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A novel bis(pyrazol-1-yl)methane derivative 9-(4-(di(1H-pyrazol-1-yl) -methyl) phenyl)-9H-carbazole (L) and its zinc halide complexes (ZnLX2, X = Cl (1), Br (2), and I (3)) were prepared and fully characterized. The structures of the ligand (L) and complexes 2 and 3 were also characterized by single-crystal X-ray diffraction analysis. The results reveal that the central zinc(II) atom in the complexes is coordinated by two nitrogen atoms from ligands (L) and two halide anion forming a distorted tetrahedron coordination geometry. And then the hydrogen bonding interactions between the molecules from 1D to 3D supramolecular structures were investigated. Furthermore, the photophysical properties of the complexes 1–3 and L were investigated both experimentally and theoretically. The experimental results are consistent with that of the theoretical calculation. [ABSTRACT FROM PUBLISHER]

A new ligand (L) and its mercury(II) complex have been synthesized under mild conditions. X-ray single-crystal structural analyses reveal 1-D, 2-D, and 3-D supermolecular structure of L and HgLI2. Solvent molecules and various weak interactions, including hydrogen bonds (N–H···N, O–H···O, and O–H···N) and π–π interactions play significant roles in the final supermolecular structures. Detailed investigation on 1H NMR spectra of L and HgLI2 are presented. Their photophysical properties were investigated both experimentally and theoretically. [ABSTRACT FROM PUBLISHER]

Abstract: The title complex, NiL2 ·C6H6, has been successfully synthesized in good yield from reaction of a novel Schiff base ligand and nickel acetate in ethanol. The ligand (hereafter abbreviated as HL), derived from S-methyldithiocarbazate and N-ethyl-3-formylcarbazole, loses a proton from its tautomeric thiol form and coordinates to Ni(II) via the mercapto sulphur and β-nitrogen atoms upon complex formation. The structural, optical and physicochemical properties of the complex were characterized by X-ray diffraction, infrared spectroscopy, electronic spectra, thermal analyse and photoluminescence measurement. Single crystal X-ray diffraction analysis established that the geometry of Ni(II) is in a distorted square planar cis-configuration with two carbazole moieties on the same side and the two carbazole rings are almost parallel, forming a conjugated and electronic delocalization system. Two-photon absorption (TPA) coefficient β and cross-section of the complex were obtained by using the open aperture Z-scan technique. The optical limiting (OL) response was also measured. [Copyright &y& Elsevier]

The novel V-shaped donor-π-acceptor-π-donor compounds bearing an aldehyde group (1Pip , 2EtO , and 3TEG) were designed, synthesized, and evaluated as the two-photon excited fluorescence probes for the selective detection of cysteine (Cys). Their structures were fully characterized by 1H NMR, 13C NMR, FT-IR, and HRMS. The optical properties of the target compounds in various solvents were studied in details and the time-dependent density functional theory calculations were performed to shed light on their electronic structures. It is found that all of them exhibit large Stokes shifts (6331-10047 cm−1). 1Pip and 3TEG are capable of detecting Cys with high selectivity, good anti-interference ability, and favorable two-photon absorption performance. The limits of detection were determined to be equal to 0.15 μM for 1Pip and 0.73 μM for 3TEG. The possible recognition mechanism was also validated by 1H NMR and HRMS. One- and two-photon fluorescence imaging experiments indicate that 3TEG shows more satisfactory cellular membrane permeability than 1Pip , and it can successfully visualize the endogenous and exogenous Cys in living cells. These results imply that 3TEG has potential as a two-photon fluorescence probe for detecting Cys in biological samples. [Display omitted] • Three novel D-π-A-π-D type two-photon absorption compounds were developed to detect Cys. • 3TEG shows high selectivity to Cys, favorable two-photon absorption property, large Stokes shifts, and good biocompatibility. • 3TEG has been successfully utilized to image endogenous and exogenous Cys in living cells. [ABSTRACT FROM AUTHOR]

Abstract: Six new fluorescent donor-π bridge-acceptor (D-π-A) structural molecules with various electron donors were synthesized and fully characterized. Influence of electron-donating strength on optical properties was investigated by the systematic alteration of the electron donors. The optical properties of the dyes were successfully tuned by choosing different electron donors. All the dyes in solution show strong one-photon excited fluorescence (OPEF) and high quantum yield. With increasing electron-donating strength of donors, dye 5 with diphenylamine and dye 6 with (4,4′-diethoxyphenyl)amino substituents, exhibit strong two-photon excited fluorescence (TPEF), and the large two-photon absorption (TPA) cross-section values are 1378 GM for 5 and 1654 GM for 6. The structure–property relationships were detailed through quantum chemical calculations and X-ray crystallography. The results of living cell imaging experiments show the values of them in one- or two-photon fluorescence microscopy bioimaging applications. [Copyright &y& Elsevier]

Abstract: A new fluorescent bipyridine derivative 1-(2-amino-5-formylphenyl)-2-[2-amino-5-[(E)-2-[6-(6-methylpyridin-2-yl)pyridin-2-yl]vinyl]phenyl]ethane-N,N,N′,N′-tetraacetic acid (abbreviated as BPYTA) has been synthesized and characterized, which can be dissolved in water. Then its optical properties have been studied. When Zn2+ ion is added into BPYTA solution, the fluorescence intensity has a linear relationship with the concentration of Zn2+ ion. Meanwhile, BPYTA has little response to the existence of many other metal ions, especially Cd2+ ion. Thus, BPYTA has potential application in determining trace Zn2+ ion in water. [Copyright &y& Elsevier]

Abstract: A novel donor–acceptor–donor (D–A–D) biferrocenyl derivative, 2-amino-4,6-diferrocenylpyrimidine, has been synthetized and characterized by 1H NMR, elemental analysis, IR and UV absorption spectroscopy, thermogravimetric analysis (TGA) and X-ray crystallography. The crystal structure revealed that the molecular configuration displayed a good coplanarity. The obtained cis-isomer showed a different arrangement due to the induced metal ion Cd(II). The electronic spectrum features were explained by density functional theory (DFT) which agreed well with the experimental data. The cyclic voltammetry (CV) showed the half wave potential of the compound was more positive than that of the standard ferrocene (Fc), indicating that the strong electron-withdrawing effect of the aminopyrimidine moiety made the ferrocene units more difficult to oxidize. Especially, the nonlinear optical (NLO) properties were determined by optical limiting and Z-scan techniques, which suggested a strong π-electron delocalization and a large polarizability in the molecule reasonably equipped for meeting the requirements for third-order NLO materials. [Copyright &y& Elsevier]

Abstract: Two heterocycle-based derivatives that can be used as two-photon absorption chromophore, 9-butyl-3-(2, 6-diphenylpyridin-4-yl)-9H-carbazole (BDPYC) and 9-butyl-3-(4-(2, 6-diphenylpyridin-4-yl)styryl)-9H-carbazole (BDPSC) have been successfully synthesized and fully characterized by elemental analysis, IR, 1H NMR, 13C NMR and MS. The molecules possess D-π-A structures, but have different π bridge. The 9-butylcarbazole is used as a donor (D), and the pyridine ring is used as an acceptor (A). One- and two-photon absorption and excited fluorescence properties in various solvents were experimentally investigated. Two-photon initiated optical data recording experiments have been carried out under 740nm laser radiation, and the possible mechanism of optical data storage is discussed based on theoretical calculations. [Copyright &y& Elsevier]

Abstract: A novel imidazole derivative, 1-[trans-4-(4-diethylaminostyryl)phenyl]imidazole (abbreviated as L), and its complex Zn(SCN)2L2 have been synthesized and fully characterized. Their crystal structures have been determined by X-ray diffraction. The molecular structure of L is approximately coplanar, the bond lengths of C–C and C–N are located between the normal double and single bonds, which show that L has a delocalized π-electron system in the molecule. In the molecular structure of Zn(SCN)2L2, zinc atom is four coordinated by two nitrogen atoms of the ligands (L) and two nitrogen atoms of thiocyanate to form a distorted tetrahedral geometry. The one-dimensional structure of Zn(SCN)2L2 is formed by C–H⋯S interactions and π–π interactions. They both crystallize in the noncentrosymmetric space group P21, and exhibit powder second-harmonic generation (SHG) efficiency approximately twenty times high as that of urea, indicating promising potential applications as useful nonlinear optical (NLO) materials. [Copyright &y& Elsevier]

Four novel two-photon absorption compounds (1MOBI , 2MOHA , 3BrBI , and 4BrHA), which have assembled stilbene π-bridge, different electron acceptors and donors, were synthesized conveniently via the one-step Horner-Wadsworth-Emmons reaction. Their configurations are A-π-D-π-A, D′-π-D-π-D′, A′-π-A-π-A′, and D-π-A-π-D, respectively. Their linear and nonlinear optical properties including linear absorption, one-photon excited fluorescence, two-photon absorption, and two-photon excited fluorescence, were systematically investigated in various solvents. The results demonstrate that the compounds with dihexylamino donors exhibit good optical properties. 2MOHA and 4BrHA exhibit large two-photon absorption cross-sections (2183 and 1737 GM) in DMF, which are larger than those of many known stilbene derivatives. The relationships between the structures and the optical properties were studied aided with the time-dependent density functional theory calculations. The results indicated that the novel D′-π-D-π-D′ and D-π-A-π-D stilbene derivatives exhibit good optical properties, the two-photon absorption cross-sections can be as large as 2183 GM and 1737 GM, respectively. [Display omitted] [ABSTRACT FROM AUTHOR]