Selective and Efficient Recognition of Thymidylylthymidine (TpT) by Bis(ZnII-cyclen) and Thymidylylthymidylylthymidine (TpTpT) by Tris(ZnII-cyclen) at Neutral pH in Aqueous Solution

As sequence-selective small molecules, bis(ZnII-cyclen) and tris(ZnII-cyclen) are excellent and novel host molecules for thymidylylthymidine (TpT) and thymidylylthymidylylthymidine (TpTpT), respectively. Bis(ZnII-cyclen) binds specifically with imide-deprotonated T−pT−(Kd=10−6 M), while the tris(ZnII-cyclen) binds more strongly with T−pT−pT− to form the 1:1 complex, [T−pT−pT−-tris(ZnII-cyclen)] (Kd=10−9 M) at pH 8 in aqueous solution (see equation).