The controlled and target-specific release of CO to a target site upon photoactivation has recently emerged as a promising tool for targeted anticancer activity. However, the present CO-releasing molecules (CORMs) suffer several limitations, including poor delivery to the tumor site. In this study, we reported the synthesis, characterization, and caspase 3/7-dependent apoptosis (IC 50 : 232 μg ml −1 or 29.03 nM) in A549 cells by manganese(I) carbonylfunctionalized gold nanoparticles (1-AuNPs) on dual photosensitization in red light (600-720 nm, 30 J cm −2). The 1-AuNPs, however, remained nontoxic to A549 cells in the dark. The Mn(I)-CO complex (1) exhibited photocytotoxicity (IC 50 : 38.1 μM in red light; IC 50 : 88 μM in dark) as well. Dual photosensitization with red light leading to rapid, synergic CO release and singlet oxygen (1 O 2) generation were the principal mechanism for the photocytotoxicity, which was studied in detail. Photoactivated CO release resulted in TURN-ON luminescence in A549 cells and renders the hybrid 1-AuNPs an ideal, nextgeneration nanotheranostic agent. K E Y W O R D S "TURN-ON" fluorescence in vitro on photo-induced CO release, dual photosensitization, manganese(I) carbonyl-functionalized gold nanoparticles, red light-induced CO release and singlet oxygen (1 O 2) generation, remarkable photocytotoxicity in red light

Herein we reported the synthesis, characterization, photophysical and photocytotoxicity studies of a new class of curcumin-based Lanthanide(III) complexes of general molecular formula, [La(1,10-phen)2(L)(NO3)2] (1-4) where L= 1-phenylbutane-1,3-dione (L1, 1), 1-(anthracen-9-yl)butane-1,3-dione...

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Four oxidovanadium (IV) complexes of 1H-imidazo[4,5-f][1,10] phenanthroline analogues with the general formula [VO(L) 2 ] (acac) 2 (1-4) were synthesized and characterized, and their invitro photodynamic activity was evaluated. The complexes showed broad, low-intensity d-d bands at wavelengths from 635 nm to 775 nm in aqueous DMSO. The 1-(pyren-2-yl)-1Himidazo[4,5-f][1,10]phenanthroline oxidovanadium(IV) complex (4) exhibited remarkable photocytotoxicity in HaCaT cells, and cellular apoptosis was confirmed in an AO/EB dual-staining assay. The IC 50 of complex 4 was 8.2 μM under visible light (400-700 nm), but it was less toxic in dark (IC 50 ∼ 70 μM). None of the complexes were less toxic to immortalized lung epithelial cells (IC 50 > 50 μM), which suggested their activity was target-specific. Annexin V-FITC/PI assays performed with 2',7'-dichlorofluorescein diacetate indicated that apoptosis induced by the photoactivated complexes was due primarily to the intracellular generation of singlet oxygen (1 O 2), a reactive oxygen species. Photophysical studies and time-dependent density functional theory (TD-DFT) calculations suggested that the lowest triplet excited states of the complexes were long-lived and facilitated effective intersystem crossing, resulting in the efficient generation of 1 O 2 with good quantum yields (0.49). The remarkable photocytotoxicity of complex 4 indicates that it is promising for the development of next-generation oxidovanadium(IV)-based photochemotherapeutic agents.

We developed a novel Pd-catalysed enantioselective synthesis of C-N bond in the chiral scaffold of DNA. The non-covalently linked Pd(phen)(OAc)2 to st-DNA catalysed the Markonicov hydroamination of methoxyamine into β-nitrostyrene...