57154-80-0Relevant articles and documents
Complexes Formed between Artificial Receptors and β-Glucopyranoside in the Crystalline State
K?hler, Linda,Mazik, Monika,Seichter, Wilhelm
, p. 7023 - 7034 (2020)
In contrast to numerous known crystal structures of protein-carbohydrate complexes, which act as a source of structural information about carbohydrate-mediated recognition processes, there are only individual literature reports on crystal structures of complexes formed between artificial receptors and sugars. In this context, the new crystalline complexes of acyclic receptors and β-d-glucopyranoside described in this article provide particularly valuable model systems to study the basic molecular features of carbohydrate recognition. The detailed analyses of the binding modes observed in these complexes have shown their remarkable similarity to those used by carbohydrate-binding proteins. It is noteworthy that many of the basic molecular features of protein-carbohydrate interactions, that have been summarized years ago in some literature reports, apply to interactions observed in complexes formed by the artificial receptors.
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Taylor et al.
, p. 1088,1093 (1975)
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Solvent extraction of americium(iii) and europium(iii) with tridentate N,N-dialkyl-1,10-phenanthroline-2-amide-derived ligands: extraction, complexation and theoretical study
Cao, Shiwei,Wang, Jieru,Tan, Cunmin,Zhang, Xin,Li, Sa,Tian, Wei,Guo, Hangxu,Wang, Lei,Qin, Zhi
, p. 10560 - 10568 (2016/12/07)
The extraction and complexation behavior of soft-hard combined N,N-dialkyl-1,10-phenanthroline-2-amide (PTA) ligands with Am(iii) and Eu(iii) in HNO3 solution was investigated. The effects of acidity of the aqueous solution, shaking time, concentration of the extractant and temperature on the distribution ratios were studied. The extraction ability for both Am(iii) and Eu(iii) was found to decrease with an increase in the length of the substituent alkyl chains, and the highest extractability and selectivity for Am(iii) over Eu(iii) were found for the diethyl-substituted ligand. The separation factor for Am(iii) over Eu(iii) reached around 7.6 at low acidity and high salinity. UV-vis titrations revealed that the dialkyl-substituted tridentate PTAs all predominantly formed 1?:?1 complexes with Eu(iii), which agreed well with the results of slope analyses in the extraction experiments. The stability constants (KEuL) as well as the protonation constants (KH) were also determined by UV-vis titration. Computational chemistry gave a good explanation of the relationship between the alkalinity and the protonation energy of the proposed PTA ligands. Density functional theory (DFT) calculations on the optimized structures of Am(iii) and Eu(iii) complexes with C2-PTA showed that the selectivity may originate from differences in the degree of covalency of the bonds between the metal ions and the donor N atoms, which fits well with the experimental results.
Hydrogen and halogen bonding in the crystal structure of a 1,3,5-substituted 2,4,6-triethylbenzene consisting of three phenanthroline units
Mazik, Monika,Hartmann, Andre,Jones, Peter G.
experimental part, p. 458 - 463 (2010/04/24)
1,3,5-Tris-[N-(l,10-phenanthrolin-2-yl-carbonyl)aminomethyl]-2,4, 6-triethylbenzene (1) was synthesized, and its crystal structure was examined. X-ray structural analysis revealed the presence of hydrogen-bonded water molecules as well as hydrogen- and halogen-bonded chloroform, molecules in the crystal structure of 1. The 1-H2O-CHCl3 associate is stabilized, by N-H...O, O-H...N, O-H...O, C-H...O, and C-H...Cl hydrogen bonds as well as C-Cl...O, C-Cl...π, and C-Cl...Cl interactions. Particularly short C-H...O hydrogen bonds with H...-O and C...O distances of 1.89 and 2.94 , respectively, are observed in the crystal structure. The H...O distance is approximately 30% shorter than the sum of the van der Waals radii of involved atoms.
