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Supramolecular Complexes (supramolecular + complex)
Selected AbstractsBienzymatic Supramolecular Complex of Catalase Modified with Cyclodextrin-Branched Carboxymethylcellulose and Superoxide Dismutase: Stability and Anti-Inflammatory PropertiesMACROMOLECULAR BIOSCIENCE, Issue 1 2007Aymara Valdivia Abstract A bienzymatic supramolecular assembly of CAT and SOD is reported. CAT was chemically glycosilated with CD branched CMC and then associated with SOD modified with 1-adamantane carboxylic acid. SOD was remarkably resistant to inactivation by H2O2 and its anti-inflammatory activity was 4.5-fold increased after supramolecular association with the modified CAT form. [source] A Novel Self-assembled Supramolecular Complex {[Cu(n) (en)2·H2O] [Cu(I)2(CN)4]}n with Honeycomb-like Structure and Its Adsorption PropertiesCHINESE JOURNAL OF CHEMISTRY, Issue 12 2002Xiao-Ping Shen Abstract A novel supramolecular complex {[Cu(n)(en)2·H2O]·[Cu(I)2(CN)4]}n (en = ethylenediamine), in which the cyanide-bridged Cu(I) forms the honeycomb-like skeleton host and the Cu(n) complex ion [Cu(en)2·H2O]2+ is encapsulated in the center of the channel cavity of the skeleton, was synthesized by two different methods. The complex was also characterized by elemental analysis, ICP analysis, IR spectra and thermal analysis. The adsorption and desorption studies of the complex indicate that H2O and NH3 can be desorbed and re-adsorbed without collapse of the channel structure of the supramolecule. [source] Tetrakis(4-pyridyl)porphyrin Supramolecular Complexes with Cyclodextrins in Aqueous SolutionPHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 2 2006Pinalysa Cosma ABSTRACT The formation of inclusion complexes of hydroxypropyl-,-cyclodextrin, heptakis(2,6-di-O-methyl)-,-cyclodextrin and heptakis(2,3,6-tri-O-methyl)-,-cyclodextrin with 5,10,15,20-tetrakis(4-pyridyl)porphyrin (TpyP) has been studied in aqueous buffer solution (phosphate buffer pH = 7 and I = 0.01 M) to give a structural and spectroscopic characterization of a new class of potential sensitizers for photodynamic therapy. The interaction was investigated by a combination of UVNis absorption, fluorescence anisotropy, time-resolved fluorescence and circular dichroism. The experimental results point to the presence of the pigment in water in a monomeric complexed form. The fluorescence anisotropy measurements suggest that TpyP forms 1:1 complexes with heptakis(2,3,6-tri-O-methyl)-,-cyclodextrin and hydroxypropyl-,-cyclodextrin, while 1:2 complexes are obtained with heptakis(2,6-di-O-methyl)-,-cyclodextrin. [source] Mechanistic investigation of the interaction between bisquaternary antimicrobial agents and phospholipids by liquid secondary ion mass spectrometry and differential scanning calorimetryRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 18 2002V. A. Pashynskaya Mechanisms of interaction between the antimicrobial drugs decamethoxinum and aethonium, which are based on bisquaternary ammonium compounds, and a phospholipid component of biological membranes, dipalmitoylphosphatidylcholine, were studied by means of liquid secondary ion mass spectrometry (LSIMS) and differential scanning calorimetry (DSC). Supramolecular complexes of the drugs with this phospholipid were recorded under secondary ion mass spectrometric conditions. The dependence of the structures of these complexes on structural parameters of the dications of the bisquaternary ammonium compounds was demonstrated. Tandem mass spectrometric investigations of the metastable decay of doubly charged ions of decamethoxinum and aethonium complexes with dipalmitoylphosphatidylcholine allowed estimation of structural parameters of these complexes in the gas phase. Interactions of decamethoxinum and aethonium with model membrane assemblies built from hydrated dipalmitoylphosphatidylcholine were studied using DSC. It was shown that while both drugs can interact with model membranes, the mechanisms of such interactions for decamethoxinum and aethonium differ. The correlation between the nature of these interactions and structural and electronic parameters of the dications of the two bisquaternary agents is discussed. Interpretation of combined mass spectrometric and calorimetric experimental data led to proposals that the molecular mechanisms of antimicrobial action of bisquaternary ammonium compounds are related to their effect on the membrane phospholipid components of microbial cells. Copyright © 2002 John Wiley & Sons, Ltd. [source] The Structure of the First Supramolecular ,-Cyclodextrin Complex with an Aliphatic Monofunctional Carboxylic AcidEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 26 2007Saddys Rodríquez-Llamazares Abstract The crystal structure of the supramolecular complex between ,-cyclodextrin and decanoic acid was determined: The aliphatic chain of the carboxylic acid is threaded through a head-to-head dimer of two cyclodextrin residues, resulting in a 1:2 stoichiometry. Head-to-head orientation is also observed between neighboring complexes. The overall degree of hydration with 25 water molecules per supramolecular complex is remarkably high. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] Poly(9,9-dioctylfluorene)-Based Conjugated Polyelectrolyte: Extended ,-Electron Conjugation Induced by Complexation with a Surfactant ZwitterionADVANCED MATERIALS, Issue 18 2010Giuseppina Pace We report on a conjugated polyelectrolyte (CPE) based on fluorene repeat units, which forms a supramolecular complex with a zwitterion surfactant. The complex self-assembles into multilamellar structures on solid substrates. The luminescence efficiency, low in the uncomplexed polymer, is strongly increased after complexation. This originates from the phase segregation between the aromatic backbone and ionic sides, reducing conformational defects and ionic dipole-induced quenching. [source] Structural improvement of unliganded simian immunodeficiency virus gp120 core by normal-mode-based X-ray crystallographic refinementACTA CRYSTALLOGRAPHICA SECTION D, Issue 4 2009Xiaorui Chen The envelope protein gp120/gp41 of simian and human immunodeficiency viruses plays a critical role in viral entry into host cells. However, the extraordinarily high structural flexibility and heavy glycosylation of the protein have presented enormous difficulties in the pursuit of high-resolution structural investigation of some of its conformational states. An unliganded and fully glycosylated gp120 core structure was recently determined to 4.0,Å resolution. The rather low data-to-parameter ratio limited refinement efforts in the original structure determination. In this work, refinement of this gp120 core structure was carried out using a normal-mode-based refinement method that has been shown in previous studies to be effective in improving models of a supramolecular complex at 3.42,Å resolution and of a membrane protein at 3.2,Å resolution. By using only the first four nonzero lowest-frequency normal modes to construct the anisotropic thermal parameters, combined with manual adjustments and standard positional refinement using REFMAC5, the structural model of the gp120 core was significantly improved in many aspects, including substantial decreases in R factors, better fitting of several flexible regions in electron-density maps, the addition of five new sugar rings at four glycan chains and an excellent correlation of the B -factor distribution with known structural flexibility. These results further underscore the effectiveness of this normal-mode-based method in improving models of protein and nonprotein components in low-resolution X-ray structures. [source] Self-Assembly of Calix[6]arene,Diazapyrenium Pseudorotaxanes: Interplay of Molecular Recognition and Ion-Pairing EffectsCHEMISTRY - A EUROPEAN JOURNAL, Issue 11 2010Monica Semeraro Abstract The calix[6]arene wheel CX forms pseudorotaxane species with the diazapyrenium-based axle 1,2PF6 in CH2Cl2 solution. The macrocyclic component is a heteroditopic receptor, which can complex the electron-acceptor moiety of the axle inside its cavity and the counterions with the ureidic groups on the upper rim. The self-assembled supramolecular species is a complex structure, which involves three components,the wheel, the axle and its counterions,that can mutually interact and affect. The stoichiometry of the resulting supramolecular complex depends on the nature and concentration of the counterions. Namely, it is observed that in dilute solution and with low-coordinating anions the axle takes two wheels, whereas with highly coordinating anions or in concentrated solutions the complex has a 1:1 stoichiometry. [source] A Novel Self-assembled Supramolecular Complex {[Cu(n) (en)2·H2O] [Cu(I)2(CN)4]}n with Honeycomb-like Structure and Its Adsorption PropertiesCHINESE JOURNAL OF CHEMISTRY, Issue 12 2002Xiao-Ping Shen Abstract A novel supramolecular complex {[Cu(n)(en)2·H2O]·[Cu(I)2(CN)4]}n (en = ethylenediamine), in which the cyanide-bridged Cu(I) forms the honeycomb-like skeleton host and the Cu(n) complex ion [Cu(en)2·H2O]2+ is encapsulated in the center of the channel cavity of the skeleton, was synthesized by two different methods. The complex was also characterized by elemental analysis, ICP analysis, IR spectra and thermal analysis. The adsorption and desorption studies of the complex indicate that H2O and NH3 can be desorbed and re-adsorbed without collapse of the channel structure of the supramolecule. [source] Crystal Structure and Surface Photovoltage Properties of MnII Coordination SupramoleculesEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 24 2007Li-Ping Sun Abstract Three MnII coordination supramolecular complexes [Mn(pdc)(H2O)]n1, {[Mn(pdc) (phen)(H2O)]·3H2O}n2, and {[Mn(cyan)2(H2O)4]·2HCl·2(Hcyan)} 3 (H2pdc = pyridine-2,3-dicarboxylic acid, Hcyan = cyanuric acid, phen = 1,10-phenanthroline) were hydrothermally synthesized and their structures determined by single-crystal X-ray diffraction. The pdc group in complex 1 bridges the MnII ions to form an infinite 3D structure. In complex 2, the MnII ion is bridged to a 1D infinite chain by pdc groups and the chain is further connected to a 2D structure by hydrogen bonds. The 3D structure of complex 3 is formed by hydrogen bonds and O···Cl weak interactions. Surface photovoltage spectroscopy (SPS) of complexes 1,3 indicate that they all possess positive SPV response in the range of 300,800 nm and show p -type semiconductor characteristic. The intensities of the SPV responses are obviously different, and this can mainly be attributed to the differences in their structures. Field-induced surface photovoltage spectroscopy (FISPS) of complexes 1,3 confirms their p -type semiconductor characteristic.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] Enantioselective Recognition of Aliphatic Amino Acids by ,-Cyclodextrin Derivatives Bearing Aromatic Organoselenium Moieties on the Primary or Secondary SideEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 8 2003Yu Liu Abstract Spectrophotometric titrations have been performed in order to determine the stability constants of inclusion complexation of some aliphatic amino acids with four structurally related organoselenium-modified ,-cyclodextrins: mono(6-phenylseleno-6-deoxy)-,-cyclodextrin (1a), mono[6-(p -methoxyphenylseleno)-6-deoxy]-,-cyclodextrin (1b), mono(2-phenylseleno-2-deoxy)-,-cyclodextrin (2a), and mono[2-(p -methoxyphenylseleno)-2-deoxy]-,-cyclodextrin (2b). Conformation analysis by circular dichroism and 2D NMR spectroscopic studies revealed that the aryl-substituted ,-cyclodextrins gave self-inclusion intramolecular complexes in aqueous solution, while the extent of penetration depended both on the positions and on the structures of substituents. Quantitative investigation on the binding ability of the hosts with amino acids showed that they were able to recognize the size and the shape of guests, affording supramolecular complexes with quite small stability constants ranging from 24 to 355 M,1. The molecular recognition abilities are discussed from the viewpoints of induced-fitting mechanisms, geometric complementary, and cooperative binding processes. Furthermore, these ,-cyclodextrin derivatives displayed considerable enantioselectivity towards L/D -amino acid isomers, giving the highest L -enantioselectivity (up to 8.4) for inclusion complexation between leucine and 2a. The binding modes of L/D -leucine with 1b were elucidated from NOESY studies and the chiral recognition phenomena were interpreted accordingly. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source] Biocomplementary interaction behavior in DNA-like and RNA-like polymersJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 23 2009Chih-Chia Cheng Abstract A series of nucleobased polymers and copolymers were synthesized through atom transfer radical polymerization (ATRP). Biocomplementary DNA- and RNA-like supramolecular complexes are formed in dilute DMSO solution through nucleobase recognition. 1H NMR titration studies of these complexes in CDCl3 indicated that thymine-adenine (T-A) and uracil-adenine (U-A) complexes form rapidly on the NMR time scale with high association constants (up to 534 and 671 M,1, respectively) and result in significant Tg increase. WAXD and differential scanning calorimetry analyzes in the bulk state indicate the presence of highly physical cross-linked structures and provide further details into the nature of the self-assembly of these systems. Furthermore, this study is of discussion on the difference in the hydrogen bond strength between T-A and U-A base pairs within polymer systems, indicating that the strength of hydrogen bonds in RNA U-A pairs is stronger than that in DNA T-A base pairs. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 6388,6395, 2009 [source] Engineering functional materials by halogen bondingJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 1 2007Pierangelo 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] Supramolecular polymers formed by cinnamoyl cyclodextrinsJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 22 2003Akira Harada Abstract 6-Cinnamoyl ,-cyclodextrin (6-CiO-,-CD) and 6-cinnamoyl ,-cyclodextrin (6-CiO-,-CD) were prepared. 6-CiO-,-CD formed intermolecular complexes to give supramolecular oligomers. 6-CiO-,-CD formed insoluble supramolecular complexes in the solid state. The structures of these complexes are discussed. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 3519,3523, 2003 [source] Improved Anti-Inflammatory Properties for Naproxen with Cyclodextrin-Grafted Polysaccharides,MACROMOLECULAR BIOSCIENCE, Issue 7 2006Héctor L. Ramírez Abstract Summary: Mannan and carboxymethylcellulose, previously activated by periodate oxidation, were grafted with mono-6-butylenediamino-6-deoxy- , -cyclodextrin derivatives by reductive alkylation in the presence of sodium borohydride. The formation of supramolecular complexes between these polymers and Naproxen was confirmed by fluorescence spectroscopy. The solubility of the drug was 3.8,4.6 fold increased in the presence of the cyclodextrin-grafted polysaccharides. The in vivo anti-inflammatory property of Naproxen was 1.7 times higher after supramolecular association with , -cyclodextrin-branched mannan. [source] A two-dimensional network formed by self-associating silver(I) perchlorate with 3-[4-(2-thienyl)-2H -cyclopenta[d]pyridazin-1-yl]benzonitrileACTA CRYSTALLOGRAPHICA SECTION C, Issue 2 2009Xiao-Yan Li In the organometallic silver(I) supramolecular complex poly[[silver(I)-,3 -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 {AgN2S,} coordination environment. Two unsymmetric multidentate 3-[4-(2-thienyl)-2H -cyclopenta[d]pyridazin-1-yl]benzonitrile (L) ligands link two AgI atoms through ,,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. [source] Structure of photosynthetic glyceraldehyde-3-phosphate dehydrogenase (isoform A4) from Arabidopsis thaliana in complex with NADACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 6 2010Simona Fermani The crystal structure of the A4 isoform of photosynthetic glyceraldehyde-3-phosphate dehydrogenase (GAPDH) from Arabidopsis thaliana, expressed in recombinant form and complexed with NAD, is reported. The crystals, which were grown in 2.4,M ammonium sulfate and 0.1,M sodium citrate, belonged to space group I222. The asymmetric unit includes ten subunits, i.e. two independent tetramers plus a dimer that generates a third tetramer by a crystallographic symmetry operation. The crystal structure was solved by molecular replacement and refined to an R factor of 23.7% and an Rfree factor of 28.9% at 2.6,Å resolution. In the final model, each subunit binds one NAD+ molecule and two sulfates, which occupy the Ps and the Pi anion-binding sites. Detailed knowledge of this structure is instrumental for structural investigation of supramolecular complexes of A4 -GAPDH, phosphoribulokinase and CP12, which are involved in the regulation of photosynthesis in the model plant A. thaliana. [source] Self-Assembled Supramolecular Nanocarrier Hosting Two Kinds of Guests in the Site-Isolation StateCHEMISTRY - A EUROPEAN JOURNAL, Issue 43 2009Xing-Long Lou Abstract Hyperbranched polyethylenimine (HPEI) was simply mixed with a solution of amphiphilic calix[4]arene (AC4), which possesses four phenol groups and four aliphatic chains, in chloroform. This resulted in the novel supramolecular complex HPEI,AC4 through the noncovalent interaction of the amino groups of HPEI with the phenol groups of AC4. The formed HPEI,AC4 supramolecular complexes were characterized by 1H,NMR spectroscopy and dynamic light scattering. The cationic water-soluble dye methyl blue (MB) and the anionic water-soluble dye methyl orange (MO) were used as the model guests to test the performance of HPEI,AC4 as a supramolecular nanocarrier. It was found that HPEI,AC4 could accommodate the anionic water-soluble MO guests into the HPEI core. The MO encapsulation capacity of HPEI,AC4 was pH sensitive, which reached maximum loading under weakly acidic conditions. The loaded MO molecules could be totally released when the pH value was reduced to be around 4.5 or raised to be around 9.5, and this process was reversible. HPEI,AC4 could not only accommodate the anionic MO with the HPEI core but could also simultaneously load the cationic MB molecules using the formed AC4 shell, thereby realizing the site isolation of the two kinds of functional units. The amount of MO and MB encapsulated by HPEI,AC4 could be controlled by varying the ratio of hydroxyl groups of AC4 to amino groups of HPEI. [source] Protonated Macrobicyclic Hosts Containing Pyridine Head Units for Anion RecognitionCHEMISTRY - A EUROPEAN JOURNAL, Issue 19 2008David Esteban-Gómez Dr. Abstract In this paper, we report two macrobicyclic receptors containing pyridine head units derived from 1,10-diaza-15-crown[5] (L1) or 4,13-diaza-18-crown[6] (L2) that can be protonated in MeCN and used for anion recognition. The interaction of these protonated lateral macrobicycles with different anions has been investigated by means of spectrophotometric titrations in MeCN. The association constants for the complexes of halide anions with the protonated macrobicycles follow the sequences Cl,>Br,>I,>F, (L1) and Cl,>F,>I,>Br, (L2), whereby an increase of more than two logarithmic units is observed from F, to Cl, for the binding constants of the receptor derived from L1. The association constants also indicate an important degree of selectivity of these macrobicyclic receptors for Cl, over Br, or I,. The X-ray crystal structure analyses of the chloride and bromide complexes confirms the formation of the envisaged supramolecular complexes. Moreover, the binding constants indicate that these receptors present a high sulfate-to-nitrate binding selectivity. The stability trend observed for the recognition of halide anions by the macrobicycles presented herein as well as the sulfate-to-nitrate binding selectivity have been rationalised by means of DFT calculations at the B3LYP/LanL2DZ level. These studies indicate that the especially high binding selectivity for Cl, is the result of the optimum fit between the protonated macrobicyclic cavity and the size of the anion, whereas the sulfate-to-nitrate selectivity results from shape complementarity between the hydrogen-binding acceptor sites on sulfate and the hydrogen-bond donors of the macrobicycle. [source] Supramolecular Complexes Self-assembled by Copper(II) Carboxylate and Monohelical Pyridylamino LigandCHINESE JOURNAL OF CHEMISTRY, Issue 3 2006Li-Jun Zhou Abstract Two novel supramolecular complexes [Cu(bpapa)(dhbd)]·CH3OH (1) and [Cu(bpapa)(ma)]·ma (2) (bpapa=bis[6-(2-pyridylamino)pyrid-2-yl]amine, dhbd=2,3-dihydroxybutanedioate dianion, ma=, -methacrylate) were rationally designed, synthesized and characterized by single crystal X-ray diffraction, IR, electronic spectroscopy and thermogravimetric analyses. Complex 1 was the first oligo- , -pyridylamino complex based on hydroxypolycarboxylate and self-assembled into a 3D honeycomb configuration network with open channels and tubes containing 1D ladder-shaped double chains formed by hydrogen bonds and aromatic ,-, stacking interactions. Complex 2 constructed a 2D supramolecular network extended by 1D chains from dimeric supramolecular synthon through noncovalent supramolecular interactions. In the two complexes, the chelating monohelical ligand adopted all- anti configuration. Density functional theory calculations were applied to 1 and 2. [source] Self-assembly of Two Novel Supramolecular Frameworks Based on Flexible Oligo- , -Pyridylamino Ligands and Copper(II) MaleateCHINESE JOURNAL OF CHEMISTRY, Issue 10 2005Cai-Hua Zhou Abstract Two novel supramolecular complexes, [Cu(bpapa)(mal)]·H2O·CH3OH (1) and {[Cu(bpapap)](Hmal)2}·2H2O (2) [bpapa=bis-[6-(2-pyridylamino)pyrid-2-yl]amine, bpapap=2,6-bis-[6-(pyrid-2-ylamino)pyrid-2-ylamino]-pyridine, mal=maleate dianion] were rationally designed and synthesized based on flexible multidentate ligands and copper(II) maleate. Complexes 1 and 2 were all characterized by elemental analysis, spectroscopic techniques, thermal analysis and single crystal X-ray diffraction analysis. Complex 1 is of an infinite 3-D supramolecular framework constructed by 2-D sheets to contain 1-D helical chains formed by intermolecular hydrogen bond interactions between the non-coordinated oxygen atoms from maleate and nitrogen atoms from amino groups of bpapa. Complex 2 also takes a 3-D supramolecular structure, which is built from 2-D rhombic sheets produced by sequential dimer units. Interestingly, three pairs of symmetrical hydrogen bonds generate these dimer units. [source] Structure and chiroptical properties of supramolecular flower pigmentsCHIRALITY, Issue 2 2006George A. EllestadArticle first published online: 30 DEC 200 Abstract Research over the last 30 years has shown that at physiological concentrations of ca. 5 × 10,3 M, flower pigments composed of anthocyanins, either alone or complexed with flavone copigments, and frequently with metals, are self-assembled into non-covalent, chiral supramolecular complexes. This serves several biological functions including color stability, protection against UV radiation and provision for specific colors to attract insects for pollination. Self-association of the monomers takes place under conditions of molecular crowding by precise matching of the ,,, stacking interactions of the aromatic chromophores and intermolecular hydrogen bonding between the attached sugars. The resulting handedness is controlled by the chiral information provided by the sugars joined glycosidically at certain positions around the periphery of the aromatic nuclei. This review gives an overview of (i) the physicochemical evidence including circular dichroism, 1H NMR, and X-ray analysis for the structure and supramolecular chirality of these amphiphilic complexes, (ii) the role of the sugars on directing the chirality of the resulting supramolecules, (iii) the energetics of monomer association, and (iv) the possible influence of stacking chirality on insect pollination. © 2005 Wiley-Liss, Inc. Chirality 18:134,144, 2006. [source] | ||||||||||||||||||||||||||||