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Supramolecular Architectures (supramolecular + architecture)

Distribution by Scientific Domains

Chemistry	75%
Polymers and Materials Science	24%

Selected Abstracts

Supramolecular Architectures: Selective Formation of Bi-Component Arrays Through H-Bonding of Multivalent Molecular Modules (Adv. Funct.

ADVANCED FUNCTIONAL MATERIALS, Issue 8 2009
Mater.
Molecular recognition occurs at dynamic interfaces too! The cover shows a donor,acceptor,donor hydrogen-bond moiety, incorporated in a tailor-made monovalent molecular module (in blue), that is able to recognize both complementary monovalent (in red) and tetravalent (in green) molecular modules at interfaces. This finding, described by P. Samori and co-workers on page 1207, paves the way towards the formation of robust multicomponent 2D functional nanostructures with tunable size and geometries. [source]

Synthesis and Characterization of Helix-Coil Diblock Copolymers with Controlled Supramolecular Architectures in Aqueous Solution,

MACROMOLECULAR RAPID COMMUNICATIONS, Issue 15 2005
Jie Zhang
Abstract Summary: A series of helix-coil diblock copolymers based on poly(ethylene oxide) and optically active helical poly{(+)-2,5-bis[4,-((S)-2-methylbutoxy)phenyl]styrene} (PMBPS) were synthesized via atom transfer radical polymerization (ATRP). The synthetic methodology permitted straightforward preparation of the diblock copolymers with relatively low polydispersities and a broad range of compositions and molecular weights. Depending on the composing block length and the initial concentration, the copolymers self-assembled into different supramolecular structures in aqueous solution, including spherical micelles, vesicles, multilamellar vesicles, large compound vesicles, and tubules. Schematic representation of the synthesis of PEO- b -PMBPS block copolymers and their aggregation in aqueous solution. [source]

Supramolecular Architectures by Fullerene-Bridged Bis(permethyl-,-cyclodextrin)s with Porphyrins

CHEMISTRY - A EUROPEAN JOURNAL, Issue 42 2009
Ying-Ming Zhang
Abstract The Hirsch,Bingel reaction of bis{4-methyl[1,2,3]triazolyl}malonic ester-bridged bis(permethyl-,-cyclodextrin) 1 with C60 has led to the formation of a new fullerene-bridged bis(permethyl-,-cyclodextrin) 2, which has been comprehensively characterized by NMR spectroscopy, MALDI-MS, and elemental analysis. Taking advantage of the high affinity between 2 and 5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrin (3) or [5,10,15,20-tetrakis(4-sulfonatophenyl)porphinato]zinc(II) (4), linear supramolecular architectures with a width of about 2,nm and a length ranging from hundreds of nanometers to micron dimension were conveniently constructed and fully investigated by transmission electron microscopy (TEM), atomic force microscopy (AFM), and scanning electron microscopy (SEM). Significantly, the photoinduced electron-transfer (PET) process between porphyrin and C60 moieties takes place within the 2,3 and 2,4 supramolecular architectures under light irradiation, leading to the highly efficient quenching of the porphyrin fluorescence. The PET process and the charge-separated state were investigated by means of fluorescence spectroscopy, fluorescence decay, cyclic voltammetry, and nanosecond transient absorption measurements. [source]

1D Ladder-like Chain and 1D Channeled 3D Supramolecular Architectures Based on Benzophenone-2,4,-dicarboxylic Acid

CHINESE JOURNAL OF CHEMISTRY, Issue 4 2008
Xiao-Gang YANG
Abstract The hydrothermal reactions of AgNO3, 2,2,-bipyridyl, and benzophenone-2,4,-dicarboxylic acid gave rise to two 3D supramolecular architectures, namely H2L·H2O (1), [Ag(bpy)2]·HL·H2O (2) (bpy2,2,-bipyridyl, H2Lbenzophenone-2,4,-dicarboxylic acid). The two compounds are extended by hydrogen bonds in two different approaches. In the case of 1, one-dimensional ladder-like structure is firstly formed through O,H···O hydrogen bonding between H2L ligands and water molecules, then extended to a 3D supramolecular architecture. Compound 2 possesses 3D supramolecular architecture containing 1D open channels, which are driven due to the strong H-bonding interactions occurring between the HL anions and water molecules; interestingly, [Ag(bpy)2]+ cations are linked together through ,-, interactions between bpy ligands and weak Ag···Ag interactions, and then reside in these channels by C,H···O hydrogen-bond. The photoluminescence properties of these compounds were also investigated, the emission maxima for 2 exhibits red-shift compared with that of free ligand and 1 due to chelating effect of the 2,2,-bipyridine ligand to the silver ion and the presence of aromatic ,-packing. [source]

Self-Assembled Multilayers of Polyethylenimine and DNA: Spectrophotometric and Electrochemical Characterization and Application for the Determination of Acridine Orange Interaction

ELECTROANALYSIS, Issue 15 2009
F. Ferreyra
Abstract This work deals with the study of the interaction between acridine orange (AO) and calf-thymus double stranded DNA (dsDNA) present in supramolecular architectures built on gold electrodes modified with mercapto-1-propanesulfonic acid (MPS) by self-assembling of polyethylenimine and dsDNA. The optimal conditions for building the supramolecular architecture were obtained from UV-vis spectrophotometric experiments. The electrochemical studies were performed by adsorptive transfer square wave voltammetry from the evaluation of the oxidation signal of AO accumulated within the multistructure. The effect of the number of PEI-dsDNA bilayers (Au/MPS/(PEI-dsDNA)n) on the accumulation and electrooxidation of AO is also discussed. [source]

Hybrid Organic/Inorganic Supramolecular Conductors D2[Au(CN)4] [D = Diiodo(ethylenedichalcogeno)tetrachalcogenofulvalene], Including a New Ambient Pressure Superconductor

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 30 2007
Tatsuro Imakubo
Abstract Five diiodo(ethylenedichalcogeno)tetrachalcogenofulvalenes, DIEDSS {2-(5,6-dihydro[1,3]diselenolo[4,5- b][1,4]diselenin-2-ylidene)-4,5-diiodo-1,3-dithiole}, DIET-STF {2-(4,5-diiodo-1,3-diselenol-2-ylidene)-5,6-dihydro[1,3]dithiolo[4,5- b][1,4]dithiine}, DIEDS-STF {2-(4,5-diiodo-1,3-diselenol-2-ylidene)-5,6-dihydro[1,4]diselenino[2,3- d][1,3]dithiole}, DIETSe {2-(4,5-diiodo-1,3-diselenol-2-ylidene)-5,6-dihydro[1,3]diselenolo[4,5- b][1,4]dithiine}, and DIEDSSe {2-(4,5-diiodo-1,3-diselenol-2-ylidene)-5,6-dihydro[1,3]diselenolo[4,5- b][1,4]diselenine},have been synthesized without the use of the highly toxic reagent CSe2, and their Au(CN)4 salts have been prepared by electrochemical oxidation. Characteristic I···N iodine bonds are constructed in all crystals, and their packing motifs are classified into two groups by the difference in the space group symmetry. The salt of DIEDSS crystallizes in the monoclinic C2/c space group and a novel helical supramolecular architecture is constructed by the strong and directional I···N iodine bond. On the other hand, the rest of the four salts crystallize in the triclinic P space group and their donor packing motifs belong to the so-called ,-type. Conducting properties of the ,-type salts strongly depend on the number and positions of the selenium atoms on the donor molecule. The salts based on the diselenadithiafulvalene (DSDTF) derivatives, DIET-STF and DIEDS-STF, show metal,semiconductor transition and the salt of fully selenated ,-donor DIEDSSe shows stable metallic behavior down to 1.6 K. On the other hand, (DIETSe)2[Au(CN)4] is semimetallic down to low temperature and the superconducting transition occurs at around 2 K (onset).(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source]

Three Novel Functional CdII Dicarboxylates with Nanometer Channels: Hydrothermal Synthesis, Crystal Structures, and Luminescence Properties

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 2 2007
Yu-Peng Tian
Abstract Three novel functional transition-metal complexes with H2A (H2A = 9-ethylcarbazole-3,6-dicarboxylic acid), Cd(HA)2(H2O)2 (1), [Cd(A)(phen)]·1.5H2O (2) (phen = 1,10-phenanthroline), and Cd(HA)2(bipy) (3) (bipy = 4,4,-bipyridine), have been successfully synthesized by a hydrothermal synthetic method and characterized by single-crystal X-ray diffraction, infrared spectroscopy, elemental analysis, thermogravimetric analysis, and photoluminescence. The results show that all of the complexes contain nanometer channels, while the coordination modes were changed by the addition of the mixed ligands. The 2D supramolecular open-framework 1 is constructed through hydrogen-bond and aromatic ,,, interactions. 2D coordination polymer 2 is constructed by ,,, interactions between adjacent metal-organic polymeric coordination chains. Interestingly, the 3D supramolecular architecture of 3 first formed 2D grid layers from 1D chains by intermolecular hydrogen bonds and then extended into a 3D structure through aromatic ,,, interactions. Furthermore, strong emissions from these complexes were also changed by the coordination modes in the solid state. However, complexes 1,3 show high thermal stability.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source]

A Ferromagnetically Coupled, Bent, Trinuclear Copper(II) Complex: Synthesis, Structure, Hydrogen-Bonding Network, Magnetic Properties and DNA Interaction Study

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 17 2006
Sumana Sarkar
Abstract A bent trinuclear copper(II) complex (1) incorporating ,-phenoxo, ,- syn - syn carboxylato, and ,3 -chloro bridges and an O,N,N -coordinated reduced Schiff-base ligand is reported. The complex shows an intramolecular ferromagnetic interaction in the solid state. The EPR spectra also support the magnetic behaviour of the complex. In the compound, each copper centre has a square-pyramidal geometry. The separation between the adjacent copper ions is about 3.05 Å and that between the terminal copper ions is about 5.0 Å. The complex forms a supramolecular architecture through N,H···Cl hydrogen bonding between the amine group of the reduced Schiff-base ligand and the counter chloride anions. Absorption and fluorescence spectral studies and viscosity measurements have been performed to determine the type of interaction with calf-thymus DNA. The nuclease activity of the complex with plasmid DNA is also studied. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source]

Polymers or Supramolecules Generated From a New V-Shaped Bis-monodentate Ligand and the Effect of Steric Hindrance on Coordination Modes of the Ligand

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 12 2006
Caihua Zhou
Abstract A new V-shaped bis-monodentate ligand L (L = 2,3,-dipyridylamine) (1) has been designed and synthesized by alkylation reaction of pyridylamine. An investigation of the charge distributions of the coordination atoms and single-point energy calculations of four conformers of ligand L based on the geometry of conformers optimized by the DFT (density functional theory) method was carried out. The results show that the four conformers of ligand L take on two stable and two less stable configurations. Theory forecasts that two relatively stable configurations present in complexes as probable coordination motifs of the ligand, and that steric hindrance of pyridine nitrogen atoms in isomers will affect its coordination ability together with the electronic factor. This forecast has been demonstrated by the coordination chemistry of ligand L, that is, configuration (a) and (b) of the ligand occur in the following reported complexes, which combines with AgI or CuII through two coordination modes (bidentate bridging or a monodentate mode) resulting in coordination polymers {[Ag (L)2]NO3}n (2), [Cu2(L)2(maa)4]n (maa = methacrylic acid) (3), and the mononuclear molecule [Cu(L)4](ClO4)2·2CH3CH2OH (4). The ligand assumes different coordination modes in the three complexes because of different levels of steric hindrance of the pyridine nitrogen atoms in the conformers. Interestingly, polymers 2 and 3 assume a 1D helical structure and a linear framework, respectively, and 4 has a 2D supramolecular architecture induced from hydrogen bond interactions. In addition, the magnetic properties of 3 have been explored, which shows a strong antiferromagnetic interaction.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source]

Supramolecular Chemistry Based on [W3S4(H2O)6Cl3]+ , A Versatile Building Block

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 1 2004
Maxim N. Sokolov
Abstract The cluster [W3S4(H2O)6Cl3]+ (which is present in solutions of [W3S4(H2O)9]4+ in 1,4 M HCl) reacts with the macrocyclic cavitand cucurbituril (C36H36N24O12) to form supramolecular adducts of 2:1 cluster/cucurbituril stoichiometry, where two portals of cucurbituril (which contains a water molecule in its cavity) are closed by two cluster cations. These aggregates are bound together in the solid by complementary hydrogen bonds between coordinated Cl, and the cations H9O4+ to give chains. Thus, a supramolecular architecture is achieved from three different but complementary building blocks. The packing of the chains affords a honeycomb structure (hexagonal symmetry) with channels (about 5.2 Å in diameter). The overall stoichiometry is (H9O4){[W3S4(H2O)6Cl3]2(C36H36N24O12)}Cl3·16.15H2O (1). [W3S4(H2O)6Cl3]+ reacts with SbCl3 in 6 M HCl to give cuboidal [W3(SbCl3)S4(H2O)6Cl3]+, which forms with the macrocyclic cavitand cucurbituril a 2:1 cluster/cucurbituril adduct , a discrete supramolecule consisting of five independent molecular units. In the solid it crystallizes as a salt of very rare anion [SbCl6]3, with the stoichiometry {[W3(SbCl3)S4(H2O)6Cl3]2(C36H36N24O12)}(SbCl6)2/3·12H2O (2). (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source]

Three-dimensional supramolecular architecture in imidazolium hydrogen 2,3,5,6-tetrafluoroterephthalate

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 4 2010
Li-Li Yu
The asymmetric unit of the title salt formed between 2,3,5,6-tetrafluoroterephthalic acid (H2tfbdc) and imidazolium (ImH), C3H5N2+·C8HF4O4,, contains one Htfbdc, anion and one ImH2+ cation, joined by a classical N,H...O hydrogen bond. The acid and base subunits are further linked by N,H...O and O,H...O hydrogen bonds into infinite two-dimensional layers with R56(32) hydrogen-bond motifs. The resulting (4,4) network layers interpenetrate to produce an interlocked three-dimensional structure. The final three-dimensional supramolecular architecture is further stabilized by the linkages of two C,H...O interactions. [source]

Bis(,-benzene-1,2-dicarboxylato)bis{aqua[2-(2-chloro-6-fluorophenyl)-1H -imidazo[4,5- f][1,10]phenanthroline]cadmium(II)} and its zinc(II) analogue

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 12 2009
Xiu-Yan Wang
In the isomorphous title compounds, [Cd2(C8H4O4)2(C19H10ClFN4)2(H2O)2] and [Zn2(C8H4O4)2(C19H10ClFN4)2(H2O)2], the CdII centre is seven-coordinated by two N atoms from one [2-(2-chloro-6-fluorophenyl)-1H -imidazo[4,5- f][1,10]phenanthroline (L) ligand, one water O atom and four carboxylate O atoms from two different benzene-1,2-dicarboxylate (1,2-bdc) ligands in a distorted pentagonal,bipyramidal coordination, while the ZnII centre is six-coordinated by two N atoms from one L ligand, one water O atom and three carboxylate O atoms from two different 1,2-bdc ligands in a distorted octahedral coordination. Each pair of adjacent metal centres is bridged by two 1,2-bdc ligands to form a dimeric structure. In the dimer, each L ligand coordinates one metal centre. The dimer is centrosymmetric, with a crystallographic inversion centre midway between the two metal centres. The aromatic interactions lead the dimers to form a two-dimensional supramolecular architecture. Finally, O,H...O and N,H...O hydrogen bonds reinforce the two-dimensional structures of the two compounds. [source]

Three quinolone compounds featuring O...I halogen bonding

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 10 2009
Jurica Bauer
Ethyl 1-ethyl-6-iodo-4-oxo-1,4-dihydroquinoline-3-carboxylate, C14H14INO3, (I), and ethyl 1-cyclopropyl-6-iodo-4-oxo-1,4-dihydroquinoline-3-carboxylate, C15H14INO3, (II), have isomorphous crystal structures, while ethyl 1-dimethylamino-6-iodo-4-oxo-1,4-dihydroquinoline-3-carboxylate, C14H15IN2O3, (III), possesses a different solid-state supramolecular architecture. In all three structures, O...I halogen-bonding interactions connect the quinolone molecules into infinite chains parallel to the unique crystallographic b axis. In (I) and (II), these molecular chains are arranged in (101) layers, via,,, stacking and C,H..., interactions, and these layers are then interlinked by C,H...O interactions. The structural fragments involved in the C,H...O interactions differ between (I) and (II), accounting for the observed difference in planarity of the quinolone moieties in the two isomorphous structures. In (III), C,H...O and C,H..., interactions form (100),molecular layers, which are crosslinked by O...I and C,H...I interactions. [source]

Unsolvated 5,10,15,20-tetra-4-pyridylporphyrin, its sesquihydrate and its 2-chlorophenol disolvate: conformational versatility of the ligand

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 9 2009
Sophia Lipstman
Unsolvated 5,10,15,20-tetra-4-pyridylporphyrin, C40H26N8, (I), its sesquihydrate, C40H26N8·1.514H2O, (II), and its 2-chlorophenol disolvate, C40H26N8·2C6H5ClO, (III), reveal different conformational features of the porphyrin core. In (I), the latter is severely deformed from planarity, apparently in order to optimize the intermolecular interactions and efficient crystal packing of the molecular entities. The molecular framework has a C1 symmetry. In (II), the porphyrin molecules are located on symmetry axes, preserving the marked deformation from planarity of the porphyrin core. The molecular units are interlinked into a single-framework supramolecular architecture by hydrogen bonding to one another via molecules of water, which lie on twofold rotation axes. In (III), the porphyrin molecules are located across centres of inversion and are characterized by a planar conformation of the 24-membered macrocyclic porphyrin ring. Two trans -related pyridyl substituents are hydrogen bonded to the 2-chlorophenol solvent molecules. The interporphyrin organization in (III) is similar to that observed for many other tetraarylporphyrin compounds. However, the organization observed in (I) and (II) is different and of a type rarely observed before. This study reports for the first time the crystal structure of the unsolvated tetrapyridylporphyrin. [source]

Poly[[hexaaquabis[,4 -2-hydroxy-5-(4-sulfonatophenyldiazenyl)benzoato]dibarium(II)] 4,4,-bipyridine solvate]

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 9 2007
Hong Liu
The title compound, {[Ba2(C13H8N2O6S)2(H2O)6]·C10H8N2}n, possesses a novel two-dimensional porous coordination network, in which each BaII ion is nine-coordinated by three carboxylate O atoms, two sulfonate O atoms and four water molecules in an irregular coordination environment. Hydrogen-bond interactions between coordinated water molecules and sulfonate/hydroxyl groups hold the network layers together and produce a three-dimensional supramolecular architecture. [source]

Columnar Mesophase Formation of Cyclohexa- m -phenylene-Based Macrocycles

CHEMISTRY - AN ASIAN JOURNAL, Issue 1 2007
Wojciech Pisula Dr.
Abstract Two novel discotic macrocycles, substituted cyclohexa- m -phenylene (CHP) and cyclo-3,6-trisphenanthrylene (CTP), and the linear oligomer 3,3,:6,,3,,-terphenanthrene (TP) as a model substance have been synthesized by repetitive cross-coupling reactions. To correlate the molecular design with the supramolecular architecture and the established macroscopic order, 2D wide-angle X-ray scattering experiments were performed on mechanically extruded filaments. At room temperature in their crystalline phases, all three compounds revealed columnar assemblies in which the macrocycles self-organized by ,-stacking interactions. The degree of macroscopic order was found to depend upon the planarity and stiffness of the aromatic core. The flexible CHP ring showed a poor macroscopic order of the columnar structures and a low isotropization temperature, whereas the more-planar, less-flexible CTP self-assembled into well-defined superstructures. The larger ,-stacking area and the more-pronounced intermolecular interactions for CTP led to the formation of a mesophase over a very large temperature range. The surprising columnar organization of the "open" TP system was explained by back-folding of the molecule into a ringlike structure. [source]

1D Ladder-like Chain and 1D Channeled 3D Supramolecular Architectures Based on Benzophenone-2,4,-dicarboxylic Acid

Self-Assembled Multilayers of Polyethylenimine and DNA: Spectrophotometric and Electrochemical Characterization and Application for the Determination of Acridine Orange Interaction

Glassy Carbon Electrodes Modified with Multiwall Carbon Nanotubes Dispersed in Polylysine

ELECTROANALYSIS, Issue 15 2008
Yamile Jalit
Abstract We report the analytical performance of glassy carbon electrodes (GCE) modified with a dispersion of multiwall carbon nanotubes (MWCNT) in polylysine (Plys) (GCE/MWCNT-Plys). The resulting electrodes show an excellent electrocatalytic activity towards different bioanalytes like ascorbic acid, uric acid and hydrogen peroxide, with important decrease in their oxidation overvoltages. The dispersion of 1.0,mg/mL MWCNT in 1.0,mg/mL polylysine is highly stable, since after 2 weeks the sensitivity for hydrogen peroxide at GCE modified with this dispersion remained in a 90% of the original value. The MWCNT-Plys layer immobilized on glassy carbon electrodes has been also used as a platform to build supramolecular architectures by self-assembling of polyelectrolytes based on the polycationic nature of the polylysine used to disperse the nanotubes. The self-assembling of glucose oxidase has allowed us to obtain a supramolecular multistructure for glucose biosensing. The influence of glucose oxidase concentration and adsorption time as well as the effect of using polylysine or MWCNT-Plys as polycationic layers for further adsorption of GOx is also evaluated. [source]

Supramolecular Self-Assembly: Self-Assembly of a Donor-Acceptor Dyad Across Multiple Length Scales: Functional Architectures for Organic Electronics (Adv. Funct.

ADVANCED FUNCTIONAL MATERIALS, Issue 15 2009
Mater.
More than the sum of its parts: by covalently coupling polycyclic donor and acceptor moieties, Samori and co-workers demonstrate on page 2486 that a donor,acceptor dyad, based on nanographene and perylene, self-assembles into highly ordered supramolecular architectures with nanosegregated coaxial donor and acceptor regions. The cover image features an atomic force microscopy image of mesoscopic ribbons along with the proposed crystallographic arrangement of the constituent molecules. [source]

Supramolecular Crystal Engineering at the Solid,Liquid Interface from First Principles: Toward Unraveling the Thermodynamics of 2D Self-Assembly

ADVANCED MATERIALS, Issue 13 2009
Carlos-Andres Palma
Abstract The formation of highly ordered 2D supramolecular architectures self-assembled at the solid,solution interfaces is subject to complex interactions between the analytes, the solvent, and the substrate. These forces have to be mastered in order to regard self-assembly as an effective bottom-up approach for functional-device engineering. At such interfaces, prediction of the thermodynamics governing the formation of spatially ordered 2D arrangements is far from being fully understood, even for the physisorption of a single molecular component on the basal plane of a flat surface. Two recent contributions on controlled polymorphism and nanopattern formation render it possible to gain semi-quantitative insight into the thermodynamics of physisorption at interfaces, paving the way towards 2D supramolecular crystal engineering. Although in these two works different systems have been chosen to tackle such a complex task, authors showed that the chemical design of molecular building blocks is not the only requirement to fulfill when trying to preprogram self-assembled patterns at the solid,liquid interface. [source]

Nanopatterning Soluble Multifunctional Materials by Unconventional Wet Lithography

ADVANCED MATERIALS, Issue 10-11 2009
Massimiliano Cavallini
Abstract Molecular multifunctional materials have potential applications in many fields of technology, such as electronics, optics and optoelectronics, information storage, sensing, and energy conversion and storage. These materials are designed exhibit enhanced properties, and at the same time are endowed with functional groups that control their interactions, and hence self-organization, into a variety of supramolecular architectures. Since most of the multifunctional materials are soluble, lithographic methods suitable for solutions are attracting increasing interest for the manufacturing of the new materials and their applications. The aim of this paper is to highlight some of the recent advances of solution-based fabrication of multifunctional materials. We explain and examine the principles, processes, materials, and limitations of this class of patterning techniques, which we term unconventional wet lithographies (UWLs). We describe their ability to yield patterns and structures whose feature sizes range from nanometers to micrometers. In the following sections, we focus our attention on micromolding in capillaries, lithographically controlled wetting, and grid-assisted deposition, the most used methods demonstrated to lead to fully operating devices. [source]

Engineering functional materials by halogen bonding

JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 1 2007
Pierangelo Metrangolo
Abstract Engineering functional materials endowed with unprecedented properties require the exploitation of new intermolecular interactions, which can determine the characteristics of the bulk materials. The great potential of Halogen Bonding (XB), namely any noncovalent interaction involving halogens as electron acceptors, in the design of new and high-value functional materials is now emerging clearly. This Highlight will give a detailed overview on the energetic and geometric features of XB, showing how some of them are quite constant in most of the formed supramolecular complexes (e.g., the angle formed by the covalent and the noncovalent bonds around the halogen atom), while some others depend strictly on the nature of the interacting partners. Then, several specific examples of halogen-bonded supramolecular architectures, whose structural aspects as well as applications in fields as diverse as enantiomers' separation, crystal engineering, liquid crystals, natural, and synthetic receptors, will be fully described. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: PolymChem 45: 1,15, 2007 [source]

Highly fluorinated compounds induce phase separation in, and nanostructuration of liquid media.

JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 14 2006
Possible impact on, use in chemical reactivity control
Abstract Liquid perfluorocarbons-like supercritical CO2 -provide valuable reaction media that can facilitate the separation of reaction products and the recovery of catalysts. Chemistry in fluorous media requires that some of the protagonist molecules, and in particular the catalysts, be grafted with one or more perfluoroalkylated chains. These chains, due to powerful hydrophobic and lipophobic effects, tend to self-assemble and induce the formation of a variety of nanocompartmented supramolecular architectures and colloids, such as micelles, vesicles, tubules, monolayers, and emulsions, thus generating microheterogenicity in the reaction medium. Fluorinated amphiphiles are, for example, known to generate fibrous gels in fluorous, organic, and aqueous media. Phase separation, nanocompartmentation, and interface-driven parameters can thus complicate otherwise simple chemistry. Conversely, they can provide useful micro- and nanoreactors and templates. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 4251,4258, 2006 [source]

Optimization of opto-electronic property and device efficiency of polyfluorenes by tuning structure and morphology

POLYMER INTERNATIONAL, Issue 5 2006
Peng Chen
Abstract Polyfluorene-based oligomers and polymers (PFs) have been studied intensively as active materials for organic optoelectronic devices. In this review, the optimization of the opto-electronic property and device efficiency of polyfluorenes in the field of light-emitting diodes (LEDs) and photovoltaic cells (PVs) by tuning structure and morphology are summarized in terms of two typical modification techniques: copolymerization and blending. The relationships between molecular structures, thin film morphologies, opto-electronic properties and device efficiencies are discussed, and some recent progress in LEDs and PVs is simultaneously reviewed. After the introduction, the basic knowledge of molecular structures and properties of polyfluorene homopolymers is presented as a background for a better understanding of their great potential for opto-electronic applications. Immediately after this, three different opinions on the origin of low-energy emission band at 520,540 nm in polyfluorene-based LEDs are addressed. Rod,coil block copolymers and alternative copolymers are focused on in the next section, which are a vivid embodiment of controlling supramolecular structures and tailoring molecular structures, respectively. In particular, various supramolecular architectures induced by altering coil blocks are carefully discussed. Recent work that shows great improvement in opto-electronic properties or device performance by blending or doping is also addressed. Additionally, the progress of understanding concerning the mechanisms of exciton dynamics is briefly referred to. Copyright © 2006 Society of Chemical Industry [source]

Supramolecular assembly of collagen triblock peptides

BIOPOLYMERS, Issue 4 2003
Raquel Martin
Abstract The relationship between primary sequence and collagen triple-helix formation is relatively well characterized, while higher levels of structural assembly from these sequences is poorly understood. To address this gap, a new collagen-like triblock peptide design was used to study the relationship between amino acid sequence and supramolecular assembly. Four collagen-like peptides with the sequence (Glu)5(Gly,Xaa,Hyp,Gly,Pro,Hyp)6(Glu)5 and corresponding to Xaa = alanine, proline, serine, or valine, and an analogous peptide without the glutamic acid end blocks, were solubilized in water at high concentrations (20,150 mg/mL) and analyzed in optical polarizing microscopy and transmission electron microscopy. Some of the peptides self-assembled into supramolecular structures, the nature of which was determined by the core collagen-like sequence. The globular end blocks appeared necessary for these short triple-helix-forming peptides to spontaneously organize into supramolecular structures in solution and also provided enhanced thermal stability based on CD analysis. The results indicate a strong dependence of the peptide triblock assembly behavior on the identity of the guest residue Xaa; nematic order when Xaa was valine, no organization when Xaa was serine, and banded spherulites displaying a cholesteric-like twist when Xaa was proline or alanine. According to these results, the identity of the amino acid in position Xaa of the triplet Gly,Xaa,Yaa dramatically determined the type of supramolecular assembly formed by short triple helices based on collagen-triblock like sequences. Moreover, the structural organization observed for these collagen-triblock peptides was analogous to some assemblies observed for native collagen in vivo and in vitro. The amino acid sequence in the native collagen proteins may therefore be a direct determinant of the different supramolecular architectures found in connective tissues. © 2003 Wiley Periodicals, Inc. Biopolymers 70:435,444, 2003 [source]

Supramolecular Architectures by Fullerene-Bridged Bis(permethyl-,-cyclodextrin)s with Porphyrins

Facile Route to Supramolecular Structures: Self-Assembly of Dendrimers and Naphthalene Dicarboxylic Acids

CHEMISTRY - A EUROPEAN JOURNAL, Issue 23 2008
Franziska Gröhn Dr.
Cylinders and spheres can be formed by simple self-assembly of cationic dendrimers and oppositely charged small divalent organic ions in methanol (see graphic). The counterion not only controls the morphology of the nanosized assembly, but also provides functionality, such as fluorescence. The concept may lead to versatile functional supramolecular architectures. [source]

Influence of Molecular Order on the Local Work Function of Nanographene Architectures: A Kelvin-Probe Force Microscopy Study

CHEMPHYSCHEM, Issue 11 2005
Vincenzo Palermo Dr.
Abstract We report a Kelvin-probe force microscopy (KPFM) investigation on the structural and electronic properties of different submicron-scale supramolecular architectures of a synthetic nanographene, including extended layers, percolated networks and broken patterns grown from solutions at surfaces. This study made it possible to determine the local work function (WF) of the different , -conjugated nanostructures adsorbed on mica with a resolution below 10 nm and 0.05 eV. It revealed that the WF strongly depends on the local molecular order at the surface, in particular on the delocalization of electrons in the , -states, on the molecular orientation at surfaces, on the molecular packing density, on the presence of defects in the film and on the different conformations of the aliphatic peripheral chains that might cover the conjugated core. These results were confirmed by comparing the KPFM-estimated local WF of layers supported on mica, where the molecules are preferentially packed edge-on on the substrate, with the ultraviolet photoelectron spectroscopy microscopically measured WF of layers adsorbed on graphite, where the molecules should tend to assemble face-on at the surface. It appears that local WF studies are of paramount importance for understanding the electronic properties of active organic nanostructures, being therefore fundamental for the building of high-performance organic electronic devices, including field-effect transistors, light-emitting diodes and solar cells. [source]

Synthesis and Characterization of Three Diverse Coordination Frameworks under Co-ligand Intervention

CHINESE JOURNAL OF CHEMISTRY, Issue 2 2009
Ping LIU
Abstract The chelating organic ligands of 2,2,-bipyridine (2,2,-bipy), di(pyrid-2-yl)amine (dpa) and 2,6-di(pyrid-2-ylamino)pyridine (dpap) were respectively applied to react with H2fum (fumaric acid) and copper salts, affording three different complexes [Cu2(fum)(2,2,-bipy)4]·2ClO4 (1), [Cu2(µ-OH)2(fum)(dpa)2]·2H2O (2) and [Cu(SO4)(H2O)(dpap)]·H2O (3). These complexes were determined by single-crystal X-ray diffraction. Each penta-coordinated Cu(II) ion exhibits a distorted trigonal bipyramidal geometry in 1. The fum ligand links copper ions to form a dinuclear copper unit. While in 2, the fum ligands connect [Cu2(µ-OH)2(dpa)2] unit to construct a 1D zigzag chain. Unexpectedly, when dpap instead of dpa was used under the same conditions, only one mononuclear complex 3 was formed. Crystal packings show that 1,3 form 3D supramolecular architectures through non-covalent interactions (multiple hydrogen bonds and C,H··· ,/,-, interactions). In addition, the study of the magnetic property reveals dominating ferromagnetic interactions between Cu(II) atoms in 1. [source]