Molecular Weights of Cyclic and Hollow Clusters Measured by DOSY NMR Spectroscopy

2009 ◽  
Vol 131 (47) ◽  
pp. 17254-17259 ◽  
Author(s):  
Sébastien Floquet ◽  
Sébastien Brun ◽  
Jean-François Lemonnier ◽  
Marc Henry ◽  
Marc-André Delsuc ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Molecular Weights ◽  
Dosy Nmr

scholarly journals NMR Spectroscopy as a Tool for Studying Asphaltene Composition

2019 ◽  
Vol 92 (3) ◽  
pp. 323-329 ◽  
Author(s):  
Jelena Parlov Vuković ◽  
Predrag Novak ◽  
Tomislav Jednačak
Keyword(s):  
Nmr Spectroscopy ◽  
Nmr Spectra ◽  
Analytical Techniques ◽  
Complex Mixtures ◽  
Aggregation Process ◽  
Molecular Architecture ◽  
Valuable Data ◽  
Molecular Weights ◽  
Nmr Techniques ◽  
Oil Components

Asphaltenes are the most polar oil components with molecular weights between 500 and 1000 Da, which primarily consist of carbons and hydrogens, some heteroatoms, such as nitrogen, sulphur, oxygen and traces of nickel, vanadium and iron. Owing to their extreme complexity, it is almost impossible to completely identify all the compounds present in asphaltene samples. Various analytical techniques and approaches were used to characterize asphaltenes but their structure and composition are still a matter of thorough investigations. NMR spectroscopy can reveal useful information on asphaltene molecular architecture and aggregation process. In that respect, one- and two-dimensional NMR techniques have widely been employed. Although NMR spectra of these complex mixtures are difficult to interpret, they still can provide valuable data, especially in combination with statistical methods. Some distinctive examples of using NMR spectroscopy to study asphaltenes are given in this review.

Integrating31P DOSY NMR Spectroscopy and Molecular Mechanics as a Powerful Tool for Unraveling the Chemical Structures of Polyoxomolybdate-Based Amphiphilic Nanohybrids in Aqueous Solution

2014 ◽  
Vol 20 (18) ◽  
pp. 5258-5270 ◽  
Author(s):  
Pavletta Shestakova ◽  
Gregory Absillis ◽  
Francisco J. Martin-Martinez ◽  
Frank De Proft ◽  
Rudolph Willem ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Nmr Spectroscopy ◽  
Molecular Mechanics ◽  
Chemical Structures ◽  
Dosy Nmr

scholarly journals Stability Evaluation and Degradation Studies of DAC® Hyaluronic-Polylactide Based Hydrogel by DOSY NMR Spectroscopy

Biomolecules ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1478
Author(s):  
Tatiana Guzzo ◽  
Fabio Barile ◽  
Cecilia Marras ◽  
Davide Bellini ◽  
Walter Mandaliti ◽  
...  
Keyword(s):  
Hyaluronic Acid ◽  
Nmr Spectroscopy ◽  
Bone Growth ◽  
Orthopedic Implants ◽  
Structured Surfaces ◽  
Physiological Conditions ◽  
Hydrophilic Character ◽  
Dosy Nmr ◽  
The Stability

The stability and the degradation of polymers in physiological conditions are very important issues in biomedical applications. The copolymer of hyaluronic acid and poly-D,L-lactic acid (made available in a product called DAC®) produces a hydrogel which retains the hydrophobic character of the poly-D,L-lactide sidechains and the hydrophilic character of a hyaluronic acid backbone. This hydrogel is a suitable device for the coating of orthopedic implants with structured surfaces. In fact, this gel creates a temporary barrier to bacterial adhesion by inhibiting colonization, thus preventing the formation of the biofilm and the onset of an infection. Reabsorbed in about 72 h after the implant, this hydrogel does not hinder bone growth processes. In the need to assess stability and degradation of both the hyaluronan backbone and of the polylactic chains along time and temperature, we identified NMR spectroscopy as a privileged technique for the characterization of the released species, and we applied diffusion-ordered NMR spectroscopy (DOSY-NMR) for the investigation of molecular weight dispersion. Our diffusion studies of DAC® in physiological conditions provided a full understanding of the product degradation by overcoming the limitations observed in applying classical chromatography approaches by gel permeation UV.

Challenges in analysis of high-molar mass dextrans: Comparison of HPSEC, AsFlFFF and DOSY NMR spectroscopy

2014 ◽  
Vol 99 ◽  
pp. 199-207 ◽  
Author(s):  
Ndegwa Henry Maina ◽  
Leena Pitkänen ◽  
Sami Heikkinen ◽  
Päivi Tuomainen ◽  
Liisa Virkki ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Molar Mass ◽  
High Molar Mass ◽  
Dosy Nmr

scholarly journals Spatially encoded diffusion-ordered NMR spectroscopy of reaction mixtures in organic solvents

The Analyst ◽  
2018 ◽  
Vol 143 (14) ◽  
pp. 3458-3464 ◽  
Author(s):  
Ghanem Hamdoun ◽  
Ludmilla Guduff ◽  
Carine van Heijenoort ◽  
Christophe Bour ◽  
Vincent Gandon ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Organic Solvents ◽  
Spatial Encoding ◽  
Nmr Data ◽  
Dosy Nmr

Using a spatial encoding of the diffusion dimension, DOSY NMR data are acquired in less than one second for reaction mixtures in organic solvents.

Single-scan 2D DOSY NMR spectroscopy

2008 ◽  
Vol 195 (2) ◽  
pp. 226-231 ◽  
Author(s):  
Yoav Shrot ◽  
Lucio Frydman
Keyword(s):  
Nmr Spectroscopy ◽  
Dosy Nmr

Kaliumgraphit - ein effizientes Reduktionsmittel zur Darstellung von Polysilinen / Potassium-Graphite - an Efficient Reducing Agent for the Formation of Polysilynes

1995 ◽  
Vol 50 (11) ◽  
pp. 1674-1678 ◽  
Author(s):  
Wolfram Uhlig
Keyword(s):  
Nmr Spectroscopy ◽  
Reducing Agent ◽  
Reductive Coupling ◽  
Soluble Polymers ◽  
Molecular Weights ◽  
High Yields

Potassium-graphite (C8K) reduces phenyltrichlorosilane to give polyphenylsilynes in high yields. Branched copolysilanes have been prepared via reductive coupling of phenyltrichlorosilane and diorganodichlorosilanes with C8K. Polymers of this type are also obtained by reductive coupling of triflate substituted polysilanes with C8K. The soluble polymers and copolymers with molecular weights in the range ≈ 4000 to 10000 have been characterized by 29Si-NMR spectroscopy.

scholarly journals Relationships between Guluronate Contents in Alginates Determined by 1H-NMR Spectroscopy and Their Average Molecular Weights

1999 ◽  
Vol 65 (6) ◽  
pp. 909-913 ◽  
Author(s):  
Masashi Shinohara ◽  
Hideki Kamono ◽  
Takako Aoyama ◽  
Hideo Bando ◽  
Makoto Nishizawa
Keyword(s):  
Nmr Spectroscopy ◽  
Molecular Weights ◽  
H Nmr

Solvation chemistry of water-soluble thiol-protected gold nanocluster Au102 from DOSY NMR spectroscopy and DFT calculations

Nanoscale ◽  
2014 ◽  
Vol 6 (14) ◽  
pp. 7823-7826 ◽  
Author(s):  
Kirsi Salorinne ◽  
Tanja Lahtinen ◽  
Sami Malola ◽  
Jaakko Koivisto ◽  
Hannu Häkkinen
Keyword(s):  
Nmr Spectroscopy ◽  
Dft Calculations ◽  
Aqueous Media ◽  
Apparent Size ◽  
Water Soluble ◽  
Hydrodynamic Diameter ◽  
Gold Nanocluster ◽  
Counter Ion ◽  
Dosy Nmr

The hydrodynamic diameter of Aum(pMBA)n clusters in aqueous media was determined by DOSY NMR spectroscopy. The apparent size of the cluster was shown to depend on the counter ion of the deprotonated pMBA− ligand.

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