Porphyrinatoerbium–crown ether conjugate for synergistic binding and chirality sensing of zwitterionic amino acids

Abstract

A porphyrinatoerbium–benzo-18-crown-6 conjugate offers efficient extraction and chirality sensing of amino acids under neutral conditions via synergistic binding of zwitterions.

References

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7. Selected data for crowned porphyrin ligand: mp 176–180 °C; m/z[FABMS (m-nitrobenzyl alcohol)] 990 (M + Na⁺)(Calc. for C₆₁H₅₃N₅O₇·0.5H₂O; C, 74.98; H, 5.57; N, 7.17. Found: C, 74.97; H, 5.45; N, 7.15%). For 1: mp 249 °C (decomp.); m/z[FABMS (m-nitrobenzyl alcohol)] 1230 (M⁺)(Calc. for C₆₆H₅₈N₅O₉Er·H₂O; C, 63.39; H, 4.84; N, 560. Found: C, 63.33; H, 4.69; N, 5.80%). For 4: mp > 300 °C; m/z(EIMS) 877 (M⁺)(Calc. for C₄₉H₃₅N₄O₂Er·H₂O; C, 65.60; H, 4.16; N, 6.25. Found: C, 65.69; H, 4.06; N, 6.52%). For 7: mp 139–141 °C (Calc. for C₂₃H₂₉NO₇·H₂O; C, 61.46; H, 6.95; N, 3.12. Found: C, 61.21; H, 6.98; N, 3.13%).
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9. The observed extraction efficiency was mostly dependent on the hydrophobicity of the guest amino acid. Octan-1-ol–water distribution co-efficients (log D) were determined at pH 5: Trp, –1.15; Phe, –1.44; Th-Ala, –1.50; Leu, –1.72; Val, –2.29; Th-Gly, –2.64; Gly, –3.02. See N. E. Tayar, R.-S. Tsai, P.-A. Carrupt and B. Testa, J. Chem. Soc., Perkin Trans. 2, 1992, 79 79 and ref. 4..