Zinc and Copper Complexes of Methylated Di‐ and Tetraaminocyclodextrins

Abstract

The α‐ and β‐cyclodextrins with two dimethylamino groups or two trimethylethylenediamino groups attached to the primary face were synthesized and their pKa values were determined by potentiometric titration. The complexation of the four cyclodextrin analogues with zinc and copper was studied by NMR and showed one or two cyclodextrins bound to the metal. Inclusion of 4‐halophenols in the metal complexes were also studied.

One-step synthesis of Ling's tetrol and its conversion into A,D-di-allo-α-cyclodextrin derivatives

“…Debenzylation of 15 was not carried out with catalytic hydrogenolysis, as debenzylation of amine-containing cyclodextrins has proven to be difficult in the past. 23 Therefore, we resorted to Birch reduction using sodium and liquid ammonia, giving 44% yield of 16 after ion-exchange chromatography. Compound 16 did not give very clear NMR spectra, perhaps due to the presence of conformational and/or protonated equilibria, and was not fully assigned.…”

“…The diamine 16 is a poor binder of the azodyes and CO 2 but binds methane 3 times better than α-CD. In this case, the conjugate acid of the amino groups is expected to have a pK a of 7-8 23,26 and be protonated at pH 3 and partially protonated at pH 7, so protonation appears to be detrimental for binding. The increased binding to methane is likely due to the decreased cavity size caused by the axial amino groups.…”

Highly specific fluorescent probes toward acetic acid via structural transformation of zinc complexes

“…Usually, transition organometallic probes possess the following characteristics: (1) highly luminous efficiency, long lifetime and high stability; (2) large Stokes shift of excitation and emission, and easy regulation of excitation and emission wavelengths; and (3) low cell imaging incubation concentration and less interference of normal cell activity. 26,27 Meanwhile, because of their low price and nontoxicity, easy functional modification and synthesis, photochemical stability, and desirable photophysical properties, [28][29][30][31][32][33][34][35][36][37] zinc complexes are widely used as excellent luminescent materials.…”