Synthesis of heterobimetallics

The synthesis of heterobimetallic cages which contain alkaline-earth metals and tin(+2) atoms succeeds by the metalation of trialkylsilyl substituted phosphanes with the bis(trimethylsilyl)amides of tin(+2) and of calcium, strontium, or barium according to Scheme 3.6-13. Heterobimetallic cages of tin and magnesium are unknown, instead their formation mixtures of the homometallic phosphanides are observed [75],... 

Scheme 3.6-13. Synthesis of heterobimetallic phosphanide-phosphandiide clusters.

Asymmetrical, Mixed Bisporphyrinates - The synthetic paths (paths — f, — j, k) preclude an easy synthesis of heterobimetallic complexes like RuOs(OEP)2. Such complexes were obtained in pure forms by stepwise metallation of H2(DPB) to RuOs(DPB) [232]. Separation of a mixture of [Ru(OEP)]2, [Ru(OETAP)]2, and Ru2(OETAPXOEP) was achieved by stepwise oxidation of these bis-metalloporphyrins using AgBF4 in toluene when first [Ru(OEP)]2BF4 and then [Ru2(OETAP)(OEP)]BF4 precipitated. The latter was then reduced with cobaltocene to give pure Ru2(OETAP)(OEP) [233]. 

A broad application of phenolic Sehiff base ligands lies in the synthesis of heterobimetallic complexes. Extended functionalization of the L2 - ligand affords the so-called compartmental ligands which ensure rich coordination chemistry by accomodation of several metals [89, 146]. Some representative ligands are depicted in Fig. 25. 

Scheme 12 Synthesis of heterobimetallic Ln/Al carboxylate complexes from Ln(02CCF3)3 (Ln = Y, Eu, Nd) and observed ligand coordination patterns (a-c) [132]...

Scheme21 Synthesis of heterobimetallic Ln(III)/Al carboxylate complexes via the tetramethylaluminate route [148]...

Scheme 43 Synthesis of heterobimetallic Ln(III)/M species from lanthanide amides Ln(NMe2)3(LiCl)3 and MMe3 (Ln = La, Nd M = Al, Ga) [206]...

The primary method of synthesis of heterobimetallic complexes may involve electron transfer between metal halides and metal-carbonyl anions " ... 

Synthesis of Heterobimetallic Alkoxides from the Component Metal Alkoxides... 

Another selective approach to the synthesis of heterobimetallic compounds is the reaction of bivalent tin with a commercially available hydroxide or acetate, with the elimination of a small molecule, such as alcohol, or a volatile byproduct, such as CO. ... 

T) -CgH5)PeCo(C0)3(Nj) ( i-CO). The synthesis of heterobimetallic complexes from metal carbonyl complexes of bis(diisopropylamino)phosphine has been described thus... 

Interest continues in the synthesis of heterobimetallic carbonyl clusters (see Polynuclear Organowetallic Cluster Complexes and most are prepared by the addition of carbonyl metallates to small- or medium-sized carbonyl clusters. For example, addition of four equivalents of [HFe(CO)4] to [Rh(/x-Cl)(CO)2]2 forms [Fe2Rh(CO)io], which is converted to (99) (L = PPhs) by addition of the phosphine. Similarly, two equivalents of [Rh(CO)4] added to Fe2(C0)g followed by refluxing in acetone forms [Fe2Rh2(CO)io] , which on reaction with [Au(PPhs)]+ gives (100) (L = PPhg). Since [Fe2Rh(CO)io] is a 46-electron cluster, it is coordinatively unsaturated which is reflected by its reactivity (equation 44). Combination of 2 mols of... 

The synthesis of heterobimetallic sesquifulvalene and hydrosesquifulvalene manganese(l)-chromium(0) complexes was reported by Tamm et al. [237] it involved the reaction between cycloheptatrienyltrimethyltin and (iodocyclopen-tadienyljtricarbonyhnanganese with subsequent chromium functionalization. Elaboration of (fluoroaryl)tricarbonylchromium complexes by reaction with vinyltributyltin has been described by Wilhelm and Widdowson [238]. 

Selective cross-metathesis of allyl-substituted awra-zirconocene dichloride with Pd, Co, and Ni complexes having the acrylate pendant resulted in the synthesis of heterobimetallic complexes Zr/Pd, Zr/Co, and Zr/Ni (Scheme 12.27) [34]. 

Scheme 32.4 Synthesis of heterobimetallic complexes derived from M (OR>2 aUcoxides and group 4 metallocenes.

Two papers document the synthesis of heterobimetallic compounds of titanium and cobalt Reaction of [MeH(OBu ),] with (HCo(CO)J affords I(Bu 0),Ti-Co(CO)4] which contains an unsupported metal-metal bond ", while addition of [Coi(CO)J to [Cp 2Ti(C2Hi)J (Cp aCjUtSiMe,) gives the radical [Cp jTi0i-CjPh)2Co(CO)l in which a weak metal-metal... 

Scheme 10.89 Synthesis of heterobimetallic compounds (217, 218) with Pd-Pt bonds.

As shown earlier Fc-NCNH pincer molecules can successfully be used in the synthesis of heterobimetallic complexes. The introduction of a further NCNH unit in Fc-NCNH opens the possibility to prepare the ferrocene-based trimetallic FeM2 complexes 68 and 69 (M = Pd, Pt) by starting from ferrocene 65 (Scheme 6). The reactions shown in Scheme 6 include metallation-transmetallation and oxidative addition processes [49, 63]. 

Scheme 8.5.1 Synthesis of Heterobimetallic Co(l) Complex with Bis(silylenyl)-Substituted Ferrocenyl LSi-Fc-SiL (Fc = ferrocenediyi, L = PhClNtBulz).

Several literature sources contain information on the synthesis of complexes with metal-metal bonds between transition metals or between transition metals and main group metals. o The use of ion exchange reactions in the rational synthesis of heterobimetallic compounds is widespread. Such reactions are of considerable utility because the starting materials are readily accessible and typically the reactions proceed cleanly and in high yield. i A number of ion exchange reactions that lead to the isolation of complexes containing metal-metal bonds have been described in Inorganic Syntheses... 

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