Pyrene-Functionalized Polyacetylenes: Synthesis and Photoluminescence Property

Four pyrene-functionalized polyacetylenes were designed and prepared through a typical post-polymerization modification route, which is the highly efficient reaction between activated ester and primary anime groups. The chemical structures of the resultant polymers were characterized with multiple spectroscopic techniques and the data indicated the successful functionalization of the polyacetylenes. The introduction of the pyrene moieties into the polymer structure allowed us to investigate the interactions between the polymer backbone and side chains. For the mono-substituted polyacetylenes, both the monomer and excimer emission features of the pyrene groups could be recorded, while for the di-substituted polyacetylenes, the fluorescence from the pyrene excimer vanished and the fluorescence intensity from the pyrene monomer decreased, the fluorescence from the polymer chain predominated the emission features. The concomitant energy transfer from the pyrene monomer and excimer to poly(diphenylacetylene) backbone was associated with the underlying mechanism. In addition to the substitution modes, the linkage between the poly(diphenylacetylene) backbone and the pyrene moiety also played a significant role in the determination of the emission species. A long alkyl spacer was beneficial to the pyrene monomer emission while a short one may be helpful to the formation of the excimer and intramolecular energy transfer.

Download Full-text

Determination of intramolecular energy-transfer efficiency in ytterbium chelates

Journal of Applied Spectroscopy ◽

10.1007/bf02681315 ◽

2000 ◽

Vol 67 (4) ◽

pp. 745-750 ◽

Cited By ~ 2

Author(s):

V. Ya. Venchikov ◽

M. P. Tsvirko

Keyword(s):

Energy Transfer ◽

Energy Transfer Efficiency ◽

Transfer Efficiency ◽

Intramolecular Energy Transfer

Download Full-text

Intramolecular energy transfer dynamics in differently linked zinc porphyrin–dithiaporphyrin dyads

RSC Advances ◽

10.1039/c5ra12600b ◽

2015 ◽

Vol 5 (104) ◽

pp. 85296-85304 ◽

Cited By ~ 1

Author(s):

R. Ghosh ◽

M. Yedukondalu ◽

M. Ravikanth ◽

D. K. Palit

Keyword(s):

Energy Transfer ◽

Transient Absorption ◽

Intramolecular Energy Transfer ◽

Spectroscopic Techniques ◽

Time Resolved ◽

Zinc Porphyrin ◽

Molecular Dyads

Intramolecular energy transfer dynamics in two molecular dyads, in which zinc porphyrin and dithiaporphyrin units were linked covalently, were studied by ultrafast time-resolved transient absorption and fluorescence spectroscopic techniques.

Download Full-text

A quantitative approach to inner shell losses

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010010977x ◽

1978 ◽

Vol 36 (1) ◽

pp. 526-527 ◽

Cited By ~ 2

Author(s):

R.D. Leapman ◽

P. Rez ◽

D.F. Mayers

Keyword(s):

Energy Transfer ◽

Cross Section ◽

Cross Sections ◽

Accurate Determination ◽

Background Intensity ◽

Core Excitation ◽

Quantitative Basis ◽

Cross Section Differential ◽

Bound Electrons

Microanalysis by EELS has been developing rapidly and though the general form of the spectrum is now understood there is a need to put the technique on a more quantitative basis (1,2). Certain aspects important for microanalysis include: (i) accurate determination of the partial cross sections, σx(α,ΔE) for core excitation when scattering lies inside collection angle a and energy range ΔE above the edge, (ii) behavior of the background intensity due to excitation of less strongly bound electrons, necessary for extrapolation beneath the signal of interest, (iii) departures from the simple hydrogenic K-edge seen in L and M losses, effecting σx and complicating microanalysis. Such problems might be approached empirically but here we describe how computation can elucidate the spectrum shape.The inelastic cross section differential with respect to energy transfer E and momentum transfer q for electrons of energy E0 and velocity v can be written as

Download Full-text

Identification of N-Substituted Triazolo-azetidines as Novel Antibacterials using pDualrep2 HTS Platform

Combinatorial Chemistry & High Throughput Screening ◽

10.2174/1386207322666190412165316 ◽

2019 ◽

Vol 22 (5) ◽

pp. 346-354

Author(s):

Yan A. Ivanenkov ◽

Renat S. Yamidanov ◽

Ilya A. Osterman ◽

Petr V. Sergiev ◽

Vladimir A. Aladinskiy ◽

...

Keyword(s):

Antibacterial Activity ◽

Large Scale ◽

Underlying Mechanism ◽

Luciferase Assay ◽

Reporter System ◽

E Coli ◽

Starting Point ◽

High Concentrations ◽

Mic Value

Aim and Objective: Antibiotic resistance is a serious constraint to the development of new effective antibacterials. Therefore, the discovery of the new antibacterials remains one of the main challenges in modern medicinal chemistry. This study was undertaken to identify novel molecules with antibacterial activity. Materials and Methods: Using our unique double-reporter system, in-house large-scale HTS campaign was conducted for the identification of antibacterial potency of small-molecule compounds. The construction allows us to visually assess the underlying mechanism of action. After the initial HTS and rescreen procedure, luciferase assay, C14-test, determination of MIC value and PrestoBlue test were carried out. Results: HTS rounds and rescreen campaign have revealed the antibacterial activity of a series of Nsubstituted triazolo-azetidines and their isosteric derivatives that has not been reported previously. Primary hit-molecule demonstrated a MIC value of 12.5 µg/mL against E. coli Δ tolC with signs of translation blockage and no SOS-response. Translation inhibition (26%, luciferase assay) was achieved at high concentrations up to 160 µg/mL, while no activity was found using C14-test. The compound did not demonstrate cytotoxicity in the PrestoBlue assay against a panel of eukaryotic cells. Within a series of direct structural analogues bearing the same or bioisosteric scaffold, compound 2 was found to have an improved antibacterial potency (MIC=6.25 µg/mL) close to Erythromycin (MIC=2.5-5 µg/mL) against the same strain. In contrast to the parent hit, this compound was more active and selective, and provided a robust IP position. Conclusion: N-substituted triazolo-azetidine scaffold may be used as a versatile starting point for the development of novel active and selective antibacterial compounds.

Download Full-text