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1.
Coordination Chemistry of [Co(acac)2] with N‐Doped Graphene: Implications for Oxygen Reduction Reaction Reactivity of Organometallic Co‐O4‐N Species 下载免费PDF全文
Jongwoo Han Young Jin Sa Yeonjun Shim Min Choi Prof. Dr. Noejung Park Prof. Dr. Sang Hoon Joo Prof. Dr. Sungjin Park 《Angewandte Chemie (International ed. in English)》2015,54(43):12622-12626
Hybridization of organometallic complexes with graphene‐based materials can give rise to enhanced catalytic performance. Understanding the chemical structures within hybrid materials is of primary importance. In this work, archetypical hybrid materials are synthesized by the reaction of an organometallic complex, [CoII(acac)2] (acac=acetylacetonate), with N‐doped graphene‐based materials at room temperature. Experimental characterization of the hybrid materials and theoretical calculations reveal that the organometallic cobalt‐containing species is coordinated to heterocyclic groups in N‐doped graphene as well as to its parental acac ligands. The hybrid material shows high electrocatalytic activity for the oxygen reduction reaction (ORR) in alkaline media, and superior durability and methanol tolerance to a Pt/C catalyst. Based on the chemical structures and ORR experiments, the catalytically active species is identified as a Co‐O4‐N structure. 相似文献
2.
Dr. Regan D. Hartnell Tomoki Yoneda Hirotaka Mori Prof. Atsuhiro Osuka Prof. Dennis P. Arnold 《化学:亚洲杂志》2013,8(11):2670-2679
A meso‐bromidoplatiniobis(triphenylphosphine) η1‐organometallic porphyrin monomer was prepared by the oxidative addition of meso‐bromoZnDPP (DPP=dianion of 5,15‐diphenylporphyrin) to a platinum(0) species. The meso–meso directly linked dimeric porphyrin ( 5 ) was prepared from this monomer by silver(I)‐promoted oxidative coupling and planarized to give a triply linked dizinc(II) porphyrin dimer ( 8 ). Acidic demetallation of 8 afforded the bis(free base) 9 . Dimer 5 was demetallated then remetallated with nickel(II) to give the dinickel(II) analogue 10 , the X‐ray crystal structure of which showed a twisted molecule with ruffled, orthogonal NiDPP rings, terminated by square‐planar trans‐[Pt(PPh3)2Br] units. New compounds were fully characterized spectroscopically, and the fused diporphyrin exhibited a broad, low‐energy, near‐IR electronic absorption band near 1100 nm. Electrochemical measurements of this series indicate that the organometallic fragment is a strong electron donor towards the porphyrin ring. The triply linked organometallic diporphyrin has a substantially lowered first one‐electron oxidation potential (?0.35 V versus the ferrocene/ferrocenium couple (Fc/Fc+)) and a narrow HOMO–LUMO gap of 0.96 V. Solutions prepared for NMR spectroscopy slowly decompose with degradation of the signals, which is attributed to partial oxidation to the cation radical. This paramagnetic species can be reduced in situ by hydrazine to restore the NMR spectrum to its former appearance. The combined influence of the two [Pt(PPh3)2Br] electron‐donating substituents is sufficient to make dimer 5 too aerobically unstable to allow further elaboration. 相似文献
3.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2018,130(18):5075-5079
Reported here is the chelate effect as a design principle for tuning heterogeneous catalysts for electrochemical CO2 reduction. Palladium functionalized with a chelating tris‐N‐heterocyclic carbene (NHC) ligand (Pd‐timtmbMe) exhibits a 32‐fold increase in activity for electrochemical reduction of CO2 to C1 products with high Faradaic efficiency (FEC1=86 %) compared to the parent unfunctionalized Pd foil (FE=23 %), and with sustained activity relative to a monodentate NHC‐ligated Pd electrode (Pd‐mimtmbMe). The results highlight the contributions of the chelate effect for tailoring and maintaining reactivity at molecular‐materials interfaces enabled by surface organometallic chemistry. 相似文献
4.
Enzyme Design from the Bottom Up: An Active Nickel Electrocatalyst with a Structured Peptide Outer Coordination Sphere 下载免费PDF全文
Dr. Matthew L. Reback Dr. Garry W. Buchko Dr. Brandon L. Kier Bojana Ginovska‐Pangovska Dr. Yijia Xiong Dr. Sheri Lense Dr. Jianbo Hou Dr. John A. S. Roberts Dr. Christina M. Sorensen Dr. Simone Raugei Dr. Thomas C. Squier Dr. Wendy J. Shaw 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(6):1510-1514
Catalytic, peptide‐containing metal complexes with a well‐defined peptide structure have the potential to enhance molecular catalysts through an enzyme‐like outer coordination sphere. Here, we report the synthesis and characterization of an active, peptide‐based metal complex built upon the well‐characterized hydrogen production catalyst [Ni(PPh2NPh)2]2+ (PPh2NPh=1,3,6‐triphenyl‐1‐aza‐3,6‐diphosphacycloheptane). The incorporated peptide maintains its β‐hairpin structure when appended to the metal core, and the electrocatalytic activity of the peptide‐based metal complex (≈100,000 s?1) is enhanced compared to the parent complex ([Ni(PPh2NAPPA)2]2+; ≈50,500 s‐1). The combination of an active molecular catalyst with a structured peptide provides a scaffold that permits the incorporation of features of an enzyme‐like outer‐coordination sphere necessary to create molecular electrocatalysts with enhanced functionality. 相似文献
5.
Dr. Samuel M. Meier Maria Novak Dr. Wolfgang Kandioller Dr. Michael A. Jakupec Prof. Dr. Vladimir B. Arion Prof. Dr. Nils Metzler‐Nolte Prof. Dr. Bernhard K. Keppler Prof. Dr. Christian G. Hartinger 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(28):9297-9307
Organometallic Ru(arene)–peptide bioconjugates with potent in vitro anticancer activity are rare. We have prepared a conjugate of a Ru(arene) complex with the neuropeptide [Leu5]‐enkephalin. [Chlorido(η6‐p‐cymene)(5‐oxo‐κO‐2‐{(4‐[(N‐tyrosinyl‐glycinyl‐glycinyl‐phenylalanyl‐leucinyl‐NH2)propanamido]‐1H‐1,2,3‐triazol‐1‐yl)methyl}‐4H‐pyronato‐κO)ruthenium(II)] ( 8 ) shows antiproliferative activity in human ovarian carcinoma cells with an IC50 value as low as 13 μM , whereas the peptide or the Ru moiety alone are hardly cytotoxic. The conjugation strategy for linking the Ru(cym) (cym=η6‐p‐cymene) moiety to the peptide involved N‐terminal modification of an alkyne‐[Leu5]‐enkephalin with a 2‐(azidomethyl)‐5‐hydroxy‐4H‐pyran‐4‐one linker, using CuI‐catalyzed alkyne–azide cycloaddition (CuAAC), and subsequent metallation with the Ru(cym) moiety. The ruthenium‐bioconjugate was characterized by high resolution top‐down electrospray ionization mass spectrometry (ESI‐MS) with regard to peptide sequence, linker modification and metallation site. Notably, complete sequence coverage was obtained and the Ru(cym) moiety was confirmed to be coordinated to the pyronato linker. The ruthenium‐bioconjugate was analyzed with respect to cytotoxicity‐determining constituents, and through the bioconjugate models [{2‐(azidomethyl)‐5‐oxo‐κO‐4H‐pyronato‐κO}chloride (η6‐p‐cymene)ruthenium(II)] ( 5 ) and [chlorido(η6‐p‐cymene){5‐oxo‐κO‐2‐([(4‐(phenoxymethyl)‐1H‐1,2,3‐triazol‐1‐yl]methyl)‐4H‐pyronato‐κO}ruthenium(II)] ( 6 ) the Ru(cym) fragment with a triazole‐carrying pyronato ligand was identified as the minimal unit required to achieve in vitro anticancer activity. 相似文献
6.
Mario Fasching Wolfgang Schmidt Bernhard Krutler Erhard Stupperich Andrea Schmidt Christoph Kratky 《Helvetica chimica acta》2000,83(9):2295-2316
Coα‐(1H‐Imidazol‐1‐yl)‐Coβ‐methylcob(III)amide ( 4 ) was synthesized by methylation with methyl iodide of (1H‐imidazol‐1‐yl)cob(I)amide, obtained by electrochemical reduction of Coα‐(1H‐imidazol‐1‐yl)‐Coβ‐cyanocob(III)amide ( 5 ). The spectroscopic data and a single‐crystal X‐ray structure analysis indicated 4 to exhibit a base‐on constitution in solution and in the crystal. The crucial lengths of the axial Co−N and Co−CH3 bonds also emerged from the crystallographic data and were found to be smaller by 0.1 and 0.02 Å, respectively, than those in methylcob(III)alamin ( 2 ). The data of 4 support the view, that the `long' axial Co−N bonds as determined by X‐ray crystallography for the B12‐dependent methionine synthase, for methylmalonyl‐CoA mutase, and for glutamate mutase represent stretched Co−N bonds. The thermodynamic effect (the `trans influence') of the 1H‐imidazole base in 4 on the organometallic reactivity of this model for protein‐bound organometallic B12 cofactors was examined by studying Me‐group‐transfer equilibria in aqueous solution and using (5′,6′‐dimethyl‐1H‐benzimidazol‐1‐yl)cobamides (cobalamins) as reaction partners (Schemes 2 – 5, Table). In comparison with methylcob(III)alamin ( 2 ), 4 was found to be destabilized for an abstraction of the Co‐bound Me group by a CoIII electrophile. In contrast, the abstraction of the Co‐bound Me group by a radical(oid) CoII species was not significantly influenced thermodynamically by the exchange of the nucleotide base. Likewise, exploratory Me‐group‐transfer experiments with Me−CoIII and nucleophilic CoI corrinoids at pH 6.8 provided an apparent equilibrium constant near unity. However, this finding also was consistent with partial protonation of the imidazolylcob(I)amide at pH 6.8, suggesting an interesting pH dependence of the Megroup‐transfer equilibrium near neutral pH. Therefore, the replacement of the 5′,6′‐dimethyl‐1H‐benzimidazole base by an 1H‐imidazole moiety, as observed in methyl transferases and in C‐skeleton mutases, does not by itself strongly alter the inherent reactivity of the B12 cofactors in the crucial homolytic and nucleophilic‐heterolytic reactions involving the organometallic bond, but may help to enhance the control of the organometallic reactivity by protonation/deprotonation of the axial base. 相似文献
7.
Investigation of calcium-induced, noncovalent association of calmodulin with melittin by electrospray ionization mass spectrometry 总被引:1,自引:0,他引:1
Olga V. Nemirovskiy Ragulan Ramanathan Michael L. Gross 《Journal of the American Society for Mass Spectrometry》1997,8(8):809-812
Noncovalent association of Ca2+-loaded calmodulin with a target peptide melittin was studied by electrospray ionization mass spectrometry (ESI-MS). ESI-MS does not reveal any binding of the apocalmodulin to the melittin. Partial loading of calmodulin with calcium leads to weak association with melittin. Upon binding of two calcium ions to the protein, changes in the conformation of calmodulin occur; these changes are sufficient to promote binding of melittin. Saturation of the protein with Ca2+ (a distribution of up to seven calcium ions is detected) induces a large increase of the binding to melittin. The stoichiometry of peptide binding to calmodulin is 1:1. 相似文献
8.
Conrad A. P. Goodwin Jing Su Thomas E. Albrecht‐Schmitt Anastasia V. Blake Enrique R. Batista Scott R. Daly Stefanie Dehnen William J. Evans Andrew J. Gaunt Stosh A. Kozimor Niels Lichtenberger Brian L. Scott Ping Yang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(34):11821-11825
We report the small‐scale synthesis, isolated yield, single‐crystal X‐ray structure, 1H NMR solution spectroscopy /solid‐state UV/Vis‐nIR spectroscopy, and density functional theory (DFT)/ab initio wave function theory calculations on an Am3+ organometallic complex, [Am(C5Me4H)3] ( 1 ). This constitutes the first quantitative data on Am?C bonding in a molecular species. 相似文献
9.
Mani Mary Sheeba Manoharan Muthu Tamizh Nattamai S.P. Bhuvanesh Ramasamy Karvembu 《应用有机金属化学》2019,33(2)
The newfangled chiral aroylthiourea ligands (L1‐L6) were produced from unprotected D/L‐alanine and their water soluble Ru (II) organometallic catalysts ( 1 – 6 ) were designed from their reaction with [RuCl2(η6‐p‐cymene)]2. The analytical and spectral methods were used to confirm the structure of the ligands and complexes. The solid state structure of L1, 5 and 6 was confirmed by single crystal XRD. The organometallic compounds ( 1 – 6 ) catalyzed the asymmetric transfer hydrogenation of aromatic, heteroaromatic and bulky ketones to yield respective enantiopure secondary alcohols with admirable conversions (up to 99%) and attractive enantiomeric excesses (ee up to 98%), in presence of formic acid and triethylamine in water medium under non‐inert atmospheric conditions. 相似文献
10.
Joachim Heinicke Nidhi Gupta Shreeyukta Singh Anushka Surana Olaf Kühl Raj K. Bansal Konstantin Karaghiosoff Martin Vogt 《无机化学与普通化学杂志》2002,628(13):2869-2876
1H‐1, 3‐Benzazaphospholes react with M(CO)5(THF) (M = Cr, Mo, W) to give thermally and relatively air stable η1‐(1H‐1, 3‐Benzazaphosphole‐P)M(CO)5 complexes. The 1H‐ and 13C‐NMR‐data are in accordance with the preservation of the phosphaaromatic π‐system of the ligand. The strong upfield 31P coordination shift, particularly of the Mo and W complexes, forms a contrast to the downfield‐shifts of phosphine‐M(CO)5 complexes and classifies benzazaphospholes as weak donor but efficient acceptor ligands. Nickelocene reacts as organometallic species with metalation of the NH‐function. The resulting ambident 1, 3‐benzazaphospholide anions prefer a μ2‐coordination of the η5‐CpNi‐fragment at phosphorus to coordination at nitrogen or a η3‐heteroallyl‐η5‐CpNi‐semisandwich structure. This is shown by characteristic NMR data and the crystal structure analysis of a η5‐CpNi‐benzazaphospholide. The latter is a P‐bridging dimer with a planar Ni2P2 ring and trans‐configuration of the two planar heterocyclic phosphido ligands arranged perpendicular to the four‐membered ring. 相似文献
11.
Dr. Henrik Junge Dr. Nicolas Marquet Anja Kammer Stefania Denurra Prof. Dr. Matthias Bauer Dr. Sebastian Wohlrab Felix Gärtner Dr. Marga‐Martina Pohl Dr. Anke Spannenberg Prof. Dr. Serafino Gladiali Prof. Dr. Matthias Beller 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(40):12749-12758
Molecularly defined Ir complexes and different samples of supported IrO2 nanoparticles have been tested and compared in the catalytic water oxidation with cerium ammonium nitrate (CAN) as the oxidant. By comparing the activity of nano‐scaled supported IrO2 particles to the one of organometallic complexes it is shown that the overall activity of the homogeneous Ir precursors is defined by both the formation of the homogeneous active species and its conversion to IrIV ‐ oxo nanoparticles. In the first phase of the reaction the activity is dominated by the homogeneous active species. With increasing reaction time, the influence of nano‐sized Ir ‐ oxo particles becomes more evident. Notably, the different conversion rates of the homogeneous precursor into the active species as well as the conversion into Ir‐oxo nanoparticles and the different particle sizes have a significant influence on the overall activity. In addition to the homogeneous systems, IrO2@MCM‐41 has also been synthesized, which contains stabilized nanoparticles of between 1 and 3 nm in size. This latter system shows a similar activity to IrCl3 ? xH2O and complexes 4 and 5 . Mechanistic insights were obtained by in situ X‐ray absorption spectroscopy and scanning transmission electron microscopy. 相似文献
12.
Clamshell Opening in the Mixed‐Metal Supramolecular Aggregates Formed by Fourfold Reduced Corannulene for Maximizing Intercalated Metal Content 下载免费PDF全文
Dr. Alexander S. Filatov Dr. Alexander V. Zabula Dr. Sarah N. Spisak Prof. Dr. Andrey Yu. Rogachev Prof. Dr. Marina A. Petrukhina 《Angewandte Chemie (International ed. in English)》2014,53(1):140-145
The first members of a new class of supramolecular organometallic compounds with mixed‐alkali‐metal cluster cores, LiK5 and Li3K3, sandwiched between two four‐fold reduced corannulene decks are prepared and fully characterized. The triple‐decker supramolecular anions, [(C20H104?)(LiK5)6+(C20H104?)]2? and [(C20H104?)(Li3K3)6+(C20H104?)]2?, illustrate a record ability of bowl‐shaped and highly charged corannulene to provide all its sites, five benzene rings fused to a central five‐membered ring, for binding of six alkali‐metal ions. The previously unseen engagement of the hub‐site of C20H104? in lithium binding is accompanied by unprecedented shifts up to ?24 ppm in 7Li NMR spectra. The discussion of product formation mechanism, augmented by calculations, is provided. 相似文献
13.
Xiao‐Yan Li Qi‐Kui Liu Jian‐Ping Ma Ru‐Qi Huang Yu‐Bin Dong 《Acta Crystallographica. Section C, Structural Chemistry》2009,65(2):m45-m47
In the organometallic silver(I) supramolecular complex poly[[silver(I)‐μ3‐3‐[4‐(2‐thienyl)‐2H‐cyclopenta[d]pyridazin‐1‐yl]benzonitrile] perchlorate methanol solvate], {[Ag(C18H11N3S)](ClO4)·CH3OH}n, there is only one type of AgI center, which lies in an {AgN2Sπ} coordination environment. Two unsymmetric multidentate 3‐[4‐(2‐thienyl)‐2H‐cyclopenta[d]pyridazin‐1‐yl]benzonitrile (L) ligands link two AgI atoms through π–AgI interactions into an organometallic box‐like unit, from which two 3‐cyanobenzoyl arms stretch out in opposite directions and bind two AgI atoms from neighboring box‐like building blocks. This results in a novel two‐dimensional network extending in the crystallographic bc plane. These two‐dimensional sheets stack together along the crystallographic a axis to generate parallelogram‐like channels. The methanol solvent molecules and the perchlorate counter‐ions are located in the channels, where they are fixed by intermolecular hydrogen‐bonding interactions. This architecture may provide opportunities for host–guest chemistry, such as guest molecule loss and absorption or ion exchange. The new fulvene‐type multidentate ligand L is a good candidate for the preparation of Cp–AgI‐containing (Cp is cyclopentadienyl) organometallic coordination polymers or supramolecular complexes. 相似文献
14.
Dr. Jennifer L. Hickey Prof. Dr. Leonard G. Luyt 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(41):12999-13007
Molecular scaffolds have been shown to facilitate and stabilise secondary structural turn elements, with a central core‐arranging functionality in a defined three‐dimensional orientation. In a peptide‐based molecular imaging probe, this approach is of particular value as it would essentially “hide” a metal radioisotope within the ligand framework, making the labelling element a critical component of the receptor‐bound structure. Starting from a 1,2‐diaminoethane loaded 2‐chlorotrityl resin, a versatile set of triamine ligand systems were synthesised by using solid‐phase Fmoc‐based peptide chemistry. The resultant resin‐bound peptides then underwent amide reduction by treatment with borane‐THF at 65 °C. This provided complete conversion to the corresponding polyamine entities in high purity for the majority of the amino acids utilised. The triamines were then coordinated on solid support by using [NEt4]2[Re(CO)3(Br)3] followed by resin cleavage and HPLC purification, to give the desired rhenium coordinated species. We have shown that amino acid sequences can be assembled, reduced and coordinated on‐resin, resulting in a versatile set of metal–ligand constructs. These studies could be expanded to generate libraries of turn‐based peptidomimetics containing Re/TcI organometallic scaffolds, with the intention of developing an improved approach for finding new diagnostic and therapeutic radiopharmaceutical entities. 相似文献
15.
Stability and Unimolecular Reactivity of Palladate(II) Complexes [LnPdR3]− (L=Phosphine,R=Organyl,n=0 and 1) 下载免费PDF全文
Marlene Kolter Prof. Dr. Konrad Koszinowski 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(44):15744-15750
The reduction of PdII precatalysts to catalytically active Pd0 species is a key step in many palladium‐mediated cross‐coupling reactions. Besides phosphines, the stoichiometrically used organometallic reagents can afford this reduction, but do so in a poorly understood way. To elucidate the mechanism of this reaction, we have treated solutions of Pd(OAc)2 and a phosphine ligand L in tetrahydrofuran with RMgCl (R=Ph, Bn, Bu) as well as other organometallic reagents. Analysis of these model systems by electrospray‐ ionization mass spectrometry found palladate(II) complexes [LnPdR3]? (n=0 and 1), thus pointing to the occurrence of transmetallation reactions. Upon gas‐phase fragmentation, the [LnPdR3]? anions preferentially underwent a reductive elimination to yield Pd0 species. The sequence of the transmetallation and reductive elimination, thus, constitutes a feasible mechanism for the reduction of the Pd(OAc)2 precatalyst. Other species of interest observed include the PdIV complex [PdBn5]?, which did not fragment via a reductive elimination but lost BnH instead. 相似文献
16.
Six novel organometallic half sandwich complexes [(η5‐C5Me5)M(L1–3)Cl]Cl.2H2O were synthesized using [{(η5‐C5Me5)M(μ‐Cl)Cl2], where M = Ir (III)/Rh (III) and L1–3 = three pyridyl pyrimidine based ligands; and characterized by NMR, Infra‐red spectroscopy, conductance, elemental and thermal analysis. The complex‐DNA binding mode and/or strength evaluated using absorption titration, electrochemical studies and hydrodynamic measurement proposed intercalative binding mode, which was also confirmed by molecular docking study. Differential pulse voltammetry and cyclic voltammetry studies indicated an alteration in oxidation and reduction potentials of complexes (M+4/M+3) in presence of CT‐DNA. The metal complexes can cleave plasmid DNA as proposed in gel electrophoretic analysis. The LC50 values of complexes evaluated on brine shrimp suggested their potent cytotoxic nature. 相似文献
17.
Friedrich Schoder Ulrike Plaia Robert Metzner Wilfried Sperber Wolfgang Beck Wolf Peter Fehlhammer Prof. Dr. 《无机化学与普通化学杂志》2010,636(5):700-709
The reactions of [Re(CO)6]+, [FeCp(CO)2CS]+ and [FeCp(CNPh)3]+ with the metallo nitrile ylides [M–{C+=N–C–(H)CO2Et}(CO)5]– (M = Cr, W) and the chromio nitrile imine [Cr–{C+=N–N–H}(CO)5]– (generated by mono‐α‐deprotonation of the parent isocyanide complexes) to give neutral 5‐metallated 1,3‐oxazolin‐ ( 1 ), 1,3‐thiazolin‐ ( 2 ), imidazolin‐ ( 3 , 4 ), 1,3,4‐oxdiazolin‐ ( 5 ), 1,3,4‐thiadiazolin‐ ( 6 ) and 1,3,4‐triazolin‐2‐ylidene ( 8 ) chromium and tungsten complexes represent the first all‐organometallic versions of Huisgen’s 1,3‐dipolar cycloadditions. The formation of 6 and 8 is accompanied by partial decomposition to (OC)5Cr–C≡N–FeCpL2 {L = CO ( 7 ), CNPh ( 9 )}. The structures of 4a and 5 have been characterized by X‐ray diffraction. 相似文献
18.
Anchoring of [(η5-C5H5)Rh(η4-C8H12)] into cavities of Na56Y and H56Y zeolites was studied. In contrast to expectation, the zeolite degree of hydration is not a key factor in the organometallic structural integrity. The thermal behavior of the occlusion reaction is the same when the zeolites are completely or partially dehydrated, showing that total absence of water is not a necessary condition to prepare an organometallic/zeolite system. For the zeolite Na56Y the product is the organometallic fragment [(η5-C5H5)Rh] which anchors to the oxygen atoms of the framework, while for the H56Y zeolite the product is a cationic organometallic species. 相似文献
19.
A. Ius M. A. Bacigalupo R. Longhi G. Meroni 《Analytical and bioanalytical chemistry》2000,366(8):869-872
Theophylline (Th) has been selectively conjugated to the four amino groups of melittin (Mel) by solid phase peptide synthesis. The cytolytic activity of the resultant Th-Mel compounds was tested on liposomes trapping the bovine serum albumin (BSA) conjugate with 4,7-bis(chlorosulfophenyl)-1,10-phenanthroline-2,9-dicarboxylic acid (BCPDA). The loss of lytic activity was the highest for Th-K7-Mel. Th-G1-Mel retains almost the same lytic activity as Mel. A homogeneous liposome time-resolved fluoroimmunoassay (LITRFIA) of Th in serum has been carried out with Th-G1-Mel between 5 ng and 10 μg. 相似文献
20.
The first montmorillonite‐supported surface single‐structure titanium complex: synthesis,characterization and catalytic activity in alkene epoxidation 下载免费PDF全文
Wei Xu Bo Yu Huaming Sun Jindou Yang Ying Zhang Zhenhua Wang Xi Chen Guofang Zhang Ziwei Gao 《Surface and interface analysis : SIA》2015,47(3):308-314
A well‐defined single‐site titanium‐modified montmorillonite (MMT) with only one geometric construction ((?SiO)3–Ti–NMe2) was obtained in moderate conditions. Reaction of tetrakis(dimethylamido)titanium with hydroxylated MMT was conducted by surface organometallic chemistry technique, and the surface structure was characterized by in situ Fourier transform infrared spectroscopy, 13C cross polarization magic angle spinning nuclear magnetic resonance, X‐ray photoelectron spectroscopy, extended X‐ray absorption fine structure, and elemental analysis. The catalytic activity in alkene epoxidation was evaluated, and the results revealed that the steric hindrance of the substances is responsible for the catalytic activity of the MMT‐supported titanium complex but to the characteristic restricted layer‐like structure of the MMT. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献