Asymmetric structure of cis-[N-(9-anthracenylmethyl)-1,2-ethanediamine]dipyridineplatinum(II) dinitrate

Abstract

Platinum antitumour agents, containing aromatic rings, which are used for targeting DNA in effective therapies for the treatment of cancer. We have synthesized the title metallocomplex with an aromatic ligand and determined its crystal structure. In many cases, complexes of platinum and other metals have a symmetrical structure. In contrast, the platinum(II) complex with pyridine and N-(9-anthracenylmethyl)-1,2-ethanediamine as ligands (systematic name: cis-{N-[(anthracen-9-yl)methyl]ethane-1,2-diamine-κN,N'}bis(pyridine-κN)platinum(II) dinitrate), [Pt(CHN)(CHN)](NO), is asymmetric. Of the two pyridine ligands, only one is π-stacked with anthracene, resulting in an asymmetric structure. Moreover, the angle of orientation of each pyridine ligand is variable. Further examination of the packing motif confirms an intermolecular edge-to-face interaction.

Characterization of platinum(II) complexes exhibiting inhibitory activity against the 20S proteasome

“…Herein, we evaluated the contribution of the ligand to proteasome-inhibitory activity. We previously synthesized complex 1 and determined its X-ray crystal structure [ 33 ]. Complexes 2 , 3 , 6 and 7 were designed as model systems of the interaction between cis -diamminedichloroplatinum (II) and DNA, and the physico-chemical properties were determined [ 34 – 36 ].…”

“…These results suggested that the electronic state of the platinum coordination plane differs between complexes 1 and 2 . Complexes 1 and 2 exhibited a stacking interaction between ligands [ 33 , 36 ], and the stability of the stack is assumed to be correlated with the surface area of the aromatic rings. There is the possibility that stacking interaction between phenanthroline and anthracenyl moiety induced electron withdrawal from the platinum atom to phenanthroline [ 55 ].…”

“…All commercial reagents and solvents were used without purification. 2,2'-Bipyridine and 9-anthracenecarbaldehyde were purchased from Tokyo Kasei Co. Ltd. K 2 PtCl 4 was purchased from Wako Co. Ltd. Complexes 1-3, 6 and 7 were synthesized according to the literature with slight modification [32][33][34][35]. The human erythrocyte 20S proteasome was obtained from Boston Biochem.…”