Structural Features of a New Dinuclear Platinum(II) Complex with Significant Antiproliferative Activity

Abstract

A novel dinuclear platinum(II) complex, [Pt(2)-N,N'-bis(2-dimethylaminoethyl oxamide)Cl(4)], showing peculiar structural features, has been prepared and characterized. X-ray diffraction data reveal that the two platinum ions are simultaneously bound to the N,N'-bis(2-dimethylaminoethyl) oxamide ligand, on opposite sides. The coordination environment of both platinum centers is square planar, with identical NOCl(2) donor sets. The complex is poorly soluble within a physiological buffer but moderately soluble in DMSO. Preliminary in vitro studies point out that this dinuclear platinum complex exhibits significant growth-inhibiting properties on a panel of cultured human tumor cell lines, although less pronounced than those of cisplatin.

Conformational landscape of platinum(II)-tetraamine complexes: DFT and NBO studies

“…It should be noted that the average value obtained here for the N3-Pt-N5 bond angle [29] to 92.5° [28], reported in the literature [24][25][26][27][28][29]. This discrepancy may be due to structural differences in the types of ligands, crystal packing or the environments in which these crystals were obtained.…”

“…A plausible explanation of these differences is that the primary amine groups were less constrained during optimizations, giving rise to a significant degree of movement away from the central Pt(II) ion. The experimental structures of some related Pt(II)-complexes with biological relevance have been elucidated via both theoretical methods using effective core potential (ECP) and a variety of basis sets [23], as well as with experimental X-ray methods [24][25][26][27][28][29]. The principal difference between the structures studied previously and the tetraamine investigated here is that the tetraamine is a single multidentate ligand that provides all the chelating moieties, while the previously reported structures comprised multiple ligands.…”

“…Among the experimental structures reported previously there were notable differences in the Pt(II)-N bond lengths, indicating that the environment of the central atom and possibly crystal packing may influence these geometrical values. For instance, the platinum-nitrogen distances in the experimental studies [24][25][26][27][28][29] ranged from 1.998 [27] to 2.121 Å [24]. Theoretical ab initio distances computed at the HF/LANL2DZ level of theory were 2.100 and 2.148 Å [23].…”

“…Despite the availability of ab initio [23] and X-ray crystallography data for other biologically active Pt(II)-amine complexes [24][25][26][27][28][29], to the best of our knowledge this is the first systematic characterization of the conformational landscape of metalpolyamine complexes of this type. Employing density functional theory methods we computed the potential energy surfaces of five diastereoisomers and determined their relative stabilities.…”

Metal Complexes as Prospective Antibacterial Agents

“…Several recent studies (Adrien,1985;David, 1972;Messori, et al 2003) investigated twenty six inorganic compounds for antiviral and anticancer activity. These included metal complexes of already established anticancer drugs such as six mercaptopurine.…”