134882-94-3Relevant academic research and scientific papers
Assembling ethylene, alkyl, hydride, and CO ligands at iridium
Barbara, Pierluigi,Bianchini, Claudio,Meli, Andrea,Peruzzini, Maurizio,Vacca, Alberto,Vizza, Francesco
, p. 2227 - 2238 (2008/10/08)
The iridacyclopropane complex [(tripos)Ir(Cl)(C2H4)] is the starting point to synthesize a number of stable iridium complexes containing various combinations of participative ligands such as hydride, ethylene, alkyls and heteroalkyls, alkynes, and carbon monoxide: Ir(H)(C2H4), Ir(H)2(C2H4), Ir(C2H5)(C2H4), Ir(CO)2, Ir(H)(C2H5)(CO), Ir(H)2(CO), Ir(H)2(CH2CH2PEt3), Ir(H)3, Ir(H)2(C2H5), Ir(H)2(C3H7), Ir(C2H4)2, Ir(RC≡CR), IrH(μ-H)2HIr, and IrH(μ-Cl)2HIr. Due to the tripodlike structure of the ligand MeC(CH2PPh2)3 (triphos), all the complexes invariably exhibit a facial arrangement of the phosphorus and non-phosphorus ligands. The contemporaneous availability of so many related species has allowed a comparative experimental study on several important reactions. These include (i) reductive elimination of C-H and H-H bonds from dihydride alkyl complexes, (ii) reductive elimination of H-H bonds vs hydride migration in dihydride ethylene species, (iii) nucleophilic additions to coordinated double bonds, (iv) phosphine arm dissociation in triphos complexes, and β-H elimination vs C-H bond reductive elimination in hydride alkyl complexes. In most instances, such reactions are characterized by stereo- and chemoselectivity. Valuable information on the role played by the nature of the metal and of the phosphine ligands in determining the reactivity has been provided by a comparison among strictly related Rh and Ir complexes containing either triphos or three comparable monophosphines.
