Fluorenone Derivatives Research Articles

Dehydrogenative [4 + 2] Annulation of 1-Indanones with Alkynes Enabled by In-Situ-Generated Nickel Hydride.

A practical and effective nickel-catalyzed dehydrogenative [4 + 2] annulation of 1-indanones with alkynes was reported. In this protocol, nickel-catalyzed desaturation of 1-indanones and nickel hydride catalyzed coupling with alkynes were first incorporated. A cyclopentadiene-type nickel hydride species was generated in situ via β-H elimination, and they subsequently reacted with a wide variety of alkynes to afford various benzo[a]fluorenone derivatives in good yields and regioselectivity.

Multi-stimuli-responsive behaviours of fluorenone-based donor–acceptor–donor triads in solution and supramolecular gel states

The newly developed fluorenone-based donor–acceptor–donor triads formed supramolecular organogels in appropriate solvents. The stimuli-responsive behaviours in solution as well as in supramolecular gels of the fluorenone derivatives were clarified.

Unraveling the substituent group effects on the emission properties of fluorenone derivatives

Elucidating the structure–property relationship is vital for developing organic luminescent materials with excellent properties and performance optimization. Herein, we designed and synthesized three types of fluorenone-based molecules named FO-Ph, FO-Na and FO-An, with similar structures but different sizes of substituent groups (benzene, naphthalene and anthracene). This slight modification resulted in significantly different optical properties of luminogens in dilute solutions and powders. FO-Ph as an aggregation-caused quenching (ACQ) emitter displayed strong emissions in solution; moreover, after the addition of a poor solution, the fluorescence intensity of FO-Ph gradually decreased. On the contrary, FO-Na displayed aggregation-induced emission enhancement properties, and FO-An was non-emissive in solutions but displayed enhanced emission owing to its molecular aggregation, indicating that FO-An comprises an AIE-active molecule. The characterization of the photophysical properties, theoretical calculations and an X-ray single crystal analysis showed that the emission properties of the three compounds could be affected by the size of substituent groups, twisted geometry and molecular packing modes. The three fluorenone luminogens exhibited different force-induced emission enhancement properties. Moreover, FO-Ph can be used as a water detector and showing high sensitivity. This study elucidates the AIE and ACQ phenomena of fluorenone complexes and provides effective ways for developing organic luminescent materials.

Density Functional Theory Study of the Secondorder Nonlinear Optical Properties of Novel Fluorenone Derivatives

Based on the molecular structure of novel fluorenone derivative named FO52, a series of new molecules have been designed by extending its π-conjugated bridge and introducing electron donor or acceptor substituents. The electronic transition and second-order non-linear optical response properties of these fluorenone derivatives were theoretically studied in detail by using the density functional theory computational methods. The results showed that the non-linear optical response of the molecule FO52 can be improved by introducing five-membered heterocycles into its skeleton structure. In addition, the introduction of strong substituents results in significant enhancement of the first hyperpolarizability of molecular nonlinear optical properties. These fluorenone derivatives could be treated as excellent candidates for nonlinear optical materials due to the narrow energy gap of its frontier molecular orbitals, distinct intramolecular charge transfer character and large first hyperpolarizabilities

Fluorenone Decorated RGO Based Electrochemical Sensor for Rapid Detection of Chlorpyrifos in Vegetable and Soil Samples

A novel synthetically accessible electrochemical sensor has been developed for the detection of chlorpyrifos (CPS) at a very minimal level by utilizing a glassy carbon electrode (GCE) modified with RGO functionalized fluorenone derivative (RGO-NS). The structural and morphological aspects of the derived composite were assessed by FTIR, XRD, FESEM, DFT with in-depth electrochemical analysis. The fluorenone appended with distinct functionalities has supported the reversible redox reactions of CPS, thus, boosting the specificity of the sensor. The design of the electrochemical sensors involved functionalization of RGO possessing high adsorption capacity, which has further amplified the electrochemical sensitivity. The sensing response has been credited to the reduction associated with hydrogen ion which on addition of CPS gets quenched due to catalytic reaction between the two. The synergy has resulted in the low detection limit of 8.89 ng ml−1 for CPS along with reliable detection of CPS in soil samples without spiking. The framework has the excellent future prospects in the practical management of pernicious pesticides usually employed in agricultral fields and their residues on food products posing a serious danger to human health.

Rapid Access to Substituted Indenones through Grignard Reaction and Its Application in the Synthesis of Fluorenones Using Ring Closing Metathesis

AbstractAn efficient, one‐step method has been used to access a variety of substituted indenones in a regiospecific manner by Grignard addition to indene‐1,3‐dione. This method provides straightforward access to natural products such as neo‐lignans and isoampelopsin D analogues. Moreover, diallyl indenones have been synthesized and employed as ring‐closing metathesis (RCM) precursors for the facile synthesis of substituted fluorenone derivatives through an RCM‐aromatization sequence.

Self-assembled organic nonlinear optical crystals based on pyridine derived fluorenone

A pair of pyridine based fluorenone derivatives with highly efficient second- and third-order nonlinear optical effects have been synthesized.

A novel pyridinium-functionalized fluorenone compound for neutral aqueous organic redox flow batteries

A novel pyridinium-functionalized fluorenone derivative with high solubility in water and highly reversible electrochemical behavior exhibited decent battery performance for aqueous organic redox flow batteries.

Red‐Light‐Driven CO2Photoreduction into CH4and CO Enabled by Narrow‐Gap Conjugated Microporous Polymers

Herein, selective CO2photoreduction into CH4and CO with red light using conjugated microporous polymers (CMPs) at room temperature is reported. By incorporating electron‐rich pyrene and electron‐deficient fluorenone derivatives in the polymer networks to constructing intramolecular donor–acceptor system, the resulting three polymers show very broad light absorption covered from 350 to 1000 nm, with narrow gaps of 1.61–1.74 eV. In the presence of triethanolamine and 1‐benzyl‐1,4‐dihydronicotinamide as the sacrificial agents, P3 exhibits the best visible‐light reduction activity, with CH4and CO evolution rates of 932.9 and 943.4 μmol h−1 g−1, respectively. Most significantly, under the irradiation of red light (>600 nm), high evolution rates of CH4and CO for P3 are achieved at 293.7 and 282.6 μmol h−1 g−1, as well as nearly 100% reaction selectivity. The better performance of P3 than P1 and P2 can be ascribed to the high absorption toward CO2and improved charge transfer under light irradiation. This work opens great opportunities for designing broadband‐responsive CMPs for solar‐driven photocatalytic conversion.

Self-Assembled Nonlinear Optical Crystals Based on an Asymmetric Fluorenone Derivative

Self-Assembled Nonlinear Optical Crystals Based on an Asymmetric Fluorenone Derivative

Odd-Even Effect on Supramolecular Co-Assemblies: Control over the Two-Dimensional Self-Assemblies of a Fluorenone Derivative with Asymmetrically Substituted Alkyl Chains.

The precise control of two-dimensional supramolecular co-assemblies presents a research topic related to advance nanotechnology. Here, we report a scanning tunneling microscopy (STM) study of the mixture behavior of three fluorenone derivatives at the liquid-solid interface. The target molecule is F-C12C13 whose structure bears asymmetrical alkyls, whereas the regulating molecules, either F-C12C12 or F-C13C13, are structurally symmetric. By STM imaging of systematic mixtures with various volumes among the sample solutions, we found that the mixing ratio mainly determined the binary outcomes. Compared with F-C12C12, F-C13C13 shows a stronger ability to dominate the patterning, explained by the larger binding and adsorption energies calculated by the force field simulations. Moreover, the odd-even effect exists in the system. Overall, we acquired knowledge about the regulating ability of bi-component supramolecular assembling, especially for structurally asymmetric molecular systems.

Scanning Tunneling Microscopy and Computational Simulation Studies of a Fluorenone-Based Organic Optoelectronic Material

Scanning tunneling microscopy (STM) and computational simulation are utilized to systematically study an organic molecule, namely, a fluorenone derivative of 2-tridecyloxy-7-tetradecyloxy-9-fluoren...

A Triad Fluorenone Derivative Bearing Two Imidazole Groups That Switches between Three States by Base and Acid Stimuli

2,7-Bis(2-phenyl-1H-imidazol-4-yl)fluorenone (BPIFO) was synthesized as a new fluorenone derivative bearing two imidazole moieties, and it exhibited remarkable and reversible changes in photo physi...

An investigation of broadband optical nonlinear absorption and transient nonlinear refraction in a fluorenone-based compound

A novel fluorenone derivative, FO52, is designed and synthesized. The fluorenone group is introduced to provide the central π-conjugated system in the molecule and triphenylamine is substituted at both sides. Intramolecular Charge Transfer (ICT) from the terminal groups to the molecular center is confirmed via DFT calculations. Ultrafast optical nonlinearities are investigated via Z-scan and transient absorption spectroscopy (TAS) studies with a 190 fs laser. Reverse saturable absorption, two-photon induced excited-state absorption, and pure two-photon absorption are observed at 532 nm, 650 nm, and 800 nm, respectively. The different mechanisms at these wavelengths are discussed and interpreted with assistance from the results from TAS. Furthermore, strong excited-state refraction and ultrafast negative refraction from the bound electron response are resolved and discussed in phase object pump probe (POPP) experiments. The results suggest that the ICT-enhanced optical nonlinearities provide FO52 with strong optical limiting capabilities at visible wavelengths and ultrafast refraction with tiny attenuation in the near infrared region. The combination of these properties in one compound could be attractive for applications like laser protection and low-loss all-optical switching.

Solvatochromism and excited-state characteristics of fluorenone-1-carboxylic acid

The solvatochromism of the fluorenone derivative 9-fluorenone-1-carboxylic acid (9F1C) was examined in binary cyclohexane-tetrahydrofuran mixtures, along with a theoretical investigation of possible excited state decay pathways. This fluorenone derivative differs from many previously investigated derivatives in that it possesses an electron withdrawing substituent and possibly undergoes intramolecular hydrogen bonding and proton transfer. A conventional Lippert-Mataga analysis was applied to the measured steady-state absorption and emission spectra to estimate the dipole moment difference between ground and emitting excited states. The estimated difference of ~2.8 D was found to be slightly larger than the average value of previously estimated differences for unsubstituted fluorenone (~2.4 D). The 9F1C derivative also differed from unsubstituted fluorenone in that fluorescence emission decreased, rather than increased, with increasing solvent polarity. Interpreting the possible cause of this difference prompted time-dependent density functional theory (TD-DFT) calculations of the relative energies of non-hydrogen bonded and intra-molecular hydrogen bonded excited states. These calculations suggested that an explanation for the decrease in emission for non-hydrogen bonded species could be enhancement of an intersystem-crossing (ISC) pathway. However, these same calculations suggested this explanation could not account for possible decreased emission from intra-molecular hydrogen-bonded species.

Synthesis and Characterization of Fluorenone-Based Donor-Acceptor Small Molecule Organic Semiconductors for Organic Field-Effect Transistors

In this study, a series of new fluorenone-based small molecules were synthesized and characterized as organic semiconductors for organic field-effect transistors. Thermal, optical, and electrochemical properties of the new compounds were characterized. Furthermore, thin films of the developed compounds were employed as organic semiconductors, and vacuum-deposited film of fluorenone derivative with alkylated double thiophene exhibited p-channel device characteristics with hole mobility as high as 0.02 cm2/Vs and current on/off ratio of 107. In addition, surface morphology and microstructure of vacuum deposited films were analyzed and correlated with the electrical characteristics.

Metal-free [3+3] benzannulation of 1-indanylidene-malononitrile with Morita-Baylis-Hillman carbonates: direct access to functionalized fluorene and fluorenone derivatives.

An efficient [3+3] benzannulation of Morita-Baylis-Hillman carbonates with 1-indanylidenemalononitrile was achieved under metal-free reaction conditions selectively delivering a wide range of functional multi-substituted fluorene or fluorenone compounds in high yields, respectively (up to 86% yield). Moreover, experiments and quantum chemical calculations were also performed to study the mechanism of the transformation.

Synthesis of Anthraquinones by Iridium-Catalyzed [2 + 2 + 2] Cycloaddition of a 1,2-Bis(propiolyl)benzene Derivative with Alkynes

[2 + 2 + 2] cycloaddition of a 1,2-bis(propiolyl)benzene derivative with terminal and internal alkynes takes place in the presence of [Ir(cod)Cl]2 (cod = 1,5-cyclooctadiene) combined with bis(diphenylphosphino)ethane (DPPE) to give anthraquinones in 42% to 93% yields with a simple experimental procedure. A fluorenone derivative can also be synthesized by iridium-catalyzed [2 + 2 + 2] cycloaddition of a benzene-linked ketodiyne with an internal alkyne to give a 94% yield.

Robust thermoelastic microactuator based on an organic molecular crystal

Mechanically responsive molecular crystals that reversibly change shape triggered by external stimuli are invaluable for the design of actuators for soft robotics, artificial muscles and microfluidic devices. However, their strong deformations usually lead to their destruction. We report a fluorenone derivative (4-DBpFO) showing a strong shear deformation upon heating due to a structural phase transition which is reproducible after more than hundred heating/cooling cycles. Molecular dynamic simulations show that the transition occurs through a nucleation-and-growth mechanism, triggered by thermally induced rotations of the phenyl rings, leading to a rearrangement of the molecular configuration. The applicability as actuator is demonstrated by displacing a micron-sized glass bead over a large distance, delivering a kinetic energy of more than 65 pJ, corresponding to a work density of 270 J kg−1. This material can serve as a prototype structure to direct the development of new types of robust molecular actuators.

Tailoring of the self-assembled structures and optical waveguide behaviour of arylaminofluorenone derivatives

In this work, the fluorenone molecule was symmetrically difunctionalised in the 3,6-positions with four different arylamine moieties. Using slow evaporation, the four fluorenone derivatives (FO1-4) exhibit good ability to arrange into microstructures in the solid state. The electronic and steric effects of arylamine substituents influence both optical features and aggregation processes, as evidenced by photophysical and XRD characterization. SEM investigations have shown that the four FO1-4 derivatives arrange in four different microstructures. More specifically, the self-assembled 1D microribbon – shaped structure of FO1 exhibited an excellent optical loss coefficient (α) as low as 0.006 dBμm−1, suggesting a potential use of these materials in the field of optical waveguide.