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.
Synthesis of some novel derivatives of 1,10-phenanthroline
Garas, Adel M. S.,Vagg, Robert S.
, p. 151 - 158 (2000)
The synthesis is described of a set of new N-heterocyclic compounds which are derivatives of 1,10-phenanthroline. The compounds are designed to be general purpose chelating agents which could function as tri-, tetra- or hexadentate ligands with transition metal ions. Fused-ring molecular components have been included in the design of the compounds so that they may function as binding agents to DNA through intercalation. This includes the synthesis of substituted derivatives of pyrazino[2,3-f][1,10]phenanthroline and dipyrido[3,2-a:2'3'-c]phenazine.
A single iron porphyrin shows ph dependent switch between "push" and "pull" effects in electrochemical oxygen reduction
Bhunia, Sarmistha,Dey, Abhishek,Dey, Somdatta Ghosh,Mukherjee, Sudipta,Nayek, Abhijit
, p. 14564 - 14576 (2020/11/02)
The "push-pull"effects associated with heme enzymes manifest themselves through highly evolved distal amino acid environments and axial ligands to the heme. These conserved residues enhance their reactivities by orders of magnitude relative to small molecules that mimic the primary coordination. An instance of a mononuclear iron porphyrin with covalently attached pendent phenanthroline groups is reported which exhibit reactivity indicating a pH dependent "push"to "pull"transition in the same molecule. The pendant phenanthroline residues provide proton transfer pathways into the iron site, ensuring selective 4e-/4H+ reduction of O2 to water. The protonation of these residues at lower pH mimics the pull effect of peroxidases, and a coordination of an axial hydroxide ligand at high pH emulates the push effect of P450 monooxygenases. Both effects enhance the rate of O2 reduction by orders of magnitude over its value at neutral pH while maintaining exclusive selectivity for 4e-/4H+ oxygen reduction reaction.
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.
Monitoring helical twists and effective molarities in dinuclear triple-stranded lanthanide helicates
Ryan, Patrick E.,Guenee, Laure,Piguet, Claude
, p. 11047 - 11055 (2013/08/23)
The replacement of terminal benzimidazole-pyridine binding units in the neutral di-tridentate segmental ligand L1 with phenanthroline in L10 reduces the number of torsional degrees of freedom by two units. Reactions of these ligands with trivalent europium or lutetium cations yield structurally similar self-assembled dinuclear triple-stranded [Ln2(Lk)3] 6+ complexes, thus demonstrating that the increased rigidity of the strand in L10 is compatible with its helical twist. With the larger lanthanum cations, the metallic coordination spheres are completed with two terminal axial triflate counter-anions to give [La2(L10)3(CF 3SO3)2]4+. Thermodynamic investigations in acetonitrile confirm the minor constraints produced by the planar phenanthroline unit in L10 leading to comparable effective molarities EMEu,L1 ≈ EMEu,L10 = 10 -3.9(4) M with mid-range EuIII cations. The striking minute effective molarities EMLn,Ln-2H ≈ 10-6-10-9 M obtained upon the replacement of terminal phenanthrolines with structurally analogous fused hydroxyquinolines in L9 can be thus unambiguously assigned to solvation effects, a new tool for controlling complexity in metal-induced self-assembly processes.
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.
Highly effective recognition of carbohydrates by phenanthroline-based receptors: α- versus β-anomer binding preference
Mazik, Monika,Hartmann, Andre,Jones, Peter G.
experimental part, p. 9147 - 9159 (2010/04/05)
1H NMR spectroscopic titrations in competitive and non-competitive media, as well as binding studies in two-phase systems, such as phase transfer of sugars from aqueous into organic solvents and dissolution of solid carbohydrates in apolar medi
Phenanthroline unit as a building block for carbohydrate receptors
Mazik, Monika,Hartmann, Andre
, p. 7444 - 7450 (2008/12/22)
(Figure Presented) An acyclic receptor 1, containing phenanthroline- and aminopyridine-based recognition sites, has been established as a powerful carbohydrate receptor. Compared to the previously described acyclic receptors, compound 1 shows significantl
Bifunctional Lewis acid-nucleophile-based asymmetric catalysis: Mechanistic evidence for imine activation working in tandem with chiral enolate formation in the synthesis of β-lactams
France, Stefan,Shah, Meha H.,Weatherwax, Anthony,Wack, Harald,Roth, Justine P.,Lectka, Thomas
, p. 1206 - 1215 (2007/10/03)
We report a mechanistically based study of bifunctional catalyst systems in which chiral nucleophiles work in conjunction with Lewis acids to produce β-lactams in high chemical yield, diastereoselectivity, and enantioselectivity. Chiral cinchona alkaloid
Metal triggered fluorescence sensing of citrate using a synthetic receptor
Cabell, Larry A.
, p. 315 - 323 (2007/10/03)
A metal containing fluorescent chemosensor was designed, synthesized, and studied for the quantification of citrate in common beverages. The sensor consists of Cu(II) bound by a 1,10-phenanthroline ligand which is attached to a bis(aminoimidazolium) recep
