Supramolecular assembly of graphene with functionalized poly(fluorene-alt-phenylene): the role of the anthraquinone pendant groups

2011 ◽  
Vol 47 (27) ◽  
pp. 7677 ◽  
Author(s):  
Marta Castelaín ◽  
Horacio J. Salavagione ◽  
Rafael Gómez ◽  
José Luis Segura
2006 ◽  
Vol 6 (12) ◽  
pp. 2769-2778 ◽  
Author(s):  
Gregorio Asensio ◽  
Mercedes Medio-Simon ◽  
Pedro Alemán ◽  
Carmen Ramírez de Arellano

2000 ◽  
Vol 78 (6) ◽  
pp. 723-731 ◽  
Author(s):  
Stefano Roelens ◽  
Paolo Dapporto ◽  
Paola Paoli

A new H-bonded supramolecular assembly of the diamine-diol family has been obtained from (1R,2R)-1,2-diaminocyclohexane (DAC) and (S)-1-phenyl-1,2-ethanediol (PED). The structure was characterized by single-crystal X-ray analysis and showed the typical architecture of DAC based assemblies, consisting of a three-stranded helicate coiling around a H-bonded core, with a predictable helicity sense determined by the configuration of DAC. The new assembly, while reconfirming the unique role of DAC as a powerful assembler of supramolecular structures, demonstrated that the C2 symmetry of diol partners employed so far is not essential for assembling helicates, although chirality is. In the case of the adduct between (1R,2R)-1,2-diaminocyclohexane and (2R,3R)-2,3-butanediol, molecular recognition and self-assembly have been shown to take place even in the absence of solvent, in the gas phase, where long crystals were formed by spontaneous organized aggregation of diamine-diol units. A thorough analysis of the results from the present and previous investigations has lead to a deeper understanding of the key features of the diamine-diol molecular code and of the requirements for recognition and assembly.Key words: supramolecular, hydrogen bonding, molecular recognition, self-assembly, diamines, diols.


2015 ◽  
Vol 429 ◽  
pp. 1-14 ◽  
Author(s):  
Ghodrat Mahmoudi ◽  
Ali Akbar Khandar ◽  
Jan K. Zaręba ◽  
Michał J. Białek ◽  
Masoumeh Servati Gargari ◽  
...  

1985 ◽  
Vol 227 (1) ◽  
pp. 57-65 ◽  
Author(s):  
S Vannucchi ◽  
M Ruggiero ◽  
V Chiarugi

In a series of attempts to reveal plasma heparin, we found that high ionic strength and modification of protein amino groups were not effective in extracting endogenous heparin (or, indeed, a large percentage of exogenous labelled heparin), whereas delipidation in the presence of 4M-guanidinium chloride gave high yields, indicating that plasma heparin may be assembled with compounds other than proteins, in a form making it inaccessible to water and ions. During the extraction of lipids, a paradoxical entry of heparin into the organic phase was observed. Detergents, including sodium dodecyl sulphate, did not shift heparin into the aqueous phase, whereas repeated chloroform/methanol extraction did so. Using purified compounds we were able to reproduce in vitro both the scavenging of heparin from water as well as the formation of heparin-phosphatidylcholine complexes soluble in organic solvents. Evidence for complexing of heparin with phosphatidylcholine was also obtained by electrophoretic and ultracentrifugation assays. The quaternary-ammonium-containing phosphatidylcholine was the more effective phospholipid in binding heparin; anionic phospholipids did not bind. Only heparin-like glycosaminoglycans bound phosphatidylcholine, but less-sulphated compounds (heparan sulphate and dermatan sulphate) were weaker ligands. Gel-filtration experiments showed that heparin was not bound to liposome vesicles, but that a measurable percentage of the phospholipids was stripped off from vesicles and was found in the form of a complex separable from liposomes by gel filtration. The molecular basis as well as the biological role of the interaction of heparin with major membrane phospholipids are discussed.


2014 ◽  
Vol 67 (10) ◽  
pp. 1504
Author(s):  
Zhu-Yan Zhang ◽  
Zhao-Peng Deng ◽  
Li-Hua Huo ◽  
Shu-E Zhang ◽  
Hui Zhao ◽  
...  

Self-assembly of three flexible bis(pyridyl) molecules with different inorganic acids (HPF6, HClO4, and HNO3) leads to the formation of eight salts, which exhibit diverse architectures involving hydrogen bonding and anion–π interactions. The three types of inorganic anions in these salts formed anion–π interactions with HM+ and H2M2+ except for 2, in which the six F atoms were involved in hydrogen bonds. Anion–π interactions produced diverse motifs of one (anion)-to-one (cation) in 1, 3, 4, and 6, two (anion)-to-one (cation) in 5 and 7, and (4,4) layer in 8. Hydrogen bonds resulted in interesting supramolecular architectures, such as right- and left-handed helical chains in 3, 2-fold interpenetrating networks in 5, and 3-fold interpenetrating networks in 8. Structural analyses indicated that the conformations of the three flexible asymmetrical bis(pyridyl) molecules and the non-covalent bonding interactions, such as hydrogen bonds and anion···π interactions, play crucial roles in the final architectures of these salts. Thermogravimetric analyses indicated that the thermal stability of the eight salts decreased in the order of perchlorates, hexafluorophosphates, and nitrates. The emission intensity of the perchlorates is much stronger than that of the hexafluorophosphates, nitrates, and their corresponding organic molecules in the solid state at room temperature.


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