Heterodimetallic complexes

Figure 7.10. Two projections of the molecular structure of the heterodimetallic complex...

The rare combination of two electron-poor metals in heterodimetallic complexes has been found in reactions of dialkynylmetallocenes with suitable metallocene precursors. Thus, reaction of Zr(f -C4H6)Cp2 with Hf(C=CPh)2Cp2 affords Cp2Zr (/x.-C2Ph)2 HfCp2 (222-Zr/Hf). Similar reactions of VCp2 with... 

A novel pentanuclear heterodimetallic metallamacrocycle 266 was prepared in three steps starting from Na2[p-CsH4C(0)]2-C6H4 264, as shown in Scheme 45. First, 264 reacted with Mo(CO)6 followed by addition of PhSnClj to yield the tetranuclear heterodimetallic complex 265. Reaction of the latter with Na2S-9H20 in boiling ethanol resulted in the formation of 266, which was characterized by IR and NMR spectra as well as X-ray stmctural analysis... 

It can be seen that in the heterodimetallic complexes, the oxidation of the ferrocenyl ligand is generally more difficult than in the related mononuclear species, whereas the reduction of the molybdenum center seems to be less affected. 

Heterodimetallic complexes with fully conjugated oligoynediyl or diethynyl arene bridges constitute another interesting family of compounds where an assignment of individual redox sites may not be trivial. In these systems, strong... 

Thus, the two tetramine receptors cyclam and tren were linked by a 1, 4-xylyl spacer to give system 14, tren-cyclam. The heterodimetallic complex [Cu(II)(tren)-Ni(II)(cyclam]4+ operates chloride anion translocation between copper and nickel centers, through the Ni(II)/Ni(III) couple, in an MeCN solution [36]. In particular, when 1 equivalent of CP is added to an MeCN solution of the heterodimetallic complex [with the nickel center in the Ni(II) state], the anion goes on the Cu(II) ion. In particular, since the log K value for the 1 1 adduct formation equilibrium is 5.7, in a lO-3 M solution of the heterodimetallic complex, 95% of the CP ion is bound to Cu(II), while the remaining 5% is dispersed in the solution. The solution has a blue-green color, due to an absorption band centered at 460 nm, pertinent to the [Cu(II)(tren]2+ fragment of the heterodimetallic complex [Cl-to-Cu(II) CT transition). If in an... 

The process is fully reversible on setting the potential of the working electrode at 0.00 vs. Fc+/Fc, Ni(III) is reduced to Ni(II), CP moves back on the Cu(II) center, and the solution takes its original blue-green color. Due to the high stability of both reduced and oxidized form of the heterodimetallic complex, the CP anion can be moved back and forth between copper and nickel centers, at will, by switching the value of the potential of the working electrode at 0.40 and 0.00 V. 

Highly polar metal-metal bonds in early-late heterodimetallic complexes (metallocycles) 00AG(E)2658. 

Factors Influencing the Stability of "Unsupported" Metal-Metal Bonds in Ti/Zr/Hf-M Heterodimetallic Complexes... 

The X-ray crystal structure of the asymmetrically bridged heterodimetallic complex [Cp2Ti(CCBut)2Pt(PPh3)] (68) has been reporte[Pg.377]

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