Porphyrin sponges

MgTPP has also been examined as a substrate for constructing porphyrin sponges, i.e., lattice clathrates that can reversibly absorb and release guest molecules. Such guests as methyl benzoate, propanol and (R)-phenethylamine) have been structurally authenticated other examples are known. " ... 

Dislcin-Posner. Y. Goldberg. I. From porphyrin sponges to porphyrin sieves A unique crystalline lattice of aquazinc tetra(4-carboxyphenyl)porphyrin with nanosized channels. Chem. Commun. 1999. 19. 1961-1962. 

FROM PORPHYRIN SPONGES" TO THE PORPHYRIN SIEVES" CONCEPT... 

Pursued applications of these clathrate porphyrin sponges include their use as materials to selectively immobilize and isolate molecular species and as intercalation compounds. The forces holding these solids... 

Figure 58. Porphyrin and guest packing in a typical porphyrin sponge. Reprinted with permission from Byrn, M. P. Curtis, C, ). Hsiou, Y. Khan, S. I. Sawin, P. A. Tendick, S. K. Terzis, A. Strouse, C. E. I- Amec Chem. Soc. 1993, /15, 9480. (S) 1993 American Chemical Society.

Kurtikyan, Ford, and coworkers have used infrared and UV spectroscopy to probe the species formed in the interaction of NO, molecules with micro-porous solvent-free layers of (por)M complexes (M=Mn (138—140), Fe (141—150), Co (151-155)) at varying temperatures. Sample preparation of such (por)M layers and their interactions with NO, have been described in detail elsewhere (156,157). Importantly, in this sample preparation technique, the (por)M species are sublimed onto KBr, Csl, or Cap2 substrates at low temperature to form porphyrin sponges which permit diffusion of volatile Hgands into the bulk layer (158). Using this method, clean IR spectra... 

Sampling in Mediterranean deep waters has revealed the first secondary n tabolites from brachiopods and unique 10-hydroxyeicosa- and docosapolyenoic acids from scleractinian corals. That these fetty acids have also been foimd in a deep-water pre-Antarctic antipatharian coral (Table 9.III) must be attributed to convergence. Deep-water Mediterranean medusae and a lithistid sponge from New Caledonia, Corallistes sp., contain huge amounts of free porphyrins. 

In summary, as far as it can be presently understood, there is little peculiarity as to the secondary metabolites of deep-water marine organisms, except, perhaps, the free porphyrins of medusae and sponges an adaptive role of sensors in the absence of light may be suggested for them. The secondary metabolism - mostly unexceptional in the global perspective of marine organisms - seems to be more related to the range of the species - a composite of many factors - than to any effect clearly attributable to the hydrostatic pressure. 

As ivill be demonstrated below, these differences in the cavity shape and distances have a huge impact on both the thermodynamics and kinetics of tautomerization. Moreover, it has been shown that the porphycene cavity dimensions are very sensitive to peripheral substituents, even such mild ones as alkyl groups. For variously alkylated porphycenes, the N-N distances can be varied from an extremely small value of 2.53 A, resembling that in proton sponges [35] to 2.80 A, close to the value for porphyrin. This provides a unique opportunity to study distance dependences in a class of very similar molecules. The material presented in this chapter will often be based on such comparisons and on the relationship with... 

C32H34N4O4, Mr 538.65 uv ,jj (dimethyl ester in CHCI3) 400,498,538,565, and 618 nm. C. A is one of the few naturally occurring, metal-fiee porphyrins. Occurrence C. A is isolated from the New Caledonian marine sponge Corallistes sp. which contains further porphyrins designated as C. B-E in addition to the main component C.A. Their substitution patterns differ slightly firom that of C. A. 

Unique is the occurrence of different porphyrin derivatives (36-40) named corallistin a-e (26) after the marine sponge Corallistes sp. which was found near to New Caledonia. The chlorophylls C1-C3 (41-43) (27) of some algae also belong to the porphyrin class though chlorophyll pigments usually have the chlorin type framework. An interesting source... 

Karuso P, Bergquist PR, Buckleton JS, Cambie RC, Clark GR, Rickard CEF (1986) 13, 17 -Cyclopheophorbide Enol, the first porphyrin isolated from a sponge. Tetrahedron Lett 27 2177... 

These molecules may have no fimction in photosynthesis as the sponges were harvested by dredging at a depth of approximately 350 m. These porphyrins are... 

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