Search results for "1H"

CCDC 1473652: Experimental Crystal Structure Determination

2017

Related Article: Mónica Giménez-Marqués, Néstor Calvo Galve, Miguel Palomino, Susana Valencia, Fernando Rey, Germán Sastre, Iñigo J. Vitórica-Yrezábal, Mónica Jiménez-Ruiz, J. Alberto Rodríguez-Velamazán, Miguel A. González, José L. Jordá, Eugenio Coronado, Guillermo Mínguez Espallargas|2017|Chemical Science|8|3109|doi:10.1039/C6SC05122G

Novel Tetramethoxy Resorcinarene Bis-Crown Ethers

2006

The synthesis and characterization of new tetramethoxy resorcinarene bis-crown ethers BC4 and BC5 are described. The complexation properties of the compounds toward alkali metal cations were studied by 1H NMR spectroscopy and X-ray crystallography, which revealed that BC5 can accommodate two cations simultaneously inside the crown pockets formed by the crown ether bridges and the resorcinarene skeleton. [reaction: see text].

1981

Polyamides 3 containing constant and definite numbers of oxyethylene units were prepared by condensation polymerization of suitable diamines and diesters, both of which containing oxyethylene units. The polymer structure was determined by IR and 1H NMR spectroscopy. Almost all polymers are crystals melting at ≈ 40°C and show a complexation ability towards alkalimetal cations. It was also found that diesters containing oxyethylene units show a higher condensation rate than alkylene diesters, which is explained by an inductive effect of the ether oxygene. However, no remarkable difference in the condensation rate was found between diamines containing oxyethylene units and the corresponding al…

Peptide synthesis with 5-amino-1-methyl-1H-[1,2,4]triazole-3-carboxylic acid

2007

Abstract In the search for the peptide synthesis of new potential lexitropsins, starting with methyl 5‐amino‐1‐methyl‐1H‐[1,2,4]triazole‐3‐carboxylate 1a, we synthesized the chloroacetyl derivative of 2a, which was hydrolyzed to acid 2b and ammonolyzed to the peptide 2c. A more effective route was the use of (t‐butoxycarbonyl)glycyl‐benzotriazolide 3 to the acylation 1a, which leads the N/C protected peptide 4. This peptide was selectively N‐deprotected to be the useful segment 5 for further peptide syntheses to the N‐terminus. It was also C‐deprotected, that is hydrolyzed to give peptide 2c for further C‐extension. To the best of our knowledge, this is the first peptide that is a derivativ…

Synthesis of a New pH-Dependent Ligand: Conformational and Complexation Studies

2003

A new macrocyclic ligand, 3, which exhibits pH-induced conformational changes, has been prepared. This ligand consists of a crown ether derived from a trans-anti-trans 1,2,4,5-tetrasubstituted cyclohexane. Due to the stereochemistry of the substituents on the carbocyclic ring, two different low-energy conformations of the crown ether are possible. Ligand 3 has been studied in solution by 1H NMR spectroscopy at different values of pH and temperature, showing that the conformation of the crown ether, and thus its complexing ability, is strongly pH-dependent. The solid-state structure of the ligand has been determined by X-ray diffraction.

The effect of silica nanoparticles on the morphology, mechanical properties and thermal degradation kinetics of PMMA

2012

Abstract Silica–PMMA nanocomposites with different silica quantities were prepared by a melt compounding method. The effect of silica amount, in the range 1–5 wt.%, on the morphology, mechanical properties and thermal degradation kinetics of PMMA was investigated by means of transmission electron microscopy (TEM), X-ray diffractometry (XRD), dynamic mechanical analysis (DMA), thermogravimetric analyses (TGA), Fourier-transform infrared spectroscopy (FTIR), 13 C cross-polarization magic-angle spinning nuclear magnetic resonance spectroscopy ( 13 C{ 1 H} CP-MAS NMR) and measures of proton spin-lattice relaxation time in the rotating frame ( T 1 ρ ( H )), in the laboratory frame ( T 1 ( H )) a…

Susceptibility of Methyl 3-Amino-1H-pyrazole-5-carboxylate to Acylation

2009

Abstract In the search for a new method of synthesis of hybrid peptides with aminopyrazole carboxylic acid, we tried to force selective acylation at the aromatic amino group instead of at the ring nitrogen atom with fairly gentle acylating agents. The acylating agents used were acid anhydrides: acetic anhydride, tert-butyl pyrocarbonate, and 2-(2-methoxyethoxy)ethoxyacetic acid/dicyclohexylcarbodiimide. We succceded in acylation at this amino group with almost none at the ring nitrogen atom. Sometimes, however, acylation in small quantities at the ring nitrogen atom was observed as a by-product. To remove this by-product, imidazole was used. Thus, we were able to obtain the hybrid peptides …

Binding and Fluorescent Sensing of Dicarboxylates by a Bis(calix[4]pyrrole)-Substituted BODIPY Dye

2013

A bis(calix[4]pyrrole)-substituted BODIPY ditopic receptor 1 has been synthesised and characterised. The binding and sensing properties of 1 towards several aliphatic and aromatic dicarboxylates have been evaluated by using UV/Vis fluorescence and 1H NMR spectroscopy. The receptor strongly binds linear α,ω-dicarboxylates of appropriate lengths (C9 and C10) by acting as a cleft. For all dicarboxylates, the binding event is detected by a bathochromic shift in the UV/Vis spectra of the receptor and by strong quenching of its fluorescence.

Incorporation of Pt(II) complex with [amino-2(methylthio)(1,2,4)triazole-(1,5-a)pyrimidine-6-carboxylic-acid] ligand in MCM41 for controlled release

2015

Drug carriers play a critical role for the loading and the release of the drug. A promising frontier is represented by a new class of innovative medicines that represents directional transport vehicles "drug delivery" and consist of assembled structures carrier (nano)-drug. Silica-based materials, nontoxic, biocompatible, have been used as adjuvant and excipient in pharmaceutical technology. In this class of compounds, the mesoporous materials, such as MCM41, SBA-15 and hexagonal mesoporous silica, have been investigated for medication and drug delivery due to their properties. In fact, these materials show a large specific pore volume made up of regular pores having a diameter in the nanom…

Crystal structure and Hirshfeld surface analysis of 1-(2,4-dichlorobenzyl)-5-methyl-N-(thiophene-2-sulfonyl)-1H-pyrazole-3-carboxamide

2018

In the title compound, C16H13Cl2N3O3S2, the thiophene ring is disordered in a 0.762 (3):0.238 (3) ratio by an approximate 180° rotation of the ring around the S—C bond linking the ring to the sulfonyl unit. The dichlorobenzene group is also disordered over two sets of sites with the same occupancy ratio. The molecular conformation is stabilized by intramolecular C—H...Cl and C—H...N hydrogen bonds, forming rings with graph-set notation S(5). In the crystal, pairs of molecules are linked by N—H...O and C—H...O hydrogen bonds, forming inversion dimers with graph-set notation R 2 2(8) and R 1 2(11), which are connected by C—H...O hydrogen-bonding interactions into ribbons parallel to (100). Th…