Electrochromic Organic Compound Wavelength Shift via 3,3'-Disubstitution
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Solution Overview
Problem
Existing electrochromic compounds, such as viologen derivatives, face issues with absorption peak wavelength and reversible redox reactions, particularly when alkyl groups are bonded to specific sites of 4,4′-bipyridinium, leading to inadequate color tone variation and stability in electrochromic elements.
Innovation Solution
An organic compound with the general formula R1-X1-A1− and R1-X2-A2−, where R1 is an alkyl or alkoxy group, and X1 and X2 are alkyl, aryl, or aralkyl groups with substituents, is introduced, shifting the absorption peak to a long wavelength band and enabling reversible electrochemical redox reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If alkyl groups are bonded to the 2,2′ sites of 4,4′-bipyridinium, then the compound can be synthesized, but the absorption peak wavelength remains almost the same as unsubstituted viologen
Solution Approach 1:
The patent applies local quality by specifically substituting at the 3,3′ positions of the bipyridinium ring rather than other positions. This localized substitution at specific carbon atoms creates the desired long wavelength absorption peak while maintaining reversible redox properties, resolving the contradiction between achieving wavelength shift and maintaining electrochromic functionality.
Solution Approach 2:
The patent changes the structural parameters of the viologen compound by introducing alkyl groups at specific positions (3,3′-disubstitution) and varying the type of alkyl groups (methyl, ethyl, propyl, butyl groups). These parameter changes in molecular structure directly result in absorption peak shifts to long wavelength region while preserving electrochemical reversibility.
2Illumination intensity
If alkyl groups are bonded to the 3,3′ sites of 4,4′-bipyridinium, then the absorption peak appears in a long wavelength band, but the redox reaction does not reversibly progress
Solution Approach 1:
The patent achieves the contradiction resolution by precise local substitution at the 3,3′ positions with specific alkyl groups. This localized modification at particular carbon atoms of the bipyridinium ring enables both long wavelength absorption and reversible redox behavior, whereas substitution at other positions or with different groups fails to achieve both properties simultaneously.
Solution Approach 2:
The patent creates composite molecular structures by combining the bipyridinium core with specific alkyl group substituents. This composite approach, where the core structure provides the electrochromic framework and the alkyl substituents provide the wavelength-shifting functionality, enables both long wavelength absorption and redox reversibility to coexist.
3Illumination intensity
If no substituents are introduced into carbon atoms of 4,4′-bipyridinium, then the compound has simple structure, but the absorption peak is in short wavelength band
Solution Approach 1:
The patent changes the structural parameters by introducing alkyl substituents at the 3,3′ positions of the bipyridinium core. This controlled structural modification shifts the absorption peak to long wavelength region while maintaining relatively simple molecular architecture, avoiding excessive complexity despite the substitution.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The compound achieves a long wavelength absorption peak and high durable stability in redox cycles, enhancing the performance of electrochromic elements in applications like optical filters, imaging devices, and window components.
Implementation Method 1
the optical absorption properties (coloration state and light transmittance) of a substance change clue to reversible progress of an electrochemical redox reaction
Implementation Method 2
An organic compound having an electrochromic property (EC property) is represented by general formula (1)
Implementation Method 3
the compound achieves a long wavelength absorption peak
Data Source
AI summary
An organic compound represented by General Formula (1),in which, in General Formula (1), R1 represents an alkyl group or an alkoxy group, X1 and X2 are each independently selected from an alkyl group which may have a substituent, an aryl group which may have a substituent, or an aralkyl group which may have a substituent, and A1− and A2− each independently represent a monovalent anion.