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Functionalization
Kinds of Functionalization Terms modified by Functionalization Selected AbstractsElectrochemical Characterization of In Situ Functionalized Gold Cysteamine Self-Assembled Monolayer with 4-Formylphenylboronic Acid for Detection of DopamineELECTROANALYSIS, Issue 5 2008Karimi Shervedani Abstract Functionalization of gold cysteamine (AuCA) self-assembled monolayer with 4-formylphenylboronic acid (BA) via Schiff's base formation, through in situ method to fabricate Au-CA-BA electrode is presented and described. The fabricated electrode was used as a novel sensor for accumulation and determination of dopamine (DA). The accumulation of DA as a diol on the topside of Au-CA-BA as a Lewis acid, was performed via esterification (AuCABADA), and followed for determination of DA. Functionalization, characterization, and determination steps were probed by electrochemical methods like cyclic voltammetry and electrochemical impedance spectroscopy. The data will be presented and discussed from which a new sensor for DA is introduced. [source] Synthesis and Functionalization of Germanium Triphenylcorrolate: The First Example of a Partially Brominated CorroleEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 16 2007Sara Nardis Abstract Ge complexes of 5,10,15-triphenylcorrole were prepared in refluxing dry DMF using GeCl4 as the source of Ge. Chromatographic separation of the crude reaction mixture afforded the ,-oxo dimer 1 and the methoxy derivative 2a. The corresponding chloride 2b can be obtained by treatment of 1 or 2a with HCl. The reaction of 2a with Br2 in CHCl3/py afforded the hexabromo derivative 3 as the main product, giving the first indication of the regioselective substitution of pyrroles B and C on the corrole ring. The fully brominated open-chain tetrapyrrole 4 was also characterized as a reaction by-product. Different partially brominated Ge complexes 5 and 6 have been obtained by variation of reaction conditions, while the heptabromo derivative was obtained in a mixture with the corresponding fully brominated Gecorrole. Photophysical characterization of Ge corrolates confirmed the high fluorescence quantum yield of such complexes, and also led to the first observation of phosphorescence emissions from corrole complexes. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] Facile Functionalization and Phase Reduction Route of Magnetic Iron Oxide Nanoparticles for Conjugation of Matrix Metalloproteinase,ADVANCED ENGINEERING MATERIALS, Issue 6 2010Dan Li Abstract A protocol for the simultaneous functionalization and phase reduction route of iron oxide magnetic nanoparticles (MNPs) and its further bioconjugation is presented. It was found that surface functionalization of maghemite (,-Fe2O3) nanoparticles with mercaptopropyltrimethoxysilane (MPTMS) under anoxic environment at above 80,°C promotes in situ conversion to magnetite (Fe3O4). Full conversion to Fe3O4, as probed by Mössbauer spectroscopy, with accompanied increase in the composite saturation magnetization, was achieved at 120,°C. By controlling the MPTMS concentration, the resultant silane-MNPs morphology can be tuned from having homogeneous thin layer (<1,nm) to thick continuous silane with embedded MNP multicores. Likewise the amount of surface distal thiol moieties was dependent on the silanization conditions. The density of distal thiols (i.e., amount of thiol per surface area) and resultant aggregate size have direct impact on the attachment, as well as the activity and reusability of the conjugated matrix metalloproteinase (MMP-2, using sulfo-SMCC as crosslinker). The work has important implication to the field of magneto-chemotherapeutics, where spatial control of conjugated active biomolecules under magnetic field and T2 -weighted MRI contrast can be achieved simultaneously. [source] Application of Selective Palladium-Mediated Functionalization of the Pyrido[3,,2,:4,5]pyrrolo[1,2- c]pyrimidine Heterocyclic System for the Total Synthesis of Variolin B and Deoxyvariolin B,EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 29 2010Alejandro Baeza Abstract The reaction of protected 3-bromo-2-(bromomethyl)-4-methoxypyrrolo[2,3- b]pyridine and tosylmethyl isocyanide (TosMIC) afforded a pyrido[3,,2,:4,5]pyrrolo[1,2- c]pyrimidine derivative in good yield. This compound was transformed through installation of the pyrimidine moiety in the C5 position, hydrolysis, and decarboxylation in an advanced intermediate for the total or formal synthesis of the naturalalkaloid variolin B. Reaction of 3-bromo-2-(bromomethyl)-4-chloropyrrolo[2,3- b]pyridine with N -tosylmethyl dichloroformimide as a synthetic TosMIC equivalent afforded trihalo-substituted pyrido[3,,2,:4,5]pyrrolo[1,2- c]pyrimidine. This compound was used in a new total synthesis of the alkaloid variolin B by selective and sequential C,N, C,C, and C,O palladium-mediated functionalization at the C9, C5, and C4 positions of the pyrido[3,,2,:4,5]pyrrolo[1,2- c]pyrimidine system. A formal synthesis of deoxyvariolin B is also described by using the same synthetic strategy. [source] Aromatic and Benzylic C,H Bond Functionalization Upon Reaction between Nitriles and Perfluoroalkyl SulfoxidesEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 31 2009Yohan Macé Abstract We studied the thermal behavior of some intermediates formed by reaction of nitriles with perfluoroalkyl sulfoxides upon trifluoromethanesulfonic anhydride activation. Bistriflate ketal 3, precursor of sulfilimine 1, may undergo a rearrangement to sulfanyl nitrile 5 after triflic acid elimination under thermal conditions. With p -tolyl trifluoromethyl sulfoxide, remote triflic acid elimination from intermediate 4 leads to benzamide 8 formation. These reactions involve, respectively, selective functionalization of the aromatic ortho C,H bond or the benzylic C,H bond para to the sulfoxide group. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] On the Functionalization of [2.2](1,4)Phenanthrenoparacyclophane,,EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 12 2007Henning Hopf Abstract Two routes for preparing functionalized [2.2](1,4)phenanthrenoparacyclophanes are described: either the parent system 2 is subjected to electrophilic substitution (bromination, Friedel,Crafts acylation, Rieche formylation: preparation of 5, 6, 7, 11 and 12) or the desired substituents are incorporated in the early stages of the synthesis by the preparation of the corresponding functionalized styryl paracyclophanes and their photocyclization to the respective phenanthrenocyclophanes. By these specific routes various bromides (22a,b), ethers (28a,c) and phenols (29a,b) were synthesized. The latter derivatives, on oxidation, furnish para - (31) and ortho -quinonophanes (30, 32, 33), useful substrates for the preparation of cyclophanes containing phenazine subunits (36). The stilbene , phenanthrene photocyclization can also be employed for the preparation of benzothiophenophanes, e.g. 43 and 44, from the respective precursors. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] N -Functionalization of Azoles through Coupling Reactions with Alkoxydienyl and Alkoxystyryl Boronic EstersEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 8 2007Annamaria Deagostino Abstract Alkoxydienyl boronates 1a and 1b and alkoxystyryl boronate 2 have been used in various copper mediated cross-coupling reactions with azoles. A variety of N -alkoxydienyl- and N -styrylazoles have been synthesized under mild conditions. The process utilizes Cu(OAc)2 in the presence of CsF in CH2Cl2 at room temperature. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] Systematic Studies on Photoluminescence of Oligo(arylene-ethynylene)s: Tunability of Excited States and Derivatization as Luminescent Labeling Probes for ProteinsEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 14 2006Yong-Gang Zhi Abstract Functionalized oligo(phenylene-ethynylene)s (OPEs) with different conjugation lengths, p -X(C6H4C,C)nSiMe3 (n = 1,4; X = NH2, NMe2, H) were synthesized by Sonogashira coupling of (phenylene-ethynylene)s and 1-iodo-4-(trimethylsilylethynyl)benzene, followed by desilylation of the p -substituted (trimethylsilylethynyl)benzenes with potassium hydroxide. The photoluminescent properties for the OPE series with different chain lengths and their solvatochromic responses were examined. The absorption maxima were red-shifted with increasing numbers of ,(C6H4C,C), units (n), and a linear plot of the absorption energy maxima vs. 1/n was obtained for each series. The emission spectra in dichloromethane showed a broad and structureless band, the energies of which (in wavenumbers) also fit linearly with 1/n. Both the absorption and emission wavelength maxima of the NH2 - and NMe2 -substituted OPEs exhibited significant solvent dependence, whereas the parent OPEs (X = H) showed only minor shifts of the ,max values in different solvents. Substituent effects upon the photoluminescent characteristics of the OPEs and the tunability of the excited states were examined with the p -X(C6H4C,C)nSiMe3 (n = 2, 3; X = NH2, NMe2, H, SMe, OMe, OH, and F) series. The H- and F-substituted counterparts exhibited high-energy vibronically structured emissions attributed to the 3(,,*) excited states of the (arylene-ethynylene) backbone. For compounds bearing NH2 and NMe2 groups, a broad red-shifted emission with a remarkable Stokes shift from the respective absorption maximum was observed, which can be assigned to an n , ,* transition. The n , ,* assignment was supported by MO calculations on the model compounds p -X(C6H4C,C)2SiH3 (X = NH2, H). Functionalization of the oligo(arylene-ethynylene)s with the N -hydroxysuccinimidyl (NHS) moiety enabled covalent attachment of the fluorophore to HSA protein molecules. A series of fluorescent labels, namely p -X(C6H4C,C)nC6H4NHS, (n = 1, X = NH2, NMe2, SMe, OMe, OH, F; n = 2, X = NH2, NMe2) and p -Me2NC6H4C,C(C4H2S)C,CC6H4NHS were synthesized, and their conjugates with HSA (human serum albumin) were characterized by MALDI-TOF mass spectrometry, UV/Vis absorption spectroscopy, and gel electrophoresis. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source] Converting Core Compounds into Building Blocks: The Concept of Regiochemically Exhaustive FunctionalizationEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 10 2005Elena Marzi Abstract In a model study, 3-fluorophenol and 3-fluoropyridine were converted into the each time four possible carboxylic acids by passing through the corresponding organometallic intermediates. As an attempt to generalize the findings reveals, a restricted set of principles and methods suffices to cope with all standard scenarios. The most valuable and versatile tools for the regiochemically exhaustive functionalization of a great variety of substrate patterns are the optionally site-selective metalation (either by reagent/substrate matching or by peripheral coordination control), the use of activating or congesting protective groups and the basicity gradient-driven heavy halogen migration (followed by halogen/metal permutation). (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source] Towards a Selective Functionalization of Amino-Terminated DendrimersEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 22 2004Fritz Vögtle Abstract Selective functionalization of the periphery of commercial polypropyleneamine (POPAM) and polyamidoamine (PAMAM) dendrimers has been investigated in preparative scale. The first generation (G1) POPAM dendrimer was for the first time selectively N,N -bis(sulfonylated) with tosyl chloride and the corresponding mono-, di-, tri-, and tetra- N -tosylsulfonamides were isolated and fully characterized. Unexpectedly, similar persulfonylation of G2 POPAM results in splitting of a central C,N bond and only fully and partially sulfonylated halves of the initial dendrimer could be isolated. Higher generations of POPAM are also split during the persulfonylation yielding complex mixtures of persulfonylated dendritic fragments which could hardly be identified. A plausible mechanism of the POPAM decomposition on the basis of the reaction product analysis is proposed. N -Sulfonylation of a peripheral octasulfonamide of G2 POPAM with tosyl chloride also leads to the destruction of the dendrimer, while its N -alkylation with benzyl bromide proved to be not selective yielding a completely alkylated derivative. Unlike POPAM dendrimers, PAMAM dendrimers were shown to be more stable during their sulfonylation and no decomposition of the dendritic backbone was detected. In contrast to the POPAM dendrimers, PAMAM dendrimers were shown to be rather inert with respect to the formation of N -tosylsulfonamides since they could only be N -monosulfonylated at all peripheral amino groups. The combination of MALDI-TOF and ESI-FT-ICR tandem mass spectrometry has been shown to be an effective method for structure assignment and purity check of selectively or fully persulfonylated dendritic oligoamines. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source] 2,3,6,7,10,11-Hexamethoxytribenzotriquinacene: Synthesis, Solid-State Structure, and Functionalization of a Rigid Analogue of CyclotriveratryleneEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 11 2004Marco Harig Abstract The syntheses of several tribenzotriquinacenes bearing six methoxy groups at the outer peripheral positions of the aromatic rings are reported. The centro -methyl derivative is accessible in surprisingly good yield through two-fold cyclodehydration in the final step of a synthesis route which requires special care in the preparation of some electron-rich key intermediates, such as 5,6-dimethoxy-2-methylindane-1,3-dione and bis(3,4-dimethoxyphenyl)methanol. X-ray single-crystal structure analysis of the centro -methyl derivative confirms its C3v -symmetrical molecular structure but, at variance from the parent centro -methyltribenzotriquinacene and the similarly shaped cyclotriveratrylene, the hexamethoxytribenzotriquinacene analog does not form columnar stacks in the solid state. Functionalization of the three benzhydrylic bridgehead positions leads to the tetramethyl analog and the bridgehead triol in good yields. In contrast, attempts to functionalize the ortho positions by nitration or bromination mainly give rise to ring cleavage through electrophilic ipso attack, which parallels the behavior of cyclotribenzylenes and cyclotriveratrylenes. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source] Regioflexibility in the Functionalization of Multiply Halogenated QuinolinesEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 5 2004Marc Marull Abstract 4-Bromo-6-fluoro-2-(trifluoromethyl)quinoline (1) and 4-bromo-7-fluoro-2-(trifluoromethyl)quinoline (13) were selected as model substrates to explore under what conditions regiochemically exhaustive functionalization reactions can be carried out. This goal was achieved by using trimethylsilyl entities and iodine atoms as the sole auxiliary substituents. The organolithium intermediates could be generated and the protective groups removed without impairing the bromine atom present at the 4-position. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source] Buttressing Effects Rerouting the Deprotonation and Functionalization of 1,3-Dichloro- and 1,3-DibromobenzeneEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 23 2003Christophe Heiss Abstract A systematic comparison between 1,3-difluorobenzene, 1,3-dichlorobenzene, and 1,3-dibromobenzene did not reveal major differences in their behavior towards strong bases such as lithium diisopropylamide or lithium 2,2,6,6-tetramethylpiperidide. Thus, all 2,6-dihalobenzoic acids 1 are directly accessible by consecutive treatment with a suitable base and dry ice. In contrast, (2,6-dichlorophenyl)- and (2,6-bromophenyl)triethylsilane (2a and 2b) were found to undergo deprotonation at the 5-position (affording acids 3 and, after deprotection, 4), whereas the 1,3-difluoro analog is known to react at the 4-position. The 2,4-dihalobenzoic acids 7 were selectively prepared from either the silanes 2 (by bromination at the 4-position, metalation and carboxylation of the neighboring position, followed by desilylation and debromination) or the 1,3-dihalo-2-iodobenzenes 8 (by base-promoted migration of iodine to the 4-position followed by iodine/magnesium permutation and subsequent carboxylation). (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source] Direct Access to Furanosidic Eight-Membered Ulosonic Esters from cis -,,,-Epoxy AldehydesEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 4 2003Claudia H. Sugisaki Abstract Direct access to bicyclic precursors of octulosonic acids is achieved by treatment of differentially (or not) protected ,,,-bis(silyloxy) cis -,,,-epoxy aldehydes with ethyl 2-(trimethylsilyloxy)-2-propenoate in the presence of boron trifluoride,diethyl ether. An X-ray crystallographic structure of a bicycle (compound 33a) was obtained and used to determine the absolute configurations of the different stereogenic centers and thus the diastereoselective preference of the aldol reaction (syn) and the regioselectivity of the epoxide ring-opening (C-6 atom). Functionalization and opening of the bicyclic compound to afford octulosonic analogues in their furanoside forms was studied. An octulosonic 8-phosphate analogue has been synthesized. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source] Synthesis of Pyrrole Derivatives through Functionalization of 3,4-Bis(lithiomethyl)dihydropyrrolesEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 4 2003José Barluenga Abstract Bis(2-lithioallyl)amines 2, substituted at the double bonds, undergo intramolecular carbolithiation of a lithiated double bond in different solvents to afford dilithiated dihydropyrroles 3. Treatment of these dianions with electrophiles allows the preparation of functionalized pyrrole derivatives 5 and 6. Interestingly, treatment of these dianions with carboxylic esters selectively affords either keto or hydroxy compounds (9 or 10), depending on the conditions. Several experiments have been carried out in order to clarify the mechanism of this selective transformation. Finally, dilithiated dihydropyrrole 3a could be transformed in a three-step procedure into the corresponding 3,4-bis(bromomethyl) derivative 31, which can easily be converted into bicyclic pyrrole compounds 32,33 by treatment with different nucleophiles. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source] Asymmmetric Diamino Functionalization of Nanotubes Assisted by BOC Protection and Their Epoxy NanocompositesADVANCED FUNCTIONAL MATERIALS, Issue 18 2010Yao Zhao Abstract Homogenous dispersion and strong interfacial bonding are prerequisites for taking full advantage of the mechanical properties of nanotubes in a composite. In order to simultaneously achieve both conditions, a highly efficient and mechanically non-destructive functionalization of nanotubes is developed. With fluoronanotubes as the precursor, asymmetric diamine molecules, N -BOC-1,6-diaminohexane, are used to replace fluorines on the wall of fluoronanotubes and construct covalent bonding to the surface of the nanotubes. A BOC de-protection reaction is conducted and the resulting exposed amino groups create strong covalent bonds with the matrix in the course of epoxy ring-opening etherification and curing chemical reactions. In comparison with the conventional functionalization based on symmetric diamine molecules, the functionalized nanotubes derived from the BOC-protected diamine molecule are more dispersed within the epoxy matrix. Dynamic mechanical analysis shows that the functionalized nanotubes have better crosslinking with the matrix. The composites reinforced by the nanotubes demonstrate improvement in various mechanical properties. The Young's Modulus, ultimate tensile strength, and storage modulus of composites loaded with 0.5 wt% functionalized nanotubes are enhanced by 30%, 25%, and 10%, respectively, compared with the neat epoxy. The increase of the glass transition temperature, as much as 10 °C, makes the composites suited for engineering applications under higher temperatures. The new functionalization method allows for an competitive enhancement in the composite performance in use of relatively low cost raw nanotubes at a small loading level. The reinforcement mechanism of the functionalized nanotubes in the epoxy resin is discussed. [source] Functionalization of Chitosan via Atom Transfer Radical Polymerization for Gene DeliveryADVANCED FUNCTIONAL MATERIALS, Issue 18 2010Yuan Ping Abstract It is of crucial importance to modify chitosan-based polysaccharides in the designing of biomedical materials. In this work, atom transfer radical polymerization (ATRP) was employed to functionalize chitosan in a well-controlled manner. A series of new degradable cationic polymers (termed as PDCS) composed of biocompatible chitosan backbones and poly((2-dimethyl amino)ethyl methacrylate) (P(DMAEMA)) side chains of different length were designed as highly efficient gene vectors via ATRP. These vectors, termed as PDCS, exhibited good ability to condense plasmid DNA (pDNA) into nanoparticles with positive charge at nitrogen/phosphorus (N/P) ratios of 4 or higher. All PDCS vectors could well protect the condensed DNA from enzymatic degradation by DNase I and they displayed high level of transfectivity in both COS7, HEK293 and HepG2 cell lines. Most importantly, in comparison with high-molecular-weight P(DMAEMA) and ,gold-standard' PEI (25 kDa), the PDCS vectors showed considerable buffering capacity in the pH range of 7.4 to 5, and were capable of mediating much more efficient gene transfection at low N/P ratios. At their own optimal N/P ratios for trasnsfection, the PDCS/pDNA complexes showed much lower cytotoxicity. All the PDCS vectors were readily to be degradable in the presence of lysozyme at physiological conditions in vitro. These well-defined PDCS polymers have great potentials as efficient gene vectors in future gene therapy. [source] Reactive Imprint Lithography: Combined Topographical Patterning and Chemical Surface Functionalization of Polystyrene- block -poly(tert -butyl acrylate) FilmsADVANCED FUNCTIONAL MATERIALS, Issue 3 2010Joost Duvigneau Abstract Here, reactive imprint lithography (RIL) is introduced as a new, one-step lithographic tool for the fabrication of large-area topographically patterned, chemically activated polymer platforms. Films of polystyrene- block -poly(tert -butyl acrylate) (PS- b -PtBA) are imprinted with PDMS master stamps at temperatures above the corresponding glass transition and chemical deprotection temperatures to yield structured films with exposed carboxylic acid and anhydride groups. Faithful pattern transfer is confirmed by AFM analyses. Transmission-mode FTIR spectra shows a conversion of over 95% of the tert -butyl ester groups after RIL at 230,°C for 5 minutes and a significantly reduced conversion to anhydride compared to thermolysis of neat films with free surfaces in air or nitrogen. An enrichment of the surface layer in PS is detected by angle-resolved X-ray photoelectron spectroscopy (XPS). In order to demonstrate application potentials of the activated platforms, a 7,nm,±,1,nm thick NH2 -terminated PEG layer (grafting density of 0.9 chains nm,2) is covalently grafted to RIL-activated substrates. This layer reduces the non-specific adsorption (NSA) of bovine serum albumin by 95% to a residual mass coverage of 9.1,±,2.9,ng cm,2. As shown by these examples, RIL comprises an attractive complementary approach to produce bio-reactive polymer surfaces with topographic patterns in a one-step process. [source] Specific Functionalization of Carbon Nanotubes for Advanced Polymer NanocompositesADVANCED FUNCTIONAL MATERIALS, Issue 24 2009Nanda Gopal Sahoo Abstract A novel approach to chemically functionalize multiwalled carbon nanotubes (MWCNTs) for making advanced polymeric nanocomposites with liquid crystalline polymers (LCPs) is presented. In this approach, two types of chemical moieties (i.e., carboxylic and hydroxyl benzoic acid groups) are selectively introduced onto the sidewalls of the MWCNTs. Fourier transform IR and Raman spectroscopy are used to examine the interaction between the functionalized MWCNTs and the LCP. The strong interaction between the functionalized MWCNTs and the LCP greatly improved the dispersion of MWCNTs in the polymer matrix as well as the interfacial adhesion. The dispersion of the MWCNTs in the LCP matrix is observed by optical microscopy and field-emission scanning electron microscopy. As a result, the addition of 1,wt% MWCNTs in the LCP resulted in the significant improvement (41 and 55%) in the tensile strength and modulus of the LCP. [source] Porous Chromium Terephthalate MIL-101 with Coordinatively Unsaturated Sites: Surface Functionalization, Encapsulation, Sorption and CatalysisADVANCED FUNCTIONAL MATERIALS, Issue 10 2009Do-Young Hong Recent ideas concerning site-selective functionalization of chromium terephtha-late MIL-101 are discussed, focusing on the utilization of unsaturated Cr(III) sites (see image). Recent advances in synthesis, selective surface functionalization, outstanding sorption properties, encapsulation of nanoobjects, and catalytic applications in MIL-101 are also discussed. [source] Photoluminescence Detection of Biomolecules by Antibody-Functionalized Diatom BiosilicaADVANCED FUNCTIONAL MATERIALS, Issue 6 2009Debra K. Gale Abstract Diatoms are single-celled algae that make microscale silica shells called "frustules", which possess intricate nanoscale features imbedded within periodic two-dimensional pore arrays. In this study, antibody-functionalized diatom biosilica frustules serve as a microscale biosensor platform for selective and label-free photoluminescence (PL)-based detection of immunocomplex formation. The model antibody rabbit immunoglobulin G (IgG) is covalently attached to the frustule biosilica of the disk-shaped, 10-µm diatom Cyclotella sp. by silanol amination and crosslinking steps to a surface site density of 3948,±,499 IgG molecules µm,2. Functionalization of the diatom biosilica with the nucleophilic IgG antibody amplifies the intrinsic blue PL of diatom biosilica by a factor of six. Furthermore, immunocomplex formation with the complimentary antigen anti-rabbit IgG further increases the peak PL intensity by at least a factor of three, whereas a non-complimentary antigen (goat anti-human IgG) does not. The nucleophilic immunocomplex increases the PL intensity by donating electrons to non-radiative defect sites on the photoluminescent diatom biosilica, thereby decreasing non-radiative electron decay and increasing radiative emission. This unique enhancement in PL emission is correlated to the antigen (goat anti-rabbit IgG) concentration, where immunocomplex binding follows a Langmuir isotherm with binding constant of 2.8,±,0.7,×,10,7M. [source] Multiple Functionalization of Mesoporous Silica in One-Pot: Direct Synthesis of Aluminum-Containing Plugged SBA-15 from Aqueous Nitrate Solutions,ADVANCED FUNCTIONAL MATERIALS, Issue 1 2008Y. Wu Abstract Aluminum-containing plugged mesoporous silica has been successfully prepared in an aqueous solution that contains triblock copolymer templates, nitrates, and silica sources but without using mineral acid. The acidity of the solution can be finely tuned from pH 1.4 to 2.8 according to the amount of the introduced aluminum species which ranged from an Al/Si molar ratio of 0.25/1 to 4.0/1. The aluminum nitrate additive in the starting mixture, along with the weak acidity produced by the nitrates, contributes to the formation of plugged hexagonal structures and the introduction of different amounts of aluminum species into the mesostructure. Characterization by X-ray diffraction, transmission electron microscopy, and N2 sorption measurements show that the Al-containing plugged silicas possess well-ordered hexagonal mesostructures with high surface areas (700,860 m2,g,1), large pore volume (0.77,1.05 cm3,g,1) and, more importantly, combined micropores and/or small mesopores in the cylindrical channels. Inductively coupled plasma,atomic emission spectrometry results show that 0.7,3.0 wt,% aluminum can be introduced into the final samples. 27Al MAS NMR results display that about 43,60% aluminum species are incorporated into the skeleton of the Al-containing silicas and the amount of the framework aluminum increases as the initial added nitrates rises. Scanning electron microscopy images reveal that the directly synthesized Al-containing plugged silica has a similar morphology to that of traditional SBA-15. Furthermore, the Al-containing plugged samples have excellent performances in the adsorption and the catalytic decomposition of isopropyl alcohol and nitrosamine. Finally, the direct synthesis method is used to produce plugged mesoporous silicas that contain other metals such as chromium and copper, and the resultant samples also show good catalytic activities. [source] Covalent Functionalization of Carbon Nanohorns with Porphyrins: Nanohybrid Formation and Photoinduced Electron and Energy Transfer,ADVANCED FUNCTIONAL MATERIALS, Issue 10 2007G. Pagona Abstract The covalent attachment of carbon nanohorns (CNHs) to ,-5-(2-aminophenyl)-,-15-(2-nitrophenyl)-10,20-bis(2,4,6-trimethyl-phenyl)-porphyrin (H2P) via an amide bond is accomplished. The resulting CNH,H2P nanohybrids form a stable inklike solution. High-resolution transmission electron microscopy (HRTEM) images demonstrate that the original dahlia-flowerlike superstructure of the CNHs is preserved in the CNH,H2P nanohybrids. Steady-state and time-resolved fluorescence studies show efficient quenching of the excited singlet state of H2P, suggesting that both electron and energy transfer occur from the singlet excited state of H2P to CNHs, depending on the polarity of the solvent. In the case of electron transfer, photoexcitation of H2P results in the reduction of the nanohorns and the simultaneous oxidation of the porphyrin unit. The formation of a charge-separated state, CNH,,,H2P,+, has been corroborated with the help of an electron mediator, hexyl-viologen dication (HV2+), in polar solvents. Moreover, the charge-separated CNH,,,H2P,+ states have been identified by transient absorption spectroscopy. [source] Synthesis, Functionalization, and Bioconjugation of Monodisperse, Silica-Coated Gold Nanoparticles: Robust Bioprobes,ADVANCED FUNCTIONAL MATERIALS, Issue 6 2005S. H. Liu Abstract Herein, we report an efficient process for preparing monodisperse Au@SiO2 nanoparticles using homogeneous shaking and without the use of surface-coupling silane agents or large stabilizers. The resulting pure-silica surface of the Au@SiO2 nanoparticles is very important for straightforward surface functionalization with different functional groups via well-established silica surface chemistry. Subsequent covalent bioconjugation of the aldehyde-functionalized Au@SiO2 nanoparticles with various biomolecules is successfully employed to make robust nanoprobes for fast, colorimetric DNA and protein detection based on the sequence-specific hybridization properties of DNA and the specific binding affinity between proteins, respectively. [source] Oligonucleotides Containing 7-Deaza-2,-deoxyinosine as Universal Nucleoside: Synthesis of 7-Halogenated and 7-Alkynylated Derivatives, Ambiguous Base Pairing, and Dye Functionalization by the Alkyne,Azide ,Click' ReactionHELVETICA CHIMICA ACTA, Issue 7 2008Frank Seela Abstract Oligonucleotides containing 7-deaza-2,-deoxyinosine derivatives bearing 7-halogen substituents or 7-alkynyl groups were prepared. For this, the phosphoramidites 2b,2g containing 7-substituted 7-deaza-2,-deoxyinosine analogues 1b,1g were synthesized (Scheme,2). Hybridization experiments with modified oligonucleotides demonstrate that all 2,-deoxyinosine derivatives show ambiguous base pairing, as 2,-deoxyinosine does. The duplex stability decreases in the order Cd>Ad>Td>Gd when 2b,2g pair with these canonical nucleosides (Table,6). The self-complementary duplexes 5,-d(F7c7I-C)6, d(Br7c7I-C)6, and d(I7c7I-C)6 are more stable than the parent duplex d(c7I-C)6 (Table,7). An oligonucleotide containing the octa-1,7-diyn-1-yl derivative 1g, i.e., 27, was functionalized with the nonfluorescent 3-azido-7-hydroxycoumarin (28) by the Huisgen,Sharpless,Meldal cycloaddition ,click' reaction to afford the highly fluorescent oligonucleotide conjugate 29 (Scheme,3). Consequently, oligonucleotides incorporating the derivative 1g bearing a terminal CC bond show a number of favorable properties: i) it is possible to activate them by labeling with reporter molecules employing the ,click' chemistry. ii) Space demanding residues introduced in the 7-position of the 7-deazapurine base does not interfere with duplex structure and stability (Table,8). iii) The ambiguous pairing character of the nucleobase makes them universal probes for numerous applications in oligonucleotide chemistry, molecular biology, and nanobiotechnology. [source] Spatially Selective Functionalization of Conducting Polymers by "Electroclick" ChemistryADVANCED MATERIALS, Issue 44 2009Thomas Steen Hansen Conducting polymer microelectrodes can electrochemically generate the catalyst required for their own functionalization by "click chemistry" with high spatial resolution. Interdigitated microelectrodes prepared from an azide-containing conducting polymer are selectively functionalized in sequence by two alkyne-modified fluorophores by control of the applied potentials. [source] SiO2 Nanoparticle Sequestration via Reactive Functionalization in Holographic Polymer-Dispersed Liquid CrystalsADVANCED MATERIALS, Issue 36 2009John D. Busbee Holographic photopolymerization of reactively functionalized silica nanoparticles in polymer/liquid-crystal systems leads to sequestration of the silica nanoparticles in the polymeric domain of holographic polymer-dispersed liquid-crystals Bragg gratings. Excellent dispersion of the nanoparticles maintains the optical properties of the reflection grating without additional scattering while lowering the voltage necessary to switch the state of the grating. [source] A Combined Process of In Situ Functionalization and Microwave Treatment to Achieve Ultrasmall Thermal Expansion of Aligned Carbon Nanotube,Polymer Nanocomposites: Toward Applications as Thermal Interface MaterialsADVANCED MATERIALS, Issue 23 2009Wei Lin Ultrasmall thermal expansion of aligned carbon nanotube,epoxy composites at temperatures below and above the glass transition is achieved by a novel combined process of in situ functionalization and microwave treatment. Carbon nanotube,polymer interfacial bonding is the key to the reduced thermal expansion, enhanced storage modulus, and improved thermal conductivity. [source] Functionalization of Porous Carbon Materials with Designed Pore Architecture,ADVANCED MATERIALS, Issue 3 2009Andreas Stein Abstract Recent progress in syntheses of porous carbons with designed pore architecture has rejuvenated the field of carbon chemistry and promises to provide new advanced materials. In order to reap the full benefit of designer carbons, it is necessary to develop chemistries for functionalizing the porous carbon surfaces. This Review examines methods of functionalizing porous carbon through direct incorporation of heteroatoms in the carbon synthesis, surface oxidation and activation, halogenation, sulfonation, grafting, attachment of nanoparticles and surface coating with polymers. Methods of characterizing the functionalized carbon materials and applications that benefit from functionalized nanoporous carbons with designed architecture are also highlighted. [source] Rational Functionalization of Carbon Nanotubes Leading to Electrochemical Devices with Striking Applications,ADVANCED MATERIALS, Issue 15 2008Jie Yan Abstract As one-dimensional carbon nanostructures, carbon nanotubes (CNTs) are a member of the carbon family but they possess very different structural and electronic properties from other kinds of carbon materials frequently used in electrochemistry, such as glassy carbon, graphite, and diamond. Although the past decade has witnessed rapid and substantial progress in both the fundamental understanding of CNT-oriented electrochemistry and the development of various kinds of electrochemical devices with carbon nanotubes, the increasing demand from both academia and industry requires CNT-based electrochemical devices with vastly improved properties, such as good reliability and durability, and high performance. As we outline here, the smart functionalization of CNTs and effective methods for the preparation of devices would pave the way to CNT-based electronic devices with striking applications. [source] | |||||||||||||||||||||||||||||||||||||