Ligand-exchange reaction induced

B. Ligand Exchange Reaction Induced by a Phosphenium Ligand... 114... 

Ligand Exchange Reactions and Core-induced Reactivity.. . 110... 

Cu inhibition of Mad occurs in a rapid manner (Pena et al., 1998) as does the reactivation of Mad. CTRl transcription is induced in cells treated with the Cu(I) chelator for 15 min. Reactivation of CuMacl presumably occurs by Cu(l) dissociation. It is unclear whether the Cu(l) conformer of Mad is inherently unstable in vivo or whether Cu(l) dissociation is facilitated by a ligand exchange reaction as suggested for the Cup 1-dependent inactivation of Ace 1. 

The dipalladium organyls 51, derived from 49 (M = Pd, X = C1) by ligand exchange reaction between the bridging group and acetylacetonate, are not mesomorphic in their pure state, but form mesomorphic charge transfer systems with the electron acceptor TNF [95]. The identity of the induced mesophase is still unknown, but seems very likely to be columnar [96]. Furthermore, lyotropic nematic phases were obtained in the ternary mixture 51/TNF/linear alkane (the binary mixture 51/alkane did not yield mesomorp-hism). The nematic phase in this system is though to have a columnar nature, namely a nematic columnar phase. 

FIGURE 8.3. Photochemically induced ligand exchange reactions in a thin, electrode-bound film of the metallopolymer [Os(bipy)2(PVP)ioCl]Cl/[Ru(bipy)2(PVP)ioCl]Cl using 1.0 M aqueous HCIO4 as an electrolyte scan rate 100 mV s surface coverage 1x10" mol cm. The interval between scans is 30 s. (From Ref 43.)... 

Scheme 8 Photoelectric conversion induced by a ligand exchange reaction...

In addition to direct metal analysis, indirect analysis for ligands that pull away the metal ion from the fluorescent metal chelate, is also possible. In this case, a decrease in fluorescence is observed. For example, fluoride causes the fluorescence of the alumi-num-Eriochrome Red B complex to decrease. In a similar way, nonfluorescent metal chelates can be used for the fluorimetric analysis of nonfluorescent analytes via a ligand-exchange reaction, according to the scheme shown in Figure 9. In the first step a nonfluorescent complex is formed between a fluorescent chelator and a metal ion. In the next step the addition of the pesticide induces the displacement of the fluorescent ligand and then combines with... 

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