Construction of Pendant‐Armed Schiff‐Base Macrocyclic Dinuclear Zinc Complexes and Their Selective Recognition of Acetate Ions

Two new flexible extended dialdehydes (H 2 hpdd and H 2 pdd) with different functional pendant arms (CH 2 CH 2 PhOH and CH 2 CH 2 Ph) have been synthesized and reacted with 1,2‐bis(2‐aminoethoxy)ethane to prepare Schiff‐base macrocyclic complexes in the presence of a Zn II ‐ion template. As a result, two preorganized dinuclear Zn II intermediates ( 1 and 2 ), as well as two 42‐membered folded [2+2] macrocyclic dinuclear Zn II complexes ( 3 and 4 ), were produced. The central zinc ions in compounds 1 – 4 showed distinguishable coordination patterns with the dialdehydes and the [2+2] macrocyclic ligands, in which a subtle pH‐adjustment function of the two pendant arms (with or without the phenolic hydroxy group) was believed to play a vital role. Furthermore, cation‐ and anion‐recognition experiments for complexes 3 and 4 revealed that they could selectively recognize acetate ions by the formation of 1:1 stoichiometric complexes, as verified by changes in their UV/Vis and MS (ESI) spectra and even by the naked eye.