A Marked Synergistic Effect in Antitumor Activity of Salan Titanium(IV) Complexes Bearing Two Differently Substituted Aromatic Rings

Salan titanium(IV) complexes of differently substituted aromatic rings, where one ring is para-nitrated and another is ortho,para-halogenated, demonstrate exceptionally high anticancer activity, with IC50 values of <1 mu M, exceeding that of cisplatin by similar to 30-fold. Whereas an additive effect in hydrolytic stability was detected for these highly stable complexes, an unexpected synergistic effect in anticancer activity makes these hybrid complexes substantially more active than both their symmetrical analogues alone and their equimolar mixture.