Cluster, binuclear

Yeast transcription factor GAL4 contains a binuclear zinc cluster in its DNA-binding domain... 

Marmorstein, R., Harrison, S.C. Crystal structure of a PPRl-DNA complex DNA recognition by proteins containing a Zn2Cys6 binuclear cluster. Genes Dev. 

N-Heterocycles as ligands in dioxygen activation by enzymes containing binuclear nonheme iron clusters 96CRV2625. 

The interaction of small, well defined, rhodium clusters, Rh and Rhs, with O2 has been investigated (220) by matrix infrared, and UV-visible, spectroscopy, coupled with metal/02 concentration studies, warm-up experiments, and isotopic oxygen studies. A number of binuclear O2 complexes were identified, with stoichiometries Rh2(02)n, n = 1-4. In addition, a trinuclear species Rhs(02)m, m = 2 or 6, was identified. The infrared data for these complexes, as well as for the mononuclear complexes Rh(02)x, = 1-2 (229), are summarized in Table XI. Metal-concentration plots that led to the determination of... 

This reaction is diffusion controlled in solid CO. The binuclear carbonyl is unstable and even at these low T decomposes to Ag2 or higher clusters. Similarly, Au forms Au(CO)[ or 2, which does not dimerize. However, Cu cocondensed with CO and Ar forms compounds Cu (CO) (n = 1-4), which after warming to 35 K decompose to larger Cu carbonyl clusters of indeterminate composition, the IR spectra of which resemble CO chemisorbed onto bulk Cu. 

Binuclear Cluster Compounds with the Lantern -Type... 

In compliance with the nuclearity principle, polynuclear clusters are subdivided into a number of other subgroups, e.g. hexanuclear, octanuclear, etc. The binuclear clusters of technetium may be classified according to the electronic structure of their Tc-Tc2 bonds. Then, the d4-d4 complexes with quadruple M-M bonds are the father of all binuclear complexes with Tc-Tc bonds. The addition or removal of electrons from Tc-Tc bonds [1,11] should result in a decrease in the formal multiplicity of M-M bonds. Thus, for instance, the formal multiplicity of Tc-Tc bonds of d3-d3 and d5-d5 binuclear complexes equals3 3, that of d4 d5 and d4-d3 complexes equals 3.5, etc. 

Among other widely used reducers for the synthesis of binuclear technetium complexes with M-M bonds, zinc in HC1 and H3P02 [1,11] are most important. These reducers, as a rule, are used for the synthesis of Re clusters of similar structure. 

Binuclear Technetium Cluster Compounds with the d4-d5 Electronic... 

Compounds 4-7 (Table 1) belong to this group. The physicochemical properties of the given binuclear clusters are close to those of the analogous rhenium and molybdenum compounds with the quadruple M-M bonds and are as a rule isostructural with them [1,89,90]. 

Binuclear Technetium Clusters Compounds with the d -d Electronic... 

It is noteworthy that all these reactions are reversible, but under reducing conditions the equilibrium shifts to the right-hand side, and under oxidizing conditions it shifts to the left-hand side. For all resulting binuclear ions at rather low concentration in solutions, reactions take place, accompanied by the rupture of the M-M bond and the formation of unstable mononuclear complexes, which are readily oxidized even by the solvent. At high concentrations of binuclear ions cycloaddition reactions of multiple M-M bonds (these reactions are considered in section 3.5) occur to form stable, under the given conditions, polynuclear clusters. 

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