Heterometallic complex

Bimetallic alkoxides ( Meerwein salts ) have been known for more than 70 years, since the report made by Meerwein and Bersin [1101] on the formation of alkoxosalts (analogs of hydroxosalts MM m(OH)n) on titration of alcohol or benzene solutions of acidic alkoxides by those of basic ones to the equivalence points determined using the acid-base indicators  

Subsequent studies by physicochemical methods — and initialy the structure studies — have shown that the majority of the derivatives of this class are molecular compounds, many of them being soluble in nonpolar solvents, volatile, their structures belonging to the same types as those of the homometallic ones described in Chapter 4. 

As has been mentioned above, the special interest in these derivatives is connected with their application in the synthesis of the complex oxide materials (see Chapter 10 for details). The heterometallic alkoxides have been discussed in a number of reviews, the most complete of those (at different moments in time) being the corresponding chapter in the book by Bradley et al. [223] and articles of Mehrotra [1138] and also of Caulton and Hubert-Pfalz-graf [306], 

The data on properties of the single compounds are presented in Chapter 12 in the tables by the more electronegative element but mentioned even in the tables describing the properties of derivatives of the other one (at the bottom). 

The synthesis of bimetallic alkoxides can be achieved using the 2 routes first described by Meerwein and Bersin [1101] complex formation of2 alkoxides and the methathesis of a metal halide with an alkali metal alkoxide. 

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Fig. 25. Heterometallic complex of 1-methylcytosine, highlighting the nature of the metal-metal interaction involving the filled Ptn dz2 with the Pd11 dl2 v2.

Heterometallic Complexes with a Bridging Alkoxy-Silyl Ligand r 2- i,2-Si(OR)3... 

The novel T 2- X2-SiO bonding mode observed in these heterometallic complexes may have relevance to the stabilization of unsaturated, catalytically active heteronuclear systems. It also provides a new structural model for the bonding of small clusters or aggregates onto silica [1], a dominant theme in heterogenous catalysis. 

Figure 7.16 View of the molecular structure of the heterometallic complex [CeEr]. Colour code red, 0 purple, N grey, C green, Ce and brown, Er. Elydrogen atoms not shown.

The synthesis, UV-vis spectroscopic and electrochemical properties of the heterometallic complex [Ru (//-dpq)PtCl2 3] (dpq = 2,3-bis(2-pyridyl)quinoxaline) have been described. " ... 

In this section, we consider heterometallic complexes in which the heterometal is one other than Ru or Os. The organization of the section is according to the type of bridge (if any) between the metal centers. 

No nitrido complexes of ruthenium(VIII) have been isolated. For osmium, the only well-established osmium(VIII) nitrido species is [0s(0)3(N)] , which has been well documented in CCC (1987). A number of heterometallic complexes formed by the interaction of [0s(0)3(N)] with a second metal center have been reported. In these complexes, the [0s(0)3(N)] ion acts as a... 

Figure 2.30 Heterometallic complexes with chalcogenide bridging ligands.

In addition to the synthetic advances, the study of the optical properties of these species is a growing field. Many complexes which exhibit these interactions are luminescent. Other interesting points are the induction of rotator phases or the modulation of magnetic properties by designing the appropriate heterometallic complexes. Gold-gold interactions are still a hot topic in gold chemistry. This is evidenced in the observation that some complexes which exhibit these interactions, characterized some years ago, are revisited and modified in order to study their properties. 

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