title: Self-assembly of ambidentate pyridyl-carboxylate ligands with octahedral ruthenium metal centers: self-selection for a single-linkage isomer and anticancer-potency studies.
abstract: The synthesis of six new [2+2] metallarectangles through the coordination-driven self-assembly of octahedral Ru(II)-based acceptors with ambidentate pyridyl-carboxylate donors is described. These molecular rectangles are fully characterized by (1)H NMR spectroscopy, high-resolution electrospray mass spectrometry, and single-crystal X-ray diffraction. In each case, despite the possible formation of multiple isomers, based on the relative orientation of the pyridyl and carboxylate groups (head-to-head versus head-to-tail), evidence for the formation of a single preferred ensemble (head-to-tail) was found in the (1)H NMR spectra. Furthermore, the cytotoxicities of all of the rectangles were established against A549 (lung), AGS (gastric), HCT-15 (colon), and SK hep 1 (liver) human cancer cell lines. The cytotoxicities of rectangles that contained the 5,8-dihydroxy-1,4-naphthaquinonato bridging moiety between the Ru centers (9-11) were particularly high against AGS cancer cells, with IC50 values that were comparable to that of reference drug cisplatin.
authors.affiliation: Department of Chemistry, University of Ulsan, Ulsan 680-749, Republic of Korea.
authors.forename: Hyunji
authors.initials: H
authors.lastname: Jung
authors.forename: Abhishek
authors.initials: A
authors.lastname: Dubey
authors.forename: Hyun Jung
authors.initials: HJ
authors.lastname: Koo
authors.forename: Vaishali
authors.initials: V
authors.lastname: Vajpayee
authors.forename: Timothy R
authors.initials: TR
authors.lastname: Cook
authors.forename: Hyunuk
authors.initials: H
authors.lastname: Kim
authors.forename: Se Chan
authors.initials: SC
authors.lastname: Kang
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Stang
authors.forename: Ki-Whan
authors.initials: KW
authors.lastname: Chi
mesh_terms: D000970:Antineoplastic Agents / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology*; D002264:Carboxylic Acids / Q000737:chemistry*; D018360:Crystallography, X-Ray; D015195:Drug Design; D004354:Drug Screening Assays, Antitumor; D006801:Humans; D007536:Isomerism; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology*; D011725:Pyridines / Q000737:chemistry*; D012428:Ruthenium / Q000737:chemistry*
chemical_list: D000970:Antineoplastic Agents; D002264:Carboxylic Acids; D008024:Ligands; D009942:Organometallic Compounds; D011725:Pyridines; D012428:Ruthenium