Non-benzenoid 1,6-methano[10]annulene Polymers for Disordered Organic Electronics
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Solution Overview
Problem
Conjugated polymers for light emitting, charge transporting, and energy harvesting applications face challenges due to aggregation, crystallization, and phase segregation issues caused by π-stacking, and controlling steric interactions between alkyl chains and aromatic rings to maintain effective conjugation is not well understood.
Innovation Solution
The development of conjugated polymers and small molecules incorporating a non-benzenoid 1,6-methano[10]annulene ring with different alkyl chain orientations, such as 'Tail In', 'Tail Out', and 'No Tail' configurations, which reduce torsional strain and promote disordered π-stacking, thereby enhancing processability and electronic properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conjugated polymers are designed to foster extensive π-stacking in the solid state, then charge transporting performance is improved, but the material becomes prone to aggregation, crystallization, and phase segregation
Solution Approach 1:
The patent employs non-planar curved aromatic rings (1,6-methano[10]annulene and 7,8,9,10-tetrahydropyrido[3,4,5,6,7,8,9,10-n]acridine) to replace traditional planar aromatic units in conjugated polymers. This curvature introduces steric hindrance that prevents extensive π-stacking and intermolecular aggregation, thereby maintaining material homogeneity while preserving charge transporting capability through the curved π-conjugated system.
Solution Approach 2:
The patent introduces different regiochemical configurations (Tail In, Tail Out, No Tail) of alkyl chains at specific positions on the curved aromatic rings. This local variation in side chain orientation and positioning allows fine-tuning of intermolecular interactions, preventing unwanted aggregation while maintaining processability and charge transport properties.
2Ease of manufacture
If alkyl chains are added to solubilize conjugated polymers, then processability is improved, but torsional strain increases and effective conjugation length decreases
Solution Approach 1:
The curved geometry of the 1,6-methano[10]annulene and related aromatic rings creates inherent steric protection that reduces torsional strain between the conjugated backbone and pendant alkyl chains. This allows the polymer to maintain better coplanarity along the conjugated path compared to planar analogs, preserving effective conjugation length while still accommodating solubilizing side chains.
Solution Approach 2:
The patent strategically positions alkyl chains at specific locations on the curved aromatic rings (using Tail In, Tail Out, and No Tail configurations) to minimize steric clashes with the conjugated backbone. This localized optimization reduces torsional strain and maintains effective conjugation length while providing sufficient solubility for processing.
3Reliability
If planar aromatic structures are used to extend conjugation, then electronic delocalization is improved, but steric interactions increase and lead to ordering and crystallization
Solution Approach 1:
The patent successfully extends electronic delocalization through curved aromatic systems (1,6-methano[10]annulene, pyridoacridine) that maintain π-conjugation along the curved path. The non-planar geometry inherently prevents the extended π-stacking and crystallization that would result from using planar aromatic units of similar conjugation length, thus maintaining the disordered state.
Solution Approach 2:
The curved aromatic rings introduce asymmetry in the molecular shape and electron distribution, which disrupts the symmetry required for efficient π-stacking and crystallization. This asymmetric geometry allows extended conjugation without the formation of ordered structures, maintaining material amorphousness.
Data Source
AI summary
Conjugated polymers and small molecules including the nonplanar aromatic 1,6-methano[10]annulene ring structure along with aromatic subunits, such as diketopyrrolopyrrole, and 2,1,3-benzothiadiazole, substituted with alkyl chains in a “Tail In,”“Tail Out,” or “No Tail” regiochemistry are disclosed.