Effects of External Field Wavelength and Solvation on the Photophysical Property and Optical Nonlinearity of 1,3-Thiazolium-5-Thiolates Mesoionic Compound

<p>The photophysical property and optical nonlinearity of an electronic push-pull mesoionic compond, 2-(4-trifluoromethophenyl)-3-methyl-4-(4-methoxyphenyl)-1,3-thiazole-5-thiolate were theoretically investigated with a reliable computing strategy. The essence of the optical properties were then explored through a variety of wave function analysis methods, such as the natural transition orbital analysis, hole-electron analysis, (hyper)polarizability density analysis, decomposition of the (hyper)polarizability contribution by numerical integration, and (hyper)polarizability tensor analysis, at the level of electronic structures. The influence of the electric field and solvation on the electron absorption spectra and (hyper)polarizabilities of the molecule are highlighted and clarified. This work will help people to understand the influence of external field wavelength and solvent on the optical properties of mesoionic-based molecules, and provide a theoretical reference for the rational design of chromophores with adjustable properties in the future.<br></p><br>

Effects of External Field Wavelength and Solvation on the Photophysical Property and Optical Nonlinearity of 1,3-Thiazolium-5-Thiolates Mesoionic Compound

<p>The photophysical property and optical nonlinearity of an electronic push-pull mesoionic compond, 2-(4-trifluoromethophenyl)-3-methyl-4-(4-methoxyphenyl)-1,3-thiazole-5-thiolate were theoretically investigated with a reliable computing strategy. The essence of the optical properties were then explored through a variety of wave function analysis methods, such as the natural transition orbital analysis, hole-electron analysis, (hyper)polarizability density analysis, decomposition of the (hyper)polarizability contribution by numerical integration, and (hyper)polarizability tensor analysis, at the level of electronic structures. The influence of the electric field and solvation on the electron absorption spectra and (hyper)polarizabilities of the molecule are highlighted and clarified. This work will help people to understand the influence of external field wavelength and solvent on the optical properties of mesoionic-based molecules, and provide a theoretical reference for the rational design of chromophores with adjustable properties in the future.<br></p><br>

1-Trifluoromethyl-prop-2-yne 1-iminium salts and 1-imines: reactions with the mesoionic „Nitron“

The heterocyclic mesoionic compound (1,4-diphenyl-1H-1,2,4-triazol-4-ium-3-yl)(phenyl)amide („Nitron“) has recently been found to exist in a prototropic equilibrium with minor amounts of a nucleophilic heterocyclic carbene of the 1,2,4-triazolyl-5-ylidene type. Here we report that Nitron reacts with 1-trifluoromethyl-substituted prop-2-yne iminium salts by conjugate nucleophilic addition of the anionic PhN‒ substituent in the mesoionic tautomer, whereas the nucleophilic triazolylidene form is involved in the reaction with 1-CF3-prop-2-yne imines. 3-(2,3-Dihydro-1H-benzo[c]azepin-5-yl)-1H-1,2,4-triazol-4-ium triflate salts were obtained in the former case and (Z)-9-arylidene-1,2,4,7-tetraazaspiro[4.4]nona-2,7-dienes in the latter.

Cytotoxic Activity of the Mesoionic Compound MIH 2.4Bl in Breast Cancer Cell Lines

In this work, we report the synthesis of a new 1,3-thiazolium-5-thiolate derivative of a mesoionic compound (MIH 2.4Bl) and the characterization of its selective cytotoxicity on a panel of breast cancer cells lines. The cytotoxic effect of MIH 2.4Bl on breast cancer cell lines was determined by XTT and crystal violet assays, flow cytometry analysis, electron microscopy characterization, and terminal deoxynucleotidyl transferase (TdT) deoxyuridine triphosphate (dUTP) nick end labeling (TUNEL) apoptosis assays. As determined using XTT cell growth and survival assays, MIH 2.4Bl exhibited growth inhibition activity on most breast cancer cell lines tested, compared with normal human mammary epithelial cells. Three breast cancer cell lines (MCF-7, T-47D, and ZR-75-1) showed a more potent sensitivity index to growth inhibition by MIH 2.4Bl than the other breast cancer cell lines. Interestingly, these 3 cell lines were derived from tumors of Luminal A origin and have ER (estrogen receptor), PR (progesterone receptor), and HER2 (human epidermal growth factor receptor 2) positive expression. Additional analysis of cytotoxicity mediated by MIH 2.4Bl was performed using the MCF-7 cell line. MCF-7 cells displayed both time- and dose-dependent decreases in cell growth and survival, with a maximum cytotoxic effect observed at 72 and 96 hours. The MCF-7 cells were also characterized for cell cycle changes upon treatment with MIH 2.4Bl. Using flow cytometry analysis of cell cycle distribution, a treatment-dependent effect was observed; treatment of cells with MIH 2.4Bl increased the G2/M population to 34.2% compared with 0.1% in untreated (control) cells. Ultrastructural analysis of MFC-7 cells treated with MIH 2.4Bl at 2 different concentrations (37.5 and 75 μM) was performed by transmission electron microscopy. Cells treated with 37.5 μM MIH 2.4Bl showed morphologic changes beginning at 6 hours after treatment, while cells treated with 75 μM showed changes beginning at 3 hours after treatment. These changes were characterized by an alteration of nuclear morphology and mitochondrial degeneration consistent with apoptotic cell death. Results of a TUNEL assay performed on cells treated for 96 hours with MIH 2.4Bl supported the observation of apoptosis. Together, these results suggest that MIH 2.4Bl is a promising candidate for treating breast cancer and support further in vitro and in vivo investigation.