# Copper(II)-5-chloro-2-hydroxybenzophenone Complexes with N–N Donors: Structural Insights and Antitumor Activity against A2780 Human Ovarian Cancer Cells of a Bathophen Derivative

## TL;DR

Scientists created new copper complexes that show strong anticancer activity, especially against ovarian cancer cells.

## Contribution

A new copper(II) complex with a bathophen derivative shows 36-fold higher potency than cisplatin against ovarian cancer cells.

## Key findings

- Complex Cu(2) has an IC50 of 0.24 μM against A2780 ovarian cancer cells.
- Cu(2) strongly interacts with DNA, affecting cell morphology and colony formation.
- The complex is more effective than cisplatin in cytotoxic activity.

## Abstract

Five novel heteroleptic
copper­(II) complexes were synthesized and
fully characterized. Unlike previously reported Cu­(II)-diimine systems,
these complexes incorporate an O,O-chelating 5-chloro-2-hydroxybenzophenone
(5-Cl2HBz) ligand, forming cytotoxic compounds active against A2780
(ovarian), A549 (lung), and MCF-7 (breast) cancer cells. The complexes
were identified as [Cu­(5-Cl2HBz)­(phen)­(NO3)] (Cu­(1)), [Cu­(5-Cl2HBz)­(bathophen)]­(NO3)­1.5H2O·CH3OH (Cu­(2)), [Cu­(5-Cl2HBz)­(bipy)­(NO3)­(H2O)] (Cu­(3)), [Cu­(5-Cl2HBz)­(5,5′-bipy)­(NO3)] (Cu­(4)), and [Cu­(5-Cl2HBz)­(tert-bipy)­(NO3)]·2H2O (Cu­(5)),
where phen = 1,10-phenanthroline, bathophen = 4,7-diphenyl-1,10-phenanthroline,
bipy = 2,2′-bipyridine, 5,5′-bipy = 5,5′-bipyridine,
and tert-bipy = 4,4′-bis­(tert-butyl)-2,2′-bipyridine. Among the series, complex Cu­(2) displayed outstanding potency in A2780 cells (IC50 = 0.24 μM), being 36-fold more potent than cisplatin. This
complex significantly affected the cell morphology and colony formation
in a concentration-dependent manner. DNA interaction studies revealed
that Cu­(2) interacts strongly with DNA, as evidenced
by viscosity, circular dichroism, and fluorescence measurements. These
findings establish Cu­(II)-bathophen derivatives as highly promising
candidates for the development of copper-based anticancer agents.