title: Tetra-2,3-pyrazinoporphyrazines with externally appended pyridine rings. 9. Novel heterobimetallic macrocycles and related hydrosoluble hexacations as potentially active photo/chemotherapeutic anticancer agents.
abstract: New homo- and heterobimetallic porphyrazine complexes of general formula [(M'Cl(2))LM] (L = tetrakis-2,3-[5,6-di-(2-pyridyl)pyrazino]porphyrazinato dianion), with M = Zn(II), Mg(II)(H(2)O), or Pd(II) in the central cavity and one M'Cl(2) unit (M' = Pd(II), Pt(II)) peripherally coordinated at the pyridine N atoms of one of the dipyridinopyrazine fragments, were prepared and characterized by elemental analyses and IR/UV-visible spectroscopy. Related water-soluble salt-like species, carrying the hexacations [(PtCl(2))(CH(3))(6)LM](6+) (neutralized by I(-) ions), were also prepared and similarly characterized. Retention of clathrated water molecules is a common feature of all the compounds. A detailed (1)H and (13)C NMR investigation in dimethylformamide (DMF-d(7)) and dimethyl sulfoxide (DMSO-d(6)) provided useful information on the type of arrangement in the neutral and hexacationic species of the metalated dipyridinopyrazine fragments, in which the metal centers (Pd(II)/Pt(II)) are bound to the pyridine N atoms ("py-py" coordination) with formation of N(2(pyr))PdCl(2) or N(2(pyr))PtCl(2) coordination sites, the latter one featuring a cis-platin-like functionality. Data obtained in DMF solution of the quantum yield (Φ(Δ)) for the generation of singlet oxygen, (1)O(2), the cytotoxic agent in photodynamic therapy (PDT), indicate that all the neutral and charged complexes, among them particularly those carrying centrally Zn(II) or Pd(II), exhibit excellent photosensitizing properties, this qualifying the externally platinated complexes as potential bimodal PDT/chemotherapeutic anticancer agents. Fluorescence data (Φ(F)) provided additional information on the photoactivity of all the species studied. The following companion paper describes the observed interaction of the Zn(II) hexacation [(PtCl(2))(CH(3))(6)LZn](6+) with a G-quadruplex (G4) structure of the telomeric DNA sequence 5'-d[AGGG(TTAGGG)(3)]-3' in water.
authors.affiliation: Dipartimento di Chimica, Università La Sapienza, P.le A. Moro 5, I-00185 Roma, Italy. mariapia.donzello@uniroma1.it
authors.forename: Maria Pia
authors.initials: MP
authors.lastname: Donzello
authors.forename: Daniela
authors.initials: D
authors.lastname: Vittori
authors.forename: Elisa
authors.initials: E
authors.lastname: Viola
authors.forename: Ilse
authors.initials: I
authors.lastname: Manet
authors.forename: Luisa
authors.initials: L
authors.lastname: Mannina
authors.forename: Luciano
authors.initials: L
authors.lastname: Cellai
authors.forename: Sandra
authors.initials: S
authors.lastname: Monti
authors.forename: Claudio
authors.initials: C
authors.lastname: Ercolani
mesh_terms: D000970:Antineoplastic Agents / Q000138:chemical synthesis* / Q000737:chemistry; D008027:Light; D047028:Macrocyclic Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D008665:Metalloporphyrins / Q000138:chemical synthesis* / Q000737:chemistry; D015394:Molecular Structure; D017319:Photosensitizing Agents / Q000138:chemical synthesis* / Q000737:chemistry; D011714:Pyrans / Q000138:chemical synthesis* / Q000737:chemistry; D011725:Pyridines / Q000138:chemical synthesis* / Q000737:chemistry; D012995:Solubility; D014867:Water / Q000737:chemistry*
chemical_list: D000970:Antineoplastic Agents; D047028:Macrocyclic Compounds; D008665:Metalloporphyrins; D017319:Photosensitizing Agents; D011714:Pyrans; D011725:Pyridines; D014867:Water