Phosphate anion recognition, coordination

Phosphate Anion Recognition Utilizing Coordination Chemistry. . . ... 

Phosphate Anion Recognition Utilizing Coordination Chemistry... 

J Structural Studies. As was true in the case of the halide anion recognition, important support for the proposed phosphate anion binding interaction has come from single crystal X-ray diffraction analyses. As shown in Figures 6 and 7, respectively, the diprotonated form of sapphyrin binds the monobasic forms of both phosphoric and phenylphosphoric acid. While, at least from the perspective of the coordinated atoms, these two structures bear a striking resemblance to those of the mono- and dihydrochloride salts alluded to above, in both cases it is of interest to note that in each relevant comparison pair, the phosphate oxyanion is far closer to sapphyrin plane. Specifically, in the case of the H2P04 structure, this chelated atom is found to reside 0.83 A (only ) above the macrocylic plane. Similarly, in the case of the 1 2 complex formed between diprotonated sapphyrin and... 

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