Small Structural Differences between Two Ferrocenyl Diphenols Determine Large Discrepancies of Reactivity and Biological Effects

The ferrocenyl diphenol complexes 1,1‐bis(4′‐hydroxyphenyl)‐2‐ferrocenyl‐but‐1‐ene ( 1 ) and 1,2‐bis(4′‐hydroxyphenyl)‐1‐ferrocenyl‐but‐1‐ene [( Z )‐ 2 ], which differ by the relative position of the two phenolic substituents, display dramatically different antiproliferative activities on cancer cells ( 1 is far more cytotoxic than 2 ). In this study, our goal was to discover the origin of this difference by comparing their reactivity and...