Synthesis, characterisation, nuclease and cytotoxic activity of phosphate-free and phosphate-containing copper 4′-(N-methylpyridinium)-2,2′: 6′,2" terpyridine complexes

Mononuclear Cu(II) pyridinium terpyridine based compounds, viz., [Cu(q-pytpy)(I)(CH3COO)] (I)center dot(2H(2)O) (1) and [Cu(dipp)(dippH)(q-pytpy)]center dot(2H(2)O)(DMF) (2) were isolated by reacting Cu(OAc)(2)center dot H2O with 4'-(N-methylpyridinium)-2,2': 6', 2 ''-terpyridine (q-pytpy) in the presence of 2,6 diisopropylphenyl phosphate (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.