Reactions of Sodium N,N-Diethyldithiocarbamate with the Chlorides and Bromides of Niobium(V), Tantalum(V), and Protactinium(V)

1971 ◽  
Vol 49 (8) ◽  
pp. 1151-1160 ◽  
Author(s):  
P. R. Heckley ◽  
D. G. Holah ◽  
D. Brown
Keyword(s):  
Electrical Conductivity ◽  
Molecular Weight ◽  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Organic Solvents ◽  
Conductivity Measurements ◽  
Nuclear Magnetic

Reactions between niobium(V), tantalum(V), and protactinium(V) chlorides and bromides and sodium N,N-diethyldithiocarbamate (Nadtc) have been examined in non-aqueous, non-oxygenated organic solvents. Complexes obtained are of the types Mdtc4X, Mdtc3X2, Mdtc3S, Mdtc2X3, and Mdtc2X3.nC6H6 (n = 0.7–1.0); not all complexes have been isolated for each metal. Within each group the niobium(V) and tantalum(V) complexes are isostructural; possible structures are discussed in the light of results from infrared (i.r.) and nuclear magnetic resonance (n.m.r.) spectra, molecular weight, and electrical conductivity measurements.

scholarly journals Cleavage of the Graft Bonds in PVDF–g–St Films by Boiling Xylene Extraction and the Determination of the Molecular Weight of the Graft Chains

Polymers ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1098 ◽  
Author(s):  
Chen ◽  
Seko
Keyword(s):  
Molecular Weight ◽  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Thermal Degradation ◽  
Gel Permeation Chromatography ◽  
Extraction Time ◽  
Gel Permeation ◽  
Irradiation Graft ◽  
Nuclear Magnetic

To determine the molecular weight of graft chains in grafted films, the polystyrene graft chains of PVDF–g–St films synthesized by a pre-irradiation graft method are cleaved and separated by boiling xylene extraction. The analysis of the extracted material and the residual films by FTIR, nuclear magnetic resonance (NMR), and gel permeation chromatography (GPC) analyses indicates that most graft chains are removed from the PVDF–g–St films within 72 h of extraction time. Furthermore, the molecular weight of the residual films decreases quickly within 8 h of extraction and then remains virtually unchanged up to 72 h after extraction time. The degradation is due to the cleavage of graft bonds, which is mainly driven by the thermal degradation and the swelling of graft chains in solution. This allows determination of the molecular weight of graft chains by GPC analysis of the extracted material. The results indicate that the PVDF–g–St prepared in this study has the structure where one or two graft chains hang from each PVDF backbone.

Structural studies of the capsular polysaccharide from Haemophilus pleuropneumoniae serotype 2

1987 ◽  
Vol 65 (5) ◽  
pp. 414-422 ◽  
Author(s):  
Eleonora Altman ◽  
Jean-Robert Brisson ◽  
Malcolm B. Perry
Keyword(s):  
Molecular Weight ◽  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
High Molecular Weight ◽  
Capsular Polysaccharide ◽  
Structural Studies ◽  
High Molecular Weight Polymer ◽  
Molecular Weight Polymer ◽  
Structure Formula ◽  
Nuclear Magnetic

The capsular polysaccharide of Haemophilus pleuropneumoniae serotype 2 (ATCC 27089) is composed of D-glucose (two parts), D-galactose (one part), glycerol (one part), and phosphate (one part). Hydrolysis, dephosphorylation, methylation, enzymic studies, and 1H and 13C nuclear magnetic resonance experiments showed that the polysaccharide is a high molecular weight polymer of a tetrasaccharide repeating units, linked by monophosphate diester and having the following structure:[Formula: see text]

The high molecular weight polyphloroglucinols of the marine brown alga Fucusvesiculosus L. 1H and 13C nuclear magnetic resonance spectroscopy

1985 ◽  
Vol 63 (2) ◽  
pp. 304-313 ◽  
Author(s):  
A. Gavin McInnes ◽  
Mark A. Ragan ◽  
Donald G. Smith ◽  
John A. Walter
Keyword(s):  
Molecular Weight ◽  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Magnetic Resonance Spectroscopy ◽  
Nuclear Magnetic Resonance Spectroscopy ◽  
High Molecular Weight ◽  
Resonance Spectroscopy ◽  
13C Nuclear Magnetic Resonance ◽  
Before And After ◽  
Nuclear Magnetic

1H and 13C nuclear magnetic resonance spectroscopy of the high-molecular-weight (> 104) polyphenol fraction from Fucusvesiculosus, before and after acetylation or methylation, demonstrates that it is composed of phloroglucinol units (48.9 ± 3.5%) and 2,2′,4,4′,6,6′-hexahydroxybiphenyl, 2,2′,2″,4,4′,4″,6,6′,6″-nonahydroxy-1,1′:3′1″-terphenyl, and related quater-and polyphenyl groups (together, 51.1 ± 3.5%) linked by ether bonds, each bond involving the carbinol and methine carbons of different units and the formal loss of a molecule of hydrogen. The polymer is highly branched, with ca. 20 – 22% of the constituent units being chain termini; there is no evidence for large rings of units. Approximately 5 – 10% of the phloroglucinol and 54 – 82% of the directly bonded units occur on the exterior of the molecule, whereas the interior backbone consists predominantly of ether-linked phloroglucinol units.

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