Six novel benzimidazole‐based D‐π‐A compounds 4 a–4 f were concisely synthesized by attaching different donor/acceptor units to the skeleton of 1,3‐bis(1H‐benzimidazol‐2‐yl)benzene on its 5‐position ...through an ethynyl link. Due to the twisted conformation and effective conjugation structure, these dual‐state emission (DSE) molecules show intense and multifarious photoluminescence, and their fluorescence quantum yields in solution and solid state can be up to 96.16 and 69.82 %, respectively. Especially, for excellent photostability, obvious solvatofluorochromic and extraordinary wide range of solvent compatibility, DSE molecule 4 a is a multifunctional fluorescent probe for the visual detection of nitroaromatic compounds (NACs) with the limit of detection as low as 10−7 M. The quenching mechanism has been proved as the results of photoinduced electron transfer and fluorescence resonance energy transfer processes. Importantly, probe 4 a can sensitively detect NACs not only in real water samples, but also on 4 a‐coated strips and 4 a@PBAT thin films.
Novel benzimidazole‐based D‐π‐A fluorophores are rationally designed and concisely synthesized. Six compounds 4 a–4 f, as dual‐state emission (DSE) materials, exhibit excellent photostability, solvatofluorochromic and extraordinary wide range of solvent compatibility. Among them, the DSE material 4 a is not only reasonably developed as a multifunctional fluorescent probe for sensitive detection of nitroaromatic compounds (NACs) in aqueous system, but also processed into test strips and thin films for visual detection of NACs.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Metal-free catalyzed intermolecular tandem Michael addition/cyclization has been developed for the synthesis of benzo4,5imidazo1,2-
a
pyridines from α-bromocinnamaldehyde and 2-substituted ...benzimidazoles. The reaction promoted by a simple inorganic base displays moderate to good yields and good functional group tolerance. The optical properties of some typical products have been investigated. We found that, due to the presence of the benzene ring at the C1-position of benzo4,5imidazo1,2-
a
pyridines which restricts intramolecular motion, as a new type of aggregation-induced emission (AIE) luminogen (AIEgen), they show very good solid-state fluorescence with quantum yields up to 88.80%. Importantly, the AIE performance of compound
3b
can be useful to detect the nitroaromatic explosive picric acid (PA) with a detection limit and quenching constant of 42.5 nM and 7.27 × 10
4
M
−M
, respectively.
Metal-free catalyzed intermolecular tandem Michael addition/cyclization is developed for the synthesis of benzo4,5imidazo1,2-
a
pyridines from α-bromocinnamaldehyde. The RIM of the benzene ring at the C1-position makes them a new class of AIE molecules.
Four unique 2-arylethenyl-8-hydroxyquinoline ligands (B1–B4) and their corresponding Zn(II) complexes (C1–C4) were synthesized and characterized by 1H NMR, ESI-MS, FTIR, and elemental analysis. The ...aggregation behavior of Zinc salt and ligands in solution was investigated by several techniques, including 1H NMR, UV–vis, and photoluminescence (PL). The electronic nature of arylethenyl substituents affects the absorption wavelength, the emission color, fluorescence lifetime, fluorescence quantum yield, and thermostability of Zn(II) complexes. Luminescent properties of the Zn(II) complexes correspond to the electron-withdrawing/-donating character of the arylethenyl substituents. Photophysical analyses combined with density functional theory (DFT) calculations established that the introduction of strong electron-withdrawing group (CN) decreased the HOMO–LUMO energy gap, and the introduction of electron-donating group (tert-butyl) enlarged the HOMO–LUMO energy gap.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
In the crystal of the title compound, C(19)H(14)FNO(2), the mol-ecules are linked by C-H⋯O hydrogen bonds in translational chains along the b axis. The dihedral angles formed by the quinoline system ...with the fluoro-benzene ring and the acet-oxy group are 8.15 (3) and 77.42 (4)°, respectively.
A novel 2-substituted-8-hydroxyquinoline ligand (E)-2-2-(2,6-dichlorophenyl)ethenyl-8-hydroxyquinoline (HL) was synthesized and characterized by ESI-MS, NMR spectroscopy, and elemental analysis. ...Using solvothermal method, a dimeric complex (ZnL2)2 (1) was fabricated by self-assembly of Zn(II) ions with ligand HL. X-ray structural analysis shows that 1 exhibits a binuclear core, which is bridged by two 8-hydroxyquinoline rings. The supramolecular structure of 1 features a lamellar solid constructed by aromatic stacking interactions, Cl⋯Cl interactions and nonclassical C–H⋯Cl hydrogen bonds derived from 2,6-dichlorophenyl group of the ligand HL. The aggregation behavior of zinc salts and HL in solutions was investigated with a variety of techniques, including 1H NMR, UV–vis, and photoluminescence (PL). In addition, we also studied the photophysical properties of compound 1 by UV–vis and PL. The experimental results show that the complex 1 emits yellow luminescence in the solid state.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
The use of a novel 2-substituted-8-hydroxyquinoline ligand (
E)-2-{2-3,5-bis (trifluoromethyl)phenylethenyl}-8-hydroxyquinoline(
4, BFHQ) characterized by EIMS,
1H NMR spectroscopy, elemental ...analysis, and FTIR spectroscopy enabled the isolation of a trimeric Zn(II) complex with the formula Zn
3(BFHQ)
6 (
5,
Scheme 1). X-ray structural analysis shows that
5 exhibits a trinuclear core, which is bridged by four 8-hydroxyquinoline rings. The trinuclear core is surrounded by three pairs of BFHQ ligands with offset π–π stacking, showing propeller-like molecular structure. The aggregation behavior of Zn(AcO)
2 and the ligand
4 in solution was investigated by UV–vis. The luminescence properties of compound
5 were investigated by UV–vis and fluorescence spectra at room temperature. The experimental results show that the complex
5 emits yellow luminescence at 553
nm (
λ
em, max) in DMSO solution and at 610
nm (
λ
em, max) in solid state. The thermogravimetric analysis was carried out to examine the thermal stability.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
The title compound, C(19)H(14)N(2)O(4), crystallizes with two molecules with very similar conformations in the asymmetric unit; the angles between the two ring systems are 8.7 (1) and 4.2 (1)°. In ...the crystal, inter-molecular π-π inter-actions centroid-centroid distance 3.973 (1) Å lead to a three-dimensional network.
The title compound, C(19)H(10)F(5)NO(2), was synthesized by the 1:1 condensation of 2-methyl-8-hydroxy-quinaldine with penta-fluoro-benzaldehyde. It crystallizes with two almost identical mol-ecules ...in the asymmetric unit. The penta-fluoro-benzene ring is essentially coplanar with the quinoline ring, forming dihedral angles of 2.49 (17) and 8.72 (16)° in the two mol-ecules.
A 2-substituted-8-hydroxyquinoline ligand (E)-2-2-(4-nitrophenyl)ethenyl-8-hydroxyquinoline (HL) was synthesized and characterized by ESI-MS, NMR spectroscopy and elemental analysis. Using ...solvothermal method, a dimeric complex Zn2Cl2L2·2DMF (1) was fabricated by self-assembly of Zn(II) ions with ligand HL, and characterized with single-crystal X-ray diffractions, powder X-ray diffractions (PXRD), thermal analyses (TGA) and elemental analyses (EA). Complex 1 features a lamellar solid constructed by aromatic stacking interactions and nonclassical CH…O hydrogen bonds. To further investigate the property of the above complex, the photoluminescent properties of 1 are also discussed.
A dimeric complex Zn2Cl2L2·2DMF (1) based on a 2-substituted-8-hydroxyquinoline ligand (HL), which was prepared in two steps from the readily available and cheap 8-hydroxyquinaldine. X-ray structural analysis shows that 1 exhibits a binuclear core, which is bridged by two 8-hydroxyquinoline rings. Display omitted
► 2-substituted-8-hydroxyquinoline ligand (HL) was synthesized and characterized. ► Dimeric complex 1 was fabricated by self-assembly of Zn(II) ions with ligand HL. ► The supramolecular structure of 1 features a lamellar solid. ► The luminescent properties of complex 1 were investigated.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
1D helical channels can be created by "sticky" end-mediated formation of 1D helical stacks composed of short cavity-containing helices and are able to host 1D chains of dichloromethane molecules ...containing extraordinarily short intermolecular Cl···Cl contacts of 2.524 Å in length that computationally destabilize the host-guest complex by 14.94 kcal mol(-1).
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