The planar rigidized molecule fluorazene (FPP) undergoes fast reversible intramolecular charge transfer (ICT) in the excited state, with a reaction time of 12 ps polar solvent ethyl cyanide at -45 degrees C. ICT state FPP has dipole moment mu(e)(ICT) 13 D, much larger than that locally LE (1 D). behavior is similar to its flexible counterpart N-phenylpyrrole (PP), for which = D. These results show can occur efficiently. In designing systems capable rapid switching, it therefore important...

Fast and efficient intramolecular charge transfer (ICT) dual fluorescence is observed with the planarized aminobenzonitrile 1-tert-butyl-6-cyano-1,2,3,4-tetrahydroquinoline (NTC6) in a series of solvents from n-hexane to acetonitrile methanol. Such reaction does not take place for related molecules 1-isopropyl (NIC6) 1-methyl (NMC6) groups, nor 1-alkyl-5-cyanoindolines methyl (NMC5), isopropyl (NIC5), or tert-butyl (NTC5) substituents. For these molecules, single band locally excited (LE)...

Branching out: Stiff, aromatic dendrimers made up of five and seventeen pyrene units, respectively, are synthesized, characterized, compared with two model compounds. The rigid strongly twisted structure allows a precise spatial arrangement in which each unit is chromophore. high extinction coefficients fluorescence quantum yields make these attractive candidates for use as labels. Detailed facts importance to specialist readers published ”Supporting Information”. Such documents...

The kinetics of the intramolecular charge-transfer (ICT) reaction 4-(dimethylamino)benzonitrile (DMABN) in polar solvent acetonitrile (MeCN) is investigated by fluorescence quantum yield and picosecond time-correlated single photon counting (SPC) experiments over temperature range from -45 to +75 degrees C, together with femtosecond Sn <-- S1 transient absorption measurements at room temperature. For DMABN MeCN, locally excited (LE) state strongly quenched, an unquenched quenched ratio 290...

The impact of surface treatment and modification on nanobubble nucleation in water has been addressed by a new combination fluorescence lifetime imaging microscopy (FLIM) atomic force (AFM). In this study, rhodamine 6G (Rh6G)-labeled nanobubbles nucleated the ethanol–water exchange were studied differently cleaned borosilicate glass, silanized glass as well self-assembled monolayers transparent gold combined AFM-FLIM. While AFM data confirmed earlier reports nucleation, size, apparent...

Calculations of molecular structures in the electronic ground state S(0) and excited fluorescence energies generally refer to gas phase. This complicates a comparison with experimental data, which often are only available for molecules solution. Therefore, absorption spectra vapor phase presented 1-tert-butyl-6-cyano-1,2,3,4-tetrahydroquinoline (NTC6), 1-methyl-6-cyano-1,2,3,4-tetrahydroquinoline (NMC6), 4-(dimethylamino)benzonitrile (DMABN), 4-(diisopropylamino)benzonitrile (DIABN). NTC6...

The photophysics of N-(4-cyanophenyl)carbazole (NP4CN) was investigated by using absorption and fluorescence spectra, picosecond decays, femtosecond transient absorption. In the nonpolar n-hexane as well in polar solvent acetonitrile (MeCN), a locally excited (LE) state is detected, precursor for intramolecular charge transfer (ICT) state. A LE → ICT reaction time τ2 at 22 °C 0.95 ps ethyl cyanide (EtCN) 0.32 MeCN determined from decay (ESA) maximum around 620 nm. ESA spectrum NP4CN...

The relaxation dynamics of the indoline dye D149, a well-known sensitizer for photoelectrochemical solar cells, have been extensively characterized in various organic solvents by combining results from ultrafast pump-supercontinuum probe (PSCP) spectroscopy, transient UV-pump VIS-probe time-correlated single-photon counting (TCSPC) measurements as well steady-state absorption and fluorescence. In spectra, position maximum shows only weak solvent dependence, whereas fluorescence Stokes shift...

For the electron acceptor/donor molecule N-phenylpyrrole (PP), fast intramolecular charge transfer (ICT) reaction accompanied by dual fluorescence from a locally excited (LE) and an ICT state is investigated in alkyl cyanide solvents as function of temperature. After comparison X-ray crystal structure PP with calculations literature, absorption spectra series over wide polarity range are discussed. strongly depends on solvent starts to appear more polar than diethyl ether. From analysis...

For the double exponential fluorescence decays of locally excited (LE) and intramolecular charge transfer (ICT) states 4-(dimethylamino)benzonitrile (DMABN) in acetonitrile (MeCN) same times tau(1) tau(2) are observed. This means that reversible LE<==>ICT reaction, starting from initially LE state, can be adequately described by a two state mechanism. The most important factor responsible for sometimes experimentally observed differences nanosecond decay time, with tau(1)(LE)<tau(1)(ICT), is...

From X-ray structure analysis, amino twist angles of 90.0° for 2,4-dimethyl-3-(dimethylamino)benzonitrile (mMMD), 82.7° 4-(di-tert-butylamino)benzonitrile (DTABN), and 88.7° 6-cyanobenzoquinuclidine (CBQ) are determined, all considerably larger than the 57.4° 3,5-dimethyl-4-(dimethylamino)benzonitrile (MMD). This large leads to lengthening amino-phenyl bond, 143.5 pm 144.1 144.6 (CBQ), 141.4 (MMD), as compared with 136.5 planar 4-(dimethylamino)benzonitrile (DMABN). As a consequence,...

This study reports on the dependence of temperature-induced changes in properties thin thermoresponsive poly(diethylene glycol) methyl ether methacrylate (PDEGMA) layers end-tethered chains polymer thickness and grafting density. PDEGMA with a dry ellipsometric 5–40 nm were synthesized by surface-initiated atom transfer radical polymerization gold. To assess changes, adsorption bovine serum albumin (BSA) was investigated systematically as function film thickness, temperature, density surface...

There is a growing demand for rapid and sensitive detection approaches pathogenic bacteria that can be applied by non-specialists in non-laboratory field settings. Here, the of typical E. coli enzyme β-glucuronidase using chitosan-based sensing hydrogel-coated paper sensor detailed analysis reaction kinetics, as detected smartphone camera, reported. The chromogenic reporter unit affords an intense blue color two-step reaction, which was analyzed modified Michaelis–Menten approach. This...

With 4-(dimethylamino)benzonitrile (DMABN), 4-(methylamino)benzonitrile (MABN), and 4-aminobenzonitrile (ABN) in an alkane solvent such as n-hexadecane, the fluorescence decay time τ quantum yield Φf strongly decrease with increasing temperature. For DMABN decreases from 3.43 ns at 25 °C to 0.163 284 °C, a simultaneous drop 0.14 0.006. Similar results are obtained for MABN ABN. By measuring τ, Φf, intersystem crossing (ISC) ΦISC of three aminobenzonitriles function temperature...

The five 2,3,5,6-tetrafluoro-4-aminobenzonitriles XABN4F with a dimethyl-amino (DMABN4F), diethyl-amino (DEABN4F), azetidinyl (AZABN4F), methyl-amino (MABN4F) or amino (ABN4F) group undergo ultrafast intramolecular charge transfer (ICT) at room temperature, in the polar solvent acetonitrile (MeCN) as well nonpolar n-hexane. ICT also takes place corresponding non-fluorinated aminobenzonitriles DMABN, DEABN and AZABN MeCN, whereas for these molecules n-hexane only minor (DMABN, DEABN) no...

The intramolecular charge transfer (ICT) reaction of 1-tert-butyl-6-cyano-1,2,3,4-tetrahydroquinoline (NTC6) in n-hexane and acetonitrile (MeCN) is investigated by picosecond fluorescence experiments as a function temperature femtosecond transient absorption measurements at room temperature. NTC6 dual fluorescent from locally excited (LE) an ICT state, with quantum yield ratio Φ'(ICT)/Φ(LE) 0.35 +25 °C 0.67 −95 °C, whereas MeCN mainly emission observed. From the dependence for n-hexane,...

Verzweigt: Steife, aromatische Dendrimere aus 5 bzw. 17 Pyreneinheiten wurden synthetisiert, charakterisiert und mit zwei Modellverbindungen verglichen. Die starre stark verdrillte Struktur ermöglicht eine genaue räumliche Anordnung, bei der jede Einheit ein Chromophor ist. Hohe Extinktionskoeffizienten Fluoreszenzquantenausbeuten machen diesen Dendrimeren attraktive Kandidaten für den Einsatz als Fluoreszenzmarker. Detailed facts of importance to specialist readers are published as...

The combination of styryl dye properties with the acidity and strong photoacidity 2,2'-[(1''-hydroxy-4''-methyl-(E)-2'',6''-phenylene)]-bisquinolizinium enables detection DNA by distinct absorption emission color changes fluorimetric in cells epifluorescence confocal fluorescence microscopy.

Abstract In this review surface nanobubbles, which are presumably gas-filled enclosures found at the solid–liquid interface, introduced and discussed together with key experimental findings that suggest these nanoscale features indeed exist filled gas. The most prominent technique used thus far has been atomic force microscopy (AFM). However, due to its potentially invasive nature, AFM data must be interpreted great care. Owing their curved Laplace internal pressure of nanobubbles exceeds...

Poly(di(ethylene glycol)methyl ether methacrylate) (PDEGMA) brushes, which are known to suppress protein adsorption and prevent cell attachment, reported here possess interesting tunable thermoresponsive behavior, if the brush thickness is reduced or grafting density altered. PDEGMA brushes with a dry ellipsometric of 5 ± 1 nm can be switched from adherent behavior at 37 °C nonadherent 25 °C. This coincides temperature‐dependent irreversible fibronectin phosphate saline buffer proteins...

Upon photoexcitation of 4-(dimethylamino)benzonitrile (DMABN) in the polar solvent acetonitrile (MeCN), a methyl group is subtracted from dimethylamino substituent, producing 4-(methylamino)benzonitrile (MABN). The fluorescence this photoproduct MABN occurs same spectral range as that locally excited (LE) state DMABN. As DMABN undergoes efficient quenching MeCN, leading to decrease LE yield by factor 290 at 25 degrees C, whereas not quenched all, even small amounts strongly increase apparent...