Near-Infrared Absorbing Composition With Stable Diimmonium Counterions
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Solution Overview
Problem
Existing near infrared absorbing compounds, such as immonium compounds, face issues with fastness, heat stability, and stability due to changes in oxidation number, and diimmonium compounds with nucleophilic anions are prone to decomposition at normal temperatures, limiting their practical use.
Innovation Solution
A coloring agent composition containing compounds represented by General Formula (1) or (2) with specific aryl or heteroaryl groups and non-nucleophilic anions, which enhance thermal stability and absorption in the long-wavelength infrared region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If immonium compounds with aryl groups substituted with amino groups are used, then near infrared absorption is achieved, but the compound has multiple oxidation numbers making it difficult to isolate with fixed oxidation number and absorption spectrum changes over time
Solution Approach 1:
The patent changes the chemical structure parameters by introducing electron-withdrawing groups (such as carbonyl, cyano, or nitro groups) at specific positions of the aryl ring, which stabilizes the oxidation state and prevents unwanted redox reactions while maintaining near-infrared absorption properties
Solution Approach 2:
The patent creates composite structures by combining the immonium core with specific substituted aryl groups and counterions, forming a stable compound system that maintains fixed oxidation number and prevents absorption spectrum changes over time
2Illumination intensity
If diimmonium compounds with nucleophilic anions (chloride ion, fluoride ion) are used, then near infrared absorption is achieved, but the compound undergoes decomposition reaction at normal temperature
Solution Approach 1:
The patent changes the counterion parameter from nucleophilic anions (Cl-, F-) to non-nucleophilic anions such as tetrafluoroborate (BF4-), perchlorate (ClO4-), or hexafluorophosphate (PF6-), which eliminates decomposition reactions while preserving near-infrared absorption
Solution Approach 2:
The patent replaces unstable nucleophilic anions with stable non-nucleophilic anions that do not participate in decomposition reactions, effectively creating a long-lived stable compound suitable for practical applications
3Illumination intensity
If aryl groups with electron-donating substituents are used, then near infrared absorption is enhanced, but fastness and heat stability are low
Solution Approach 1:
The patent optimizes the electronic parameters of substituents by selecting groups with moderate electron-donating or electron-withdrawing effects (Hammett σ values within specific ranges), balancing near-infrared absorption enhancement with heat stability and fastness requirements
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 composition provides thermal stability and improved absorption in the near infrared region, addressing issues of oxidation and decomposition, and can be used in various applications including optical filters and image forming materials.
Implementation Method 1
a compound which has absorption in a long-wavelength infrared region
Data Source
AI summary
Provided are a near infrared absorbing compound represented by General Formula (1), and a coloring agent composition containing the near infrared absorbing compound. In General Formula (1), R1 to R8 each independently represent a group selected from a phenyl group having a substituent in which a σp value on Hammett's rule is −0.5 or more, an aryl group having 7 to 20 carbon atoms, which may have a substituent, or a heteroaryl group which may have a substituent, and two or more of R1 to R8 may be linked to each other to form a ring. R9 to R13 each independently represent a monovalent substituent, and five n's each independently represent an integer of 0 to 4. m is 1 or 2, and X− represents a non-nucleophilic anion.