Dual model strategy

To find out applications and rules of the metala-logy principle, we systematically investigated the influence of HOMO/LUMO- or LUMO/HOMO-perturbations (dual model) as well as relative donor/acceptor- or acceptor/donor-interactions (double-dual model) in metal-complexesin their model-reactions and in metal catalysis The strategy we followed is depicted in Scheme 2.2-2. For our purposes, we separated the studied catalytic system into two r-systems (substrates S Case I),... 

Figure 22 Introducing normative prosthetic group into metalloproteins. (a) by chemical modification of heme propionate. (Reprinted with permission fi-om Ref. 25. 2002 the American Chemical Society) (b) by noncovalent addition strategy. The crystal stmcture of the Fe (3,3-Me2-salophen) incorporated into AlalTGlaMb. (Reprinted with permission from Ref 287. 2004 the American Chemical Society) (c) by a single attachment strategy. The computer model of adipoc)4e lipid binding protein-phenanthroline complex. (Reprinted with permission from Ref. 291. 1997 the American Chemical Society) (d) by a dual covalent attachment strategy. The computer model of Mb(L72C/Y 103C) with a Mn "-Salen complex covalently attached at two-points and overlayed with heme. (Reprinted with permission from Ref 288. 2004 the American Chemical Society)...

The preparation of substituted five- and six-membered lactones served as a model system to examine the feasibility of this novel ring-forming strategy. A hydroxythioamide (168) was allowed to react with chloroacetyl chloride, and the resulting a-chloro ester (169) was treated with sodium iodide and the Eschenmoser dual base-thiophile reagent (28) to afford the cyclic enamino lactone (170) in high yield (Scheme 35). No epimerization of the lactone was observed. Likewise, the five-membered enamino lactone (172) resulted from reaction of the hydroxythioamide (171) with chloroacetyl chloride followed by sulfide contraction. 

While useful in certain research studies, this type of control of ion shutters and drift tubes was impractical for more complex chemical measurements and analytical applications. Nonetheless, a nearly identical strategy was employed with the Franklin GNO model Beta VI, the inaugural commercial IMS instrument in 1970 (Figure 2.2a) ion shutters of the BN design were operated with rectangular waveforms instead of the sinusoidal waveforms of Tyndall. A dual-shutter approach was used largely due to relatively slow data acquisition capability of that era, and... 

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