Synthesis, characterisation, nuclease and cytotoxic activity of phosphate-free and phosphate-containing copper $4^{\prime }$-(N-methylpyridinium)-$2,2^{\prime }:6^{\prime },2^{\prime \prime }$ terpyridine complexes

Mononuclear Cu(II) pyridinium terpyridine based compounds, viz., [Cu(q- pytpy)(I)$\left({\text{CH}}_3\text{COO}\right)\left]\right(\text{I})\cdot (2{\text{H}}_2\text{O})$ (1) and [Cu(dipp)(dippH)(q-pytpy)]$\cdot (2{\text{H}}_2\text{O}$)(DMF) (2) were isolated by reacting $\text{Cu}(\text{OAc}{)}_2\cdot {\text{H}}_2\text{O}$ with $4^{\prime }$-(N-methylpyridinium)-2,$2^{\prime }:6^{\prime },2^{\prime \prime }$-terpyridine (q-pytpy) in the presence of 2,6 diisopropylphenyl phosphate (${\text{dippH}}_2$). Both the new compounds were isolated as single crystals and characterised by spectroscopic (IR, ESI-MS, EPR, UV–Vis), thermogravimetric and microanalytical techniques. The molecular structures of both the compounds were determined in the solid-state by single crystal X-ray diffraction studies. Complexes 1 and 2 were evaluated for their nuclease and in vitro anti-tumor activities against human breast and colorectal cancer cell lines. The DNA cleavage and cytotoxic assays revealed that both 1 and 2 are effective in cleaving DNA, while the cytotoxic activity of 1 is better than 2 in both human colon and breast cancer cell lines.

Graphical Abstract

SYNOPSIS New phosphate-free and phosphate containing mononuclear pyridinium terpyridine-based Cu (II) compounds, isolated from a single reaction, have been demonstrated as anti-proliferative agents in human colon and breast cancer lines. .