Polymeric ruthenium compounds: Synthesis and employment as synthons

Polymeric organometallic ruthenium systems have been known for more than 50 years, and their chemistry and synthetic pathways have been extensively studied mainly for their reaction patterns to give an array of neutral and cationic ruthenium complexes which in turn shows to be highly reactive complexes. Worldwide research over the last few decades on the synthesis and reactivity of ruthenium complexes in solution gave rise to a range of different versatile and stable catalysts which are increasingly employed in organic synthesis. These complexes find widespread use in the synthesis of complex organic molecules which have application in the pharmaceutical, plastic and other commercial industries. The ongoing search for inexpensive and trivial synthetic routes to these chemo- and regio-selective ruthenium complexes have in many accounts made use of polymeric ruthenium precursors, and is still of interest to date. Some of these polymeric complexes also exhibit other interesting physical properties which renders them useful for other applications. This chapter covers the initial discovery of selected organometallic polymeric- and oligomeric Ru(0), Ru(I), and Ru(II) species for the specific application as highly reactive synthons to fine organo- and inorganic ruthenium complexes, their associated solid state structures that has been investigated, and their reactions involving both stoichiometric and catalytic amounts of these complexes with a wide range of ligands under various reaction conditions. Modern approaches to other polymeric ruthenium species that has been synthesized in the last 15 years are also discussed. Selected reactions, reactions with ligands, and selected characterization of the polymeric complexes have been tabulated and are included herein.