Accession Number:

ADA235264

Title:

Structural Transformations in Crystalline Oligomers of Polyparaphenylene,

Descriptive Note:

Corporate Author:

DAYTON UNIV OH DEPT OF CHEMISTRY

Personal Author(s):

• Baker, Kenneth N.
• Knachel, Howard C.
• Fratini, Albert V.
• Adams, W. W.

Report Date:

1989-01-01

Pagination or Media Count:

8.0

Abstract:

We report the room and low temperature crystal structures of the unsubstituted p-quinquephenyl PQP and p-sexiphenyl PSP, and substituted 2,4- diphenyl-p-quinquephenyl DPQP, 2,6-diphenyl-p-septiphenyl DPSP, and 1,2,4- triphenylbenzene TPB polyparaphenylene oligomers. The unsubstituted oligomers exhibit a solid state transition when cooled from room temperature to 110K, as indicated by a change in crystallographic space group. No transition is observed for the substituted oligomers other than the usual thermal contraction of the unit cell. The transition observed for the unsubstituted oligomers is interpreted in terms of a conformational change from an averaged planar structure to a static non-planar one. Comparisons of room temperature and low temperature crystal data are presented. Chemical reactions.

Descriptors:

• *OLIGOMERS
• CONTRACTION
• LOW TEMPERATURE
• CRYSTAL STRUCTURE
• STRUCTURAL PROPERTIES
• CELLS
• ROOM TEMPERATURE
• CHEMICAL REACTIONS
• PLANAR STRUCTURES
• TRANSITIONS
• SUBSTITUTES
• NONPLANAR
• STATICS
• SOLID STATE PHYSICS
• TRANSFORMATIONS
• THERMAL PROPERTIES
• REPRINTS

Subject Categories:

• Physical Chemistry

Distribution Statement:

APPROVED FOR PUBLIC RELEASE