Self-assembly reactions

In contrast to the use of self-assembly reactions and metal ion coordination preferences to direct the construction of mixed cofactor systems, the use of SPPS or selective chemical ligation allows for the direct covalent attachment of cofactors for the construction of mixed cofactor systems within de novo design. Figure 11 shows the flavocy-tochrome maquette constructed by Dutton and co-workers (149) using a flavin moiety covalently attached to a unique cysteine residue inside a four helix bundle with bis-histidine binding sites for heme... 

Other Fe-S Clusters. Spontaneous self-assembly reactions using phosphines as terminal ligands have been reported to yield a variety of new Co-S (22) and Ni-S clusters (23). Extension to Fe-S clusters was initially effected by the following reaction in heterogeneous solution (2A). 

Synthetic efforts at preparing model complexes for the FeMo-cofactor have largely focussed on two types of Mo-Fe-S cluster, both of which are prepared via self-assembly reactions using tetrathiomolybdate as starting material. The first of these is the "linear" type of cluster, containing the MoS2Fe unit formed by coordination of discrete MoS - units to Fe. The second is the... 

Polynuclear Fe-M-S Complexes from "spontaneous self assembly" reactions. Synthetic analog clusters for the Fe2S2 and Fe4S4 centers in the Fe/S proteins (ferredoxins) have been obtained by procedures that are based on the concept of "spontaneous self assembly". The latter (30) assumes that the cores of the Fe/S centers are thermodynamically stable units that should be accessible fiom appropriate reagents even in the absence of a protein environment. 

Schottel, B. L., Chifotides, H. T., Shatruk, M., et al., Anion s interactions as controlling elements in self-assembly reactions of Ag(l) complexes with K acidic aromatic rings. J. Am. Chem. Soc. 2006,128, 5895-5912. 

If the self-assembly reaction of Cul with bis(phenylthio)pentane is conducted in a 1 1 ratio, elemental analyses of the colorless blocks isolated from a concentrated MeCN solution were in accordance with the ligation of one dithioether ligand per copper center with composition [(CuI)2 g-PhS (Cl hfsSPhj2] 22 (Scheme 11). Alternatively, compound 22 is formed after addition of second equivalent of bis(phenylthio)pentane to a solution of 21. 

After publication of our work,22 new self-assembled Zn(II) terpyridine polymers were prepared and used in PLEDs. Following the methodology reported by us, Lin et al. similarly prepared a series metallopolymers by self-assembled reaction containing Zn(II) terpyridine units, including a metallo-homopolymer and metallo-u/t-copolymer containing carbazole pendants attached to the C-9 position of fluorene by long alkyl spacers.27... 

The salt is essentially operating through a medium effect and in this experiment we have a particularly dramatic salt effect in which the free energy barrier for the assembly reaction is systematically decreased as the salt concentration is increased. As the temperature is lowered, it is found that the rate of the self-assembly reaction increases. This can be understood from considerations of Fig. 19.7. As the temperature is lowered, the esc decreases, so if the salt concentration is kept constant, there will be a... 

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