نتایج جستجو برای: dynamic nmr

تعداد نتایج: 462263  

2007
C. J. Meledandri

Magnetic iron oxide nanoparticles were synthesized and stabilized inside phospholipid vesicles by two different methods. The resulting magnetoliposome suspensions were characterized by dynamic light scattering and NMR. The NMR analysis demonstrated conclusively that the magnetic cores of the magnetoliposomes contained clusters of smaller, superparamagnetic primary particles. The application of ...

2015
ALI AMINKHANI

Synthesis of the Guanidium-Meldrum acid zwitterionic salts was developed through a three component reaction of 2, 2-dimethyl-1, 3-dioxane-4, 6-dione (Meldrum acid), aromatic aldehydes and N, N, N’, N’-Tetramethyl-guanidine in benzen at room temperature. These reaction conditions allow the preparation of stable zwitterionic salts in good yields. A dynamic NMR effect is observed as a result of re...

2003
J. Strand B. D. Schultz A. F. Isakovic P. A. Crowell

We report the observation of nuclear magnetic resonance (NMR) in a ferromagnet-semiconductor heterostructure in the presence of a spin-polarized current. Spin-polarized electrons injected from a metallic ferromagnet generate a large nuclear spin population in a GaAs quantum well by dynamic polarization. The characteristic time for the polarization process is approximately 20 sec, and the nuclea...

Journal: :Chemical science 2017
Wei-Chih Liao Ta-Chung Ong David Gajan Florian Bernada Claire Sauvée Maxim Yulikov Margherita Pucino Roman Schowner Martin Schwarzwälder Michael R Buchmeiser Gunnar Jeschke Paul Tordo Olivier Ouari Anne Lesage Lyndon Emsley Christophe Copéret

Dynamic Nuclear Polarization Surface Enhanced NMR Spectroscopy (DNP SENS) is an effective method to significantly improve solid-state NMR investigation of solid surfaces. The presence of unpaired electrons (polarizing agents) is crucial for DNP, but it has drawbacks such as leading to faster nuclear spin relaxation, or even reaction with the substrate under investigation. The latter can be a pa...

2009
Santhosh Ayalur-Karunakaran Siegfried Stapf

Poly (Dimethyl siloxane) thin films were prepared by solvent evaporation method in porous alumina hosts. The thickness of these layers ranged from multilayer to sub-monolayer. Different NMR methods (FFC relaxometry, transverse relaxation, H Double quantum NMR) were applied to study the dynamics and order in these thin films. We found that dynamic restrictions and order increased with decreasing...

ژورنال: :international journal of new chemistry 0

in this study, the drug atenolol on c60 fullerene were the drug and its derivatives were optimized fullerene. nbo and nmr for complex computations required in the hf/6-31g (d) and b3lyp/6-31g (d) quantum chemistry method was used. mechanical quantum calculations in theory level of b3lyp/6-31g were performed on structure of atenolol and nano fullerene atenolol with different positions of linking...

Journal: :Journal of the American Chemical Society 2002
Mattias Edén Julia Grinshtein Lucio Frydman

A novel approach to the determination of structure and potential dynamics in the solid-state NMR spectroscopy of half-integer quadrupolar nuclei is proposed and demonstrated. The new experiment combines into a single three-dimensional sequence, 2D multiple-quantum magic-angle-spinning NMR and 2D exchange NMR protocols. The result separates for each inequivalent chemical site its spin-diffusion ...

2017
Yong Xia Sha Ding Yuejun Liu Zhengjian Qi

We demonstrated here a facile and efficient synthesis of polyhedral oligomeric silsesquioxane-based amphiphilic polymer by thiol-ene click chemistry. The properties of polyhedral oligomeric silsesquioxane (POSS)–PEG amphiphilic polymers were studied in detail by a combination of 1H NMR, 13C NMR, 29Si NMR FT-IR, GPC, and TG analysis. The newly-designed thiol-ene protocol obtains only anti-Markov...

2015
Jiri Jonas

I& ABSTRACT (Mnu/vm 290 word) As outlined in the original proposal our work deals with NMR and laser Raman scattering experiments on highly viscous liquids, including lubricants, both in bulk and confined geometries, over a wide range of pressures and temperatures. In a general sense we focus on the relationship between molecular level properties as obtained from our experiments and the macrosc...

Journal: :Dalton transactions 2014
James M Ludlow Iii Masato Tominaga Yoshiki Chujo Anthony Schultz Xiaocun Lu Tingzheng Xie Kai Guo Charles N Moorefield Chrys Wesdemiotis George R Newkome

The self-assembly of the o-carborane-based, bisterpyridyl monomer, 1,2-bis[4'-(4-ethynylphenyl)-2,2':6',2''-terpyridine]-o-carborane, utilizing either Zn(II) or Fe(II) in a precise metal : ligand ratio (1 : 1), generated a family of metallomacrocycles that were studied via ESI-TWIM-MS, (1)H NMR, and 2D NMR (COSY, NOESY). Under kinetic control, via formation of Fe(II) complexes, the main cyclic ...

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