A new class of carbon-rich organometallics.: The C3, C4 and C5 metallacumulenes Ru=(C=)nCR2

This review article profiles the advances in ruthenium chemistry for the synthesis of a new class of organometallic complexes containing conjugated carbon-rich chains. The preparation and reactivity of recently described metallacumulenes complexes, or reactive intermediates, of general formula LnRu = (C=)(n)CR2 (n = 2,3,4), are presented. Their are shown to be produced, under very mild conditions, via the activation of propargyl alcohols derivatives HC = C-CR2OR, conjugated diynes HC=C-C=C-R and pentadiynes HC=C-C=C-CR2(Y) by Ruthenium(II) precursors of type RuCl2(PR3)(arene) and RuCl2(Ph2P(CH2)(n)PPh2)(2) (n = 1,2) in the presence of a non coordinating salt. (C) 1998 Elsevier Science S.A. All rights reserved.