title: Pyrazinoporphyrazines with externally appended pyridine rings. 13. Structure, UV-visible spectral features, and noncovalent interaction with DNA of a positively charged binuclear (Zn(II)/Pt(II)) macrocycle with multimodal anticancer potentialities.
abstract: We investigated with spectroscopic techniques the noncovalent interaction of a bimetallic water-soluble (Zn(II)/Pt(II)) porphyrazine hexacation, [(PtCl(2))(CH(3))(6)LZn](6+), and its octacationic analogue [(CH(3))(8)LZn](8+), lacking the cis-platin-like functionality, with a 21-mer double strand (ds) 5'-d[GGG(TTAGGG)(3)]-3'/3'-d[CCC(AATCCC)(3)]-5', as model for B-DNA. Both hexacation and octacation tend to aggregate in water. The structure as well as the ground and excited-state electronic properties of the Zn(II)/Pt(II) hexacation [(PtCl(2))(CH(3))(6)LZn](6+) in water solution were investigated using density functional theory (DFT) and time-dependent DFT (TDDFT) methods. TDDFT calculations of the lowest excited states of [(PtCl(2))(CH(3))(6)LZn](6+) in water provided an accurate description of the Q-band spectral region. In particular, the calculated optical spectra were in agreement with the experimental ones, obtained in the presence of micelles favoring complete disruption of the aggregates. The model for dsDNA binding that emerges from the analysis of UV-vis absorption and time-resolved fluorescence data shows the presence of complexes of 1 dsDNA molecule with 1, 2, and 4 macrocycles. Comparing the results for the hexacation [(PtCl(2))(CH(3))(6)LZn](6+) with those for the [(CH(3))(8)LZn](8+)octacation, we observed a higher degree of monomerization for the [(PtCl(2))(CH(3))(6)LZn](6+) derivative.
authors.affiliation: Istituto per la Sintesi Organica e la Fotoreattività, Consiglio Nazionale delle Ricerche, via Gobetti 101, I-40129 Bologna, Italy. ilse.manet@isof.cnr.it
authors.forename: Ilse
authors.initials: I
authors.lastname: Manet
authors.forename: Francesco
authors.initials: F
authors.lastname: Manoli
authors.forename: Maria Pia
authors.initials: MP
authors.lastname: Donzello
authors.forename: Elisa
authors.initials: E
authors.lastname: Viola
authors.forename: Annalisa
authors.initials: A
authors.lastname: Masi
authors.forename: Giuseppina
authors.initials: G
authors.lastname: Andreano
authors.forename: Giampaolo
authors.initials: G
authors.lastname: Ricciardi
authors.forename: Angela
authors.initials: A
authors.lastname: Rosa
authors.forename: Luciano
authors.initials: L
authors.lastname: Cellai
authors.forename: Claudio
authors.initials: C
authors.lastname: Ercolani
authors.forename: Sandra
authors.initials: S
authors.lastname: Monti
mesh_terms: D000970:Antineoplastic Agents / Q000138:chemical synthesis / Q000737:chemistry*; D004247:DNA / Q000737:chemistry*; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D010984:Platinum / Q000737:chemistry*; D011166:Porphyrins / Q000737:chemistry*; D011719:Pyrazines / Q000737:chemistry*; D011725:Pyridines / Q000737:chemistry*; D011789:Quantum Theory; D013056:Spectrophotometry, Ultraviolet; D015032:Zinc / Q000737:chemistry*
chemical_list: D000970:Antineoplastic Agents; D009942:Organometallic Compounds; D011166:Porphyrins; D011719:Pyrazines; D011725:Pyridines; D010984:Platinum; D004247:DNA; D015032:Zinc; C023666:pyridine