Synthesis of 21,23-Selenium- and Tellurium-Substituted 5‑Porphomethenes, 5,10-Porphodimethenes, 5,15-Porphodimethenes, and Porphotrimethenes and Their Interactions with Mercury

The 3+1 condensation of symmetrical 16-Selena/telluratripyrranes with symmetrical selenophene-2,5-diols/tellurophene-2,5-diols in the presence of BF<sub>3</sub>-etheratre or BF<sub>3</sub>-methanol followed by oxidation with DDQ gave 5,10-porphodimethenes, whereas the process with unsymmetrical selenophene-2,5-diols/tellurophene-2,5-diols gave 5-porphomethenes. In addition, the reaction of unsymmetrical 16-Selena/telluratripyrranes with symmetrical selenophene-2,5-diols/tellurophene-2,5-diols gave the corresponding porphotrimethenes, whereas the process with unsymmetrical selenophene-2,5-diols/tellurophene-2,5-diols gave the 5,15-porphodimethenes. The structures of different products were characterized by IR, <sup>1</sup>H and <sup>13</sup>C NMR, <sup>1</sup>H–<sup>1</sup>H COSY, CHN analysis, and mass spectrometry. The binding of mercury with the calix[4]­phyrins mentioned above had been observed in the decreasing order of porphodimethenes > porphomethenes > porphotrimethenes by UV–vis and <sup>1</sup>H NMR spectroscopy.