Environmental pollution with chiral organic compounds is an emerging problem requiring innovative sensing methods. Amino-functionalized thioureas, such as 2-(dimethylamino)cyclohexyl-(3,5-bis(trifluoromethyl)phenyl)thiourea (Takemoto’s catalyst), are widely used organocatalysts with virtually unknown environmental safety data. Ecotoxicity studies based on the Vibrio fischeri luminescence inhibition test reveal significant toxicity of Takemoto’s catalyst (EC50 = 7.9 mg/L) and its NH2-substituted analog (EC50 = 7.2–7.4 mg/L). The observed toxic effect was pronounced by the influence of the trifluoromethyl moiety. En route to the porphyrin-based chemosensing of Takemoto-type thioureas, their supramolecular binding to a series of zinc porphyrins was studied with UV-Vis and circular dichroism (CD) spectroscopy, computational analysis and single crystal X-ray diffraction. The association constant values generally increased with the increasing electron-withdrawing properties of the porphyrins and electron-donating ability of the thioureas, a result of the predominant Zn⋯N cation–dipole (Lewis acid–base) interaction. The binding event induced a CD signal in the Soret band region of the porphyrin hosts—a crucial property for chirality sensing of Takemoto-type thioureas.

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The article provides the route to trifluoroacetylated fluorescent boron dipyrromethene dye (2). The compound performs intensive absorption and emission bands in near-red wavelength region. Photophysical properties of 2 are investigated in different solvents. A notable increase of fluorescence quantum yield after trifluoroacetyl group insertion connected with a change in intramolecular interactions parameters. The role of molecular geometry aspects in observed photophysical properties and molecular fragments rotation energy barriers are explained by quantum-mechanical calculations. 2 performs considerable antimycobacterial activity. According to molecular docking simulations, 2 is capable of affinity binding in the active sites of mycobacterial MycP1 and MycP3 serine proteases. The geometries of final ligand-protein complexes show the possibility of protein active site covalent modification at the serine residue of the catalytic triad. At lower concentrations, 2 can act as a fluorescent dye for microscopy analysis and corresponding staining patterns are shown for Mycobacterium smegmatis and Staphylococcus aureus cells.

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