Halogen-Chelate Ruthenium Complexes for Stable Olefin Metathesis
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Solution Overview
Problem
Ruthenium complexes used in olefin metathesis reactions face challenges with stability at elevated temperatures and require protective gas atmospheres, which limits their industrial application and catalytic activity.
Innovation Solution
Development of new ruthenium complexes with a halogen-chelate ring structure that maintains thermal stability and exhibits significant changes in catalytic activity with temperature, allowing for broader reaction versatility, including ring-closing, homometathesis, cross metathesis, and ROMP, without the need for protective gas atmospheres.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If ruthenium complexes are designed to be stable at elevated temperatures, then thermal stability is improved, but catalytic activity is reduced
Solution Approach 1:
The patent introduces a halogen atom (X) in the chelate ring structure to modify the electronic and steric properties of the catalyst. This parameter change allows the complex to maintain thermal stability while preserving catalytic activity through enhanced Ru-C bond strength and optimized electron distribution at the metal center.
Solution Approach 2:
The catalyst combines multiple functional components: a ruthenium carbene core, a chelating ligand system with halogen atoms, and varying auxiliary ligands (L1, L2, L3). This composite structure integrates the benefits of thermal stability from the halogen-chelate framework with the catalytic activity provided by the carbene and auxiliary ligands.
2Reliability
If protective gas atmospheres are used to maintain catalyst stability, then reliability is improved, but device complexity and operational ease are worsened
Solution Approach 1:
The halogen-chelate ring structure provides intrinsic stability to the ruthenium complex, allowing it to maintain its catalytic activity and structural integrity without external protective measures. The chelate effect and halogen bonding create a self-protecting framework that eliminates the need for inert atmosphere controls.
3Productivity
If reaction temperature is increased to improve yield, then productivity is improved, but catalyst stability deteriorates
Solution Approach 1:
The catalyst exhibits dynamic temperature-dependent behavior where the halogen-chelate structure allows the ruthenium center to adapt to varying thermal conditions. The flexible chelate ring can adjust its conformation and bonding characteristics in response to temperature changes, maintaining stability across a broader temperature range while enabling higher reaction temperatures for improved yield.
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 new ruthenium complexes demonstrate improved thermal stability and catalytic activity, enabling longer reaction times and higher yields, and can be used in various metathesis reactions without the need for protective gas atmospheres, enhancing their industrial applicability.
Implementation Method 1
Complexes with formula 1, in accordance with the invention, are applied broadly. With a good result, numerous reactions can be carried out consisting not only in ring-closing metathesis but also in homometathesis, cross metathesis and metathesis of the alkene-alkyne (ene-yne) type, and ring-opening metathesis polymerisation (ROMP).
Implementation Method 2
This invention concerns new ruthenium complexes which act as (pre)catalysts, a method for their preparation, and their application in olefin metathesis reactions.
Data Source
AI summary
The present invention provides new ruthenium complexes of Formula (1), which contain a chelate ring created by a halogen atom X. The invention concerns also a method for the preparation of the new ruthenium complexes and their application in metathesis reactions.