Anionic Oligomerization as a Route to Chain Clusters

Abstract

The combination of two old concepts (the "sigma-donor" capability of M-H bonds and the propensity of unsaturated complexes for addition reactions) has led to the first example of addition oligomerization of an organometallic analogue of olefins: chains containing cis-[Re(CO)4] units joined by Re-H-Re interactions have been obtained through the oligomerization of the unsaturated complex [Re2(micro-H)2(CO)8] promoted by anionic "initiators". The limits of the method and the possible extension to other substrates are discussed.

A Triply Bonded Dimolybdenum Hydride Complex with Acid, Base and Radical Activity

“…Organometallic compounds having hydride ligands across metal−metal bonds of formal order (BO) higher than 1 are usually very active species which react under mild conditions with a great variety of molecules to give products that cannot be prepared through other routes. This is well illustrated by the rich chemistry developed around the complexes [Os 3 ( μ -H) 2 (CO) 10 ], [Re 2 ( μ -H) 2 (CO) 8 ], and [Mn 2 ( μ -H) 2 (CO) 6 ( μ -L 2 )] (L 2 = (EtO) 2 POP(OEt) 2 , Ph 2 PCH 2 PPh 2 ), all of which display an unsaturated M 2 ( μ -H) 2 moiety with a formal BO = 2. Recently, we reported the synthesis of the 30e hydride [Mo 2 Cp 2 ( μ -H)( μ -PCy 2 )(CO) 2 ] ( 1 ; Cp = η 5 -C 5 H 5 ), for which a formal BO = 3 can be formulated according to the effective atomic number rule.…”

Insertion, Rearrangement, and Coupling Processes in the Reactions of the Unsaturated Hydride Complex [W2(η5-C5H5)2(H)(μ-PCy2)(CO)2] with Isocyanides

“…Electron-deficient organometallic compounds having hydride ligands bridging over metal–metal bonds are usually very active species that react under mild conditions with a great variety of molecules to give products that cannot be prepared through other routes. This is well illustrated by the rich chemistry developed around the complexes [Os 3 (μ-H) 2 (CO) 10 ], [Re 2 (μ-H) 2 (CO) 8 ], and [Mn 2 (μ-H) 2 (CO) 6 (μ-L 2 )], (L 2 = (EtO) 2 POP­(OEt) 2 or Ph 2 PCH 2 PPh 2 ), all of which display an unsaturated M 2 (μ-H) 2 moiety, or that around the 30-electron hydrides [M 2 Cp* 2 (μ-H) 4 ] (M = Fe, Ru), [M 2 (η 6 -C 6 Me 6 ) 2 (μ-H) 3 ] + (M = Ru, Os), and [Mo 2 Cp 2 (μ-H)­(μ-PCy 2 )­(CO) 2 ] . These reactions usually involve partial or complete transfer of the hydride ligands to the incoming molecule and are thus related to the stoichiometric and catalytic hydrogenation reactions of simple reagents such as alkynes, nitriles, isocyanides, and related unsaturated molecules.…”

Reactivity of the Unsaturated Hydride [Mo2(η5-C5H5)2(μ-H)(μ-PCy2)(CO)2] toward 17- and 16-Electron Metal Carbonyl Fragments: Rational Synthesis of Electron-Deficient Heterometallic Clusters

“…These hydrides are also reactive toward [Au(PPh 3 )] + (a fragment isolobal to H + ) and other group 11 and 12 compounds, such as CuX (X = halogen), Zn(Hg), or [M(C⋮CPh)] (M = Au, Cu, Ag), thus allowing the synthesis of different trinuclear (M = Au, Ag, Zn), pentanuclear (M = Au), or hexanuclear (M = Cu, Ag) Mn 2 M x clusters. Extensive studies have also been carried out with the isoelectronic dirhenium complex [Re 2 (μ-H) 2 (CO) 8 ], which reacts easily with different transition-metal complexes such as the metal carbonyl anions [M(CO) x ] - (M = Mn, Re, Ir; x = 4, 5) and [Re 2 H(CO) 9 ] - 8a,9 or the neutral late transition-metal compounds [Pt(PPh 3 ) 2 (C 2 H 4 )], [Pt(COD) 2 ], or [Ir(CO)(η 5 -C 9 H 7 )(η 2 -C 8 H 14 )], to give new tri- or tetranuclear clusters. Finally, the reactivity of the triosmium dihydride [Os 3 (μ-H) 2 (CO) 10 ] toward organometallic fragments has been also widely studied, allowing the synthesis of heterometallic clusters with higher nuclearity and incorporating transition-metal atoms from groups 6, , 8, − 9, − 10, 19a, 11, 19a, and 12 …”