Zheng Zheng

Anhui University, Luchow, Anhui Sheng, China

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Publications (16)31.9 Total impact

  • Journal of Molecular Structure. 01/2014; 1068:182–188.
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    ABSTRACT: By self-assembly of (E)-2-(3-(4-(1H-imidazol-1-yl)styryl)-5,5-dimethylcyclohex-2-enylidene)malononitrile (L(1)) and (E)-2-(3-(4-(1H-1,2,4-triazol-1-yl)styryl)-5,5-dimethylcyclohex-2-enylidene)malononitrile (L(2)) with silver(i) salts, eight new complexes, namely AgL(1)2ClO4 (), AgL(1)2NO3 (), [AgL(1)2NO3]·C6H6 (), [AgL(1)2OOCCF3]·C6H6 (), [AgL(1)2PF6]·C6H6 (), AgL(2)2NO3 (), [AgL(2)OOCCF3]2 () and AgL(2)2PF6 (), are presented along with an analysis of their structural features. The structures are built up through the combination of coordination bonds, Agπ, AgF (or O), hydrogen bonding, and ππ stacking interactions to generate new supramolecular architectures. We observed the formation of two-dimensional coordination polymers for complex . Solvent benzene molecules and anions are dispersed in the supramolecular structure and play a vital role in building the supramolecular structures of the complexes. The nonlinear optical (NLO) properties of the complexes were investigated using the Z-scan technique and complexes , , , and show obviously nonlinear absorption compared with ligands (L(1) and L(2)).
    Dalton Transactions 10/2013; · 3.81 Impact Factor
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    ABSTRACT: Five triphenylamine containing benzimidazole derivatives (a1–a5) with different D/A groups (D and A stand for donor and acceptor, respectively), conjugation length or configuration were designed and synthesized. The one- and two-photon spectroscopic properties of these molecules were studied. All of these compounds have amazing fluorescence quantum yields in the range of 0.39–0.61. Besides, for a1–a5, the λem (emission maximum wavelength of one- and two-photons) are only dominated by the D/A groups, and the conjugation length is irrelevant, implying that the molecular rotation is in the excited-state. To better explain this phenomenon, the structure–property relationships of a1–a5, especially the molecular rotation in the excited-state, have been discussed in detail, and were identified by density functional theory calculations. Furthermore, four azo-heterocycle containing benzimidazole derivatives, which have weak electron-donating ability, were synthesized and discussed as a comparison. Finally, considering their optical action, cytotoxicity and solubility, a1, a2 and a4 were chosen for bio-imaging. The results show that the small molecule a2 is the best candidate for one-photon excited fluorescence and two-photon excited fluorescence imaging.
    J. Mater. Chem. C. 10/2013; 1(42).
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    ABSTRACT: Three Schiff bases containing phenylbenzoxazole were synthesized and characterized, which exhibited distinct aggregation-induced enhanced emission (AIEE) behavior in THF–water. However, the single-crystals of L3 show obvious π–π stacking that would induce fluorescent quenching in the solid state. In order to further gain insight into the AIEE mechanism of the three compounds, the size and growth process of particles with different water fractions were studied using SEM, TEM and DLS. The results show that the molecules of compounds can slowly assemble in an ordered fashion to form more-crystalline but less-emissive particles in the THF–water mixtures with low water contents, while in mixtures containing very large amounts of water, the molecules of compounds abruptly agglomerate to form less-crystalline or even amorphous but more-emissive clusters, which effectively avoid π–π stacking.
    J. Mater. Chem. C. 10/2013; 1(42).
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    ABSTRACT: Two novel soluble chemosensors based on Schiff-base diaminomaleonitrile derivatives which were modified by an aza-crown ether moiety have been synthesized. These chemosensors were fully characterized by 1H NMR, 13C NMR spectroscopy, mass spectrometry, IR, DSC and single crystal X-ray diffraction. The recognition abilities of the sensors with a range of metal ions were evaluated and their photophysical properties have been systematically investigated. DFT theoretical calculations were employed to understand the behavior of the sensors toward the Cu(II). The sensing mechanism was derived through experimental and theoretical calculations. The results consistently indicated that the monoaza-10-crown-5 species was the ideal sensor, which can be utilized to monitor Cu(II) in solution over a wide pH range.
    Dyes and Pigments 07/2013; 98(1):1–10. · 3.53 Impact Factor
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    ABSTRACT: A series of new isophorone derivatives (1-5), incorporation of the heterocyclic ring or aza-crown-ether group, with large Stokes shifts (>140 nm) have been synthesized and characterized. 1-4 display aggregation-induced emission (AIE) behaviors, while dye 5 is highly emissive in solution but quenched in the solid state. It was found that the tuning of emission color of the isophorone-based compounds in the solid state could be conveniently accomplished by changing the terminal substituent group. The photophysical properties in solution, aqueous suspension and crystalline state, along with their relationships, are comparatively investigated. Crystallographic data of 1-4 indicate that the existence of multiple intermolecular hydrogen bonding interactions between the adjacent molecules restrict the intramolecular vibration and rotation and enable the compounds 1-4 to emit intensely in the solid states. The size and growth process of particles with different water fractions were studied using a scanning electron microscope (SEM), indicating that smaller globular nanoparticles in aqueous suspension are in favour of fluorescence emissions. The above results suggest that substituent groups have a great influence on their molecular packing, electronic structure, and aggregation-induced emission properties. In addition, fluorescence cell imaging experiment proved the potential application of 5.
    The Journal of Organic Chemistry 03/2013; · 4.56 Impact Factor
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    ABSTRACT: A new series of D–π–A type two-photon absorption (2PA) dyes (1–4) based on imidazo[4,5-f]1,10-phenanthroline have been synthesized and their photophysical properties have been systematically investigated. These dyes showed obvious positive solvatochromic effects mainly due to intramolecular charge transfer (ICT). The two-photon absorption (2PA) cross-section values measured by two-photon excited fluorescence (TPEF) were determined to be 1232 GM and 4752 GM for dye 3 and dye 4, while dyes 1 and 2 do not display 2PA activity. These results demonstrate that their 2PA cross section values (σ) increase with increasing donor/acceptor (D/A) strength of the corresponding molecule. The results also imply that the replacement of the tetrazol group with the aza-crown-ether group results in an opposite charge transfer direction, which has been verified by density functional theory (DFT) calculations. In addition, a two-photon fluorescence cell imaging experiment proved the suitability of dye 3 for this potential application .
    J. Mater. Chem. C. 12/2012; 1(4):822-830.
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    ABSTRACT: A new multidentate ligand containing pyridyl and pyrazolyl groups, 6-phenyl-4-(4-(1H-pyrazolyl)phenyl)-2,2′-bipyridine (L) was designed and synthesized. By self-assembly of L with silver(I) salts, three new complexes containing disilver(I) metallocycles, namely [TsOAgL]2 (1), [AgL]2(ClO4)2 (2) and [AgL2]2(NO3)2[AgLNO3]2·(H2O)2 (3), were obtained. Polymorph (II) of L was obtained unexpectedly when AgSCN complex was prepared. In complexes 1 and 2, two ligands in a head-to-tail mode bridge two Ag(I) ions via pyridyl and pyrazolyl N atoms to generate binuclear [AgL]2 unit. While, in complex 3, the asymmetric unit contains two kinds of crystallographically and conformationally independent molecules with completely different structures and coordination environments of Ag(I) ions. The structure of one kind of molecule is similar to that of complex 1. However, the other kind has a uninuclear structure, and the Ag(I) center is coordinated by four pyridyl nitrogen atoms from two ligands. Different anions have shown a great influence on both the molecular structures and the packing structures of the complexes. The nonlinear optical (NLO) properties of L and the complexes were measured through Z-scan technique. The results show that they may be good candidates for non-linear optical materials.
    CrystEngComm 11/2012; 14(24):8409-8417. · 3.88 Impact Factor
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    ABSTRACT: In the title compound, C(15)H(11)N(5), the benzimidazole ring system is nearly planar [maximum deviation = 0.039 (2) Å], and is oriented at a dihedral angle of 28.85 (10)° with respect to the benzene ring; the dihedral angle between the triazole and benzene rings is 17.30 (15)°. In the crystal N-H⋯N hydrogen bonds link the mol-ecules into chains. Weak C-H⋯N inter-actions are also present.
    Acta Crystallographica Section E Structure Reports Online 10/2012; 68(Pt 10):o2890. · 0.35 Impact Factor
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    ABSTRACT: A series of new one, two and three-branched two-photon absorption triazine dyes containing triphenylamine with a π-bond and a σ-electron pair as a bridge, and different electron-donating groups, have been synthesized and their photophysical properties have been systematically investigated. These dyes showed obvious solvatochromic effects, i.e., significant bathochromic shifting of the emission spectra and larger Stokes shifts were observed in more polar solvents mainly due to intramolecular charge-transfer (ICT). The two-photon absorption (2PA) cross section values were determined by two-photon excited fluorescence (TPEF) measurements in DMF. This result further proved that a σ-electron pair as a bridge is an efficient way to transfer charge as well as a π bridge to provide a large 2PA cross section, and that their 2PA cross section values (δ) increase with increasing electron-donating strength of the end group and branch number. In addition, two-photon fluorescence cell imaging of dye 7a in HeLa and MCF-7 cancer cells was demonstrated.
    Dyes and Pigments 09/2012; 94(3):570–582. · 3.53 Impact Factor
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    ABSTRACT: A series of new one, two, and three-branched two-photon absorption triazine derivatives with a π-bond and a σ-electron pair as a bridge have been synthesized and their photophysical properties have been systematically investigated. These chromophores showed obvious solvatochromic effects, i.e., significant bathochromic shifting of the emission spectra and larger Stokes shifts were observed in more polar solvents mainly due to intra-molecular charge transfer (ICT). The two-photon absorption (2PA) cross-section values were determined by the two-photon excited fluorescence (TPEF) measurements in DMF. This result further proved that a σ-electron pair as a bridge is an efficient way to transfer charge as well as a π bridge, and that their 2PA cross-section values (δ) increase with increasing branch number.
    Tetrahedron. 08/2012; 68(32):6569–6574.
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    ABSTRACT: Aggregation-induced emission (AIE) compounds, dye2 and dye3, with a rotatable N–N single bond and aza-crown-ether, have been synthesized. The fluorescence intensities of both dyes are very weak in THF, while become extraordinarily strong in a mixture of H2O–THF (v/v 95%). They are increased by 88.9 and 70.7 times, respectively, indicating enhanced blue-green fluorescence emissions. The λem of these two compounds in different states has been well studied. Besides this, dye1 and dye2 were characterized by single crystal X-ray structural determination. The results show that molecular interactions are formed in the particles, which considerably restrict the intramolecular vibration and rotation.
    Journal of Materials Chemistry 07/2012; 22(33). · 5.97 Impact Factor
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    ABSTRACT: A novel 2,2':6',2′′-terpyridine-based ligand (L) and eight complexes have been synthesized and fully characterized. Six of these complexes ([CdLBr2]2·CHCl3 (2), ZnLI2 (3), [CdLI2]2·CH2Cl2 (4), ZnL(SCN)2·CHCl3 (5), [ZnL2]2(ClO4)4·7H2O (7) and [CdL2](ClO4)2·CH3OH (8)) were determined by single crystal X-ray diffraction analysis. Various weak interactions, including hydrogen bonds (C–HN, C–HX), C–Hπ and π–π interactions played significant roles in the final supramolecular structures. Linear and nonlinear optical properties of the ligand and eight complexes are described. Experimental results reveal that two-photon absorption (TPA) cross-sections of these complexes are extraordinarily larger than that of the ligand, with maximum values of 97, 661, 787, 218, 133, 613, 230, 384 and 241 GM for L and complexes 1–8 in DMF, respectively. Density functional theory (DFT) calculations were performed on 1–6 and revealed that the halogen affects the accepting capability of surrounding metals due to different electron inductive effects, in the order Br > SCN > I. Thus, this in turn affects the TPA cross-section values. The results indicate that the TPA cross-sections vary in the order Br > SCN > I, which is consistent with the experimental results.
    CrystEngComm 07/2012; 14(17):5613-5621. · 3.88 Impact Factor
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    ABSTRACT: Six novel organotin(IV) carboxylates have been successfully synthesized, namely, the polymer (C6H5)3Sn(L1)∞ (1) [HL1 = 4-imidazolyl benzoic acid], the mononuclear (C6H5)3Sn(L2) (2) [HL2 = 4-pyrazolylbenzoic acid], (C6H5)3Sn(L3)·CH3OH (3) [HL3 = 4-triazolylbenzoic acid] and (C6H5)3Sn(L4) (4) [HL4 = 4-tetrazolyl benzoic acid] and the tetranuclear [(n-Bu2Sn)4(L2)2O2(OCH3)2] (5) and [(n-Bu2Sn)4(L3)2O2(OCH3)2] (6). X-ray diffraction analyses show 1D infinite chain of polymer 1, single molecular structures of isomorphous complexes 2 and 4, single molecule structures of complex 3 containing solvent CH3OH molecule and similar ladder-type structures of complexes 5 and 6. The photoluminescence of ligands and 1–6 were also measured in the solid state at room temperature.
    Polyhedron 01/2012; 31(1):738–747. · 2.05 Impact Factor
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    ABSTRACT: In the title mol-ecule, C(10)H(8)N(2)O(2), the imidazole and benzene rings form a dihedral angle of 14.5 (1)°. In the crystal, inter-molecular O-H⋯N hydrogen bonds link the mol-ecules into chains extending in [01], which are further linked into sheets parallel to (102) through weak C-H⋯O inter-actions.
    Acta Crystallographica Section E Structure Reports Online 01/2011; 67(Pt 2):o524. · 0.35 Impact Factor
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    ABSTRACT: A new donor–bridge–acceptor (D–π–A) type ligand (L: 4′-(4-[4-(imidazole)styryl]phenyl)-2,2′:6′,2″-terpyridine) with two-photon absorption and coordination ability was designed and synthesized. Self-assembly of the ligand with HgX2 (X = Cl, Br, I) yielded a series of new coordination complexes (Dyes 1–3) with five-coordinated mercury (ΙΙ), which were characterized by single crystal X-ray diffraction determination. Solvent molecules and various weak interactions, including hydrogen bonds (C–H···N, C–H···X) and π–π interactions played significant roles in the final topological structures. Linear and nonlinear optical properties of the ligand and three dyes were described. Experimental results revealed that two-photon absorption cross sections of three dyes are extraordinary stronger than that of ligand.
    Dyes and Pigments - DYE PIGMENT. 01/2011; 91(2):237-247.