Access to multinuclear salen complexes using olefin metathesis?

Dalton Transactions Pub Date: 2011-02-04 DOI: 10.1039/C0DT01411G

Abstract

The use of olefin metathesis as a construction tool for multimetallic salen-based structures is described. The approach involves mono- and diallyl-functionalized metallosalen complexes that can be directly coupled by metathesis leading to dimetallic species or mixtures of linear and cyclic oligomers. The metathesis of bis-allyl Ni(salen) complexes has been studied in detail. At high concentration it is possible to selectively obtain di-Ni species rather than heavier oligomers while under dilute conditions cyclic rather than linear oligomers are preferentially obtained. A mono-allyl Zn(salphen) complex was efficiently coupled using metathesis to give the di-Zn(salphen) product, which was subsequently transmetalated with a variety of metals to yield dimetallic salens of potential catalytic interest. Finally, a tetranuclear Zn4 macrocycle was also prepared using buildings blocks obtained by metathesis from commercially available precursors. The methods described herein allow for the facile construction of multi-centered Schiff base complexes of catalytic or supramolecular interest.

Graphical abstract: Access to multinuclear salen complexes using olefin metathesis
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