Perspectives on push–pull chromophores derived from click-type [2 + 2] cycloaddition–retroelectrocyclization reactions of electron-rich alkynes and electron-deficient alkenes

• Michio Yamada

Beilstein J. Org. Chem. 2024, 20, 125–154, doi:10.3762/bjoc.20.13

• . This suggests that exciplexes ([(F12SubPc–TCBD)δ−–anilineδ+]*) are generated where the negative charge is delocalized over F12SubPc and TCBD. The radiative exciplex formation was also confirmed by time-resolved fluorescence measurements. In fact, in toluene, 60 showed maximum emission at 675 nm and a

Thienothiophene-based organic light-emitting diode: synthesis, photophysical properties and application

• Recep Isci and
• Turan Ozturk

Beilstein J. Org. Chem. 2023, 19, 1849–1857, doi:10.3762/bjoc.19.137

• efficiencies pointed out that DMB-TT-TPA (8) is among the best D–π–A modal fluorophores suitable for an OLED application. Moreover, the photophysical properties of DMB-TT-TPA (8) were investigated through time-resolved fluorescence studies (390 nm laser source in THF). The fluorescence lifetime (τ) of DMB-TT

• -TPA (8) exhibited a mono-exponential profile having a 3.20 ns fluorescence decay pattern (Figure S1 in Supporting Information File 1), demonstrating a strong pull–push interaction in steady-state time resolved fluorescence performance. OLED application An OLED was fabricated using a standard

• chemical shift values are reported in ppm downfield from tetramethylsilane (TMS). UV–vis absorption spectra were obtained using a HITACHI U-0080D spectrophotometer. Fluorescence spectra were recorded on a HITACHI F-4500 fluorescence spectrophotometer. Time-resolved fluorescence studies were performed on a

Charge carrier transport in perylene-based and pyrene-based columnar liquid crystals

• Alessandro L. Alves,
• Simone V. Bernardino,
• Carlos H. Stadtlober,
• Edivandro Girotto,
• Giliandro Farias,
• Rodney M. do Nascimento,
• Sergio F. Curcio,
• Thiago Cazati,
• Marta E. R. Dotto,
• Juliana Eccher,
• Leonardo N. Furini,
• Hugo Gallardo,
• Harald Bock and
• Ivan H. Bechtold

Beilstein J. Org. Chem. 2023, 19, 1755–1765, doi:10.3762/bjoc.19.128

• ) and excited with a UV lamp of 365 nm wavelength. The emission spectra were captured using an optical fiber placed close to the film to guide the light until the Ocean Optics USB4000 spectrophotometer. Time-resolved fluorescence decay curves were recorded using the technique of time-correlated single

Synthesis, optical and electrochemical properties of (D–π)₂-type and (D–π)₂Ph-type fluorescent dyes

• Kosuke Takemura,
• Kazuki Ohira,
• Taiki Higashino,
• Keiichi Imato and
• Yousuke Ooyama

Beilstein J. Org. Chem. 2022, 18, 1047–1054, doi:10.3762/bjoc.18.106

• stannyl D–π unit with 1,3-diiodobenzene, respectively. Their optical and electrochemical properties were investigated by photoabsorption and fluorescence spectroscopy, time-resolved fluorescence spectroscopy, cyclic voltammetry (CV) and molecular orbital (MO) calculations. In toluene the photoabsorption

• –π)2Ph-type fluorescent dyes. Herein, we report the syntheses of (D–π)2-type and (D–π)2Ph-type fluorescent dyes and their optical and electrochemical properties based on photoabsorption and fluorescence spectroscopy, time-resolved fluorescence spectroscopy, cyclic voltammetry (CV) and molecular

• -resolved fluorescence spectroscopy of the two dyes revealed that the fluorescence lifetimes (τfl) are 0.62 ns for OTK-2 and 0.66 ns for OTT-2, indicating that there is a little difference in the τfl values of the two dyes. The radiative rate constant (kr = 6.2 × 108 s−1) for OTT-2 is slightly larger than

Selective recognition of ATP by multivalent nano-assemblies of bisimidazolium amphiphiles through “turn-on” fluorescence response

• Rakesh Biswas,
• Surya Ghosh,
• Shubhra Kanti Bhaumik and
• Supratim Banerjee

Beilstein J. Org. Chem. 2020, 16, 2728–2738, doi:10.3762/bjoc.16.223

• spectrofluorometer. Images were taken under a 365 nm UV lamp. DLS and zeta potential measurements were carried out using a Malvern Zetasizer NanoZS. A Horiba Jobin Yvon Fluorocube instrument fitted with a 340 nm diode laser excitation source (with a temporal resolution of 70 ps) was used for the time-resolved

• fluorescence experiments applying the time correlated single photon counting (TCSPC) method. 1H and 13C NMR were performed on Jeol 400 MHz and Bruker 500 MHz spectrometers. Mass spectra were recorded in a Bruker mass spectrometer. SEM images was recorded by using the instrument CARL ZEISS (model SUPRA 55VP

Probing of local polarity in poly(methyl methacrylate) with the charge transfer transition in Nile red

• Aydan Yadigarli,
• Qimeng Song,
• Sergey I. Druzhinin and
• Holger Schönherr

Beilstein J. Org. Chem. 2019, 15, 2552–2562, doi:10.3762/bjoc.15.248

• substrate-supported ultrathin films [13], the analysis of the photophysical properties of tracer dye molecules was found to be beneficial. In time-resolved fluorescence measurements and dye diffusion studies, the nanoenvironments in polymersomes could be assigned [1][12], solute transport be characterized

Ultrafast processes triggered by one- and two-photon excitation of a photochromic and luminescent hydrazone

• Alessandro Iagatti,
• Baihao Shao,
• Alberto Credi,
• Barbara Ventura,
• Ivan Aprahamian and
• Mariangela Di Donato

Beilstein J. Org. Chem. 2019, 15, 2438–2446, doi:10.3762/bjoc.15.236

• absorption cross-section of the molecule. Keywords: hydrazone; molecular switch; pump-probe spectroscopy; time-resolved fluorescence; Introduction Molecular switches are systems that are able to rapidly respond to an external stimulus, which can be of chemical or physical nature, through a variation of

• the fluorescence band and the emission quantum yield depend on the solvent, with the emission strongly quenched in protic media [29]. Time-resolved fluorescence Detailed analysis of the fluorescence features of the two forms in toluene has been performed by time-resolved luminescence measurements in

• , fluorescence toggling and two-photon induced switching. Using a combination of time-resolved fluorescence and transient absorption spectroscopies we were able to gain new insights into the isomerization process of this molecule. Time-resolved luminescence measurements allowed us to determine the excited state

Fluorogenic PNA probes

• Tirayut Vilaivan

Beilstein J. Org. Chem. 2018, 14, 253–281, doi:10.3762/bjoc.14.17

• autofluorescence by time-resolved fluorescence measurements. A few monomer–excimer switching PNA probes have been reported. Two or more pyrene labels may be conveniently placed anywhere in the PNA molecule by attaching them to a C5-functionalized thymine via amide or click chemistries, and applications for the

Fluorescent nucleobase analogues for base–base FRET in nucleic acids: synthesis, photophysics and applications

• Mattias Bood,
• Sangamesh Sarangamath,
• Moa S. Wranne,
• Morten Grøtli and
• L. Marcus Wilhelmsson

Beilstein J. Org. Chem. 2018, 14, 114–129, doi:10.3762/bjoc.14.7

• distances that can be monitored range between 15–90 Å which well match the dimensions of biomolecules. The efficiency of an energy-transfer process (E, between 0 and 100%) can be established using either steady-state or time-resolved fluorescence spectroscopy by comparing fluorescence properties with and

Novel β-cyclodextrin–eosin conjugates

• Gábor Benkovics,
• Damien Afonso,
• András Darcsi,
• Szabolcs Béni,
• Sabrina Conoci,
• Éva Fenyvesi,
• Lajos Szente,
• Milo Malanga and
• Salvatore Sortino

Beilstein J. Org. Chem. 2017, 13, 543–551, doi:10.3762/bjoc.13.52

• absorption spectra of aqueous solutions of (a) eosin Y (2) and (b) conjugate 2–β-CD and fluorescence emission spectra of aqueous solutions of (c) 2 and (d) 2–β-CD. λexc = 490 nm. The fluorescence spectra were recorded with the two samples having the same absorbance at the excitation wavelength. Time-resolved

• fluorescence observed for aqueous solutions of (a) eosin Y (2) and (b) the 2–β-CD conjugate. λexc = 455 nm; λem = 570 nm. 1O2 luminescence detected upon 528 nm light excitation of D2O solutions of (a) eosin Y (2) and (b) 2–β-CD conjugate having the same absorbance at the excitation wavelength. Supporting

Friedel–Crafts-type reaction of pyrene with diethyl 1-(isothiocyanato)alkylphosphonates. Efficient synthesis of highly fluorescent diethyl 1-(pyrene-1-carboxamido)alkylphosphonates and 1-(pyrene-1-carboxamido)methylphosphonic acid

• Anna Wrona-Piotrowicz,
• Janusz Zakrzewski,
• Anna Gajda,
• Tadeusz Gajda,
• Anna Makal,
• Arnaud Brosseau and
• Rémi Métivier

Beilstein J. Org. Chem. 2015, 11, 2451–2458, doi:10.3762/bjoc.11.266

• we performed a time-resolved fluorescence study of 3a, 4 and 5. The fluorescence decay curves are shown in Figure 3, whereas the fluorescence lifetimes and decay rate constants are presented in Table 2. All of the compounds under study displayed monoexponential decays, thus indicating one emitting

The effect of permodified cyclodextrins encapsulation on the photophysical properties of a polyfluorene with randomly distributed electron-donor and rotaxane electron-acceptor units

• Aurica Farcas,
• Ana-Maria Resmerita,
• Pierre-Henri Aubert,
• Flavian Farcas,
• Iuliana Stoica and
• Anton Airinei

Beilstein J. Org. Chem. 2014, 10, 2145–2156, doi:10.3762/bjoc.10.222

• absorption spectra were recorded on a SPECORD 200 Analytik Jena spectrometer with 10 mm quartz cells. Fluorescence measurements were carried out an on Perkin Elmer LS 55 spectrometer. The excitation wavelength corresponds to the maximum absorption band. Time-resolved fluorescence data were acquired with an

Multichromophoric sugar for fluorescence photoswitching

• Stéphane Maisonneuve,
• Rémi Métivier,
• Pei Yu,
• Keitaro Nakatani and
• Juan Xie

Beilstein J. Org. Chem. 2014, 10, 1471–1481, doi:10.3762/bjoc.10.151

• promoted in their closed form 2-CF, whose fluorescence is almost totally quenched by FRET. This phenomenon is well-supported by time-resolved fluorescence measurements. Fluorescence decay curves of 6, 2-OF, and 2 after irradiation at 335 nm were recorded in acetonitrile by the time-correlated single photon

• FRET yield close to unity. This study is supported by time-resolved fluorescence experiments. This result represents a step forward, compared to our previous report on the 1/1 system 1. The increase of the OF to CF conversion extent of the photochromic unit is among our future perspectives, since this

Interaction of cyclodextrins with pyrene-modified polyacrylamide in a mixed solvent of water and dimethyl sulfoxide as studied by steady-state fluorescence

• Akihito Hashidzume,
• Yongtai Zheng and
• Akira Harada

Beilstein J. Org. Chem. 2012, 8, 1312–1317, doi:10.3762/bjoc.8.150

• with Py-modified water-soluble polymers, including the formation of the dynamic excimer, requires not only steady-state fluorescence measurements but also time-resolved fluorescence measurements [38][39][40][41][42][43]. In this study, however, equilibrium constants are roughly estimated by analyzing

Fluorometric recognition of both dihydrogen phosphate and iodide by a new flexible anthracene linked benzimidazolium-based receptor

• Kumaresh Ghosh and
• Debasis Kar

Beilstein J. Org. Chem. 2011, 7, 254–264, doi:10.3762/bjoc.7.34

• magnitude. In the series I− shows a higher value of Ka. We presume that it is due to the dimension of the open cavity of 1 in CHCl3 containing 0.1% CH3CN for which I− anion fits sterically with 1:1 stoichiometry. Other complexes in CHCl3 containing 0.1% CH3CN had also 1:1 stoichiometry. Time resolved

• fluorescence measurements were additionally carried out to study the dynamics of the flexible receptor 1 (λexc = 369 nm) in the presence and absence of the anions such as H2PO4− in CH3CN. The emission decay profile of 1 monitored at 420 nm could be fitted bi-exponentially with two constants τ1 = 3.42 ns (12.22