Bimetallic complexes carbonyls

Bimetallic Complexes. There are two types of bimetaUic organometaUic thorium complexes those with, and those without, metal—metal interactions. Examples of species containing metal—metal bonds are complexes with Ee or Ru carbonyl fragments. Cp ThX(CpRu(CO)2), where X = Cl or 1, and Cp7Th(CpM(CO)2), where M = Ee or Ru, have both been prepared by interaction of CP2TI1X2 or Cp ThCl [62156-90-5] respectively, with the anionic metal carbonyl fragment. These complexes contain very polar metal—metal bonds that can be cleaved by alcohols. 

Fe—Fe bond can be assigned structures 201 or 202 based on spectral data. The other product of this reaction is 193 (R = r-Bu), however, it is produced in minor amounts. Complexes 199 (R = R = r-Bu, R = Ph, R = r-Bu) were obtained. Reaction of 146 (M = Mo, R = Ph, R = R = Ft, R = r" = Me) with (benzyli-deneacetone)iron carbonyl gives rise to the bimetallic complex 200 (M = Mo), which reacts further with the free phosphole to form the bimetallic heteronuclear sandwich 203. The preferable coordination of the molybdenum atom to the dienic system of the second phosphole nucleus is rather unusual. The molybdenum atom is believed to have a greater tendency to coordinate via the trivalent phosphorus atom than via the dienic system. 

A broad range of olefins, acetals, epoxides, alcohols, and chlorides were demonstrated effective alternative starting materials. Cobalt and rhodium carbonyls and bimetallic complexes were shown to catalyze the domino hydro-... 

The photochemical synthesis of the tungsten carbonyl metallocarborane [Eq. (18) ] is also effective in the preparation of the molybdenum carbonyl analog. The resulting air-sensitive complexes show chemical behavior similar to the cyclopentadienyl analogs, C5H5M(CO)3, in that they undergo protonation with anhydrous HOI and met.hylation with CH3I. They also react further with metal hexacarbonyls to afford bimetallic complexes 54) ... 

It is also possible to prepare bimetallic rhodium(I) complexes containing A-frame ditertiary phosphine ligands. However, the majority of these complexes contain carbonyl ligands and have been dealt with in the companion volume.17 Nevertheless (143) upon heating in toluene decarbonyla-tes and forms the bimetallic complex (144).13,0... 

Disproportionation of bimetallic fulvalene carbonyl complexes to bimetallic zwitterions... 

A rare redox reaction carried out by ETC catalysis is the disproportionation of bimetallic metal carbonyl complexes such as [MoCp(CO)3]2 containing a metal-metal bond, in the presence of a two-electron donor such as PMc3. In this typical example, the reaction leads to the ion pair [Mo Cp(CO)2(PMe3)2][Mo°Cp(CO)2]. The photolysis of the dimer gives the 17-electron iron radical [Mo Cp(CO)3] re-... 

The molecular ions of the bimetallic complex [Cr(CO)5]2AsPh (150) lose consecutively 10 CO groups and the Cr atom leading to CrAsPh . Its tiimetallic analogue 151 also loses consecutively all carbonyl ligands and two iron atoms with the formation of... 

Erker and co-workers (13,206-224) have introduced a new synthetic route for the synthesis of Ficher-type metallocene oxocarbene complexes. This method, whereby a terminal carbonyl ligand is converted to a carbene by a second, early transition metal center, involves C-C coupling of a coordinated alkene with an 17 -coordinated terminal carbonyl at an early transition metal center [Eq. (30)]. Review articles (13,207-209) have appeared in the literature that extensively cover this area of chemistry, so only a short summary concerning bimetallic complexes with cr-carbene and ir-allyl bridging ligands is presented. 

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