Poly beta-diketones: Prime ligands to generate supramolecular metalloclusters

Coordination supramolecular chemistry owes its great expansion to the efforts made in designing and synthesizing new families of sophisticated multi-nucleating ligands. An emerging group of such multi-donor species is made of molecules that feature more than one beta-diketone moiety within their structure. The progressive use of such ligands in coordination chemistry is leading to a growing family of supramolecular architectures that, in many instances could have not been observed otherwise. These include homo- and heterometallic linear arrays, metallamacrocycles of different sizes, metallacoronates, triple-stranded helicates, or cage clusters of various nuclearities. This manuscript revises the advances made to date on this particular area of supramolecular coordination chemistry. We first present a compendium of all the relevant ligands made that have been employed in this context, summarizing the synthetic routes to their preparation. Next we discuss the synthesis, structure and some aspects of the coordination compounds that have resulted from their reactions with various metals. Given the large amount and the great structural variety of the existing compounds, these have been divided into categories based on the main features of their structure. This division is in some instances discretionary, and some compounds could easily have been included in more than one category simultaneously. (c) 2007 Elsevier B.V. All rights reserved.