Browse
Submit Data
Databases
API
Help

Dataset Information

24 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Selective formation of twisted intramolecular charge transfer and excimer emissions on 2,7-bis(4-diethylaminophenyl)-fluorenone by choice of solvent.

ABSTRACT: We designed and synthesized a donor-acceptor-donor dye consisting of a 2,7-disubstituted fluorenone with diethylaminophenyl moieties present as strong electron donating groups. Switching between twisted intramolecular charge transfer (TICT) emission and excimer emission was achieved, with no ground state changes, by simply changing the solvent used. In a nonpolar solvent, excimer emission was observed; with increasing polarity, the emission gradually disappeared, and the TICT emission appeared.

SUBMITTER: Shigeta M

PROVIDER: S-EPMC6268939 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

Carborane-Induced Excimer Emission of Severely Twisted Bis-o-Carboranyl Chrysene.

Project description:The synthesis of a highly twisted chrysene derivative incorporating two electron deficient o-carboranyl groups is reported. The molecule exhibits a complex, excitation-dependent photoluminescence, including aggregation-induced emission (AIE) with good quantum efficiency and an exceptionally long singlet excited state lifetime. Through a combination of detailed optical studies and theoretical calculations, the excited state species are identified, including an unusual excimer induced by the presence of o-carborane. This is the first time that o-carborane has been shown to induce excimer formation ab initio, as well as the first observation of excimer emission by a chrysene-based small molecule in solution. Bis-o-carboranyl chrysene is thus an initial member of a new family of o-carboranyl phenacenes exhibiting a novel architecture for highly-efficient multi-luminescent fluorophores.

| S-EPMC6099267 | biostudies-literature

Twisted Intramolecular Charge Transfer State of a "Push-Pull" Emitter.

Project description:The excited state Raman spectra of 4-dicyanomethylene-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran (DCM) in the locally-excited (LE) and the intramolecular charge transfer (ICT) states have been separately measured by time-resolved stimulated Raman spectroscopy. In a polar dimethylsulfoxide solution, the ultrafast ICT of DCM with a time constant of 1.0 ps was observed in addition to the vibrational relaxation in the ICT state of 4-7 ps. On the other hand, the energy of the ICT state of DCM becomes higher than that of the LE state in a less polar chloroform solution, where the initially-photoexcited ICT state with the LE state shows the ultrafast internal conversion to the LE state with a time constant of 300 fs. The excited-state Raman spectra of the LE and ICT state of DCM showed several major vibrational modes of DCM in the LE and ICT conformer states coexisting in the excited state. Comparing to the time-dependent density functional theory simulations and the experimental results of similar push-pull type molecules, a twisted geometry of the dimethylamino group is suggested for the structure of DCM in the S1/ICT state.

| S-EPMC7662227 | biostudies-literature

Boosting Circularly Polarized Luminescence of Organic Conjugated Systems via Twisted Intramolecular Charge Transfer.

Project description:Realizing a high luminescence dissymmetry factor (g lum) is a paramount yet challenging issue in the research field of circularly polarized luminescence (CPL). Here, we reported a novel set of organic conjugated systems with twisted intramolecular charge transfer (TICT) characteristics based on conjugated o-carborane-binaphthyl dyads composing of binaphthyl units as chiral electron donors and o-carborane units as achiral electron acceptors, demonstrating intense CPL with large g lum values. Interestingly, single-crystalline o-1 exhibited a high-level brightness and a large g lum factor as high as +0.13, whereas single-crystalline o-2 processed a relatively low brightness with a decreased g lum value to -0.04. The significant diversity of CPL-active properties was triggered by the selective introduction of o-carborane units onto the binaphthyl units. Benefiting from the large magnetic dipole transition moments in TICT states, the CPL activity of TICT o-carborane-based materials exhibited amplified circular polarization. This study provides an efficient molecular engineering strategy for the rational design and development of highly efficient CPL-active materials.

| S-EPMC7193308 | biostudies-literature

Ultrafast Excimer Formation and Solvent Controlled Symmetry Breaking Charge Separation in the Excitonically Coupled Subphthalocyanine Dimer.

Project description:Knowledge of the factors controlling excited state dynamics in excitonically coupled dimers and higher aggregates is critical for understanding natural and artificial solar energy conversion. In this work, we report ultrafast solvent polarity dependent excited state dynamics of the structurally well-defined subphthalocyanine dimer, μ-OSubPc2 . Stationary electronic spectra demonstrate strong exciton coupling in μ-OSubPc2 . Femtosecond transient absorption measurements reveal ultrafast excimer formation from the initially excited exciton, mediated by intramolecular structural evolution. In polar solvents the excimer state decays directly through symmetry breaking charge transfer to form a charge separated state. Charge separation occurs under control of solvent orientational relaxation.

| S-EPMC8251754 | biostudies-literature

Twisted Intramolecular Charge Transfer (TICT) Controlled by Dimerization: An Overlooked Piece of the TICT Puzzle.

Project description:Organic dyes have shown high efficiencies in solar cells, which is mainly attributed to the push-pull strategy present in such dyes upon attaching to the semiconductor surfaces. We deeply studied the fundamental photophysical properties of cyanoacrylic dyes, mostly the L1 dye, and found unique emission properties that depend on many factors such as the solvent polarity and the concentration of the dye and could present a complete emission picture about this family of dyes. The L1 dye shows an intramolecular charge transfer (ICT) emission state at low concentrations (approximately nanomolar scale) and shows a twisted intramolecular charge transfer (TICT) emission state in specific solvents upon increasing the concentration to the micromolar scale. Moreover, the associated emission lifetimes of the ICT and TICT states of the L1 dye depend on solvent basicity, highlighting the role of hydrogen bond formation on controlling such states. Density functional theory calculations are performed to gain insight into the photophysical properties of the dye and revealed that H-bonding between the carboxylic groups triggers the dimerization at low concentrations. Using femtosecond transient absorption, we assigned the rate of TICT formation to be in the range (160-650 fs)-1, depending on the size of the studied cyanoacrylic dye. Therefore, we add herein a new dimension for controlling the formation of the TICT state, in addition to the solvent polarity and acceptor strength parameters. These findings are not limited to the studied dyes, and we expect that numerous organic carboxylic acids dyes show similar properties.

| S-EPMC8154600 | biostudies-literature

Direct observation and control of ultrafast photoinduced twisted intramolecular charge transfer (TICT) in triphenyl-methane dyes.

Project description:Femtosecond time-resolved infrared spectroscopy was employed to study intramolecular charge transfer in triphenylmethane dyes, including malachite green (MG), malachite green carbinol base (MGCB), and leucomalachite green (LMG). A local excited state (LE) and a twisted intramolecular charge-transfer (TICT) state have been observed directly in MG. Furthermore, solvent-controlled TICT measurements in a series of linear alcohols indicate that the transition time (4-11 ps) from LE to TICT is strongly dependent on alcohol viscosity, which is due to rotational hindrance of dimethylaniline in high-viscosity solvents. For LMG, no TICT is observed due to steric hindrance caused by the sp(3)-hybridized central carbon atom. However, for MGCB, TICT is rescued by the addition of the electron-donating hydroxyl group to the bridge. These results for MG and its analogues provide new insight regarding the dynamics and mechanism of twisted intramolecular charge transfer (TICT) in triphenylmethane dyes.

| S-EPMC3475756 | biostudies-literature

Photophysical Properties of an Azine-Linked Pyrene-Cinnamaldehyde Hybrid: Evidence of Solvent-Dependent Charge-Transfer-Coupled Excimer Emission.

Project description:We report the photophysical properties of a synthetic asymmetric azine-based compound (17Z,18E)-4'-((E)-3-phenylallylidene)-1'-(dimethylamino)-1-((pyren-8-yl)methylene)hydrazine (PYNC). The molecule PYNC shows an appreciable red shift in the emission maximum in a wide range of solvents. In water, PYNC shows the characteristic feature of excimer formation exclusively. However, in all other solvents, the excimer band is present alongside the charge transfer emission band. The assignment of charge transfer and excimer bands has been established by various steady-state emission spectral data. PYNC, owing to this novel excimer-coupled charge transfer phenomenon, can be a potential probe for studying various supramolecular assemblies of biological interest.

| S-EPMC6648816 | biostudies-literature

Fluorescent Polystyrene Films for the Detection of Volatile Organic Compounds Using the Twisted Intramolecular Charge Transfer Mechanism.

Project description:Thin films of styrene copolymers containing fluorescent molecular rotors were demonstrated to be strongly sensitive to volatile organic compounds (VOCs). Styrene copolymers of 2-[4-vinyl(1,1'-biphenyl)-4'-yl]-cyanovinyljulolidine (JCBF) were prepared with different P(STY-co-JCBF)(m) compositions (m% = 0.10-1.00) and molecular weights of about 12,000 g/mol. Methanol solutions of JCBF were not emissive due to the formation of the typical twisted intramolecular charge transfer (TICT) state at low viscosity regime, which formation was effectively hampered by adding progressive amounts of glycerol. The sensing performances of the spin-coated copolymer films (thickness of about 4 µm) demonstrated significant vapochromism when exposed to VOCs characterized by high vapour pressure and favourable interaction with the polymer matrix such as THF, CHCl? and CH?Cl?. The vapochromic response was also reversible and reproducible after successive exposure cycles, whereas the fluorescence variation scaled linearly with VOC concentration, thus suggesting future applications as VOC optical sensors.

| S-EPMC6152380 | biostudies-literature

Temperature-Controlled Locally Excited and Twisted Intramolecular Charge-Transfer State-Dependent Fluorescence Switching in Triphenylamine-Benzothiazole Derivatives.

Project description:Triphenylamine-benzothiazole derivatives, N-(4-(benzo[d]thiazol-2-yl)phenyl)-N-phenylbenzenamine (1), N-(4-(benzo[d]thiazol-2-yl)-3-methoxyphenyl)-N-phenylbenzenamine (2), and 2-(benzo[d]thiazol-2-yl)-5-(diphenylamino)phenol (3), showed unusual temperature-controlled locally excited (LE) and twisted intramolecular charge-transfer (TICT) state fluorescence switching in polar solvents. The detailed photophysical studies (absorption, fluorescence, lifetime, and quantum yield) in various solvents confirmed polarity-dependent LE and TICT state formation and fluorescence tuning. 1 and 2 exhibited strong fluorescence with short lifetime in nonpolar solvents compared to polar solvents. 1, 2, and 3 in dimethylformamide (DMF) at room temperature showed low-energy weak TICT state fluorescence, whereas high-energy strong LE state fluorescence was observed at -196 °C. Interestingly, further increasing the temperature from 20 to 100 °C, the DMF solution of 1 and 2 exhibited rare fluorescence enhancement with a slight blue shift of λmax via activating more vibrational bands of the TICT state. Thus, 1 and 2 showed weak TICT state fluorescence at room temperature, strong LE state fluorescence at -196 °C, and activation of TICT state at 100 °C. Moreover, molecular conformation and aggregation in the solid state influenced strongly on the fluorescence properties of 1, 2, and 3. Solid-state fluorescence and pH-responsive imidazole nitrogen have been exploited for demonstrating halochromism-induced fluorescence switching. Computational studies provided further insights into the fluorescence tuning and switching. The present studies provide understanding and opportunity to make use of D-A organic molecules in the LE and TICT states for achieving fluorescence switching and tuning.

| S-EPMC6648163 | biostudies-literature

2,7-Dimethyl-2,7-diazo-niapyrene bis-(hexa-fluoro-phosphate).

Project description:In the title compound, C(16)H(14)N(2) (2+)·2PF(6) (-), the 2,7-dimethyl-2,7-diaza-pyrenium (DM-diaz) cation lies on a crystallographic twofold rotation axes. The diaz groups are nearly coplanar, with a maximum deviation of 0.008?(3)?Å. In the crystal, mol-ecules are linked into a two-dimensional lamellar framework parallel to (104) through weak C-H?F inter-actions.

| S-EPMC3051768 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data