Search

Reaction of the Pt(II) complexes [PtMe2(pbt)], 1a, (pbt = 2-(2-pyridyl)benzothiazole) and [PtMe(C^N)(PPh2Me)] [C^N = deprotonated 2-phenylpyridine (ppy), 1b, or deprotonated benzo[h]quinoline (bhq), 1c] with benzyl bromide, PhCH2Br, is studied. The reaction of 1a with PhCH2Br gave the Pt(IV) product complex [PtBr(CH2Ph)Me2(pbt)]. The major trans isomer is formed in a trans oxidative addition (2a), while the minor cis products (2a' and 2a″) resulted from an isomerization process. A solution of Pt(II) complex 1a in the presence of benzyl bromide in toluene at 70 °C after 7 days gradually gave the dibromo Pt(IV) complex [Pt(Br)2Me2(pbt)], 4a, as determined by NMR spectroscopy and single-crystal XRD. The reaction of complexes 1b and 1c with PhCH2Br gave the Pt(IV) complexes [PtMeBr(CH2Ph)(C^N)(PPh2Me)] (C^N = ppy; 2b; C^N = bhq, 2c), in which the phosphine and benzyl ligands are trans. Multinuclear NMR spectroscopy ruled out other isomers. Attempts to grow crystals of the cycloplatinated(IV) complex 2b yielded a previously reported Pt(II) complex [PtBr(ppy)(PPh2Me)], 3b, presumably from reductive elimination of ethylbenzene. UV-vis spectroscopy was used to study the kinetics of reaction of Pt(II) complexes 1a-1c with benzyl bromide. The data are consistent with a second-order SN2 mechanism and the first order in both the Pt complex and PhCH2Br. The rate of reaction decreases along the series 1a ≫ 1c > 1b. Density functional theory calculations were carried out to support experimental findings and understand the formation of isomers.

The reaction of complex [Pt(Me)(DMSO)(pbz)], 1, (pbz = 2-(2-pyridyl)benzimidazolate) with [PtMe(Cl)(DMSO)2], B, followed by addition of bis(diphenylphosphino)acetylene (dppac), gave the novel tetranuclear platinum complex [Pt4Me4(μ-dppac)2(pbz)2Cl2], 2, bearing both the pbz and dppac ligands. In this structure, the pbz ligands are both chelating and bridging to stabilize the tetraplatinum framework. The tetranuclear Pt(II) complex was fully characterized by NMR spectroscopy, X-ray crystallography, and mass spectrometry, and its electronic structure was investigated and supported by DFT calculations.

Background: Despite substantial efforts to leverage natural killer (NK) cells in cancer immunotherapy, challenges associated with limited cell numbers and sources persist. In this study, our objective is to differentiate NK cells from cord blood hematopoietic stem cells (CB-HSCs) and assess their anti-tumor effects. Methods: Cord blood samples were obtained from pregnant women undergoing normal delivery. Mononuclear cells (MNC) were isolated by gradient centrifugation. Subsequently, HSCs were isolated using the MACs cell separation kit. The isolated HSCs were cultured in NK cell differentiation and expansion media for 21 days and 7 days, respectively. The NK cells were examined for expression of activating markers, cytokine secretion and cytolytic effects by flow cytometry, ELISA and XTT tests, respectively. Results: High-purity HSCs and NK cells were obtained in this study. The CB-HSCs-derived NK cells exhibited significantly higher expression of NKG2D, NKp30, NKp44and NKp46 receptors (at day 28 of treatment) after treatment by IL-15 and IL-2, compared to the early differentiated NK cells (day 21). NK cells derived from CB-HSCs treated with the combination of IL-15 and IL-2 could robustly lyse breast cancer MCF-7 and K562 cells. Also, the obtained NK cells were able to release higher amounts of TNF-α and IFN-γ cytokines in response to tumor cell experiences. Conclusions: Our findings showed that functionally active CB-HSCs-derived NK cells can be successfully generated ex vivo using a cytokine cocktail without a need for stroma for potential use in the cancer immunotherapy. [ABSTRACT FROM AUTHOR]

The pollen morphology of 33 species belonging to the genera Lactuca, Launaea, Cicerbita, Sonchus, Condrilla (tribe Cichorieae: Asteraceae) from Iran were studied with light and electron microscopies. The pollen grains of the investigated taxa are almost oblate‐spherical to prolate‐spherical, the shapes are circular in equatorial view, hexagonal in polar view, only Sonchus species are triangular or quadrangular in polar view, isopolar, symmetrical and trizonocolporate, except Sonchus and Chondrilla species, which have tri‐ to tetrazonocolporate pollen grains, and echinolophate. The size and number of spines in the polar area and the number of spines in the paraporal ridges and equatorial ridges proved to be the most taxonomically authentic characteristics in this study. Three pollen types were distinguished, as in alignment with previous studies. Cluster analysis by Ward method based on 10 quantitative morphological characteristics of pollen grains revealed that the species could be grouped based on the pollen characteristics. Moreover, three species of Cicerbita including Cicerbita scoparia (Rech. f. & Köie) Kitam, C. rechingeriana (Tuisl) Coșkunç., M. Güzel & N. Kilian and C. microcephala (DC.) M. Güzel, Coșkunç. & N. Kilian were recorded for the first time in Iran. Although the characteristics of the pollen grains were useful for distinguishing the species in sub‐tribes, in some cases, this did not confirm recent phylogenetic results. The pollen characteristics described in this study provide data that may be useful for future systematic studies aiming to complete the knowledge on Cichorieae species. Research Highlights: In the present study, the pollen morphology of 33 species belonging to five genera of the Cichorieae are investigated with scanning electron microscopy and 12 species are analyzed for the first time.The cluster analysis based on the quantitative morphological characteristics of pollen grains revealed that the species could be grouped based on the pollen characteristics.In addition, three species of Cicerbita are reported for the first time in Iran. [ABSTRACT FROM AUTHOR]

An easy, safe, simple, and efficient pH‐switchable hydrophobic deep eutectic solvent (DES)‐based liquid‐phase microextraction was developed for the extraction of chlorobenzenes (CBs) from water samples followed by a gas chromatography–electron capture detector (GC–ECD). The switchability of the synthesized DESs was tested by changing the pH. The DES synthesized from thymol:octanoic acid (OA) in a molar ratio of 2:1 had the highest efficiency in extracting CBs from water samples. 1,4‐Dibromobenzene was used as internal standard (IS). The optimal conditions were established to be 20.0 µL of thymol:OA (2:1), 100 µL of 5 mol L−1 KOH, 100 µL of 5 mol L−1 HCl, 60 s of extraction time, and without salt addition. Under the optimum conditions, the calibration graphs were linear in the range of 0.005–150 µg L−1, and limits of detection were in the range of 0.001–0.03 µg L−1. The relative standard deviations, including intraday and inter‐day for 5.0 µg L−1 of dichlorobenzene isomers, 2.0 µg L−1 of trichlorobenzene and tetrachlorobenzene isomers, and 0.50 µg L−1 of pentachlorobenzene and hexachlorobenzene isomers in water with using IS, were in the range of 0.6%–3.2% (n = 7) and 3.8%–6.7% (n = 7), respectively. The accuracies, including inter‐day and intraday, were in the range of 93.5%–106.3% and 91.7%–109.4%, respectively. [ABSTRACT FROM AUTHOR]