Planar triazinium cations from vanadyl-mediated ring cyclizations: the thiazole species for efficient nuclear staining and photocytotoxicity.
Planar triazinium cationic species from vanadyl-assisted cyclization of 1-(2-thiazolylazo)-2-naphthol (H-TAN, 1), 1-(2-pyridylazo)-2-naphthol (H-PAN, 2), 2-(2'-thiazolylazo)-p-cresol (H-TAC, 3) and 6-(2'-thiazolylazo)-resorcinol (H-TAR, 5) were prepared and characterized. A dioxovanadium(V) species [VO(2)(TAR)] (4) was also isolated. Compounds 1, 2 and 4 were structurally characterized. Both 1 and 2 have planar structures. Complex 4 has V(V)O(3)N(2) coordination geometry. The cyclised triazinium compound forms a radical species within -0.06 to -0.29 V vs. SCE in DMF-0.1 M tetrabutylammonium perchlorate with a second response due to formation of an anionic species. A confocal microscopic study showed higher nuclear uptake for 1 having a fused thiazole moiety than 2 with a fused pyridine ring. The compounds showed a partial intercalative mode of binding to calf thymus DNA. Compound 1 showed plasmid DNA photo-cleavage activity under argon and photocytotoxicity in HeLa and MCF-7 cells with IC(50) values of 15.1 and 3.4 μM respectively in visible light of 400-700 nm, while being essentially non-toxic in the dark with IC(50) values of 90.4 and 21.9 μM. A TDDFT study was done to rationalize the experimental data.
Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore 560012, India.
Puja
P
Prasad
Imran
I
Khan
Pijus K
PK
Sasmal
Debasis
D
Koley
Paturu
P
Kondaiah
Akhil R
AR
Chakravarty
D000818:Animals; D001391:Azo Compounds / Q000737:chemistry; D002412:Cations / Q000737:chemistry; D002417:Cattle; D002470:Cell Survival / Q000187:drug effects; D056831:Coordination Complexes / Q000138:chemical synthesis / Q000737:chemistry / Q000633:toxicity; D003408:Cresols / Q000737:chemistry; D018360:Crystallography, X-Ray; D003500:Cyclization; D004247:DNA / Q000737:chemistry; D053837:DNA Cleavage; D006367:HeLa Cells; D006801:Humans; D008027:Light; D061986:MCF-7 Cells; D018613:Microscopy, Confocal; D008968:Molecular Conformation; D009284:Naphthols / Q000737:chemistry; D013844:Thiazoles / Q000737:chemistry*; D014227:Triazines / Q000737:chemistry*; D014638:Vanadates / Q000737:chemistry*; D014639:Vanadium / Q000737:chemistry
D001391:Azo Compounds; D002412:Cations; D056831:Coordination Complexes; D003408:Cresols; D009284:Naphthols; D013844:Thiazoles; D014227:Triazines; D014639:Vanadium; C041728:1-(2-pyridylazo)-2-naphthol; C054556:1-(2-thiazolylazo)-2-naphthol; C032538:4-cresol; D014638:Vanadates; D004247:DNA; C427203:calf thymus DNA