106868-21-7

Dibenzyl-14-crown-4 (6,6-Dibenzyl-1,4,8,11-tetraoxacyclotetradecane) is a crown ether derivate, which serves as neutral carrier in PVC ion-selective electrode, improves the Li+ selectivity against Na+ and K+[1].

Dissolve it in CHCl3, wash this with saturated aqueous NaCl, dry (MgSO4), evaporate and purify it by chromatography on silica gel and gradient elution with *C6H6/MeOH followed by preparative reverse phase HPLC on an octadecyl silanised silica (ODS) column and eluting with MeOH. It can be recrystallised from MeOH (max 1120 cm-1, C-O-C in KBr). [Kimura et al. Anal Chem 59 2331 1987, see also Maruyama et al. J Chem Soc Perkin Trans 1 2069 1986 and Tsukube et al. J Chem Soc Perkin Trans 1 1033 1986.] It complexes selectively with Li ions.

[1] Kimura K, et al., Lithium ion selective electrodes based on crown ethers for serum lithium assay. Anal Chem. 1987 Oct 1;59(19):2331-4. DOI:10.1021/ac00146a004