Zero-Valent Transition Metal Complex Synthesis via Zinc Reduction

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Solution Overview

Problem

Current methods for producing transition metal-isocyanide complexes often involve the use of toxic substances like mercury and carbon monoxide, and unstable precursors, posing safety and handling challenges, while also being inefficient and lacking in catalytic activity.

Innovation Solution

A method involving the reaction of a transition metal compound with an isocyanide compound in the presence of an alkali metal supported by a solid substance insoluble in organic solvents, allowing for the efficient and safe production of zero-valent transition metal-isocyanide complexes without the use of harmful substances, using mild conditions and facilitating easy removal of the alkali metal by filtration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional methods using mercury amalgam or carbon monoxide are used to produce zero-valent transition metal complexes, then catalytic activity can be improved, but toxic substances are introduced creating safety hazards and contamination risks

Engineering Contradiction:
Improvecatalytic activityVSAvoidtoxicity
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces toxic mercury amalgam and carbon monoxide with zinc dust as a reducing agent. Zinc dust reacts with transition metal halides to produce zero-valent transition metal complexes without introducing toxic substances. The byproduct zinc halide is non-toxic and easily removable, thus converting a potentially harmful process into a safe one while maintaining catalytic activity.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent introduces an intermediary substance - zinc dust - to mediate the reduction of transition metal halides. Zinc acts as a safe reducing agent that transfers electrons to the transition metal without introducing toxicity. The reaction proceeds through zinc halide as an intermediary product, which can be easily removed, thus eliminating the need for toxic mercury or carbon monoxide while achieving the desired zero-valent complexes.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If unstable precursors are used in the synthesis method, then reaction efficiency can be improved, but handling difficulty and safety risks increase

Engineering Contradiction:
Improvereaction efficiencyVSAvoidhandling ease
Core Design Contradiction:
ProductivityVSEase of operation

Solution Approach 1:

The patent employs zinc dust as a disposable reducing agent that is stable, inexpensive, and easy to handle. Zinc dust can be stored and handled under ambient conditions without special precautions, unlike unstable precursors that may require inert atmospheres or low temperatures. The zinc dust is consumed in the reaction to produce zinc halide, which is easily removed by filtration or washing, thus improving ease of operation without sacrificing reaction efficiency.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Manufacturing precision

If complex purification procedures are used to remove toxic byproducts, then product purity can be improved, but process complexity and time consumption increase

Engineering Contradiction:
Improveproduct purityVSAvoidprocess complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent converts the byproduct of the reduction reaction from toxic (as in traditional methods) to non-toxic zinc halide. This non-toxic byproduct is easily removable through simple filtration or washing procedures, eliminating the need for complex purification steps. The reaction produces high purity zero-valent transition metal complexes directly, with zinc halide being removed by standard aqueous workup, thus achieving high product purity with minimal process complexity.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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

This method eliminates the risks associated with toxic substances, improves safety, and enhances the efficiency of transition metal-isocyanide complex production, providing a more stable and catalytically active catalyst for hydrosilylation reactions.

Implementation Method 1

reacting together a compound containing a transition metal and an isocyanide compound in the presence of an alkali metal supported by a solid substance insoluble in an organic solvent

Methodology Applied
Scientific EffectReduction: Reduction

Data Source

PatentEP3590947B1Method for producing transition metal-isocyanide complex
Publication Date: 2021.08.18 SHIN ETSU CHEMICAL CO LTD
  • EP3590947B1 patent drawingFigure 1~2
  • EP3590947B1 patent drawingFigure 3~4
  • EP3590947B1 patent drawingFigure 5~6

AI summary

This method is for producing a transition metal complex represented by formula (2), the method comprising reacting a compound containing a transition metal selected from V, Cr, Mo, W, Fe, Ru, Co, Rh, Ni, Pd, and Pt with an isocyanide compound represented by formula (1) in the presence of an alkali metal supported by a solid substance which is insoluble in an organic solvent. This production method can be used to easily and efficiently produce a transition metal complex that includes a predetermined transition metal having an oxidation number of 0 and that has the same or different isocyanide compounds, without using a compound harmful to the human body. (1): (CN)x-R1 {R1 represents a mono- to tri-valent organic group having 1-30 carbon atoms, and x represents an integer of 1-3}. (2): M1a(L)b {M1 represents V, Cr, Mo, W, Fe, Ru, Co, Rh, Ni, Pd, or Pt, and is a zero-valent transition metal, L represents an isocyanide compound represented by formula (1), M1 and L may be the same or different from each other, "a" represents an integer of 1-8, and b represents an integer of 2-12}.