摘要:
The reaction of 4-R-benzaldehyde thiosemicarbazones (denoted in general as H2L-R, where H-2 stands for the two dissociable protons and R (R = OCH3, CH3, H, Cl and NO2) for the substituent on the phenyl ring) with [Pt(PPh3)(2)Cl-2] in the presence of NEt3 afforded a family of organometallic complexes of platinum(II) of the type [Pt(PPh3)(L-R)]. Reaction of the same group of ligands with K-2[PtCl4] in the presence of NEt3 afforded complexes of the type [Pt(HL-R)(2)]. The crystal structure of [Pt(PPh3)(L-CH3)] and [Pt(HL-CH3)(2)] have been determined. In the [Pt(PPh3)(L-R)] complexes, the benzaldehyde thiosemicarbazones are coordinated to platinum as dianionic tridentate C,N,S-donors. In the [Pt(HL-R)(2)] complexes, the benzaldehyde thiosemicarbazones are coordinated to the metal center as bidentate N,S-donors, forming five-membered chelate rings, and with reference to the structure of the uncoordinated thiosemicarbazone ligand, this coordination mode is associated with a change in stereochemistry around the C=N bond. All the [Pt(PPh3)(L-R)] and [Pt(HL-R)(2)] complexes display intense absorptions in the visible and ultraviolet regions. The cytotoxic effects of these complexes, examined on the human leukemia cell line HL-60 and human lymphoma cell line U-937, have shown that all the [Pt(PPh3)(L-R)] and [Pt(HL-R)(2)] complexes are cytotoxic in nature and their IC50 values indicate their potential use as antitumor agents. (C) 2012 Elsevier Ltd. All rights reserved.