521960-80-5

Upstream product

• 2523-42-4 2-iodo-9H-fluorene 
• 302554-80-9 2-bromo-9,9-dioctyl-9H-fluorene 
• 1066-54-2 trimethylsilylacetylene 

Relevant academic research and scientific papers

Strong Dipolar Effects on an Octupolar Luminiscent Chromophore: Implications on their Linear and Nonlinear Optical Properties

Design parameters derived from structure-property relationships play a very important role in the development of efficient molecular-based functional materials with optical properties. Here, we report on the linear and nonlinear optical properties of a fluorene-derived dipolar system (DS) and its octupolar analogue (OS), in which donor and acceptor groups are connected by a phenylacetylene linkage, as a strategy to increase the number of delocalized electrons in the π-conjugated system. The optical nonlinear response was analyzed in detail by experimental and theoretical methods, showing that, in the octupolar system OS, the dipolar effects induced a strong two-photon absorption process whose magnitude is as large as 2210 GM at infrared wavelengths. Solvatochromism studies were implemented to obtain further insight on the charge transfer process. We found that the triple bond plays a fundamental role in the linear and nonlinear optical responses. The strong solvatochromism behavior in DS and OS was analyzed by using four empirical solvent scales, namely Lippert-Mataga, Kamlet-Taft, Catalán, and the recently proposed scale of Laurence et al., finding consistent results of strong solvent polarizability and viscosity dependence. Finally, the role of the acceptor groups was further studied by synthesizing the analogous compound 2DS, having no acceptor group.

APEX Strategy Represented by Diels–Alder Cycloadditions—New Opportunities for the Syntheses of Functionalised PAHs

Diels–Alder cycloaddition of various dienophiles to the bay region of polycyclic aromatic hydrocarbons (PAHs) is a particularly effective and useful tool for the modification of the structure of PAHs and thereby their final properties. The Diels–Alder cycloaddition belongs to the single-step annulative π-extension (APEX) reactions and represents the maximum in synthetic efficiency for the constructions of π-extended PAHs including functionalised ones, nanographenes, and π-extended fused heteroarenes. Herein we report new applications of the APEX strategy for the synthesis of derivatives of 1,2-diarylbenzo[ghi]perylene, 1,2-diarylbenzo[ghi]perylenebisimide and 1,2-disubstituted-benzo[j]coronene. Namely, the so far unknown cycloaddition of 1,2-diarylacetylenes into the perylene and perylenebisimide bay regions was used. 1,2-Disubstituted-benzo[j]coronenes were obtained via cycloaddition of benzyne into 1,2-diarylbenzo[ghi]perylenes by using a new highly effective system for benzyne generation and/or high pressure conditions. Moreover, we report an unprecedented Diels–Alder cycloaddition–cycloaromatisation domino-type reaction between 1,4-(9,9-dialkylfluoren-3-yl)-1,3-butadiynes and perylene. The obtained diaryl-substituted core-extended PAHs were characterised by DFT calculation as well as electrochemical and spectroscopic measurements.

Designed Synthesis and Crystallization of Isomorphic Molecular Gyroscopes with Cell-like Bilayer Self-Assemblies

Two molecular rotors featuring pyridine and fluorobenzene rings as polar rotators and 9-octylfluorenyl stators were synthesized. Their crystal structures were established through SXRD techniques, crystallizing in the monoclinic chiral P21 space group. The supramolecular assemblies of both isomorphs showed an orientation of static dipoles through the crystal lattice and the formation of intriguing 2D layers that resemble cell membranes, a typical example of an amphidynamic system. Small activation energies and the modulation of the first-order hyperpolarizabilities of these compounds as a function of rotational dynamics were revealed through DFT computations at the CAM-B3LYP/M06-2X/cc-pVDZ level of theory and correlated with a potential use of these materials as photonic switches.

Synthesis and photophysical properties of new perylene bisimide derivatives for application as emitting materials in OLEDs

Three novel perylene diimide derivatives with bulky aromatic moieties (fluorene, carbazolyl-fluorene, and anthracyl-fluorene) connected via triple bonds with perylene core were successfully designed and synthesized. The chemical structure of prepared compounds was confirmed by 1H and 13C NMR and mass spectrometry. Their optimized ground-state geometry and frontier molecular orbitals were theoretically estimated based on density functional theory. The compounds undergo the reversible electrochemical reduction process and exhibit very low energy band gaps (1.56–1.98 eV) being promising for electronic applications. They also display excellent solubility, high thermal stability and luminescence in solution and in the solid state as a film in the red spectral region. The highest photoluminescence quantum yield (79% in solution and 28% in the film) was found for perylene diimide bearing fluorene unit. All molecules showed the ability for light emission under an applied voltage. The fabricated diodes with structure ITO/PEDOT:PSS/compound/Al exhibited electroluminescence with maximum emission band located between 685 and 732 nm. The most intense electroluminescence, which was additionally plasmonically enhanced by incorporating silver nanowires, was observed for the device based on molecules with anthracene structure.

Synthesis, chemicaleoptical characterization and solvent interaction effect of novel fluorene-chromophores with DeAeD structure

The synthesis, chemical characterization and optical studies of three novel fluorene derivatives is reported. These compounds comprise a DeAeD architecture with fluorene moieties as donor groups and fluorenone or benzothiadiazole derivatives as acceptor groups. Theoretical analysis confirmed the existence and the nature of two principal electronic transitions (π → π* and intramolecular charge transfer). Spectroscopic studies in solution revealed that the intramolecular charge transfer character, and in turn the two-photon activity i.e., the fluorescence induced by two-photon absorption, is strongly affected by solvent polarity. The influence of specific solventesolute interactions over emission properties was also studied through LipperteMataga plot. Evaluation of the two-photon absorption cross-sections, gave a maximum value of 105 GM (1 GM = 10-50 cm4 s) in toluene and a minimum value of 23 GM in THF solutions at 750 nm for the fluorenone derivative, a molecule with poor intramolecular charge transfer character and thus weak two-photon absorption; however the benzothiadiazole derivative, with stronger intramolecular charge transfer transition, produced a maximum value of 1000 GM in THF and a minimum value of 236 GM in methanol. Fluorescence quantum efficiency of these compounds was also affected by the medium, with fluorescence quenching in protic solvents such as methanol due to specific solvent interactions (i.e., hydrogen-bonding). Nevertheless, in a more polar medium such as water, nanoaggregates synthesized from the benzothiadiazole derivative exhibited good two-photon activity, i.e., w500 GM and fluorescence quantum efficiency of 0.83. Furthermore, these nanoaggregates exhibited more resistance against photodegradation processes than any of the organic solutions tested.

Tuning the photophysical properties of N∧N Pt(II) bisacetylide complexes with fluorene moiety and its applications for triplet-triplet- annihilation based upconversion

Fluorene-containing aryl acetylide ligands were used to prepare N∧N Pt(ii) bisacetylide complexes, where aryl substituents on the fluorene are phenyl (Pt-1), naphthal (Pt-2), anthranyl (Pt-3), pyrenyl (Pt-4), 4-diphenylaminophenyl (Pt-5) and 9,9-di-n-octylfluorene (Pt-6) (where N∧N ligand = 4,4′-di-tert-butyl-2,2′-bipyridine, dbbpy). All the complexes show room temperature (RT) phosphorescence. The emissive T1 excited states of Pt-1, Pt-5 and Pt-6 were assigned as metal-to-ligand-charge- transfer state (3MLCT), whereas for Pt-2, Pt-3 and Pt-4, the emissive T1 excited states were identified as the intraligand state ( 3IL), based on steady state emission spectra, the lifetime of the T1 state, emission spectra at 77 K, spin density analysis and the time-resolved transient absorption spectroscopy. Exceptionally long lived T 1 excited state was observed for Pt-3 (τ = 66.7 μs) and Pt-4 (τ = 54.7 μs), compared to a model complex dbbpy Pt(ii) Bisphenylacetylide (τ = 1.25 μs). RT phosphorescence of anthracene was observed at 780 nm with Pt-3. The critical role of the fluorene is to move the absorption of the complexes to the red-end of the spectra, but at the same time, without compromising the energy level of the T1 state of the complexes. The advantage of this unique spectral tuning effect and the long-lived T1 excited states of Pt-4 was demonstrated by the enhanced performance of the complexes as triplet sensitizers for triplet-triplet annihilation (TTA) based upconversion; an upconversion quantum yield (ΦUC) up to 22.4% was observed with Pt-4 as the sensitizer. Other complexes described herein show negligible upconversion. The high upconversion quantum yield of Pt-4 is attributed to its intense absorption of visible light and long-lived T1 excited state. Based on the result of Pt-4, we propose that weakly phosphorescent, or non-phosphorescent transition metal complexes can be used as triplet sensitizers for TTA upconversion, compared to the phosphorescent triplet sensitizers currently used for TTA upconversion. Our results will be useful for the design of transition metal complexes to enhance the light-absorption and thereafter the cascade photophysical processes, without decreasing the T1 excited state energy levels, which are important for the application of the complexes as triplet sensitizers in various photophysical processes. The Royal Society of Chemistry 2012.

ETHYNYL CONTAINING ELECTRON TRANSPORT AGENTS AND THEIR USE IN ORGANIC LUMINESCENT DEVICES

Compounds of formula (I), compositions, organic electronic devices, and methods for preparing organic electronic devices are described. The compounds of the invention contain at least two carbon-carbon triple bonds and a heteroaromatic ring E having at least one -C=N unit. The compounds can be used as electron transport agents in organic electronic devices such as organic electroluminescent devices.

Synthesis, characterisation and optical spectroscopy of diynes and poly-ynes containing derivatised fluorenes in the backbone

A series of trimethylsilyl-protected and terminal mono- and bis-alkynes based on 9,9-dioctylfluorene, 2-(trimethylsilylethynyl)-9,9-dioctylfluorene la, 2-ethynyl-9,9-dioctylfluorene 1b, 2,7-bis(trimethylsilylethynyl)-9,9-dioctylfluorene 2a, 2,7-bis(ethynyl)-9,9-dioctylfluorene 2b, have been synthesised. Reaction of trans-[(PnBu3)2PtCl2] with 2 equivalents of the terminal ethyne 1b yields the mononuclear platinum(II) diyne 3, reaction of trans-[(Ph)(Et3P)2PtCl] with 0.5 equivalents of the diterminal ethyne 2b gives the dinuclear platinum(II) diyne 4 while 1 : 1 reaction between trans-[(PnBU3) 2PtCl2] and 2b gives the platinum(II) poly-yne 5. Treatment of 2,5-dioctyloxy-1,4-diiodobenzene with 1b in 1 : 2 stoichiometry produces the organic di-yne 6 while 1 : 1 reaction between 2,5-dioctyloxy-1,4-diiodobenzene and 2b, 2,7-bis(ethynyl)fluorene or 2,7-bis(ethynyl)fluoren-9-one produces the organic co-poly-ynes 7-9. All the new materials have been characterised by analytical and spectroscopic methods and the single crystal X-ray structures of 2a and 3 have been determined. The diynes and poly-ynes are soluble in organic solvents and are readily cast into thin films. Optical spectroscopic measurements reveal that the attachment of octyl side-chains on the fluorenyl spacer reduces inter-chain interaction in the poly-ynes while a fluorenonyl spacer creates a donor-acceptor interaction along the rigid backbone of the organometallic poly-ynes and organic co-poly-ynes. The Royal Society of Chemistry 2003.