Structural analysis of regular copolymers of Butadiene and methylene with repeat unit [But-(CH2)n-But] by the use of model compounds—III. An analysis of the factors which influence the ratio of cis and trans 1,4 addition

1973 ◽  
Vol 9 (2) ◽  
pp. 125-136 ◽  
Author(s):  
A.V. Cunliffe ◽  
R.J. Pace ◽  
D.H. Richards ◽  
N.F. Scilly
Keyword(s):  
Structural Analysis ◽  
Repeat Unit ◽  
Model Compounds ◽  
Cis And Trans

13C-nuclear magnetic resonance spectra of oxiranes. Configuration of 1,2-epoxypropyl side chains in fungal metabolites

1978 ◽  
Vol 56 (24) ◽  
pp. 3117-3120 ◽  
Author(s):  
Suzanne Lesage ◽  
Arthur S. Perlin
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Side Chain ◽  
Fungal Metabolites ◽  
Trans Isomers ◽  
Model Compounds ◽  
Nmr Data ◽  
Nuclear Magnetic Resonance Spectra ◽  
13C Nuclear Magnetic Resonance ◽  
Cis And Trans ◽  
C Nmr

13C nmr data indicate that the epoxypropyl side chain of 'asperlin' (1) has a trans configuration. This assignment follows from associated measurements on model compounds, showing that the 13C chemical shift of an epoxypropyl CH3 group is close to either 17 ppm (trans isomers) or 13 ppm (cis isomers). Synthesized as oxirane derivatives related to 1 are diastereomeric pairs of 8-deoxy-6,7-cis- and -trans-epoxy-1,2:3,4-di-O-isopropylidene-α-D-galacto-octopyranoses.

Bulk Synthesis of Completely and Partially Sn filled CoSb3 Using the Multilayer Repeat Method

2000 ◽  
Vol 626 ◽  
Author(s):  
Heike Sellinschegg ◽  
David C. Johnson ◽  
Michael Kaeser ◽  
Terry M. Tritt ◽  
George S. Nolas ◽  
...  
Keyword(s):  
Structural Analysis ◽  
Physical Properties ◽  
Repeat Unit ◽  
Phonon Modes ◽  
Filled Skutterudite ◽  
Modulated Elemental Reactants ◽  
Wide Range ◽  
Elemental Reactants ◽  
Binary Compounds ◽  
Thermal Conductivities

ABSTRACTFilled skutterudite compounds possess very low thermal conductivities due to the scattering of a wide range of phonon modes caused by a loosely bound cation incorporated in a cavity of the structure. The inclusion of such a filler cation causes several synthetic difficulties since the desired compounds are thermodynamically unstable with respect to disproportionation. Modulated elemental reactants were used in this study to circumvent these difficulties. SnxCo4Sb12 samples with x=0.5 and nearly 1.0 were synthesized using this method. To prevent nucleation of unwanted binary compounds, the repeat unit made up of elemental layers was less than 20 angstroms 500mg of each sample were produced, allowing for the samples to be hot pressed into a pellet. Structural analysis as well as measurements of the physical properties are presented.

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