Chiral Binaphthol Esters for High Helical Twisting Power
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Solution Overview
Problem
Chiral liquid crystal compounds with low helical twisting power require high concentrations, affecting the properties of the LC host mixture and leading to crystallization issues, high costs, and synthesis challenges, necessitating the development of compounds with high helical twisting power, easy synthesis, good solubility, and minimal impact on LC host properties.
Innovation Solution
The use of chiral esters comprising a [1,1']binaphthalenyl-2,2'-diol group, which can be synthesized enantiomerically pure and exhibit high helical twisting power, good solubility, and stability in LC host materials, allowing for the formation of twisted structures without negatively impacting the host's properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If chiral compounds with low HTP are used, then high amounts are needed to induce a short pitch, but this negatively affects the properties of the LC host mixture
Solution Approach 1:
The patent changes the molecular structure parameters of chiral compounds by introducing specific functional groups (carboxylic acid, ester, amide, urea, or carbonyl groups) attached to the binaphthalenyl-2,2'-diol core. This structural parameter change increases the HTP value, allowing short pitch to be achieved at low concentrations without negatively affecting LC host properties such as clearing point, dielectric anisotropy, viscosity, and switching times.
2Length of moving object
If high amounts of chiral compounds are used to achieve short pitch, then the helical twisting power requirement is reduced, but the cost and synthesis difficulty increase
Solution Approach 1:
The patent modifies the molecular parameters of chiral compounds by incorporating readily available building blocks like binaphthalenyl-2,2'-diol and common carboxylic acid derivatives. This allows the synthesis of high-HTP compounds using standard synthetic procedures and commercially available materials, reducing both cost and synthesis difficulty while achieving the desired short pitch at low concentrations.
3Length of moving object
If chiral compounds with high HTP are used, then low concentrations are sufficient for short pitch, but solubility issues and crystallization may occur
Solution Approach 1:
The patent changes the solubility parameters of chiral compounds by introducing flexible alkyl chains (1-20 carbon atoms) and various functional groups (carboxylic acid, ester, amide, urea, carbonyl) that enhance compatibility with LC host materials. These parameter changes improve solubility and prevent crystallization at low temperatures while maintaining high HTP for short pitch formation.
Solution Approach 2:
The patent creates composite molecular structures combining the chiral binaphthalenyl-2,2'-diol core with various functional groups and alkyl chains. This composite approach allows optimization of both HTP and solubility properties, preventing crystallization issues while maintaining the desired helical twisting behavior at low concentrations.
4Stability of the object's composition
If multiple different chiral dopants are added to overcome solubility and crystallization issues, then the pool of available compounds is expanded, but costs and temperature compensation requirements increase
Solution Approach 1:
The patent systematically varies molecular parameters (functional groups, alkyl chain lengths) within a single chiral compound class to achieve both high solubility and high HTP. This eliminates the need for multiple different chiral dopants, reducing device complexity while maintaining temperature-independent twisting power and preventing crystallization.
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
These compounds enable the creation of LC materials with high helical twisting power at low concentrations, reducing crystallization issues and maintaining the host's properties, thus enhancing the efficiency and cost-effectiveness of LC applications.
Implementation Method 1
chiral liquid crystal (LC) materials... consist of an LC host material containing one or more chiral dopants which induce the desired helical twist... The effectiveness of a chiral compound to induce a helically twisted molecular structure in a liquid crystal host material is described by its so-called helical twisting power (HTP)
Implementation Method 2
chiral compounds... chiral ester comprising a [1,1']binaphthalenyl-2,2'-diol group... enantiomerically pure
Data Source
AI summary
The invention relates to ch'iral binaphthol derivatives, methods of their preparation, and to their use in optical, electrooptical, electronic, semiconducting or luminescent components or devices, and in decorative, security, cosmetic or diagnostic applications.