A novel selective fluorescent chemosensor for Fe3+ ions based on phthalonitrile dimer: synthesis, analysis, and theoretical studies

PubMed: 33488226Phenyl-4,4-di(3,6-dibutoxyphthalonitrile) (3) was synthesized by the reaction of 1,4-phenylenebisboronic acid (1) and 4-bromo-3,6-dibutoxyphthalonitrile (2), using Suzuki cross-coupling reaction. The newly synthesized compound (3) was characterized by FT-IR, MALDI-MS, ESI-MS, H-1-NMR, C-13-NMR, and C-13-DEPT-135-NMR. The fluorescence property of phenyl-4,4-di(3,6-dibutoxyphthalonitrile) (3) towards various metal ions was investigated by fluorescence spectroscopy, and it was observed thatthe compound (3) displayed a significantly 'turn-off' response to Fe3+, which was referred to 1:2 complex formation between ligand (3) and Fe3+. The compound was also studied via density functional theory calculations revealing the interaction mechanism of the molecule with Fe3+ ions

Prismatic edge dislocations in graphite

Dislocations are a central concept in materials science, which dictate the plastic deformation and damage evolution in materials. Layered materials such as graphite admit two general types of interlayer dislocations: basal and prismatic dislocations, of which prismatic dislocations have been relatively less studied. Using density functional theory (DFT) calculations, we have examined different prismatic core structures in graphite and evaluated their structure, energetics and mobility. We find close energetic interplay between bonded and “free-standing” core structures in both zigzag and armchair directions, with a reconstructed stable zigzag core identified. We explore grain boundaries and prismatic dislocation pile-up, identifying metastable structures which may be important in energy storage. The role of interlayer stacking in core structure, dislocation glide and climb is also considered in-depth. Our calculations suggest that the prismatic dislocation core is stable up to high temperatures of approximately 1500 K in bulk graphite. Above this temperature, the breaking of bonds in the dislocation core can facilitate climb, grain-boundary motion, and the annealing of damage through prismatic dislocation glide

Selective decoration of isolated carbon nanotubes by potassium evaporation: scanning photoemission microscopy and density functional theory

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Spectromicroscopy of C-60 and azafullerene C59N: Identifying surface adsorbed water

International audienceC fullerene crystals may serve as important catalysts for interstellar organic chemistry. To explore this possibility, the electronic structures of free-standing powders of C and (CN) azafullerenes are characterized using X-ray microscopy with near-edge X-ray adsorption fine structure (NEXAFS) spectroscopy, closely coupled with density functional theory (DFT) calculations. This is supported with X-ray photoelectron spectroscopy (XPS) measurements and associated core-level shift DFT calculations. We compare the oxygen 1s spectra from oxygen impurities in C and CN, and calculate a range of possible oxidized and hydroxylated structures and associated formation barriers. These results allow us to propose a model for the oxygen present in these samples, notably the importance of water surface adsorption and possible ice formation. Water adsorption on C crystal surfaces may prove important for astrobiological studies of interstellar amino acid formation

Spectromicroscopy of C60 and azafullerene C59N: Identifying surface adsorbed water

C60 fullerene crystals may serve as important catalysts for interstellar organic chemistry. To explore this possibility, the electronic structures of free-standing powders of C60 and (C59N)2 azafullerenes are characterized using X-ray microscopy with near-edge X-ray adsorption fine structure (NEXAFS) spectroscopy, closely coupled with density functional theory (DFT) calculations. This is supported with X-ray photoelectron spectroscopy (XPS) measurements and associated core-level shift DFT calculations. We compare the oxygen 1s spectra from oxygen impurities in C60 and C59N, and calculate a range of possible oxidized and hydroxylated structures and associated formation barriers. These results allow us to propose a model for the oxygen present in these samples, notably the importance of water surface adsorption and possible ice formation. Water adsorption on C60 crystal surfaces may prove important for astrobiological studies of interstellar amino acid formation