Hydrogen bonding in noncovalent synthesis: selectivity and the directed organization of molecular strands

Archer, Eric A.; Gong, Hegui; Krische, Michael J.

doi:10.1016/s0040-4020(00)00986-8

Cited by 175 publications

(65 citation statements)

References 103 publications

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“…It is possible that a similar reaction with urate was the cause of the Chinese formula illnesses. These patterns are also most likely related to the increased crystal formation at sufficient concentrations in the kidney [22][23][24][25][26] (see Figs. 2 and 3).…”

Section: Chemistry and Toxicologymentioning

confidence: 97%

Melamine Toxicity

2010

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Melamine contamination of infant formula in China and its health effects highlight the safety of the global food supply especially as it relates to formula-fed infants. Melamine is a widely used industrial chemical not considered acutely toxic with a high LD 50 in animals. The data available on acute and chronic human exposure to melamine have been limited and extrapolated from animal data. Pet food contamination in 2004 and 2007 showed stone formation and illness in animals when melamine was co-ingested with cyanuric acid. The recent outbreak in infants showed that melamine ingested in large doses may cause stones and illness without significant ingestion of cyanuric acid or other melamine-related chemicals. This may be due to increased uric acid excretion in infants and formation of melamineuric acid stones. Diagnosis and treatment of infants exposed to melamine requires further study. Clinical signs and symptoms in infants are nonspecific. The stones may be radiolucent and are not consistently seen on ultrasound. The use of alkalinization of the urine for treatment has been proposed, but is of unproven benefit. The FDA and other regulatory agencies have recommended acceptable levels of melamine in foods for consumption. Melamine ingestion has been implicated in stone formation when co-ingested with cyanuric acid, but will cause urinary stones in infants when large amounts of melamine alone are ingested.

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Section: Chemistry and Toxicologymentioning

confidence: 97%

Melamine Toxicity

2010

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“…A study of bifunctional nitrogen-containing bases characterized by the presence of a basic nitrogen atom in the molecule, which exhibits strong proton acceptor properties in the formation of complexes with hydrogen bonding (ɇ bonds) and, simultaneously, proton donor NH groups, is of great interest from both the standpoint of fundamental problems of the formation of associates with ɇ bonds and a number of relevant applied problems because these compounds are of practical importance since they are structural units in many substances used in biochemical and pharmaceutical processes (see, e.g., [1][2][3]). The presence of a few different active centers in the molecule enables the investigation of diverse types of molecular and ionic structures with hydrogen bridges and their spectral features in the IR absorption spectra.…”

Section: Introductionmentioning

confidence: 99%

Structure of adducts of the intermolecular interaction of dimethylpyrazole and diphenylformamidine with hydrogen halides in the solution

Бурейко

Kucherov

2012

J Struct Chem

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The structure of adducts forming in the solution due to the interaction of bifunctional azo compounds (dimethylpyrazole (DMP) and diphenylformamidine (DPFA)) with hydrogen halides (HF, HCl, and HBr) is found from the data of the IR absorption spectra and quantum chemical calculations. It is shown that in the interaction with HCl or HBr proton donors, proton transfer via the hydrogen bond to the basic N atom of the azo compound occurs with the formation of an NH + …Hal -ionic pair. Strong evidences of proton transfer and the anion-cation pair formation are not found for the DMP-ɇF structure, and complexes with the molecular N…HF hydrogen bond are the dominant structures. Geometric parameters of the formed structures are calculated. The formation of trimers, containing two molecules of the azo compound and one HHal molecule, with an increase in the nitrogenous base concentration is experimentally proved, and the trimer structure is determined.

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“…[9] Apart from the supramolecular design built into the components of these nanometre scale objects, the importance of the deposition method, the solution nature [10][11][12][13][14] and concentration, [15][16][17][18] the chain-length dependence, [19][20][21][22][23] and the nature of the surfaces [24][25][26] on the characteristics of aggregates have been demonstrated for some molecules. To selfassemble wires required for new challenges in molecular electronics, in this work we report the influence of these factors as well as the molecular constitution on hydrogenbonded assemblies [27][28][29][30][31] of functional p-electron-rich compounds.…”

Section: Introductionmentioning

confidence: 99%

Chemical and Constitutional Influences in the Self‐Assembly of Functional Supramolecular Hydrogen‐Bonded Nanoscopic Fibres

Puigmartí‐Luis

Minoia

Pino

et al. 2006

Chemistry A European J

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A new series of secondary amides bearing long alkyl chains with pi-electron-donor cores has been synthesized and characterised, and their self-assembly upon casting at surfaces has been studied. The different supramolecular assemblies of the materials have been visualized by using atomic force microscopy (AFM) and transmission electron microscopy (TEM). It is possible to obtain well-defined fibres of these aromatic core molecules as a result of the hydrogen bonds between the amide groups. Indeed, by altering the alkyl-chain lengths, constitutions, concentrations and solvent, it is possible to form different rodlike aggregates on graphite. Aggregate sizes with a lower limit of 6-8 nm width have been reached for different amide derivatives, while others show larger aggregates with rodlike morphologies which are several micrometers in length. For one compound that forms nanofibres, doping was performed by using a chemical oxidant, and the resulting layer on graphite was shown to exhibit metallic-like spectroscopy curves when probed with current-sensing AFM. This technique also revealed current maps of the surface of the molecular material. Fibre formation not only takes place on the graphite surface: nanometre scale rods have been imaged by using TEM on a grid after evaporation of solutions of the compounds in chloroform. Molecular modelling proves the importance of the hydrogen bonds in the generation of the fibres, and indicates that the constitution of the molecules is vital for the formation of the desired columnar stacks, results that are consistent with the images obtained by microscopic techniques. The results show the power of noncovalent bonds in self-assembly processes that can lead to electrically conducting nanoscale supramolecular wires.

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Hydrogen bonding in noncovalent synthesis: selectivity and the directed organization of molecular strands

Cited by 175 publications

References 103 publications

Melamine Toxicity

Melamine Toxicity

Structure of adducts of the intermolecular interaction of dimethylpyrazole and diphenylformamidine with hydrogen halides in the solution

Chemical and Constitutional Influences in the Self‐Assembly of Functional Supramolecular Hydrogen‐Bonded Nanoscopic Fibres

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