607-57-8Relevant academic research and scientific papers
A new and efficient pyridine-2,6-dicarboxamide-based fluorescent and colorimetric chemosensor for sensitive and selective recognition of Pb2+ and Cu2+
Hosseinzadeh, Rahman,Rahimi, Hannaneh,Tajbakhsh, Mahmood
, (2020/12/02)
A new fluorene-bearing pyridine-2,6-dicarboxamide (3) as an effectint fluorescent and colorimetric cation sensor was successfully synthesized and well-characterized using FT-IR, NMR, ESI+-MS and elemental analysis. The metal ion binding ability of the chemosensor 3 in the presence of different metal ions was investigated using UV–vis, fluorescence experiments and results exhibited a desirable selectivity and significant sensitivity of the chemosensor 3 for the detection of Cu2+ and Pb2+ ions. The association constant (Ka) of 3-Cu2+ and 3-Pb2+ complexes were determined to be 8.89 × 103 M?1 and 5.65 × 108 M-2, respectively. The obtained limit of detection (LOD) values (1.49 × 10?6 M for Cu2+ and 2.31 × 10?6 M for Pb2+) clearly revealed the considerable sensitivity of the chemosensor 3.
Microwave-induced surface-mediated highly efficient regioselective nitration of aromatic compounds: Effects of penetration depth
BANIK, BIMAL K.,DAS, APARNA,YADAV, RAM NARESH
, p. 2203 - 2206 (2021/08/24)
Surface mediated highly regioselective nitration of aromatic compounds under diverse microwave-induced conditions was investigated in this work. The effects of the penetration depth of the surfaces were found to be more crucial than other dielectric parameters. Despite significant progress of microwave-induced reactions, no reports have examined the penetration depth of the surfaces used in these processes.
A new fluorene-based Schiff-base as fluorescent chemosensor for selective detection of Cr3?+ and Al3?+
Tajbakhsh, Mahmood,Chalmardi, Gholam Babaei,Bekhradnia, Ahmadreza,Hosseinzadeh, Rahman,Hasani, Nahid,Amiri, Mohammadreza Azizi
, p. 22 - 31 (2017/08/08)
2-((9H-fluoren-2-ylimino) methyl)phenol (F3) was synthesized by condensation reaction of 9H-fluoren-2-amine and 2-hydroxybenzaldehyde in EtOH and characterized by its melting point, 1H-,13C NMR and molecular mass. F3 exhibits a high selectivity for detection of Cr3?+ and Al3?+ ions as a fluorescent chemosensor and showed a single emission band at 536?nm upon excitation at 333?nm according to fluorescence emission studies. The addition of Cr3?+ and Al3?+ make a significant increase in fluorescent intensity at 536?nm in CH3CN, while other metal ions have almost no influence on the fluorescence. The fluorescence enhancement was attributed to the inhibited C[dbnd]N isomerization and the obstructed excited state intra-molecular proton transfer (ESIPT) of compound F3. Job's plot and DFT calculations data showed that the binding stoichiometries of F3 with Cr3?+ and Al3?+ are 2:1. The association constants (Ka) for Cr3?+ and Al3?+ were calculated and found to be 8.33?×?104?M??1 and 5.44?×?104?M??1, respectively. The detection limits were also calculated for Cr3?+ and Al3?+ and found to be 2.5?×?10??7?mol/L and 3.1?×?10??7?mol/L, respectively.
Comparative analysis to explore the suitability of a short chain dyad in its pristine and nanocomposite forms for designing artificial light energy conversion device
Paul, Somnath,Mitra, Ishani,Dutta, Rituparna,Bardhan, Munmun,Bose, Mridul,Das, Subrata,Saha, Mithu,Ganguly, Tapan
, p. 7873 - 7881 (2018/09/06)
From the UV-vis, steady state and time resolved spectroscopic investigations on the pristine dyad, dyad-spherical gold nanoparticles (GNP) and dyad-star shaped gold nanoparticles (GNS), it was observed that though in the ground state the dyad in its pristine form possesses trans-type (elongated and planar) isomer but on photoexcitation trans-form converts into cis-structure (folded). Interestingly, the dyad exhibits different behavior when it combines with GNP or GNS. In nanocomposite form, even on photoexcitation some ground state trans-structure still retains its identity in the excited state. The 60% of the trans-species remains unchanged in the excited state due to excitation of dyad-GNS system and possibly this configuration facilitates the hindrance of energy destructive charge recombination processes as in this conformer the donor and acceptor moieties tend to move far away from each other causing lack of overlapping of charge clouds within the two redox components. The dyad-GNS nanocomposite appears to be the best possible light energy conversion or storage device within the three system studied in the present investigation. Investigations are underway to examine how the degree of surface coverage of the dyad on the surface of gold nanoparticles affect its geometry or conformational changes on photoexcitation.
Aromatic azoxybenzene compound and preparation method thereof
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Paragraph 0018; 0027, (2017/10/25)
The invention discloses an aromatic azoxybenzene compound and a preparation method thereof. The preparation method comprises the following steps: firstly reducing aromatic nitro-compounds into azoxybenzene through photoinduction in an alkaline condition; firstly synthesizing different aromatic nitro-compounds; secondly, carrying out nitro reduction under the irradiation of a xenon lamp under the conditions of potassium hydroxide, methylbenzene and isopropyl alcohol, and thus synthesizing the aromatic azoxybenzene compound. The preparation method disclosed by the invention has the advantages of simple components, mild reaction conditions, low toxicity, environmental protection, high selectivity and the like; the obtained aromatic azoxybenzene compound has potential application in the aspects of dyes, liquid crystal materials, optical materials and the like.
Amidofluorene-appended lower rim 1,3-diconjugate of calix[4]arene: Synthesis, characterization and highly selective sensor for Cu2+
Hosseinzadeh, Rahman,Nemati, Mohammad,Zadmard, Reza,Mohadjerani, Maryam
, p. 1749 - 1757 (2016/10/05)
Functionalization of calix[4]arene with amidofluorene moieties at the lower rim led to formation of the 1,3-diconjugate of calix[4]arene L as a novel fluorescent chemosensor for Cu2+. The receptor molecule L exhibited a pronounced selectivity towards Cu2+ over other mono and divalent ions. The formation of the complex between L and Cu2+ was evaluated by absorption, fluorescence and 1H NMR spectroscopy. The sensor L showed a remarkable color change from colorless to purple and a fluorescence quenching only upon interaction with Cu2+. The 1:1 stoichiometry of the obtained complex has been determined by Job's plot. The association constant determined by fluorescence titration was found to be 1.8 × 106 M-1. The sensor showed a linear response toward Cu2+ in the concentration range from 1 to 10 μM with a detection limit of 9.6 × 10-8 M.
Fluorene-morpholine-based organic nanoparticles: Lysosome-targeted pH-triggered two-photon photodynamic therapy with fluorescence switch on-off
Gangopadhyay, Moumita,Mukhopadhyay, Sourav K.,Gayathri, Sree,Biswas, Sandipan,Barman, Shrabani,Dey, Satyahari,Singh, N. D. Pradeep
supporting information, p. 1862 - 1868 (2016/03/12)
Nanocarrier-mediated photodynamic therapy (PDT) is an effective tool for anti-tumour treatment due to the targeted and image-guided delivery of photosensitizers (PSs) to diseased tissues. These nanocarriers range from inorganic, ceramic, polymeric to biological nanoparticles (NPs). Such PS-grafted bicomponent nanocarriers have limitations like (i) difficulty in surface modification, (ii) lower loading percentages of the therapeutic agent, (iii) unstable physical encapsulation, etc. By any means, if we can prepare PSs directly as NPs then we can surpass the above drawbacks. Hence, we synthesised new two-photon fluorene-functionalised morpholine (Fluo-Mor)-based organic NPs that showed strong fluorescence and profound photodynamic therapy (PDT) activity only in acidic medium. Such a pH-responsive appearance of fluorescence enables Fluo-Mor NPs for the real time monitoring of photodynamic therapeutic activity selectively in low-pH organelles viz. lysosome. Cytotoxicity of Fluo-Mor NPs was monitored using time-dependent and dose-dependent cancer cell viability assay and confocal imaging.
Platinum(II) complexes bearing 2-(9,9-dihexadecyl-7-R-fluoren-2-yl)-1,10- phenanthroline ligands: Synthesis, photophysics and reverse saturable absorption
Liu, Xu-Guang,Sun, Wenfang
supporting information, p. 4732 - 4742 (2013/09/24)
Six platinum(II) complexes bearing 2-(9,9-dihexadecyl-7-R-fluoren-2-yl)-1, 10-phenanthroline ligands (R = NO2, CN, I, H, benzothiazole, thiophene for ligands 1-6, respectively) were synthesized and their photophysics and reverse saturable absorption (RSA) were systematically investigated. All complexes exhibit intense absorption bands between 350 and 450 nm, which are attributed to 1π,π/1ILCT (intraligand charge transfer) transitions, and broad 1MLCT (metal to ligand charge transfer) transitions between 475 and 550 nm. All complexes are emissive at room temperature in a variety of solvents and at 77 K in butyronitrile glassy matrix, with the long-lived, structured emission appearing between 600 and 750 nm. The emitting states are assigned to predominantly the 3π, π* state with an admixture of 3MLCT characters. Upon ns laser excitation at 355 nm, all complexes display broad, moderately strong transient absorption from the visible to the near-IR region. As a result, RSA is observed from all complexes at 532 nm for ns laser pulses. The strength of the RSA for these complexes follows the trend: Pt-2 > Pt-3 > Pt-4 > Pt-1 >> Pt-5 > Pt-6, which correlates well with the trend of the estimated ΦTσex/σ0 values (where ΦT is the triplet excited state quantum yield, and σex and σ0 are the excited-state and ground-state absorption cross-section, respectively) at 532 nm. It is revealed that substitution at the 7-position of the fluorenyl component exerts a distinct effect on the photophysics and RSA of the complexes. Aromatic substituents such as benzothiazol-2-yl and 2-thionyl cause pronounced red-shifts of the absorption bands, the emission bands, and the transient difference absorption bands, but a decrease of the RSA at 532 nm. Platinum(II) complexes bearing 2-(9,9-dihexadecyl-7-R-fluoren-2-yl)-1,10-phenanthroline ligands exhibit a long-lived, broadband-absorbing excited state and strong reverse saturable absorption (RSA) at 532 nm for ns laser pulses. The substituent at the 7-position of the fluorenyl component exerts a pronounced effect on both the photophysical properties and the RSA. Copyright
Variation of the backbone conjugation in NLO model compounds: Torsion-angle-restricted, biphenyl-based push-pull-systems
Rotzler, Juergen,Vonlanthen, David,Barsella, Alberto,Boeglin, Alex,Fort, Alain,Mayor, Marcel
scheme or table, p. 1096 - 1110 (2010/04/27)
Terminal piperidinyl- and nitro-functionalized biphenyls, bridged between the 2 and. 2′ positions by a variable number of methylene groups, are synthesized and fully characterized. These push-pull systems with defined and restricted torsion angles between their phenyl rings are ideal model compounds to investigate the influence of the chromophore's conjugation in nonlinear optic (NLO) responses, A general synthetic route that can be implemented to access these model compounds is reported, starting from dibromo or ditriflate biphenyls. Hartwig-Buchwald cross-coupling, a selective azacycloalkylation of diaminobiphenyls and a mild oxidation of primary amines to nitro groups in the presence of a tertiary amine summarizes the synthetic pathway towards the desired model compounds. NLO properties of the series of torsionally constrained push-pull biphenyls are collected by electric-field-induced second-harmonic generation (EFISH) experiments. The results agree qualitatively with semi-empirical simulations based on the AM1 Hamiltonian. A. linear dependence of the quadratic response on the cos2(o) of the inter-aryl dihedral angle is observed, which points to oscillator strength loss as the dominant effect of increasing backbone twist
White-light emitting hydrogen-bonded supramolecular copolymers based on #-conjugated oligomers
Abbel, Robert,Grenier, Christophe,Pouderoijen, Maarten J.,Stouwdam, Jan W.,Leclere, Philippe E. L. G.,Sijbesma, Rint P.,Meijer, E. W.,Schenning, Albertus P. H. J.
supporting information; scheme or table, p. 833 - 843 (2009/07/01)
Three different ?-conjugated oligomers (a blue-emitting oligofluorene, a green-emitting oligo(phenylene vinylene), and a red-emitting perylene bisimide) have been functionalized with self-complementary quadruple hydrogen bonding ureidopyrimidinone (UPy) units at both ends. The molecules self-assemble in solution and in the bulk, forming supramolecular polymers. When mixed together in solution, random noncovalent copolymers are formed that contain all three types of chromophores, resulting in energy transfer upon excitation of the oligofluorene energy donor. At a certain mixing ratio, a white emissive supramolecular polymer can be created in solution. In contrast to their unfunctionalized counterparts, bis-UPy-chromophores can easily be deposited as smooth thin films on surfaces by spin coating. No phase separation is observed in these films, and energy transfer is much more efficient than in solution, giving rise to white fluorescence at much lower ratios of energy acceptor to donor. Light emitting diodes based on these supramolecular polymers have been prepared from all three types of pure materials, yielding blue, green, and red devices, respectively. At appropriate mixing ratios of these three compounds, white electroluminescence is observed. This approach yields a toolbox of molecules that can be easily used to construct ?-conjugated supramolecular polymers with a variety of compositions, high solution viscosities, and tuneable emission colors.
