A series of copper complexes were synthesized from benzo[d][1,3]dioxole-5-carbaldehyde (piperonal) thio-semicarbazones (RHpTSC where R=H, CH3, C2H5 or C6H5 (Ph)). The complexes show interesting variations in geometry depending on the thiosemicarbazone; a dinuclear complex [Cu(HpTSC)Cl]2, a mononuclear complex [Cu(RHpTSC)2Cl2] (R=CH3 or C2H5) and another mononuclear complex [Cu(PhHpTSC)(PhpTSC)Cl] was generated. The complexes bind in a moderately strong fashion to DNA with binding constants on the order of 104M‒1. They are also strong binders of human serum albumin with binding constants near 104 M‒1. The complexes show good in vitro cytotoxic profiles against two human colon cancer cell lines (HCT-116 and HT29) and two human breast cancer cell lines (MCF-7 and MDA-MB-231) with IC50 values in the low millimolar concentration range.

We have used a novel microwave-assisted method to synthesize a pair of half-sandwich ruthenium-arene-thiosemicarbazone complexes of the type [(h 6 -C 6 H 6 Ru(TSC)Cl]PF 6 . The thiosemicarbazone (TSC) ligands are 2-(anthracen-9-ylmethylene) hydrazinecarbothioamide and 2-(anthracen-9-ylmethylene)-N-ethylhydrazinecarbothioamide derived from 9-anthraldehyde. The complexes are moderately strong binders of DNA, with binding constants of 10 4 M À1 . They are also strong binders of human serum albumin, having binding constants of the order of 10 5 M À1 . The complexes show some in vitro anticancer activity against human colon cancer cells, Caco-2 and HCT-116, with positive therapeutic indices. They did not show any activity as antibacterial agents against the organisms that were studied.

A series of half-sandwich ruthenium complexes, two containing an arene face-cap and the other a thiacrown ether face-cap were synthesized to investigate the necessity of the arene for anticancer activity in this class of compounds. The complexes are formulated as [(η 6 -p-cymene)Ru(dmabTSC)Cl]PF 6 , [(η 6 -benzene) Ru(dmabTSC)Cl]PF 6 (arene complexes), and [([9]aneS 3 (dmabTSC)Cl]PF 6 (dmabTSC = dimethylaminobenzaldehye thiosemicarbazone). It was observed that none of the complexes showed good anticancer activity in vitro against HCT-116 and Caco-2 (colon adenocarcinoma) cells. All three complexes can bind strongly to calfthymus DNA with binding constants on the order of 10 5 M -1 . In addition they all bind strongly to human serum albumin with binding constants between 10 5 and 10 6 M -1 . There appears to be a single binding site on the protein for these complexes. A computational investigation of these complexes and their hydrolysis products was carried out by molecular docking with DNA and topoisomerase II. From this analysis it is noted that the type of face-capping ligand had different effects on the two macromolecules. It is therefore noted that the knowledge gained from this study will be useful in identifying the type of complexes in this class that show useful metallodrug potential.