Double-strapped porphyrins

Figure 6. Three types of double-strapped porphyrins.

Li s porphyrin rosettes (18) [22], Yagai s photoswitchable rosettes (19) [23], and Fenniri s nanotubes (20) [24] nicely illustrate the former approach. Thus, CA3M3 rosettes (Figure 3.7) endowed with a pyridine moiety at the melamine component and a strapped Zn-porphyrin (to enhance coordination from only one side of the ring) at the cyanuric acid component are more stable than the CA3 M3 model rosette initially reported by Whitesides. Even more complex versions of the same concept, involving one all-pyridine rosette and one all-porphyrin rosette to self-assemble into double rosettes were studied, although only NMR evidence was presented [22],... 

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