X-ray molecular structures and multinuclear NMR studies of the tetranuclear iridium clusters [Ir4(CO)7(μ4-η3-PhCC(H)CCPh)(μ-PPh2)3] and [Ir4(CO)7(μ3-η2-HCCPh)(η1-CCPh)(μ-PPh2)3]

Facile Single or Double C−H Bond Activation on a Cp* Ligand Promoted by the Presence of Alkynylphosphine Ligands

“…On the other hand, alkynylphosphines have been shown to be a very useful type of ligand with excellent promise in coordination chemistry, mainly due to their ability to coordinate via the phosphorus atom and/or the CC moiety, thus favoring the formation of a rich variety of homo- and heteropolynuclear species. – Furthermore, they present a varied and rich chemistry related to several processes, among which are (i) the phosphorus−carbon bond cleavage to generate phosphido and alkynyl fragments via interaction with metal carbonyl clusters, ,− (ii) their possible engagement in characteristic insertion reactions of the triple bonds ,− or their activation with electrophilic or nucleophilic substrates, − and also (iii) intermolecular coupling of the alkynyl moieties leading to the association of two coordinated alkynylphosphines. ,,− The last reactions are of particular interest, owing to the fact that they are employed in the synthesis of macrocyclic systems from bis(diphenylphosphino) complexes with high atom efficiency , and in the study of Bergman-cyclization processes of bis(phosphino)enediynes upon complexation to metal ions. ,, Our research group has obtained very interesting results in the study of these coupling reactions on platinum and palladium precursors containing at least two alkynylphosphines, having reported the formation of novel coordinated diphosphinonaphthalene or 1,2-diarylalkenyl-1,2-diphosphine ligands, activated by complexation of a “ cis -Pt(C 6 F 5 ) 2 ” fragment, , under thermal or photochemical conditions …”