Homobinuclear complexes

The crystal and molecular structure of the macrobicyclic heteronuclear [FeCo(trom)](BF4) complex with the encapsulated high-spin Fe2+ and Co ions in the strongly distorted coordination polyhedra, intermediate between a TP and a TAP, was described in Ref 192. The X-ray powder diffraction patterns obtained for other hetero- and homobinuclear complexes of the binucleating trom ligand confirmed that they are isomorphic to heterobinu clear... 

An extensive series of homo-bimetallic and hetero-bimetallic complexes of the 10-donor, doubly deprotonated ligand Hj-XXXI has been recently obtained (Guerriero et al. 1990). Both the direct complexation of the lanthanide salt(s) with the presynthesized ligand, in the presence of a base, and the metal-templated synthesis from 2,6-diformyl-4-methylphenol and l,8-diamino-3,5-dioxaoctane were found to be suitable for the preparation of the complexes. The homobinuclear complexes were obtained as homogeneous mierocrystals (5 10 pm thick platelets). The heterobi-nuelear eomplexes were microerystalline powders for which all evidence indicated. 

All these compounds were shown to be generally suitable hosts for the common incorporation of several cations, and they can complex identical or different metal ions (homo- or heteronuclear complexes, respectively). The symmetrical double loop compounds (38) (fe = 0, I = 0 fe = 1, I = 1 fe = 2, I = 2), (41) (R = H), and (43), which have oxygen donor sites only but which, however, gradually exhibit larger rings and donor numbers, readily form homobinuclear complexes with alkali/ alkaline-earth metal ions of suitable size. The asymmetrical diloop compounds... 

Homobinuclear complexes also can be formed if weakly-bound ligands are substituted by a bifunctional ligand. Thus, the interaction between [Mn(CO)2(THF)Cp ] and 4,4 -bipyridyl in a 2 1 molar ratio leads to the formation of the bridged compound, 3 Figure 3.5 ... 

Additional examples of deoxygenation of Re=0 complexes have been reported by Herrmann and coworkersl37-140 ho have shown that a homobinuclear complex of rhenium(V) is formed as a result of partial... 

Mono- and bimetallic lanthanide complexes of the tren-based macrobicyclic Schiff base ligand [L58]3- have been synthesized and structurally characterized (Fig. 15), and their photophysical properties studied (90,91). The bimetallic cryptates only form with the lanthanides from gadolinium to lutetium due to the lanthanide contraction. The triplet energy of the ligand (ca. 16,500 cm-1) is too low to populate the terbium excited state. The aqueous lifetime of the emission from the europium complex is less than 0.5 ms, due in part to the coordination of a solvent molecule in solution. A recent development is the study of d-f heterobimetallic complexes of this ligand (92) the Zn-Ln complexes show improved photophysical properties over the homobinuclear and mononuclear complexes, although only data in acetonitrile have been reported to date. 

Costes J. P. and Fernandez Garcia M. I., Synthesis and characterization of homobinuclear and heterobinuclear imidazalate-bridged complexes, Inorg. Chim. Acta, 173 (1990) pp.247-254. 

Homobinuclear macrobicyclic copper, cobalt, and iron(II) complexes and a heteronuclear iron(II)/cobalt(II) clathrochelate of the [MiM2(trom)] type arise from interaction of a sodium complex of trom ligand with the corresponding metal salts. 

The temperature-dependent magnetic susceptibility study of the homobinuclear [M2(trom)](BF4) complexes indicated that the magnetic moment decreases substantially with decrease in the temperature. The intramolecular antiferromagnetic exchange between the metal centres was also observed. This interaction occurs... 

For more examples of this type of complexes, see Section 4.05.6. The synthesis of homobinuclear and heterobi-nuclear bis-Cp titanium complexes is reviewed. The research about their activity on polymerization of cr-olefins is summarized. The mechanism about binuclear metallocene catalyst is also discussed in this chapter.1079... 

The ansa-bridged homobinuclear titanium and heterobinuclear titanium-zirconium complexes have been reported. For more examples of this type of complexes, see Sections 4.05.4.1.1.(i).(g) and 4.05.4.1.3.(i)... 

As expected the absorption spectra of the homobinuclear metal complexes of bis-macrocycles not having a coordinating bridging chain are very similar to those of the corresponding mononuclear species (Table 1). 

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