Efficient catalytic alkyne metathesis with a fluoroalkoxy-supported ditungsten(III) complex

Area of Science:

• Organometallic Chemistry
• Catalysis
• Molybdenum and Tungsten Complexes

Background:

• Molybdenum and tungsten complexes are known catalysts for alkyne metathesis.
• Bimetallic complexes offer unique reactivity profiles.
• Alkyne metathesis is a crucial reaction in organic synthesis.

Purpose of the Study:

• To synthesize and characterize new bimetallic molybdenum and tungsten complexes.
• To evaluate the catalytic activity of these complexes in various alkyne metathesis reactions.
• To compare the activity of bimetallic complexes with related alkylidyne catalysts.

Main Methods:

• Synthesis of bimetallic molybdenum and tungsten complexes (Mo2F6, W2F3).
• Preparation of a tungsten benzylidyne complex (WF3) via W≡W bond cleavage.
• Catalytic testing in self-metathesis, ring-closing alkyne metathesis, and cross-metathesis.

Main Results:

• Bimetallic tungsten complex W2F3 and tungsten alkylidyne complex WF3 exhibited high catalytic activity in alkyne metathesis.
• Molybdenum bimetallic complex Mo2F6 showed no significant alkyne metathesis activity.
• Activity was observed for both internal and terminal alkynes.

Conclusions:

• Bimetallic tungsten complexes can serve as effective precursors for active alkyne metathesis catalysts.
• Tungsten exhibits higher efficacy than molybdenum in these specific catalytic systems.
• The W≡W bond cleavage provides a viable route to catalytically active tungsten species.