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Heterogeneous Removal of Water-Soluble Ruthenium Olefin Metathesis Catalyst from Aqueous Media Via Host-Guest Interaction
Published on: August 23, 2018
Assembling heterometals through oxygen: an efficient way to design homogeneous catalysts
Swadhin K Mandal1, Herbert W Roesky
1Department of Chemical Sciences, Indian Institute of Science Education and Research-Kolkata, Mohanpur-741252, India.
Accounts of Chemical Research
|October 13, 2009
Summary
Synthesizing heterobimetallic complexes with diverse metals is challenging but enables cooperative catalysis. New oxygen-bridged structures offer efficient polymerization catalysts, some activated by methylalumoxane (MAO) at low concentrations.
Area of Science:
- Inorganic Chemistry
- Organometallic Chemistry
- Catalysis
Background:
- Assembling molecules with two distinct metal centers presents synthetic challenges.
- Heterometallic complexes, particularly M-O-M' frameworks, are crucial for cooperative catalysis.
- These complexes enable chemical communication between metals, modifying their fundamental properties.
Purpose of the Study:
- To develop synthetic routes for heterobimetallic complexes with diverse metal properties.
- To explore the M-O-M' motif for creating novel heterometallic structures.
- To investigate the catalytic applications of these newly synthesized complexes.
Main Methods:
- Synthesis of hydroxide precursors: LMR(OH), [LSr(mu-OH)](2).(THF)(3), and Cp*(2)ZrMe(OH).
- Utilizing the Brønsted acidic proton in M(O-H), Sr(O-H), or Zr(O-H) for M-O-M' bond formation.
- Assembly of main group, transition, and lanthanide metals through oxygen bridging.
Main Results:
- Successful synthesis of new heterobimetallic complexes via oxygen bridging.
- Demonstrated catalytic activity in polymerization of epsilon-caprolactone, ethylene, and styrene.
- Developed catalysts with grafted methylalumoxane (MAO) units, enabling efficient ethylene polymerization at low MAO concentrations.
Conclusions:
- The M-O-M' synthetic strategy provides access to novel heterobimetallic complexes.
- These complexes exhibit excellent catalytic performance, particularly in polymerization reactions.
- Grafted MAO units and bridging oxygen enhance Lewis acidity and catalytic efficiency.
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