Proton‐ionizable crown compounds. <b>4</b>. New macrocyclic polyether ligands containing a triazole subcyclic unit

Abstract

Abstract A series of macrocyclic polyether (crown) ligands containing the proton‐ionizable s‐triazole subcyclic unit were prepared by reacting the 1‐THP blocked 3,5‐bis(chloromethyl)‐1 H ‐1,2,4‐triazole with various oligoethylene glycols. The starting bis(chloromethyl)triazole is a vessicant and must be used with caution. Triazolo‐18‐crown‐6 ( 5 ) formed stable complexes with barium, strontium, copper and benzylammonium cations but not with potassium or lithium. The crystal structure of 5 showed the triazole proton to be on nitrogen 3 which is outside the macroring cavity.