Investigations into cluster formation with alkyl-tethered bis-calix[4]arenes.

Calix[4]arenes are versatile ligands capable of forming a wide range of cluster motifs when reacted with 3d, 4for 3d/4fmetal ions. Synthetic modification at the calix[4]arene methylene bridge offers a unique opportunity to explore cluster formation with these alternative building blocks. Here, we present the synthesis of a range of bis-calix[4]arenes that are tethered by alkyl chains, as well as exploratory structural studies into cluster-forming reactions. Single crystals were formed in four cases, and from the X-ray structures elucidated it is possible to conclude that sufficiently long alkyl tethers allow for the formation of established cluster topologies without disruption to the core coordination chemistry. Synthetic modification at the calix[4]arene methylene bridge offers a unique opportunity to synthesise alternative supramolecular building blocks. This paper describes the synthesis of a range of alkyl-tethered bis-calix[4]arenes, as well as exploratory structural studies into polymetallic cluster formation. [ABSTRACT FROM AUTHOR]