Displacement from complex

We must however keep in mind that some of the above reactions may not be simple reactions at the silicon atom, since transition metal complexes show multicenter reactivity (metal atom, ligands) as exemplified in the chemistry of triphenylgermyl-carbene complexes of cobalt carbonyl (253). Thus, displacements of a silyl ligand may result from a multistep process and a thorough examination of these reactions has to be made. An example can be drawn from molybdenum-germanium chemistry (247). As shown in Scheme 59, germanium is displaced from complex 167 by HO with retention of configuration. Actually,... 

Norbornadiene likewise is readily displaced from complexes of the type C7HjjM(CO)4 (M = Cr, Mo, W) under mild conditions and this synthetic route is particularly useful for obtaining the cis-L2M(CO)4 isomer (L = fluorophosphine) (S-10, 144,145, 250). 

Silver is formed in nature as argentite. AgjS and horn silver. AgCl. The extraction of silver depends upon the fact that it very readily forms a dicyanoargentate(I) complex, [Ag(CN)2] (linear), and treatment of a silver ore with aqueous cyanide ion CN extracts the silver as this complex. The silver is then displaced from the complex by zinc ... 

Ca + if a small amount of Mg -EDTA is added to the solution containing the analyte. The Mg + is displaced from the EDTA by Ca +, freeing the Mg + to form the red Mg -indicator complex. After all the Ca + has been titrated, Mg + is displaced from the Mg -indicator complex by EDTA, signaling the end point by the presence of the uncomplexed indicator s blue form. 

An interesting application is the titration of calcium. In the direct titration of calcium ions, solochrome black gives a poor end point if magnesium is present, it is displaced from its EDTA complex by calcium and an improved end point results (compare Section 10.51). 

This reaction will proceed if the metal indicator complex M-In is less stable than the metal-EDTA complex M EDTA. The former dissociates to a limited extent, and during the titration the free metal ions are progressively complexed by the EDTA until ultimately the metal is displaced from the complex M-In to leave the free indicator (In). The stability of the metal-indicator complex may be expressed in terms of the formation constant (or indicator constant) Ku ... 

In the back-titration small amounts of copper and zinc and trace amounts of manganese are quantitatively displaced from the EDTA and are complexed by the triethanolamine small quantities of cobalt are converted into a triethanolamine complex during the titration. Relatively high concentrations of copper can be masked in the alkaline medium by the addition of thioglycollic acid until colourless. Manganese, if present in quantities of more than 1 mg, may be oxidised by air and forms a manganese(III)-triethanolamine complex, which is intensely green in colour this does not occur if a little hydroxylammonium chloride solution is added. 

Homopolymerization of the olefin occurred if its basicity was higher than that of 2-furaldehyde, i.e. the initiator displacement from the complex was strong and thereafter only occasional inclusion of aldehyde in the growing polymer chain took place 2-furaldehyde units in the products were less than 5%. This situation was observed with acenaphthylene and N-vinylcarbazole. 

Fe(TPP)(CCl2)(H20)] is not significantly displaced from the porphyrin plane. Despite the different structures of [Fe(F20-TPP)CPh2], [(Melm)Fe(F2o-TPP) CPh2], and [Fe(TPP)(CCl2)(H20)], the average Fe-N(pyrrole) distances in these three complexes are similar. 

Ion exchange is actually a far more complicated process than the simple exchange of one cation for another or one anion for another, particularly for complex polyions such as proteins and oligonucleotides. Each ion of the stationary or mobile phase is surrounded by a cluster of counterions and water. When an ion in the mobile phase is transferred to the stationary phase, the cluster of counterions and water surrounding it is partially or completely displaced. A similar event occurs at the binding site of the stationary phase. Ions displaced from the stationary phase undergo the converse process. The... 

Halide displacement from the carbene ligands of Ru, Os, and Ir halocarbene complexes by N-, O-, and S-based nucleophiles frequently leads to the formation of new heteroatom-substituted carbene complexes. This important class of reactivity will be discussed in more detail in Section V,D, but it is appropriate here to illustrate the scope of this method with several examples ... 

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