Other Metal ion Complexes

The electrochemical synthesis of cadmium and zinc thiolate complexes and their properties were reviewed in addition to other metal ion complexes [152]. 

The NaSa-containing analog of sarcophaginate 3 was obtained from 5,5 -bis-(4-amino-2-thiabutyl)-3,7-dithianonane-l,9-diamine by Scheme 63 [144], After reduction with zinc dust the resultant NaSa-sarcophaginate underwent demetallation with NaCN. Thus, the ligand obtained may be employed for the synthesis of other metal ion complexes. 

To check whether other metal ions complexed to BU cleave myoglobin, metal ions, such as Co(III), Fe(III), Hf(IV), Pt(IV), Zr(TV), Pd(II), and Ce(IV), were tested. Among the metal ions tested, only Co(III) manifested the protein-cleaving activity upon complexation to BU. An example of kinetic data obtained with Co BU is illustrated in Fig. 4. Up to 2.5 or 6 molecules of myoglobin were cleaved by each molecule of Cu U or Co BU, respectively, for the data of Fig. 4, indicating the catalytic nature of the action of Cu BU and Co BU. 

Interactions of heme and other metal ion complexes with the bacterial Fe-uptake regulatory protein and with hacterioferritin... 

Figure 4 compares the UV-visible spectra in the range 400-900 nm of CR-MCM-41 as synthesised and after contact with water and ethanol solutions of CUSO4. After contact with aqueous solution (curve 2) the band due the 71-it transition at about 500 nm appears more intense and less structured and no new absorptions are seen. This can be due to a small change in the solvation state of the dye. Instead, after contact with ethanol solution (curve 3), a new absorption appears at about 630 nm and comparing curve 2 and curve 3 a sort of isosbestic point is seen at 570 nm. Absorption at 630 nm is ascribed to n-n trasition of molecules complexing Cu ions, in agreement with what observed for other metal ions complexed by CR linked to a polymeric matrix [8]. A fraction of this absorption is probably due to the weaker d-d transition of Cu ions [15]... 

Because Bicine is derived from glycine, it was expected already nearly 50 years ago that this buffer forms complexes with metal ions [216]. For Tris and Bistris the awareness of metal ion interactions is much lower, and the fact that also mixed ligand complexes may form [212,213], has hardly been reaUzed. Therefore, the stabilities of the ternary Cd " and some other metal ion complexes formed between these buffers and ATP are briefly summarized. The stability constants according to equilibria (28) and (29) are listed in Table 13 together with the stability differences defined in equation (30). 

The stoichiometry and stability constants of the complexes were determined most frequently by means of potentiometric techniques, but these data were very often completed with results of polarography. The structures of complexes were proposed on the basis of the stoichiometiy and stability of various species and via the analogy to other metal ion complexes. In some cases, the suggested structures of complexes were supported by the use of IR-spectroscopy, Cd NMR, and X-ray studies. 

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