Mononuclear Ruthenium Complex for Selective Hydrosilylation
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Solution Overview
Problem
Current catalysts for hydrosilylation, hydrogenation, and carbonyl compound reduction reactions, particularly those using platinum, palladium, and rhodium, face issues such as low selectivity, high costs, and the need for harsh conditions, while existing ruthenium complexes lack superior reactivity and cost-effectiveness.
Innovation Solution
Development of neutral or cationic mononuclear divalent ruthenium complexes with specific ruthenium-silicon bonds, which exhibit excellent catalytic activity in hydrosilylation, hydrogenation, and carbonyl compound reduction reactions under mild conditions, using ligands like isonitriles, amines, and triorganohydrosilanes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If platinum compounds (Speier's catalyst, Karstedt's catalyst) are used for hydrosilylation reactions, then the reaction can proceed, but internal rearrangement of the olefin occurs as a secondary reaction and selectivity deteriorates
Solution Approach 1:
The patent changes the chemical parameters of the catalyst system by replacing platinum compounds with ruthenium-based catalysts having different electronic and steric properties. The ruthenium complex features a specific coordination environment with phosphine ligands and variable counterions, creating a new catalytic system that achieves both high activity and selectivity through altered reaction parameters rather than modifying the fundamental catalytic mechanism
Solution Approach 2:
The patent replaces expensive platinum catalysts with more economical ruthenium-based catalysts. The ruthenium complex can be used in small amounts (0.01-5 mol%) and provides cost-effective catalysis while maintaining or improving reaction performance, effectively substituting a valuable material with a more affordable alternative
2Productivity
If excess olefin is used to compensate for secondary reactions, then reaction completion is achieved, but the cost and complexity increase
Solution Approach 1:
The ruthenium catalyst enables complete reaction with stoichiometric or near-stoichiometric amounts of olefin, eliminating the need for excess reagent. The catalyst's high activity and selectivity allow quantitative conversion without waste, improving atom economy and reducing material costs
3Reliability
If noble metals (Pt, Pd, Rh) are used as catalysts, then catalytic activity is achieved, but the cost becomes highly expensive
Solution Approach 1:
The patent systematically replaces expensive noble metals (Pt, Pd, Rh) with ruthenium-based catalysts that are significantly more economical. The ruthenium complex maintains catalytic functionality while reducing material cost, and can be employed in small loadings (0.01-5 mol%), making the overall process cost-effective
Solution Approach 2:
The patent changes the metallic center from expensive noble metals to more affordable ruthenium, altering the fundamental economic parameter of the catalytic system while maintaining or improving performance through optimized ligand environment and coordination chemistry
4Reliability
If conventional methods are used to reduce carboxylic acid derivatives, then reduction can be achieved, but harsh conditions (high temperature, high pressure hydrogen) are required
Solution Approach 1:
The patent changes the reaction conditions from harsh (high temperature, high pressure) to mild (room temperature or slightly elevated temperature, atmospheric pressure) by employing the ruthenium catalyst with hydrosilane reagents. This parameter change makes the reduction process more accessible and safer while maintaining effectiveness
Solution Approach 2:
The ruthenium catalyst acts as an intermediary that enables carboxylic acid derivative reduction under mild conditions. The catalyst facilitates the reaction between the substrate and hydrosilane reagent, mediating the transfer of reducing equivalents without requiring extreme conditions, thus making the process practical and scalable
5Reliability
If aluminum or boron hydride compounds are used as reducing agents, then reduction of carbonyl compounds is achieved, but the reagents are ignitable and water-prohibitive, making them difficult to handle
Solution Approach 1:
The patent replaces hazardous reducing agents (aluminum or boron hydrides) with safer hydrosilane compounds that are stable in air and moisture. The hydrosilanes can be handled without special precautions, eliminating safety risks while maintaining reducing capability through the ruthenium-catalyzed hydrosilylation-reduction sequence
Solution Approach 2:
The patent converts the traditionally hazardous properties of hydride reagents into beneficial features by using hydrosilanes that are inherently safer (air-stable, non-ignitable) yet still provide effective reduction when catalyzed by ruthenium. The system transforms a safety problem into an operational advantage
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 ruthenium complexes enable effective catalysis of aliphatic unsaturated compounds, polysiloxanes, and carbonyl compounds at room temperature to 100°C, with improved selectivity and yield, and tolerate varying reaction conditions, including hydrogen gas pressures.
Implementation Method 1
Hydrosilylation reactions, which entail the addition reaction of a Si-H functional compound with a compound having a carbon-carbon double bond or triple bond
Implementation Method 2
olefin hydrogenation reactions
Implementation Method 3
Methods for reducing carbonyl compounds includes methods that use an aluminum or boron hydride compound or use hydrogen in the presence of a noble metal catalyst
Data Source
Figure 1~3
Figure 4~5
Figure 6~7
AI summary
A neutral or cationic mononuclear ruthenium divalent complex represented by formula (1) can actualize exceptional catalytic activity in at least one reaction among a hydrosilylation reaction, hydrogenation reaction, and carbonyl compound reduction reaction. (In the formula, R1-R6 each independently represent a hydrogen atom or an alkyl group, aryl group, aralkyl group, organooxy group, monoorganoamino group, diorganoamino group, monoorganophosphino group, diorganophosphino group, monoorganosilyl group, diorganosilyl group, triorganosilyl group, or organothio group optionally substituted by X; at least one pair comprising any of R1-R3 and any of R4-R6 together represents a crosslinkable substituent; X represents a halogen atom, organooxy group, monoorganoamino group, diorganoamino group, or organothio group; L each independently represent a two-electron ligand other than CO and thiourea ligands; two L may bond to each other; and m represents an integer of 3 or 4.)