Cis Trans Ruthenium Complexes for Olefin Metathesis
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Solution Overview
Problem
There is a need for further development of metathesis catalysts in olefin metathesis chemistry, as existing ruthenium complexes, while efficient, have limitations in terms of stability and reactivity, particularly in requiring specific conditions for optimal performance.
Innovation Solution
The development of cis and trans ruthenium complexes with monodentate ligands, specifically incorporating phosphite and nucleophilic carbene ligands, which allow for greater tuning of catalyst behavior and stability, and can be converted between isomeric forms to optimize catalytic activity across various metathesis reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing ruthenium complexes are used for olefin metathesis, then catalytic activity is achieved, but stability and reactivity are limited and require specific conditions for optimal performance
Solution Approach 1:
The patent modifies the ligand parameters of ruthenium complexes by introducing phosphite ligands with varying alkoxy substituents (P(OMe)3, P(OEt)3, P(OiPr)3, P(OPh)3) to systematically change electronic and steric properties. This allows optimization of catalyst stability and reactivity for different metathesis reactions, resolving the contradiction between stability and adaptability across different reaction conditions
Solution Approach 2:
The patent creates composite ruthenium complexes combining multiple ligand types (phosphite ligands A, nucleophilic carbene ligands Z, and anionic ligands X) to achieve synergistic effects. The composite structure allows simultaneous optimization of stability through phosphite ligands and reactivity through carbene ligands, addressing both requirements
2Adaptability or versatility
If cis and trans ruthenium complexes with monodentate ligands are developed, then tuning of catalyst behavior is enabled, but complexity of complex structure increases
Solution Approach 1:
The patent divides the ligand system into distinct functional segments: phosphite ligands (A) providing stability and tunability, nucleophilic carbene ligands (Z) providing catalytic activity, and anionic ligands (X) providing basic coordination. This segmentation allows independent optimization of each function while maintaining manageable structural complexity
Solution Approach 2:
The patent exploits the dynamic equilibrium between cis and trans isomeric forms of the ruthenium complexes. The cis form provides robustness at elevated temperatures while the trans form shows good activity at room temperature. This dynamic interconversion allows the catalyst system to adapt to different reaction conditions without requiring multiple separate catalysts
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 complexes demonstrate enhanced catalytic activity and stability, with the cis form being robust at elevated temperatures and the trans form showing good activity at room temperature, enabling efficient catalysis of reactions such as ring closing metathesis, enyne ring closing metathesis, and cross metathesis.
Implementation Method 1
Ruthenium complexes for use in olefin metathesis... enhanced catalytic activity... efficient catalysis of reactions such as ring closing metathesis, enyne ring closing metathesis, and cross metathesis
Implementation Method 2
cis ruthenium complex... groups A, X, Z... A is a nucleophilic carbene, and a phosphorus ligand... Z is a phosphorus ligand... bond to Ru by the phosphorus atom
Data Source
AI summary
Cis ruthenium complexes that can be used as catalysts are described. The complexes are generally square pyramidal in nature, having two anionic ligands X adjacent to each other. The complexes can be used as catalysts, for example in olefin metathesis reactions. Corresponding trans ruthenium complexes are also described, together with cationic complexes where one or both of the anionic ligands X are replaced by a non-co-ordinating anionic ligand.