A single-molecule conformation modulating crystalline polymorph of a physical π–π pyrene dimer: blue and green emissions of a pyrene excimer

2020 ◽  
Vol 8 (10) ◽  
pp. 3367-3373 ◽  
Author(s):  
Wenzhe Jiang ◽  
Yue Shen ◽  
Yunpeng Ge ◽  
Changjiang Zhou ◽  
Yating Wen ◽  
...  
Keyword(s):  
Single Molecule ◽  
Molecular Conformation ◽  
Green Fluorescence ◽  
Blue Fluorescence ◽  
Molecule Conformation

Blue fluorescence and green fluorescence were observed in two crystals with different pyrene dimers, which are modulated by the molecular conformation.

Quantitative mass determination of conjugated polymers for single molecule conformation analysis: enhancing rigidity with macrocycles

2010 ◽  
Vol 46 (26) ◽  
pp. 4686 ◽  
Author(s):  
Klaus Becker ◽  
Gerald Gaefke ◽  
Jasmin Rolffs ◽  
Sigurd Höger ◽  
John M. Lupton
Keyword(s):  
Conjugated Polymers ◽  
Single Molecule ◽  
Mass Determination ◽  
Conformation Analysis ◽  
Molecule Conformation

Using the First Steps of Hydration for the Determination of Molecular Conformation of a Single Molecule

2014 ◽  
Vol 136 (38) ◽  
pp. 13341-13347 ◽  
Author(s):  
Jörg Henzl ◽  
Konrad Boom ◽  
Karina Morgenstern
Keyword(s):  
Single Molecule ◽  
Molecular Conformation

A New Fluorescent Material of Zn (II) Complex with 1-Acetyl-2-Naphthol-4, 4’-Diaminodiphenylmethane

2011 ◽  
Vol 399-401 ◽  
pp. 1026-1029
Author(s):  
Li Hua Wang
Keyword(s):  
Schiff Base ◽  
Solid State ◽  
Organic Solvents ◽  
Green Fluorescence ◽  
Blue Fluorescence ◽  
Complex Material ◽  
Fluorescent Material

A novel bi-Schiff-base Zn (II) complex, 1-acetyl-2-naphthol-4, 4’-diaminodiphenylmethane Zn (II), has been synthesized. The luminescent characterizations of the Zn (II) complex material have been studied in solid state and in organic solvents, and the effect of Mg (II) ion on the fluorescence of Zn (II) complex has also been investigated in organic solvents. The results show that the Zn (II) complex material emits weak green fluorescence at 536 nm in solid, emits strong blue fluorescence 451 nm in DMSO. However, there do have luminescent emissions in methanol and in ethanol duo to the influence of overtones.

A surprising way to control the charge transport in molecular electronics: the subtle impact of the coverage of self-assembled monolayers of floppy molecules adsorbed on metallic electrodes

2017 ◽  
Vol 204 ◽  
pp. 35-52 ◽  
Author(s):  
Ioan Bâldea
Keyword(s):  
Molecular Electronics ◽  
Single Molecule ◽  
Molecular Species ◽  
Molecular Conformation ◽  
Theoretical Work ◽  
Self Assembled Monolayers ◽  
Scanning Tunneling ◽  
Assembled Monolayers ◽  
Self Assembled ◽  
Twisting Angle

Inspired by earlier attempts in organic electronics aiming at controlling charge injection from metals into organic materials by manipulating the Schottky energy barrier using self-assembled monolayers (SAMs), recent experimental and theoretical work in molecular electronics showed that metal–organic interfaces can be controlled via changes in the metal work function that are induced by SAMs. In this paper we indicate a different route to achieve interface-driven control over the charge transfer/transport at the molecular scale. It is based on the fact that, in floppy molecule based SAMs, the molecular conformation can be tuned by varying the coverage of the adsorbate. We demonstrate this effect with the aid of benchmark molecules that are often used to fabricate nanojunctions and consist of two rings that can easily rotate relative to each other. We show that, by varying the coverage of the SAM, the twisting angle φ of the considered molecular species can be modified by a factor of two. Given the fact that the low bias conductance G scales as cos2 φ, this results in a change in G of over one order of magnitude for the considered molecular species. Tuning the twisting angle by controlling the SAM coverage may be significant, e.g., for current efforts to fabricate molecular switches. Conversely, the lack of control over the local SAM coverage may be problematic for the reproducibility and interpretation of the STM (scanning tunneling microscope) measurements on repeatedly forming single molecule break junctions.

scholarly journals Structure Determination, Thermal Stability and Dissolution Rate of δ Indomethacin

2021 ◽  
Author(s):  
Iryna Andrusenko ◽  
Victoria Hamilton ◽  
Arianna E. Lanza ◽  
Charlie L. Hall ◽  
Enrico Mugnaioli ◽  
...  
Keyword(s):  
Dissolution Rate ◽  
Molecular Conformation ◽  
Three Dimensional ◽  
Asymmetric Unit ◽  
Dimensional Electron ◽  
Enhanced Dissolution ◽  
Structure Solution ◽  
Tentative Interpretation ◽  
Molecule Conformation ◽  
Ir And Raman

<div> <p>The structure solution of the δ-polymorph of indomethacin was obtained using three-dimensional electron diffraction. This form shows a significantly enhanced dissolution rate compared with the more common and better studied α- and γ-polymorphs, indicating an increased bioavailability for medicinal applications. The structure was solved in non-centrosymmetric space group <i>P</i>2<sub>1</sub> and comprises two molecules in the asymmetric unit. Packing and molecule conformation closely resemble indomethacin methyl ester and indomethacin methanol solvate. Knowledge of the structure allowed the rational interpretation of spectroscopic IR and Raman data for δ-polymorph and a tentative interpretation for still unsolved indomethacin polymorphs. Finally, we observed a solid-solid transition from δ-polymorph to α-polymorph that can be driven by similarities in molecular conformation.</p> </div> <br>

scholarly journals Resolving dual binding conformations of cellulosome cohesin-dockerin complexes using single-molecule force spectroscopy

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Markus A Jobst ◽  
Lukas F Milles ◽  
Constantin Schoeler ◽  
Wolfgang Ott ◽  
Daniel B Fried ◽  
...  
Keyword(s):  
Single Molecule ◽  
Molecular Conformation ◽  
Bacterial Species ◽  
Force Spectroscopy ◽  
Binding Mode ◽  
Site Directed Mutagenesis ◽  
Binding Modes ◽  
Single Molecule Force Spectroscopy ◽  
Vast Number ◽  
Knock Out

Receptor-ligand pairs are ordinarily thought to interact through a lock and key mechanism, where a unique molecular conformation is formed upon binding. Contrary to this paradigm, cellulosomal cohesin-dockerin (Coh-Doc) pairs are believed to interact through redundant dual binding modes consisting of two distinct conformations. Here, we combined site-directed mutagenesis and single-molecule force spectroscopy (SMFS) to study the unbinding of Coh:Doc complexes under force. We designed Doc mutations to knock out each binding mode, and compared their single-molecule unfolding patterns as they were dissociated from Coh using an atomic force microscope (AFM) cantilever. Although average bulk measurements were unable to resolve the differences in Doc binding modes due to the similarity of the interactions, with a single-molecule method we were able to discriminate the two modes based on distinct differences in their mechanical properties. We conclude that under native conditions wild-type Doc from Clostridium thermocellum exocellulase Cel48S populates both binding modes with similar probabilities. Given the vast number of Doc domains with predicteddual binding modes across multiple bacterial species, our approach opens up newpossibilities for understanding assembly and catalytic properties of a broadrange of multi-enzyme complexes.

scholarly journals Amphiphilic Fluorescent Well-Defined Living Polymer from Indole-3-Carboxaldehyde and 4-Bromo-1, 8-Naphthalic Anhydride: Synthesis and Characterization

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Ambika Srivastava ◽  
Pooja Singh ◽  
Arti Srivastava ◽  
Rajesh Kumar
Keyword(s):  
Aqueous Solution ◽  
Fluorescence Emission ◽  
Green Fluorescence ◽  
Blue Fluorescence ◽  
Naphthalic Anhydride ◽  
H Nmr ◽  
Uv Visible ◽  
Polymer Bearing ◽  
Absorption And Emission Spectroscopy ◽  
Good Agreement

We reported a well-defined amphiphilic fluorescent polymer bearing indole repeating units with naphthalimide pendants obtained by ATRP followed by chemical modification. The obtained polymer poly (N-allyl indole-2-(4-hydroxybutyl)-1, 8-naphthalimide) (PAIHN) was characterized by 1H NMR, FTIR, and GPC. The polymer showed a specific fluorescence emission maximum at 538 nm excited at 435 nm in aqueous solution. The amphiphilic nature of the polymer was investigated in aqueous solution using two spectroscopic methods, namely, absorption and emission spectroscopy. The Critical Miceller Concentration values obtained by UV-visible and fluorescence are in good agreement with each other. The micelles were characterized by TEM at concentration of 0.014 mg/mL. The polymer PAIHN prepared after tweaking exhibits green fluorescence at 538 nm due to the significant effect of naphthalimide moieties, whereas before tweaking the polymer poly (1-allyl indole-3-carbaldehyde) (PAIC) exhibits blue fluorescence at 425 nm due to indole repeating units of the polymer.

OBSERVATIONS SUR LES COULEURS DE LA FLUORESCENCE PRIMAIRE DES MICROORGANISMES

1960 ◽  
Vol 6 (5) ◽  
pp. 519-528
Author(s):  
S. Sonea ◽  
J. de Repentigny
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Culture Media ◽  
Visible Spectrum ◽  
Green Fluorescence ◽  
Blue Fluorescence ◽  
Experimental Conditions ◽  
Microbial Cells ◽  
Precise Meaning ◽  
Supplementary Method ◽  
Primary Fluorescence

Primary fluorescence of microbial cells may show contrasting colors. According to our results, 36 species were divided in two groups: (1) 30 presenting exclusively a yellow-green fluorescence, (2) the 6 others for which reddish cells were observed among yellow-green cells. The species of the second group were: Candida albicans, Pseudomonas aeruginosa, Saccharomyces cerevisiae, Salmonella typhimurium, Sarcina lutea, and Serratia marcescens. In this work, we have deliberately excluded any staining (with fluorochrome or other stain) to avoid possible confusion on the precise meaning of primary fluorescence.These observations were completed by (a) examining, with a "pupillary spectroscope", the light which emerged from the microscope. All the wavelengths of the visible spectrum were, thus, found to be present in the primary fluorescence of the 36 species; (b) verifying macroscopically, under the Wood lamp, the resulting dominant color of the fluorescence of washed microorganisms and of their extracts in alcohol, acetone, or water. Thus was confirmed the presence of yellow, green, or reddish fluorescent substances, already found by the previously mentioned methods.In our experimental conditions (bright condenser, dry objective, and OGI yellow secondary filter), the blue fluorescence was eliminated.The color of the fluorescence of each species examined could be influenced by culture media, temperature, pH, and age of the cultures, but no reddish fluorescence was observed in the first group. After the smears were prepared, the colors were stable and did not fade for months.The color variations of the primary fluorescence is suggestive that between microbial cells there are very discreet metabolic differences which could hardly be observed otherwise.For the classification and the identification of microorganisms, our preliminary findings suggest that the color of primary fluorescence could be a supplementary method, at least for the minority of species producing the reddish fluorescence.

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