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Abstract: This review provides an overview of the synthetic pathways, structure, reactivity and applications of platinum based ruthenium and osmium carbonyl clusters of the types Pt n Ru m (CO) x L y and Pt n Os m (CO) x L y (where m + n =2 to 10 and L y =other ligands). Some important binuclear complexes are also included. The structural aspects of the clusters are briefly discussed. The application of these clusters in organic transformations and catalysis is reviewed and the future prospects are also highlighted. [Copyright &y& Elsevier]

A historical perspective is followed by an overview of methods used to synthesize transition metal-alkenyl complexes of the type LmM(CH2)n–CH=CH2 (where Lm = other ligands, M=transition metal and n≥2). Both mono- and bis(alkenyl) compounds are discussed. X-ray structures show that the alkenyl groups can coordinate either in an η1- or an η1,η2-fashion. We have shown that reactivity patterns for these metal-alkenyl complexes can be different to those shown by metal-alkyl complexes and these differences are highlighted. For example bis(alkenyl) complexes can undergo ring closing metathesis (RCM) reactions to give metallacycloalkenes, as demonstrated recently by our research group. The intermediacy of transition metal-alkenyl species in ethylene oligomerization and other catalytic reactions is also discussed. [Copyright &y& Elsevier]

Abstract: This review deals with the synthesis, properties and applications of dialkyl complexes of the type L x MR2 (R=alkyl; L x =ligands; M=transition metals of groups VI to X. Discussion on the comparison with analogous monoalkyl-metal complexes is also carried out. Possible reactivity patterns include: insertions of small molecules into the metal and carbon σ-bond, cyclometalations, oxidative addition, transmetalation, and thermal decomposition; these are discussed. The influence of various factors on the stability and reactivity of these title compounds is described. The applications and intermediacy of transition metal-dialkyl species in various catalytic reactions are highlighted. [Copyright &y& Elsevier]