Studies on the effects of metal ions and counter anions on the aggregate behaviors of meso-tetrakis(p-sulfonatophenyl)porphyrin by absorption and fluorescence spectroscopy

The aggregation behaviors of meso-tetrakis(p-sulfonatophenyl)porphyrin (TPPS) in the function of metal ions and their counter anions (Cl(-), SO(4)(2-), and NO(3)(-)) were investigated by absorption, fluorescence spectroscopy and resonance scattering spectrum. It was shown that the TPPS J-aggregates could be effectively promoted by metal ions under lower ionic strength. Moreover, the prominent effects of counter ions (Cl(-), SO(4)(2-), and NO(3)(-)) on TPPS J- and/or H-aggregate formation at higher ionic strength were observed. These results suggested that the counter anions play a significant role in the formation of TPPS J- and/or H-aggregates and their conversion each other. Very interestingly, the absorption spectrum of metal ions investigated except for Co(2+) leaves a WINDOW from ca. 450 to 550nm centered at 490nm in which the absorption of Cu(2+) or Ni(2+) ions per se was very weak. The spectrum window might be really significant in avoiding possible spectrum interferences when porphyrins are chosen as spectrometric reagents for the determination of metal ions based on J-aggregation.     

氧化石墨烯固载四(p-硝基苯基)钴卟啉催化氧化乙苯的性能

为了模拟细胞色素P450酶的催化活性功能,提高金属卟啉的重复使用催化效率,通过π-π叠加相互作用将CoTNPP固载在氧化石墨烯(GO)上,形成一种仿生催化材料(CoTNPP/GO).用紫外可见光谱(UV-Vis)、傅里叶红外光谱(FT-IR)、比表面测试(BET)、X射线光电子能谱(XPS)、扫描电镜(SEM)和热重分析(TG)技术对该催化材料进行表征,并用于催化分子氧氧化乙苯.在最佳的反应温度和氧气压力(150℃和0.8 MPa)条件下,0.25g固载催化材料可重复使用8次,平均的乙苯转化率和醇酮产率分别为24.5%和16.3%.     

Study on the supramolecular system of meso-tetrakis (4-sulfonatophenyl) porphyrin and cyclodextrins by spectroscopy

The ability of beta-cyclodextrin (beta-CD), sulfurbutylether-beta-CD (SBE-beta-CD) and hydroxypropyl-beta-CD (HP-beta-CD) to break the aggregate of the meso-Tetrakis (4-sulfonatophenyl) porphyrin (TPPS4) and to form 2:1 inclusion complexes has been studied by adsorption and fluorescence spectroscopy. The formation constants are calculated, respectively by fluoremetry, from which the inclusion capacity of different CDs is compared and the inclusion mechanism of charged-beta-CD (SBE-beta-CD) is quite different from that of parent beta-CD. At lower pH, the complexation between HP-beta-CD and H2TPPS(2+)4 (the form of the diprotonated TPPS4) hampers the continuous protonation of the pyrrole nitrogen of TPPS4 and the hydrophobic cavity may prefer to bind an apolar neutral porphyrin molecule. 1HNMR data support the inclusion conformation of the porphyrin-cyclodextrin supramolecular system, indicating the interaction of meso-phenyl groups of TPPS4 with the cavity of CDs. For this host-guest inclusion model, cyclodextrin, being regarded as the protein component, which acts as a carrier enveloping the active site of heme prosthetic group within its hydrophobic environment, provides a protective sheath for porphyrin, creating artificial analogues of heme-containing proteins. However, the TPPS4, encapsulated within this saccharide-coated barrier, its physico-chemical, photophysical and photochemical properties changed strongly.     

环糊精和α-萘乙酸包络物的核磁共振研究

利用溶液2D-ROESY谱,利用溶液2D-ROESY谱, 13C固体高分辨谱以及自扩散系数测量等核磁共振技术, 研究了环糊精(CD)和α-萘乙酸(α-NAA)的相互作用. 结果表明, α-CD和β-CD均能与α-NAA形成包络物, 但是由于尺寸更为匹配, β-CD与α-NAA体系的包络相互作用强度明显比α-CD和α-NAA体系的大; 通过测量 β-CD与α-NAA混合溶液中α-NAA的自扩散系数, 计算出包络物结合与解离的平衡常数, 以此为基础对β-CD/α-NAA 体系在实现α-NAA缓释方面的应用方式进行了探讨. 13C固体高分辨谱以及自扩散系数测量等核磁共振技术, 研究了环糊精(CD)和α-萘乙酸(α-NAA)的相互作用. 结果表明, α-CD和β-CD均能与α-NAA形成包络物, 但是由于尺寸更为匹配, β-CD与α-NAA体系的包络相互作用强度明显比α-CD和α-NAA体系的大; 通过测量 β-CD与α-NAA混合溶液中α-NAA的自扩散系数, 计算出包络物结合与解离的平衡常数, 以此为基础对β-CD/α-NAA 体系在实现α-NAA缓释方面的应用方式进行了探讨.     

离子受体对自由卟啉探针荧光识别性能的影响

通过对2个N,N-二吡啶胺基受体修饰的自由卟啉化合物（Porphyrin-2-DPA）光学识别性能的系统研究,可以得知：该卟啉化合物中心刚性共轭的四吡咯环状结构不仅作为灵敏的光学信号基团、更是作为第一离子配位受体,在非共轭的N,N-二吡啶胺基受体辅助下,对Pb²⁺/Cu²⁺离子表现出灵敏的多重信号分析识别功能。     

Glucomannan from Narcissus poeticus Studied by PMR and 13C NMR Spectroscopy

Native acetylated glucomannan of molecular weight (MW) 32000 with a glucose:mannose ratio 1:30 was isolated from bulbs of Narcissus poeticus. Glucomannan was depolymerized to a fragment of MW 15000 with an unchanged primary structure and was studied using PMR and ¹³C NMR spectroscopy. It was found that the linear chain of the biopolymer consists of 1-4-bound D-gluco- and D-mannopyranose units and the O-Ac groups are localized on C-2, C-3, and C-6 hydroxyls in certain anhydromannose units.     

Cyclodextrin inclusion of four phenylurea herbicides: determination of complex stoichiometries and stability constants using solution 1H NMR spectroscopy

An inclusion complex formation between α- and β-cyclodextrin and four phenylurea analogues, namely metobromuron, monolinuron, monuron and fenuron, is reported. Complex formation was established using solution ¹H NMR spectroscopy. Complex stoichiometries were determined by the method of continuous variation using the chemically induced shifts of both the host and guest protons. An analysis of the spectroscopic data revealed the stoichiometry as 1:1 in all cases while a further analysis of the same data yielded values for the association constant K ranging from 208 to 2749 M^? 1. From the observed chemical shifts it was deduced that in all cases, only the guest aromatic ring enters the host cavities, the substituted urea moiety protruding from the secondary rim in the case of α-cyclodextrin, but from the primary rim in the case of β-cyclodextrin.     

Measurement of the Hydrolysis of Tin Tetraacetate by Proton and Carbon-13 NMR Spectroscopy

Solid-state ^l3C CP/MAS spectral analysis of the hydrolysis products of Sn(OAc)₄ allowed the hydrolysis intermediates, Sn(OH)(OAc)₃, Sn(OH)₂(OAc)₂ and Sn(OH)₃(OAc), to be identified. The results show that the hydrolysis consists of three steps; the first and second steps are consecutive reactions and the third is reversible. Intermolecular exchange between hydrolysis products (i.e. Sn(OAc)⁴, Sn(OH)(OAc)₂, Sn(OH)₂(OAc)₂ and Sn(OH)₃(OAc),) and acetic acid was observed from the measurement of ¹H and ¹³C solution spectra at varied temperatures in CD₂Cl₂ with ΔG^?₃₄₈ 50.5 kJ mol^?1.     

四-(对甘-缬二肽苯基)卟啉及其过渡金属配合物的研究

本文以四-(对氨基苯基)卟啉和N-氯乙酰缬氨酸为原料，在DMF中首次合成了一种新型的含二肽基团的四苯基卟啉，四-(对甘-缬二肽苯基)卟啉(H₂L)，及其Mn(Ⅲ)、Fe(Ⅲ)、Co(Ⅱ)、Ni(Ⅱ)、Cu(Ⅱ)、Zn(Ⅱ)配合物MnLCl, FeLCl, CoL, NiL, CuL, ZnL，用元素分析、红外光谱、电子光谱、荧光光谱、氢核磁共振谱和激光拉曼光谱进行了表征，研究了这些新型配合物与含N、S碱的轴向加合性质。     

Stabilization of All-trans-retinol by Cyclodextrins: A Comparative Study Using HPLC and Fluorescence Spectroscopy

Purpose: To formulate preparations incorporating cyclodextrins (CDs) which could be used for direct delivery to the retina of vitamin A (all-trans-retinol), while also protecting it from degradation in the aqueous environment. Vitamin A supplementation is being considered for treatment of several ophthalmic diseases characterised by progressive photoreceptor degeneration. Methods: The complexation between vitamin A and ten cyclodextrins, Captisol^®(sulfobutyl ether-7--cyclodextrin), hydroxypropyl--CD, 2-hydroxypropyl--CD, -CD, hydroxypropyl--CD, hydroxypropyl--CD, -CD, methyl--CD,Heptakis-(2,6-di-O-methyl)--CD andHeptakis-(2,3,6-tri-O-methyl)--CD,was investigated using bothhigh sensitivity fluorescence spectrometry and HPLC (high pressure liquid chromatography). Samples of retinol-CD complexes in phosphate buffer, pH 7.4 were analysed for up to 72 hours. Optimum conditions for formation of the Captisol-retinol complexes were investigated. Results: Using spectroscopic measurements and HPLC, the complexes formed between ten cyclodextrins and all-trans-retinol were evaluated. The results indicate that all cyclodextrins tested were able to form inclusion complexes as shown by the fluorescence signals which are considerably larger than those obtained in the absence of cyclodextrin. Only minimal degradation of retinol over 48 hours was observed with three of these cyclodextrins. Captisol was able to stabilise all-trans-retinol for up to 72 hours, as shown by HPLC, and the optimum ratio of Captisol to retinol was determined to be 50 to 1. Addition of glutathione and decrease in pH did not improve stability of the complex. Conclusions: This survey suggests that Captisol and other cyclodextrins could be used to stabilise and solubilise vitamin A in aqueous media and this establishes the basis for an ocular Captisol-retinol drug delivery system now under development in our laboratory.     

核磁共振谱研究PAA-F108-PAA 嵌段共聚物的胶束化行为

采用原子转移自由基聚合伴随水解的方法合成了聚丙烯酸-聚醚嵌段共聚物(PAA-F108-PAA), 并通过氢核磁共振波谱和二维核Overhauser效应谱(2D NOE)研究了温度、 羧酸基团中和度(α)及盐浓度对PAA-F108-PAA嵌段共聚物在水溶液中胶束化行为的影响. 结果表明, PAA-F108-PAA分子的临界胶束化温度受α影响较小, 受盐的种类和浓度影响较大. 当α=0.14(0.01 mol/L KCl)时, 在6 ℃条件下, PAA-F108-PAA分子处于塌缩状态, 而在60 ℃条件下, 聚氧化丙烯(PPO)链段发生疏水聚集形成胶束的核, PAA链段与PEO链段相互作用形成胶束的壳; 当α=0.80(0.01 mol/L KCl)时, 在6 ℃条件下, PAA-F108-PAA分子处于相对伸展状态, 而在60 ℃条件下, PPO链段仍发生疏水聚集形成胶束的核, PEO与PAA彼此分离形成胶束的壳. 增加KCl的浓度至1 mol/L, PAA-F108-PAA分子的临界胶束化温度显著降低, KCl对PPO和PEO链段都表现出脱水作用. 但KI的浓度增加至1 mol/L时, PAA-F108-PAA分子的临界胶束化温度仅略微增加, KI对PPO链段表现出脱水作用, 而对PEO链段表现出增溶作用.     

Glycosylation States on Intact Proteins Determined by NMR Spectroscopy

Protein glycosylation is important in many organisms for proper protein folding, signaling, cell adhesion, protein-protein interactions, and immune responses. Thus, effectively determining the extent of glycosylation in glycoprotein therapeutics is crucial. Up to now, characterizing protein glycosylation has been carried out mostly by liquid chromatography mass spectrometry (LC-MS), which requires careful sample processing, e.g., glycan removal or protein digestion and glycopeptide enrichment. Herein, we introduce an NMR-based method to better characterize intact glycoproteins in natural abundance. This non-destructive method relies on exploiting differences in nuclear relaxation to suppress the NMR signals of the protein while maintaining glycan signals. Using RNase B Man5 and RNase B Man9, we establish reference spectra that can be used to determine the different glycoforms present in heterogeneously glycosylated commercial RNase B.     

5,10,15,20-四(对-磺酸苯基)卟啉四钠盐水溶液的稀释热和活度系数的研究

使用LKB 2107微热量计系统和等压法测量仪,分别测量了25℃时5,10,15,20-四(对-磺酸苯基)卟啉四钠盐水溶液的稀释热和活度系数,计算了相对偏摩焓。     

Chirality Recognition of Selenium Compounds by NMR Spectroscopy in the Presence of a Chiral Dirhodium Complex

Abstract

Diastereomeric adducts of chiral soft-base selenium ligands with the enantiopure dirhodium complex Rh* allows stereodifferentiation by NMR spectroscopy of various nuclei (dirhodium method). The individual adduct species can be identified by low-temperature NMR spectroscopy.     

超高灵敏显色剂meso-四(4-氯苯基)卟啉与钴反应的分光光度法研究

本文研究了新显色剂meso-四(4-氯苯基)卟啉与钴的反应条件。在表面活性剂存在下,90℃恒温加热15min,试剂与钴形成稳定的1:1配合物。λ_(max)=420nm,ε_(420)=7.94×10~5L·mol~(-1)·cm~(-1),0～3.2μgCo/25ml符合比尔定律,为目前已报道的分光光度法测定钴最灵敏的方法。用来测定维生素B_(12)针剂中微量钴,结果满意。     

Study on Inclusion Complexes of Cyclodextrin with Sodium Dodecyl Polyoxyethylenated Sulfonate Using Microcalorimetry and 1H NMR

The association of α‐, β‐ and γ‐cyclodextrin (α‐CD, β‐CD and γ‐CD) with sodium dodecyl polyoxyethylenated sulfonate (C₁₂E_nS n=1, 3) was studied by means of isothermal titration calorimetry and ¹H NMR measurements in aqueous solution at T=298.15 K. The results indicate that the binding processes of β‐CD with the surfactants are characterized by both enthalpy favorable and entropy favorable, while those of α‐CD or γ‐CD with the surfactants are mainly entropy driven. The stoichiometry of β‐CD binding with the surfactants is different with different numbers of oxyethyl groups in surfactant molecules, while that of α‐CD or γ‐CD binding with the surfactants makes no difference. The ¹H NMR spectra reveal that chemical shift data of all protons in α‐CD, β‐CD and γ‐CD molecules move to high field in the presence of C₁₂E_nS, which can be regarded as a microscopic evidence of the occurrence of inclusion interaction.     

The increment scheme for the prediction of13C NMR chemical shifts in polychlorinated dibenzo-p-dioxins

A topological method for the calculation of¹³C NMR chemical shifts was developed for polychlorinated dibenzo-p-dioxins (PCDD). Based on previous results for polychlorinated benzenes and polyhydroxybenzenes, the collective influence of the substituents on carbon chemical shifts is presented as the sum of two-particle increments. The increments only of two new monosubstituted graphs have to be added to those known for PCDD spectra: 1-Cl-DD and 2-Cl-DD. All structural situations in the¹³C NMR chemical shifts of the whole class of 75 PCDD can be covered with a few model compounds. The coefficients of the increment scheme are independent of the change of CDCl₃ for acetone-d₆, so it may be a new reliable criterion for recognizing PCDD by¹³C NMR, in spite of the close resemblance of NMR spectra of aromatic compounds.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 280–284, February, 1995.     

分子筛材料的酸性和择形选择性的固体核磁共振研究

分子筛材料具有酸性可调节和择形选择性的优势, 因而在多相催化反应中表现出优异的性能. 本文综述了利用固体核磁共振(ssNMR)光谱对分子筛的酸性和择形选择性进行研究的最新进展. 通过采用或不采用探针分子的ssNMR技术, 探测了分子筛中酸性位的数量、 酸强、 酸类型及酸位之间的协同作用. 此外, 通过直接观察多相催化反应中关键中间体的存在, ssNMR光谱提供了分子筛择形选择性的证据. 酸性和择形选择性的协同作用有助于更好地设计分子筛材料, 以实现更好的多相催化.     

Study of Lysozyme Glycation Reaction by Mass Spectrometry and NMR Spectroscopy

The Advanced Glycation End Products (AGEs) are the causative substances of lifestyle‐habit illness. To elucidate the glycation mechanism of the protein, the reaction of lysozyme with D ‐glucose was analyzed by the fluorescence, TOF‐MS, and ¹³C‐NMR spectroscopy under the physiological condition. The fluorescence intensity of lysozyme in the glycation solution increased proportionally with a reaction time of ten weeks. The MALDI‐TOF‐MS spectra of the reaction solution after two weeks showed a peak at m/z 15066, which indicated the presence of a larger molecule than the native lysozyme (m/z 14331), and new peaks at m/z 30105 (dimer) and 45000 (trimer) were also observed. The spectral analysis supported the assumption of a continuous glycation reaction of D ‐glucose with lysozyme and a 30% transformation of lysozyme to the dimeric form during ten weeks. The ¹³C‐NMR spectra of lysozyme showed six [¹³C]‐labeled signals by the glycation reaction with [¹³C]‐glucose after two weeks of reaction. The combined analysis of TOF‐MS and ¹³C‐NMR spectra uncovered that first products of the glycation reaction of lysozyme with D ‐glucose can be observed already three hours after starting the reaction and that nine D ‐glucose units are attached during ten weeks at 37°.