Local Conformation and Crystal StructureH. Tadokoro. Structure of Crystalline Polymers, Wiley-Interscience, New York (1979). (a) C. W. Bunn. Proc. R. Soc. London, A 180, 67 (1942); (b) M. L. Huggins. J. Chem. Phys. 13, 37 (1945); (c) L. Pauling, R. B. Corey, H. R. Branson. Proc. Natl. Acad. Sci. USA 37, 205 (1951); (d) G. Natta, P. Corradini. Nuovo Cimento Suppl. 15, 9 (1960). P. Corradini. “Chain conformation and crystallinity”, in Stereochemistry of Macromolecules, Vol. III, A. Ketley (Ed.), pp. 1–60, Marcel Dekker, New York (1968). C. De Rosa. “Chain conformation, crystal structures and structural disorder in stereoregular polymers”, in Materials-Chirality, Vol. 24 of Topics in Stereochemistry, M. Green, R. J. M. Nolte, E. W. Meijer (Eds.), John Wiley, New York (2003).

2016 ◽  
Author(s):  
Stefano V. Meille ◽  
Giuseppe Allegra ◽  
Phillip H. Geil ◽  
Jiasong He ◽  
Michael Hess ◽  
...  
Keyword(s):  
New York ◽  
Crystal Structures ◽  
Structural Disorder ◽  
Chem Phys ◽  
Chain Conformation ◽  
Crystalline Polymers ◽  
Local Conformation ◽  
Stereoregular Polymers

New solutions to the problems of chain orientation and chain continuity in structure analysis of fibrous polymers. A reconsideration of the structure of polyisobutene

2007 ◽  
Vol 40 (1) ◽  
pp. 10-15 ◽  
Author(s):  
Attilio Immirzi ◽  
Davide Alfano ◽  
Consiglia Tedesco
Keyword(s):  
New York ◽  
Degrees Of Freedom ◽  
Structure Refinement ◽  
General Interest ◽  
Structural Refinement ◽  
X Ray Diffraction ◽  
Chain Orientation ◽  
Crystalline Polymers ◽  
Internal Coordinates ◽  
Fibrous Polymers

Two points of general interest in structural refinement of polymers based on internal coordinates are discussed: the chain orientation and the chain continuity. Using a proprietary computer program, based on revised approaches to these questions, the structure of polyisobutene has been reconsidered, using new X-ray diffraction measurements (Fuji image plate) and performing a structure refinement based on internal coordinates. Three refinement schemes, with a decreasing number of degrees of freedom, have been considered, with the conclusion that the distortion from the 83regular helix, claimed by Tadokoro [(1979).Structure of Crystalline Polymers, p. 136. New York: Wiley-Interscience], is confirmed, though lower than supposed. The new procedures implemented for chain orientation and chain continuity work excellently.

Influence of aromatic sulfonation on the geometry of [2.2]paracyclophane: crystal structures of one sulfonate, one disulfonic anhydride and five disulfonimides

2001 ◽  
Vol 57 (6) ◽  
pp. 780-790 ◽  
Author(s):  
Dirk J. A. De Ridder ◽  
Kees Goubitz ◽  
Margot Fontijn ◽  
Pavla Čapková ◽  
Eva Dova ◽  
...  
Keyword(s):  
Organic Chemistry ◽  
New York ◽  
Single Crystal ◽  
Crystal Structures ◽  
Structural Changes ◽  
Symmetry Plane ◽  
Academic Press ◽  
Molecular Symmetry ◽  
X Ray Diffraction ◽  
X Ray

The crystal structures of potassium [2.2]paracyclophane-4-sulfonate (1), [2.2]paracyclophane-4,15-disulfonic anhydride (2), [2.2]paracyclophane-4,15-disulfonimide (3), N-n-propyl-[2.2]paracyclophane-4,15-disulfonimide (4), N-isopropyl-[2.2]paracyclophane-4,15-disulfonimide (5), N-cyclopropyl-[2.2]paracyclophane-4,15-disulfonimide (6) and N-phenyl-[2.2]paracyclophane-4,15-disulfonimide (7) were established by single-crystal X-ray diffraction. The structural changes caused by sulfonation are discussed with respect to the parent [2.2]paracyclophane (tricyclo[8.2.2.24,7]hexadeca-4,6,10,12,13,15-hexaene). The main features are a change in the non-bonding distances between the para-phenylene rings and a rotation of these rings with respect to the molecular symmetry plane. The rings are rotated away from each other in the case of monosulfonation (1), but are rotated in the opposite way in the case of the disulfonic anhydride (2) or the disulfonimide compounds (3)–(7). The results are also discussed in terms of the parameters proposed by Keehn [(1983), Organic Chemistry, A Series of Monographs 45, edited by P. H. Keehn & S. M. Rosenfeld, Vol. 1, pp. 69–238. New York: Academic Press] showing that (bonded and non-bonded) angles involving the para-phenylene rings are mainly affected.

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