Fuying Hao

Synthesis, photophysical properties and TD-DFT calculation of four two-photon absorbing triphenylamine derivatives

In this study, linear absorption, single-photon excited fluorescence, fluorescence quantum yields, fluorescence lifetime and two-photon excited fluorescence of a series of triphenylamine derivatives (L1, L2, L3 and L4) have been measured. L1 and L3 are D-π-A type dyes, while L2 and L4 are D-π-D-π-A type dyes (D = donor, A = acceptor). The investigated compounds consist of triphenylamine-bearing donor-substituted and/or systematically extended π-conjugated length, which are designed to gain insight into the effect of the ethoxyl unit and π-linkage length on the linear and nonlinear optical properties. The influence of solvent polarity on the photophysical properties was investigated. Employing time-dependent density functional theory (TD-DFT) calculations, the structure-property relationships are discussed.

Role of anions in preparing silver(I) complexes with a new multidentate ligand: polymorphs, structures and nonlinear optical properties

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.

Tuning the optical properties of flurophore-hexylcarbazole organic nanoribbons with dispersed inorganic nanocrystals (AgNCs)

A carbazole derivative (3-(2,2-dicyanovinyl)-9-hexylcarbazole, abbreviated as L) has been designed, synthesized and used to prepare a novel organic–inorganic nanohybrid consisting of silver nanocrystals (Ag NCs) uniformly dispersed on the surface of L nanoribbons. Detailed characterizations have been performed. The results reveal that L couples with Ag NCs through a π-conjugated unit, which results in a significant red-shift of the fluorescence (FL), an obvious increase of FL lifetime and enhanced Raman scattering.

Four new two-photon polymerization initiators with varying donor and conjugated bridge: synthesis and two-photon activity.

A specific series of dumbbell-shaped bis-carbazoles or bis-phenothiazines dyes (1, 2, 3 and 4) constructed with styrene or biphenylethyne as the π-bridge have been synthesized and characterized. Detailed spectral properties including linear absorption, one and two-photon fluorescence properties were investigated. The results show that extending conjugated chain and introducing donors have substantial effect on their photophysical properties. Among them, two-photon absorption cross sections (σ) of the four dyes in DMF determined by the Z-scan technique are successively increased from 1 to 4 with enhancing electron-donating ability and extending conjugated chain, but electron-donating ability has larger contribution to the σ values than extending conjugated chain based on the comparison of small molecules (D-π-D). Two-photon initiation polymerization (TPIP) microfabrication experiments have been carried out using compound 4 as an initiator under irradiation of 200 fs, 76 MHz femtosecond laser at 760 nm. The results confirm that the four dyes can be effectively used as organic two-photon photopolymerization initiators.

A-π-D-π-A pyridinium salts: synthesis, crystal structures, two-photon absorption properties and application to biological imaging

Three different pyridinium salts with I−, BPh4− or [Eu(TTA)4]− anions were synthesized and fully characterized. The crystal structures and 1H-NMR spectra of the dipyridinium cations showed that the coplanarity of the cation was controlled by the type of anion. Their one- and two-photon absorption properties were studied in combination with their structure. The two-photon absorption properties were shown to be tunable by the counter-anions. A pyridinium salt containing L[Eu(TTA)4]2 was selected as a marker for use in fluorescence microscopy to image living cells. This salt clearly displayed the cell structure and was used successfully in two-photon excited fluorescence microscopy.

New dyes with enhanced two-photon absorption cross-sections based on the Cd(II) and 4′-(4-[4-(imidazole)styryl]phenyl)-2,2′ : 6′,2″-terpyridine

A series of new cadmium complexes (dyes 1–5) were obtained by assembly of the donor–bridge–acceptor (D–π–A)-type ligand (L: 4′-(4-[4-(imidazole)styryl]phenyl) 2,2′ : 6′,2″-terpyridine) with CdX2 (X=Cl, Br, I, NCS, ClO4), in which dye 3 was characterized by single crystal X-ray diffraction. 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 non-linear optical properties of ligand and the complexes were investigated. The two-photon absorption cross-section of these complexes are larger than that of ligand with maximum values of 577 GM (dye 1), 242 GM (dye 2), 171 GM (dye 3), 326 GM (dye 4), and 215 GM (dye 5) in N,N-dimethylformamide.

Spectral and temporal properties of two-photon pumped amplified spontaneous emission and cavity lasing of a new organic dye

Abstract The spectral and temporal properties of the two-photon absorption (TPA) fluorescence, amplified spontaneous emission (ASE) and cavity lasing of a new organic dye, trans-4-[p-(N-n-butyl-N-n-butylamino)-styryl]-N-methyl-pyridinium tris(thiocyanato)cadmates(II), in chloroform have been reported in this paper. The spectral modulation effect was observed in the TPA cavity lasing due to the multicavity structure of the cuvette. Obvious oscillations were observed in the temporal spectrum of the TPA cavity lasing with a total oscillation time of 200 ps. The lifetime of TPA fluorescence was measured to be 248 ps. The upconversion efficiencies of the TPA ASE of the dye in dimethyl formamide (DMF) at different pump energies were measured and the highest efficiency was ≍4.8% at a pump energy of 4–6 mJ.

Synthesis, crystal structures, one/two-photon optical properties and bioimaging application of two organic molecules with D–A and D–π–A models containing 6-phenyl-2,2′-bipyridine

Two novel organic compounds with D–A (L1) and D–π–A (L2) models containing 4-(N,N-dipropylamino)phenyl [donor group (D)] and 6-phenyl-2,2′-bipyridine [acceptor (A)] groups were synthesized and characterized by IR, 1H NMR, 13C NMR, MS and single crystal X-ray diffraction. Their photophysical properties were systematically investigated using both experiments and theoretic calculations. It was found that the two-photon action cross-section (δΦ) of the D–π–A model molecule (δΦL2 = 119 GM) was approximately three times larger than that of the D–A type molecule (δΦL1 = 43 GM). Furthermore, their cytotoxicity and applications in bioimaging were determined. The results showed that L1 and L2 could be used as cytoplasmic dyes with high stability and low cytotoxicity.

CCDC 850218: Experimental Crystal Structure Determination

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CCDC 725513: Experimental Crystal Structure Determination

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