Search results for "Linker"
showing 10 items of 100 documents
A two-step synthesis of new macrobicyclic aza-ligands starting from “trans”dioxocyclam as diprotected macrocycle
1997
Abstract A rapid and convenient synthesis of two small aza-cryptands containing a 1,4,8,11-tetraazacyclotetradecane backbone is reported. This strategy can be applied to the preparation of many other aza-cages by varying the nature of the cross linker. Moreover, the two remaining secondary amine sites may allow the functionalization of these ligands or their grafting on a polymer.
Peptide metal-organic frameworks under pressure: flexible linkers for cooperative compression
2018
We investigate the structural response of a dense peptide metal-organic framework using in situ powder and single-crystal X-ray diffraction under high-pressures. Crystals of Zn(GlyTyr)2 show a reversible compression by 13% in volume at 4 GPa that is facilitated by the ability of the peptidic linker to act as a flexible string for a cooperative response of the structure to strain. This structural transformation is controlled by changes to the conformation of the peptide, which enables a bond rearrangement in the coordination sphere of the metal and changes to the strength and directionality of the supramolecular interactions specific to the side chain groups in the dipeptide sequence. Compar…
Solid state halogen bonded networks vs. dynamic assemblies in solution: explaining N⋯X interactions of multivalent building blocks
2015
Tetrapyridine functionalized resorcinarene macrocycles were used as multivalent building blocks for the construction of halogen bonded networks with aryl halide linkers. In the solid state, resorcinarene macrocycles and aryl halide linker molecules assembled into interpenetrated, multidimensional halogen bonded networks with porous structure caused by the 3D block scaffold of the resorcinarenes. 19F NMR spectroscopy proved halogen bond formation also in solution, as either upfield or downfield shifts were observed depending on the bivalent or monovalent halogen bond binding mode. The binding mode in solution was explained by density functional theory computations. peerReviewed
A bio-orthogonal functionalization strategy for site-specific coupling of antibodies on vesicle surfaces after self-assembly
2019
Attaching targeting ligands on the surface of self-assembled drug delivery systems is the key request for a controlled transport of the drug to a desired location. Most commonly, the amphiphilic molecules (blockcopolymers, lipids etc.) are therefore pre-functionalized before the self-assembly takes place. However, this strategy cannot be applied, if it interferes with the self-assembly process, if the introduced functional groups react with loaded cargo or if natural carriers like extracellular vesicles should be functionalized. Here, we present the site-specific coupling of antibodies to the surface of amino group-terminated liposomes via bio-orthogonal copper-free click chemistry after li…
A fluorinated 2D magnetic coordination polymer
2021
Herein we show the versatility of coordination chemistry to design and expand a family of 2D materials by incorporating F groups at the surface of the layers. Through the use of a prefuntionalized organic linker with F groups, it is possible to achieve a layered magnetic material based on Fe(ii) centers that are chemically stable in open air, contrary to the known 2D inorganic magnetic materials. The high quality of the single crystals and their robustness allow to fabricate 2D molecular materials by micromechanical exfoliation, preserving the crystalline nature of these layers together with the desired functionalization.
Carbohydrates as Polyfunctional Scaffolds in Combinatorial Synthesis
2006
Carbohydrates are inexpensive, polyfunctional molecules which contain a high density of stereogenic centers. Taking advantage of these particular properties monosaccharides like glucose or mannose have been used for the construction of peptidomimetics which simulate recognition sites of somatostatin or RGD ligands of integrins. Due to their poly functionality, carbohydrates are considered promising scaffolds for combinatorial syntheses either in solution or on solid phase. The application of carbohydrate scaffolds, however, requires sets of orthogonally stable, selectively removable protecting groups, and the challenge in this combinatorial strategy increases with increasing number of hydro…
ChemInform Abstract: 1,2,3-Triazole in Heterocyclic Compounds, Endowed with Biological Activity, Through 1,3-Dipolar Cycloadditions
2014
1,3-Dipolar cycloaddition reactions can be considered a powerful synthetic tool in the building of heterocyclic rings, with applications in different fields. In this review we focus on the synthesis of biologically active compounds possessing the 1,2,3-triazole core through 1,3-dipolar cycloaddition reactions. The 1,2,3-triazole skeleton can be present as a single disubstituted ring, as a linker between two molecules, or embedded in a polyheterocycle. The cycloaddition reactions are usually catalysed by copper or ruthenium. Domino reactions can be achieved through dipolarophile anion formation, generally followed by cyclisation. The variety of attainable heterocyclic structures gives an ill…
Electrochemistry, spectroelectrochemistry and catalytic activity of biscobalt bisporphyrin dyads towards dioxygen reduction
2011
Three face-to-face biscobalt bisporphyrin dyads, including one incorporating a copper(II) ion inside the linker, were synthesized and characterized both spectroscopically and electrochemically in three non-aqueous solvents, dichloromethane, benzonitrile and pyridine. The electrocatalytic reduction of dioxygen with these derivatives on an electrode surface in 1.0 M HClO4 was also investigated and the results are compared to that obtained with "regular" Pacman biscobalt bisporphyrins under the same experimental conditions. Surprisingly, the tris-metal species ( Cu-bisCo ) catalyzes the reduction of O2 mainly via a 2e- transfer process, leading to H2O2 , while the bis-metal (bisCo) catalyst p…
ChemInform Abstract: Synthesis of New Bis(tetrahydropyrrolo[3,4-b]carbazoles) with a Functionalized Diaryl Spacer.
2010
Some new bis(tetrahydropyrrolo[3,4-b]carbazoles) were synthesized by Diels–Alder reactions of in-situ generated indole-2,3-quinodimethanes with a variety of bismaleimides as dienophiles and also by reaction of dianilines with a succinic acid anhydride group incorporated into a biscarbazole. In a special reaction a spermine linker was introduced. The new biscarbazoles represent potential DNA ligands for the development of new antitumor active drugs.