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The fluorescence imaging technique is becoming a useful tool in the natural and life sciences. Commercial biomarkers are available; however, some disadvantages exist like high isolation cost, low-temperature storage, photodegradation, and low yields. Here two new fluorescent molecular rotors (SB-B 2 and SB-B2 3) derived from Boron Schiff bases (BOSCHIBAs) were synthesized and characterized by NMR (1H and 13C), UV/Vis, and fluorescence spectroscopy. The crystal structure of SB-B2 3 by X-ray diffraction showed a binuclear complex and C2 symmetry. Both compounds showed viscochromic and thermochromic properties. The binuclear rotor 3 showed a greater luminescence intensity increase than the mononuclear one at the highest level of viscosity (90%). From the remarkable findings and to our best knowledge this is the first time low cytotoxicity BOSCHIBAs exhibit selective fluorescent staining of endoplasmic reticulum in HeLa cells and HUVECs. [ABSTRACT FROM AUTHOR]

The interaction of small gas molecules as H2, N2, CO, H2S, NH3, SO2 and CH4 on Li-functionalized graphitic carbon nitride was investigated by using the density functional theory, to explore their gas adsorption properties. The calculated Eads values of all gas molecules on [Li g-C3N4]+ show that these gas molecules present favourable interaction with the lithium atom coordinated on the sheet. NH3 and SO2 molecules present strong interactions, with Eads values of −18.60 and −9.50 kcal mol−1. The natural bond orbital analysis indicates that donor orbitals belong to the lone pairs of oxygen, nitrogen, sulphur and carbon atoms from SO2, N2, NH3, H2S, CO molecules, and acceptor orbitals (LP*) from the lithium atom. Computational studies suggest that H2, N2, CO, H2S, NH3, SO2 and CH4 molecules on [Li g-C3N4]+ present physisorption. [ABSTRACT FROM AUTHOR]

We report the design, synthesis, and characterization of two new fluorescent molecular rotors of boron derived from Schiff bases: (2,4,8,10-tetra-tert-butyl-6-phenyldibenzo[d,h][1,3,6,2]dioxazaboronine (3) and 1,4-bis(2,4,8,10-tetra-tert-butyldibenzo[d,h][1,3,6,2]dioxazaboronin-6-yl)benzene (4), as well as the free ligand 2-[[(3,5-di-tert-butyl-2-hydroxyphenyl)imino]methyl]-4,6-di-tert-butylphenol 1. All compounds were fully characterized by NMR (¹H, 11B, and 13C), IR, UV/vis, fluorescence spectroscopy, and high-resolution mass spectrometry. The crystal structures of 3 and 4 showed tetracoordinated boron atoms with semiplanar skeleton ligands. The free rotation of the fluorescent molecular rotor, only observed in the binuclear compound, was decreased with increasing viscosity, while the quantum yield was increased. Interestingly, the property of reversible thermochromism was found in organoboron 4 in the solid state. DFT calculations to determine the both complexes have free rotation around the CPh-B1 bond. The boron compounds 3 and 4 have shown low cytotoxicity activity in cell line A-431 and low green staining in cells. [ABSTRACT FROM AUTHOR]