Selective recognition of thymidylylthymidine (TpT) and antitumor effects of a macrocyclic dizinc(II) complex

A polyamino dizinc(II) complex, [(N-bisdien)Zn-2(II)Cl-2](ClO4)(2), (LZn), has been synthesized as a new nucleobase receptor molecule in aqueous solution at physiological pH, and shows to be highly selective in recognizing deoxythymidine (dT) and thymidylylthymidine (TpT). The strong acidic Zn(II) ions in LZn at the fifth coordination sites interact with a variety of nucleosides. The binding and recognition processes have been studied by potentiometric titration. The X-ray crystal analysis of LZn shows that the two zinc ions are out of the basal plane of the macrocycle, favoring the effective, recognition of TpT on the single strand of DNA. In vitro antitumor investigation shows that LZn is a patent inhibitor of tumor cell. growth with IC50 values below 10 micromolar.