title: Access to multinuclear salen complexes using olefin metathesis.
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 Zn(4) 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.
authors.affiliation: Institute of Chemical Research of Catalonia (ICIQ), Av. Països Catalans 16, 43007, Tarragona, Spain.
authors.forename: Robert M
authors.initials: RM
authors.lastname: Haak
authors.forename: Ana M
authors.initials: AM
authors.lastname: Castilla
authors.forename: Marta Martínez
authors.initials: MM
authors.lastname: Belmonte
authors.forename: Eduardo C
authors.initials: EC
authors.lastname: Escudero-Adán
authors.forename: Jordi
authors.initials: J
authors.lastname: Benet-Buchholz
authors.forename: Arjan W
authors.initials: AW
authors.lastname: Kleij