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

Abstract

Mononuclear Cu(II) pyridinium terpyridine based compounds, viz., [Cu(q- pytpy)(I) $$(\hbox {CH}_{3}\hbox {COO})](\hbox {I})\cdot (2\hbox {H}_{2}\hbox {O})$$ (1) and [Cu(dipp)(dippH)(q-pytpy)] $${\cdot }(2\hbox {H}_{2}\hbox {O}$$ )(DMF) (2) were isolated by reacting $$\hbox {Cu}(\hbox {OAc})_{2}{\cdot }\hbox {H}_{2}\hbox {O}$$ with $$4^{\prime }$$ -(N-methylpyridinium)-2, $$2^{\prime }{:}6^{\prime }{,}2^{\prime \prime }$$ -terpyridine (q-pytpy) in the presence of 2,6 diisopropylphenyl phosphate ( $$\hbox {dippH}_{2}$$ ). 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. 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.