THE ISOLATION, CHARACTERIZATION AND OXIDATION REACTION OF ACTIVE INTERMEDIATES OF CYTOCHROME-P-450 MODEL SYSTEM OXOCHROMIUM(V) TETRAPHENYLPORPHYRIN COMPLEXES

Oxochromium (V) tetraphenylporphyrin complexes, O = Cr (V) TPP (Cl) PhI. O = Cr-(V) TPP (N3) PhI and O = Cr (V)TPP (p-CH3OC6H4O)1/2PhI were isolated from the reaction of Cr (III) TPP (Cl). Cr (III) TPP (N3) Py or Cr (III) TPP (p-CH3OC6H4O) THF with iodosy

OH~-存在下四苯基卟啉合钴氧化过程的电化学和光谱电化学

本文利用薄层伏安和现场光谱电化学方法考察了在EtCl_2中OH~-存在下四苯基卟啉合钴(TPP)CO~Ⅱ的电极氧化反应. 在低浓度OH~-存在下,(TPP)CO~Ⅱ与OH~-生成一配位的配合物(TPP)CO~Ⅱ(OH)~-,此配合物不可逆地被氧化为(TPP)CO~Ⅲ(OH)~-,氧化峰电位负移到0.53V,而卟啉环第一步氧化电位也负移到0.88 V.在高浓度OH~-存在下,(TPP)CO~Ⅱ(OH)~-氧化生成(TPP)Ca~Ⅲ(OH)_2~(2-),氧化电位随OH~-度增加向负移.卟啉环第一步和第二步氧化电位分别负移到0.57V和1.07V.同时观察到第二步氧化伴随后行化学反应,产物氧化电位在1.32V.测定了(TPP)CO~Ⅱ(OH)~-,(TPP)CO~Ⅲ(OH)~-和(TPP)Co~Ⅲ(OH)_2~(2-),(TPP)~+Co~Ⅲ(OH)~-和(TPP)~+Co~(Ⅲ)(OH)_2~(2-)各级配位化合物稳定常数.提出一个在OH~-滴定过程中(TPP)Co的各步配位反应及电化学反应的机理.

细胞色素P—450模拟体系的活性中间体-氧配位铬(V)四苯基卟啉配合物的分离、表征和氧化反应

氮气保护下二氯甲烷中铬(Ⅲ)四苯基卟琳衍生物在-40℃与亚碘酰苯反应,分离得氧配位铬(V)四苯基叶啉配合物:O=Cr(V)TPP(CI)PhI,O—Cr(V)TPP(N_3)PhI,O—Cr(V)TPP(p-CH_3O-C_6H_4O)1/2PhI.已经元素分析、可见、红外、顺磁、核磁和质谱法结构表征.这些配合物能氧化苯乙烯,环己醇,环己烯和环己烷,可作为细胞色素P—450模拟体系的活性中间体.

一种简易型顺磁波谱电化学池的设计和卟啉π-阳离子自由基的检测

设计了一种简易型全玻璃ESR薄层现场波谱电化学池,以高7mm,直径0.5mm的铂柱工作电极安放在直径1mm的玻璃管中,形成体积为4.7μl的薄层池,2ml溶液就可以工作。在二氯乙烷中,进行了薄层电化学性能表征,并对(TPP)H_2的电极氧化过程进行了研究,发现电生的(TPP)H_2阳离子自由基有动力学后行反应。可能的机理是自由基岐化反应伴随着Cl~-引起的异卟啉的生成反应。

ELECTROCHEMICAL AND INSITU SPECTROELECTROCHEMICAL STUDY OF (TETRAPHENYLPORPHINATO)MANGANESE (III) PERCHLORATE IN THE PRESENCE OF CHLORIDE ANIONS .1. REDUCTION PROCESSES

The mechanism of electrochemical redox reactions of (tetra-phenylporphinato) managanese(III) perchlorate, (TPP)Mn(III)ClO4, was studied In the presence of chloride anions in dichloroethane solution. It was demonstrated that Mn(II) or Mn (III) centre can be coordinated with only one chloride anion, this result makes an about 100 mV negative shift of half-wave potential of Mn (III)/Mn (II) reduction. An equilibrium constant of 2.2 x 10(4) was determined for the complexation reaction of Cl- and Mn(III) centre.

氯离子存在下四苯基卟啉合锰的电化学和现场光谱电化学 Ⅰ.还原过程

在二氯乙烷溶液中,研究了氯离子存在下四苯基卟啉合锰,(TPP)Mn(III)ClO_■,各步电极氧化还原的过程机理,证明了Mn(II),Mn(III)中心都只与一个Cl~-配位,其结果使锰卟啉中心金属Mn(III)/Mn(II)的半波电位负移约100mV,测定了Cl~-与Mn(III)中心的配位反应的平衡常数为2.2×10~4.

BIOMIMITICS OF OXIDASE AND OXYGENASE THE ELECTRONIC SPECTRA AND THE OXYGEN UPTAKE KINTICS FOR MPc AND MTPP (M = Fe, Co, Cu, Pc AND TFP - ARE DIANIONS OF PHTHALOCYANIN AND TETRAPHENYLPORPHYRINE, RESPECTIVELY)

The reaction rates of MTPP with oxygen in air are Inas than that with pure oxygen, the ratio is roughly the same as to the partial presence of imygen in air, The influences of S-ligand etbanethiol and O- litand Vc on the above Systems have also been investigated, the former makes the MP hands having more changes and the reaction rate constants becoming greater, the latter has less influence.

SURFACE CHARACTERIZATION OF COBALT TETRAPHENYLPORPHYRIN MODIFIED GLASSY CARBON ELECTRODE BY XPS

Surface structure of the glassy carbon surface modified with cobalt tetraphenyl-porphyrin (CoTPP) by thermal-treatment has been studied by XPS, DTA and TG. During the thermal treatment a bond can be formed between the glassy carbon surface and TPP. Therefore the stability of electrode for the catalysis of dioxygen reduction is improved. Upon thermal treatment at 600 degrees C, FWHM of Co(2p(2/2)) is broadened, the reason is due to overlapping of peaks of multiple states, the spin orbit separation between Co (2p(1/2)) and Co (2p(3/2)) increases to 15.5-16.3eV, which indicated a change from low spin divalent states, the kinetic energy of Co L3VV Auger line and Auger parameter also increase. These changes of central cobalt ion provide a suitable redox potential for Co(III)/Co(II) which is related to the activity for catalysis of dioxygen reduction.

Cloning and Comparative Studies of Seaweed Trehalose-6-Phosphate Synthase Genes

The full-length cDNA sequence (3219 base pairs) of the trehalose-6-phosphate synthase gene of Porphyra yezoensis (PyTPS) was isolated by RACE-PCR and deposited in GenBank (NCBI) with the accession number AY729671. PyTPS encodes a protein of 908 amino acids before a stop codon, and has a calculated molecular mass of 101,591 Daltons. The PyTPS protein consists of a TPS domain in the N-terminus and a putative TPP domain at the C-terminus. Homology alignment for PyTPS and the TPS proteins from bacteria, yeast and higher plants indicated that the most closely related sequences to PyTPS were those from higher plants (OsTPS and AtTPS5), whereas the most distant sequence to PyTPS was from bacteria (EcOtsAB). Based on the identified sequence of the PyTPS gene, PCR primers were designed and used to amplify the TPS genes from nine other seaweed species. Sequences of the nine obtained TPS genes were deposited in GenBank (NCBI). All 10 TPS genes encoded peptides of 908 amino acids and the sequences were highly conserved both in nucleotide composition (>94%) and in amino acid composition (>96%). Unlike the TPS genes from some other plants, there was no intron in any of the 10 isolated seaweed TPS genes.

Transfer and transport of phosphorus and silica in the turbidity maximum zone of the Changjiang estuary

The concentration of suspended particulate matter (SPM), sedimentation flux, and various forms of phosphorus and silica in turbidity maximum zone (TMZ) in the Changjiang (Yangtze) estuary was studied. Based on the budget of P and Si, their mass balances in the TMZ were calculated. Results show that the variation in concentration of dissolved inorganic silicon (DISi) was mainly controlled by seawater dilution, while that of dissolved inorganic phosphor-us (DIP) was considerably affected by the buffering of suspended matter and sediment. Our experiments showed that the sedimentation fluxes of SPM and particulate inorganic phosphorus (PIP), total particulate phosphorus (TPP), particulate inorganic silicon (PISi), and biological silicon (BSi) in the TMZ were 238.4 g m(-2) d(-1) and 28.3, 43.1, 79.0, 63.0 mg m(-2) d(-1), respectively. In addition, a simple method to estimate the ratio of resuspension of sediment in the TMZ was established, with which the rate in surface and bottom waters of the TMZ accounted for 55.7 and 66.1% of the total SPM, respectively, indicating that the sediment resuspension in the TMZ influenced significantly the mass balances of P and Si. Particulate adsorbed P (60.8%) and 35.5% of total particulate P discharged from the river were filtered and then deposited in the TMZ. The input flux of PIP from the river mouth was 55.9% of that of DIP, being important as biologically available P, while that of PISi was only 3.5% of DISi, showing that particulate adsorbed Si was much less important than particulate adsorbed P. (c) 2008 Elsevier Ltd. All rights reserved.