porphyrins with Co²⁺, Cu²⁺, Zn²⁺, Pb²⁺ were presented in this paper.Meso-tetrakis (4-alkoxyphenyl) porphyrins were prepared by condensation of 4-alkoxybenzaldehydes with pyrrole, then treated with corresponding metallic acetate to produce mentioned complexes, IR, UV, ¹H NMR, MS and elementary analysis were explored to confirm the structures of all theses new complexes.Characteristic spectrometric data of IR, UV, ¹H NMR related to these complexes have been systematically summarized.Ten of the fourteen complexes were found to exhibit liquid crystal properties.     

Enhancement of phlorin stability by the incorporation of meso-mesityl substituents

The effect of sterically bulky mesityl substituents on the stability of meso-substituted phlorins was examined. Three different phlorins bearing zero, two or three mesityl substituents were prepared via alkylation of the appropriate porphyrins. The stability of each phlorin was examined by UV-vis spectral monitoring of dilute solutions exposed to ambient light and air. UV-vis and mass spectral analyses performed after decomposition revealed qualitative differences in the degradation products. This study shows that the selection and positioning of peripheral substituents can enhance phlorin stability.     

ZnIn2S4/Au纳米片阵列的制备及其可见光响应光电化学固氮特性

采用简单的水热法合成出单晶ZnIn₂S₄纳米片阵列以实现可见光响应光电化学固氮。并采用光沉积法将超细Au纳米颗粒（5 nm）沉积于ZnIn₂S₄纳米片的棱角位置处,实现了可见光俘获和载流子分离能力的同时增强。当负载合适含量的Au纳米颗粒,ZnIn₂S₄纳米片阵列的光电固氮活性由1.092 μg·cm^-2·h^-1提升至2.262 μg·cm^-2·h^-1。我们还提出一个简单模型用以阐明其性能增强机制,这也被光致发光（PL）谱和光电化学（PEC）性能结果所证实。     

Synthesis of thiadiazabicyclane and bis-1,3,5-dithiazinane by cyclothiomethylation of aliphatic diamines with CH2O and H2S

Cyclocondensation of aliphatic diamines with CH₂O and H₂S (1:3:2 ratio, 0 °C) was carried out to give thiadiazabicyclanes and dithiadiazabicyclanes (1:6:4 ratio), which were previously difficult to synthesize. Symmetric α,ω-bis-1,3,5-dithiazinanes were synthesized at 80 °C by this reaction. The stereochemistry of thiadiazabicyclanes was assigned by ¹H and ¹³C NMR spectroscopy and by theoretical DFT calculations, and of bis-dithiazinanes by X-ray diffraction study in the solid state.     

Conversion of NO in NO/N2, NO/O2/N2, NO/C2H4/N2 and NO/C2H4/O2/N2 Systems by Dielectric Barrier Discharge Plasmas

An experimental study on the conversion of NO in the NO/N₂, NO/O₂/N₂, NO/C₂H₄/N₂ and NO/C₂H₄/O₂/N₂ systems has been carried out using dielectric barrier discharge (DBD) plasmas at atmospheric pressure. In the NO/N₂ system, NO decomposition to N₂ and O₂ is the dominating reaction; NO conversion to NO₂ is less significant. O₂ produced from NO decomposition was detected by an on-line mass spectrometer. With the increase of NO initial concentration, the concentration of O₂ produced decreases at 298 K, but slightly increases at 523 K. In the NO/O₂/N₂ system, NO is mainly oxidized to NO₂, but NO conversion becomes very low at 523 K and over 1.6% of O₂. In the NO/C₂H₄/N₂ system, NO is reduced to N₂ with about the same NO conversion as that in the NO/N₂ system but without NO₂ formation. In the NO/C₂H₄/O₂/N₂ system, the oxidation of NO to NO₂ is dramatically promoted. At 523 K, with the increase of the energy density, NO conversion increases rapidly first, and then almost stabilizes at 93–91% of NO conversion with 61–55% of NO₂ selectivity in the energy density range of 317–550 J L⁻¹. It finally decreases gradually at high energy density. A negligible amount of N₂O is formed in the above four systems. Of the four systems studied, NO conversion and NO₂ selectivity of the NO/C₂H₄/O₂/N₂ system are the highest, and NO/O₂/C₂H₄/N₂ system has the lowest electrical energy consumption per NO molecule converted.     

Convergent synthesis of meso-ferrocenyl porphyrins for TiO2 sensitization

Electron-donating ferrocenyl moieties have been incorporated into supramolecular carboxyporphyrin architectures Zn(II)-5-ferrocenyl-10,20-bistolyl-15-(4-methylbenzoate)porphyrin (trans-Fc-ZnP-CO₂Me), Zn(II)-5-ferrocenyl-10,15,20-tris(4-methylbenzoate)porphyrin [trans-Fc-ZnP-(CO₂Me)₃], and Zn(II)-5,15-bisferrocenyl-10,20-bis(4-benzoate)porphyrin [trans-Fc₂-ZnP-(CO₂Me)₂] for self-assembly on metal oxide nanoparticles. Efficient and economic synthesis has required a convergent strategy toward reduced symmetry trans-A₂B₂ and trans-AB₂C substitution patterns about the porphyrin macrocycle minimizing the production of porphyrin side products and increasing yields of the target ferrocenylporphyrins. Preliminary spectroscopic data in solution and in the solid state bound to mesoporous TiO₂ films are discussed.     

g-C3N4/Bi2O2CO32D纳米片复合材料的制备及可见光催化性能研究

采用自组装和化学沉淀法分别制得两种可见光驱动复合材料石墨相氮化碳/碳酸氧铋(g-C_3N_4/Bi_2O_2CO_3).采用X射线衍射光谱(XRD),紫外可见光谱、扫描电镜(SEM)、N_2吸附、电化学阻抗谱(EIS)和X射线光电子能谱(XPS)等分析手段对制备的催化剂进行了表征.结果表明,制备方法对纳米复合材料的晶相、形态及光学性能没有影响,但是影响g-C_3N_4和Bi_2O_2CO_3之间的相互作用力,导致光生电子-空穴对的分离速率存在显著差异.以可见光驱动苯酚和罗丹明B的降解实验为探针反应检测催化剂的光催化性能.实验结果表明自组装法得到的异质结催化剂中相互作用力更强,催化效果最高.O_2-是罗丹明B降解反应的主要活性物种,染料的光敏化、Bi_2O_2CO_3与g-C_3N_4综合效应,导致光生载流子电荷分离效率更高.     

Synthesis, crystal structure, infrared and Raman spectra of Sr4Cu3(AsO4)2(AsO3OH)4·3H2O and Ba2Cu4(AsO4)2(AsO3OH)3

The two new compounds, Sr₄Cu₃(AsO₄)₂(AsO₃OH)₄·3H₂O (1) and Ba₂Cu₄(AsO₄)₂(AsO₃OH)₃(2), were synthesized under hydrothermal conditions. They represent previously unknown structure types and are the first compounds synthesized in the systems SrO/BaO-CuO-As₂O₅-H₂O. Their crystal structures were determined by single-crystal X-ray diffraction [space group C2/c, a=18.536(4) Å, b=5.179(1) Å, c=24.898(5) Å, β=93.67(3)°, V=2344.0(8) Å³, Z=4 for 1; space group P4₂/n, a=7.775(1) Å, c=13.698(3) Å, V=828.1(2) Å³, Z=2 for 2]. The crystal structure of 1 is related to a group of compounds formed by Cu²⁺-(XO₄)³⁻ layers (X=P⁵⁺, As⁵⁺) linked by M cations (M=alkali, alkaline earth, Pb²⁺, or Ag⁺) and partly by hydrogen bonds. In 1, worth mentioning is the very short hydrogen bond length, D···A=2.477(3) Å. It is one of the examples of extremely short hydrogen bonds, where the donor and acceptor are crystallographically different. Compound 2 represents a layered structure consisting of Cu₂O₈ centrosymmetric dimers crosslinked by As1φ₄ tetrahedra, where φ is O or OH, which are interconnected by Ba, As2 and hydrogen bonds to form a three-dimensional network. The layers are formed by Cu₂O₈ centrosymmetric dimers of CuO₅ edge-sharing polyhedra, crosslinked by As1O₄ tetrahedra. Vibrational spectra (FTIR and Raman) of both compounds are described. The spectroscopic manifestation of the very short hydrogen bond in 1, and ABC-like spectra in 2 were discussed.     

CH2(X 3B1)自由基与N2O反应的研究

The reaction dynamics of methylene radical CH2(X3B1) with N2O was investigated by Time-Resolved Fourier Transform Infrared Spectroscopy(TR-FTIRS). Pure CH2(X3B1) radicalwas produced via laser photolysis of ketene at 351 nm. Nascent viabrationally excited products CO, NO and HCN were observed. Some reaction pathways which may lead to these products were proposed and a possible reaction mechanism was outlined.     

The Al2O3-Fe2O3 Mixed Oxidic System, II. Catalytic Decomposition of N2O

N₂O decomposition was examined over a series of Al₂O₃-Fe₂O₃ mixed oxidic solids with composition ranging from 0 to 100% of Fe₂O₃. The catalytic activity of the solids runs parallel to the number of atoms of iron in the Al_2−x Fe_xO₃ solid solution phase. Two compensation effects are present. The first corresponds to catalysts rich in alumina, and the second one to catalysts rich in hematite. This revised version was published online in June 2006 with corrections to the Cover Date.     

水热法制备Sb2S3纳米棒有序阵列

以Sb(S₂CNEt₂)₃为单源前驱体，通过改变时间、温度、表面活性剂等反应条件，用水热法成功合成了各种尺寸的Sb₂S₃纳米棒及其有序阵列。X-射线衍射(XRD)、能量分散光谱(EDS)以及选区电子衍射(SAED)研究表明纳米棒由正交晶系Sb₂S₃单晶构成。扫描电子显微镜(SEM)和透射电子显微镜(TEM)研究显示Sb₂S