Design, Synthesis, Biological Evaluation, and Structure–Activity Relationships of Substituted Phenyl 4-(2-Oxoimidazolidin-1-yl)benzenesulfonates as New Tubulin Inhibitors Mimicking Combretastatin A-4

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Enhanced Luminescent Iridium(III) Complexes Bearing Aryltriazole Cyclometallated Ligands

Herein we report the synthesis of 4-aryl-1-benzyl-1<i>H</i>-1,2,3-triazoles (atl), made via “Click chemistry” and their incorporation as cyclometallating ligands into new heteroleptic iridium(III) complexes containing diimine (N^∧N) ancillary ligands 2,2′-bipyridine (bpy) and 4,4′-di-<i>tert</i>-butyl-2,2′-bipyridine (dtBubpy). Depending on decoration, these complexes emit from the yellow to sky blue in acetonitrile (ACN) solution at room temperature (RT). Their emission energies are slightly blue-shifted and their photoluminescent quantum efficiencies are markedly higher (between 25 and 80%) than analogous (C^∧N)₂Ir(N^∧N)⁺ type complexes, where C^∧N is a decorated 2-phenylpyridinato ligand. This increased brilliance is in part due to the presence of the benzyl groups, which act to sterically shield the iridium metal center. X-ray crystallographic analyses of two of the atl complexes corroborate this assertion. Their electrochemistry is reversible, thus making these complexes amenable for inclusion in light-emitting electrochemical cells (LEECs). A parallel computational investigation supports the experimental findings and demonstrates that for all complexes included in this study, the highest occupied molecular orbital (HOMO) is located on both the aryl fragment of the atl ligands and the iridium metal while the lowest unoccupied molecular orbital (LUMO) is located essentially exclusively on the ancillary ligand

Activation of Phenyl 4‑(2-Oxo-3-alkylimidazolidin-1-yl)benzenesulfonates Prodrugs by CYP1A1 as New Antimitotics Targeting Breast Cancer Cells

Prodrug-mediated utilization of the cytochrome P450 (CYP) 1A1 to obtain the selective release of potent anticancer products within cancer tissues is a promising approach in chemotherapy. We herein report the rationale, preparation, biological evaluation, and mechanism of action of phenyl 4-(2-oxo-3-alkylimidazolidin-1-yl)­benzenesulfonates (PAIB-SOs) that are antimicrotubule prodrugs activated by CYP1A1. Although PAIB-SOs are inert in most cells tested, they are highly cytocidal toward several human breast cancer cells, including hormone-independent and chemoresistant types. PAIB-SOs are <i>N</i>-dealkylated into cytotoxic phenyl 4-(2-oxo-3-imidazolidin-1-yl)­benzenesulfonates (PIB-SOs) in CYP1A1-positive cancer cells, both in vitro and in vivo. In conclusion, PAIB-SOs are novel chemotherapeutic prodrugs with no equivalent among current antineoplastics and whose selective action toward breast cancer is tailored to the characteristic pattern of CYP1A1 expression observed in a large percentage of human breast tumors

Design, Synthesis, Biological Evaluation, and Structure–Activity Relationships of Substituted Phenyl 4-(2-Oxoimidazolidin-1-yl)benzenesulfonates as New Tubulin Inhibitors Mimicking Combretastatin A-4

Sixty-one phenyl 4-(2-oxoimidazolidin-1-yl)benzenesulfonates (PIB-SOs) and 13 of their tetrahydro-2-oxopyrimidin-1(2<i>H</i>)-yl analogues (PPB-SOs) were prepared and biologically evaluated. The antiproliferative activities of PIB-SOs on 16 cancer cell lines are in the nanomolar range and unaffected in cancer cells resistant to colchicine, paclitaxel, and vinblastine or overexpressing the P-glycoprotein. None of the PPB-SOs exhibit significant antiproliferative activity. PIB-SOs block the cell cycle progression in the G₂/M phase and bind to the colchicine-binding site on β-tubulin leading to cytoskeleton disruption and cell death. Chick chorioallantoic membrane tumor assays show that compounds <b>36</b>, <b>44</b>, and <b>45</b> efficiently block angiogenesis and tumor growth at least at similar levels as combretastatin A-4 (CA-4) and exhibit low to very low toxicity on the chick embryos. PIB-SOs were subjected to CoMFA and CoMSIA analyses to establish quantitative structure–activity relationships

Gold–Manganese Oxide Core–Shell Nanoparticles Produced by Pulsed Laser Ablation in Water

A single-step procedure for the preparation of Au–MnO_<i>x</i> NPs was achieved through pulsed laser ablation of a gold–manganese metal target made of a pressed metal powder mixture. First, a 248 nm nanosecond laser at 66.7 J cm^–2 was used to synthesize Au–MnO_<i>x</i> NPs from a gold–manganese metal target immersed in an aqueous solution at pH 11 (NaOH). It is demonstrated that the Au–MnO_<i>x</i> NPs are made of a small Au core (around 5 nm in diameter) surrounded by a very thin manganese oxide layer (0.3–1.3 nm) as characterized by TEM, HAADF HR-STEM, and EELS. The superficial MnO_<i>x</i> layer has a local structure that bears a close resemblance to that of Mn₂O₃ and MnO₂ as revealed by EXAFS and XANES measurements. Comparative studies were also performed with a 1064 nm nanosecond laser at 1.4 J cm^–2. In that case, the resulting colloids are mainly made of a mixture of Au NPs and MnO_<i>x</i> NPs, with few Au–MnO_<i>x</i> NPs, thereby suggesting the impact of the laser wavelength and fluence on the synthesis process. The mechanisms responsible for the production of Au–MnO_<i>x</i> core–shell NPs are discussed

Characterizing Nanoparticle Mass Distributions Using Charge-Independent Nanoresonator Mass Spectrometry

Due to their unique size-dependent properties, nanoparticles (NPs) have many industrial and biomedical applications. Although NPs are generally characterized based on the size or morphological analysis, the mass of whole particles can be of interest as it represents the total amount of material in the particle regardless of shape, density, or elemental composition. In addition, the shape of nonspherical NPs presents a conceptual challenge, making them difficult to characterize in terms of size or morphological characteristics. Here, we used a novel nano-electro-mechanical sensor mass spectrometry (NEMS-MS) technology to characterize the mass distributions of various NPs. For standard spherical gold NPs, mass distributions covered the range from ∼5 to 250 MDa (8 to ∼415 attograms). Applying the density of gold (19.3 g/cm3) and assuming perfect sphericity, these mass measurements were used to compute the equivalent diameters of the NPs. The sizes determined agreed well with the transmission electron microscopy (TEM) imaging data, with deviations of ∼1.4%. Subsequently, we analyzed the mass distribution of ∼50 nm synthetic silicon dioxide particles, having determined their size by electron microscopy (SEM and TEM). Their estimated density was in line with the literature values derived from differential mobility analyzer and aerosol particle mass analyzer data. Finally, we examined the intact gold nanotetrapods and obtained a mass distribution revealing their controlled polydispersity. The presence of polyethylene glycol coating was also quantified and corroborated nuclear magnetic resonance observations. Our results demonstrate the potential of NEMS-MS-based measurements as an effective means to characterize NPs, whatever their composition, shape or density