New heteroleptic palladium(II) dithiocarbamates: synthesis, characterization, packing and anticancer activity against five different cancer cell lines

Two new heteroleptic palladium(II) complexes have been synthesized by reacting equimolar quantities of palladium(II) chloride, sodium 4-(2-methoxyphenyl)piperazine-1-carbodithioate and diphenyl-p-tolylphosphine (1) or tri-p-tolylphosphine (2). Complexes 1 and 2 have been characterized using elemental analysis, Fourier transform infrared spectroscopy, multinuclear NMR (H-1, C-13 and P-31) spectroscopy and single-crystal X-ray analysis. The latter technique confirms a pseudo square-planar geometry in which two adjacent positions are occupied by bidentate dithiocarbamate while chloro and substituted triphenylphosphine are present at the remaining two positions. The anticancer activity of both complexes against five different cancer cell lines (LU - human lung carcinoma, established at UIC, Department of Surgical Oncology; MCF7 - human breast adenocarcinoma, ATCC number HTB-22 (TM); MDA-MB-231 - human breast adenocarcinoma, ATCC number HTB-26 (TM); Hepa-1c1c7 - mouse liver hepatoma, ATCC number CRL-2026 (TM); PC-3 - human prostate adenocarcinoma, ATCC number CRL-1435 (TM)) was determined by MTT assay, revealing 2 has higher activity than 1. A drug-calf thymus DNA binding study with UV-visible spectroscopy reveals a higher DNA binding affinity of 2 (3.511 x 10(4) M-1) than 1 (4.213 x 10(3) M-1). Density functional theory studies confirm the relatively more stable nature of 2 than 1. Copyright (C) 2016 John Wiley & Sons, Ltd.