Fluorescent probes of d-(+)-gluconic acid δ-lactone based on binary hosts of chiral calix[5]arene

Chiral calix[5]arenes, (R)- and (S)-1 and (R)- and (S)-2, were synthesized. The complexation properties of binary hosts [(R)-1·Cu2+] and [(S)-1·Cu2+] towards carbohydrates were explored. The fluorescent titration experiments show that they can selectively recognize d-(+)-gluconic acid δ-lactone 4 with the association constant KR′=4.45(±0.20)×104M-1 and KS′=1.81(±0.20)×104M-1 between various carbohydrates in a MeCN–H2O (4:1 v/v) solution of HEPES buffer (0.3 mM, pH 7.4), respectively.

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31,32-p-tert-Butylcalix[5](R)-1,1′-bi-2-naphtho-crown-6C83H96O9[α]D25=+106 (c 0.9, CH2Cl2)Source of chirality: (R)-1,1′-bi-2-naphtholAbsolute configuration: R

31,32-p-tert-Butylcalix[5](S)-1,1′-bi-2-naphtho-crown-6C83H96O9[α]D25=-110 (c 0.9, CH2Cl2)Source of chirality: (S)-1,1′-bi-2-naphtholAbsolute configuration: S

33,34,35-Trimethoxy-31,32-p-tert-butyl-calix[5](R)-1,1′-bi-2-naphtho-crown-6C86H102O9[α]D25=+44 (c 2.7, CH2Cl2)Source of chirality: (R)-1,1′-bi-2-naphtholAbsolute configuration: R

33,34,35-Trimethoxy-31,32-p-tert-butylcalix[5](S)-1,1′-bi-2-naphtho-crown-6C86H102O9[α]D25=-45 (c 2.7, CH2Cl2)Source of chirality: (S)-1,1′-bi-2-naphtholAbsolute configuration: S