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Published on: July 14, 2015
Investigation of a Privileged Polymorphic Motif: a Dimeric ROY Derivative
Katie M Lutker1, Zachary P Tolstyka, Adam J Matzger
1Department of Chemistry, University of Michigan, 930 N. University, Ann Arbor, MI 48109.
This study reveals that Bis(5-methyl-2-[(2-nitrophenyl)amino]-3-thiophenecarbonitrilyl)acetylene exhibits trimorphism. Structural analysis shows symmetry breaking in one form, highlighting the propensity of ROY derivatives for polymorphism.
Area of Science:
- Solid-state chemistry
- Crystallography
- Organic materials science
Background:
- The compound 5-methyl-2-[(2-nitrophenyl)amino]-3-thiophenecarbonitrile (ROY) is known for its high degree of polymorphism.
- Bis(5-methyl-2-[(2-nitrophenyl)amino]-3-thiophenecarbonitrilyl)acetylene is a derivative of ROY featuring two electronically coupled chromophores via a triple bond.
Purpose of the Study:
- To investigate the polymorphic behavior of Bis(5-methyl-2-[(2-nitrophenyl)amino]-3-thiophenecarbonitrilyl)acetylene.
- To analyze the structural differences between the observed polymorphic forms.
Main Methods:
- Synthesis of Bis(5-methyl-2-[(2-nitrophenyl)amino]-3-thiophenecarbonitrilyl)acetylene.
- Single-crystal X-ray diffraction to determine crystal structures.
- Analysis of structural symmetry and molecular arrangement.
Main Results:
- The compound was found to be trimorphic, existing in three distinct crystalline forms.
- Structural data for two forms revealed one with maintained symmetry and another with broken symmetry.
- The broken symmetry form showed spontaneous differentiation of the methyl-thiophenecarbonitrile units.
Conclusions:
- Bis(5-methyl-2-[(2-nitrophenyl)amino]-3-thiophenecarbonitrilyl)acetylene exhibits significant polymorphism, consistent with the known behavior of ROY derivatives.
- The observed structural variations underscore the sensitivity of this molecular system to crystallization conditions.
- This research adds to the understanding of polymorphism in organic functional materials.
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