Synthesis, structural and spectral properties of diarylamino-functionalized pyrene derivatives via Buchwald–Hartwig amination reaction

Bromopyrene Symphony: Synthesis and Characterisation of Isomeric Derivatives at Non-K Region and Nodal Positions for Diverse Functionalisation Strategies

Pyrene, a renowned aromatic hydrocarbon, continues to captivate researchers due to its versatile properties and potential applications across various scientific domains. Among its derivatives, bromopyrenes stand out for their significance in synthetic chemistry, materials science, and environmental studies. The strategic functionalisation of pyrene at non-K region and nodal positions is crucial for expanding its utility, allowing for diverse functionalisation strategies. Bromo-substituted precursors serve as vital intermediates in synthetic routes; however, the substitution pattern of bromoderivatives significantly impacts their subsequent functionalisation and properties, posing challenges in synthesis and purification. Understanding the distinct electronic structure of pyrene is pivotal, dictating the preferential electrophilic aromatic substitution reactions at specific positions. Despite the wealth of literature, contradictions and complexities persist in synthesising suitably substituted bromopyrenes due to the unpredictable nature of substitution reactions. Building upon historical precedents, this study provides a comprehensive overview of bromine introduction in pyrene derivatives, offering optimised synthesis conditions based on laboratory research. Specifically, the synthesis of mono-, di-, tri-, and tetrabromopyrene isomers at non-K positions (1-, 3-, 6-, 8-) and nodal positions (2-, 7-) is systematically explored. By elucidating efficient synthetic methodologies and reaction conditions, this research contributes to advancing the synthesis and functionalisation strategies of pyrene derivatives, unlocking new possibilities for their utilisation in various fields.

Reductive O-triflylation of naphthalene diimide: access to alkyne- and amine-functionalized 2,7-diazapyrenes

A reductive one-pot triflylation and silylation of naphthalene diimide is presented. Post-functionalization of the 1,3,6,8-tetratriflato key compound leads to so far non-accessible UHV processable tetraalkynyl and tetraaminyl 2,7-diazapyrenes.

Synthesis, Photophysical and Electronic Properties of Mono-, Di-, and Tri-Amino-Substituted Ortho-Perylenes, and Comparison to the Tetra-Substituted Derivative

We synthesized a series of new mono-, di-, tri- and tetra-substituted perylene derivatives with strong bis(para-methoxyphenyl)amine (DPA) donors at the uncommon 2,5,8,11-positions. The properties of our new donor-substituted perylenes were studied in detail to establish a structure-property relationship. Interesting trends and unusual properties are observed for this series of new perylene derivatives, such as a decreasing charge transfer (CT) character with increasing number of DPA moieties and individual reversible oxidations for each DPA moiety. Thus, (DPA)-Per possesses one reversible oxidation while (DPA)4 -Per has four. The mono- and di-substituted derivatives display unusually large Stokes shifts not previously reported for perylenes. Furthermore, transient absorption measurements of the new derivatives reveal an excited state with lifetimes of several hundred microseconds, which sensitizes singlet oxygen with quantum yields of up to 0.83.

Functionalization of Pyrene To Prepare Luminescent Materials-Typical Examples of Synthetic Methodology

Pyrene-based π-conjugated materials are considered to be an ideal organic electro-luminescence material for application in semiconductor devices, such as organic light-emitting diodes (OLEDs), organic field-effect transistors (OFETs) and organic photovoltaics (OPVs), and so forth. However, the great drawback of employing pyrene as an organic luminescence material is the formation of excimer emission, which quenches the efficiency at high concentration or in the solid-state. Thus, in order to obtain highly efficient optical devices, scientists have devoted much effort to tuning the structure of pyrene derivatives in order to realize exploitable properties by employing two strategies, 1) introducing a variety of moieties at the pyrene core, and 2) exploring effective and convenient synthetic strategies to functionalize the pyrene core. Over the past decades, our group has mainly focused on synthetic methodologies for functionalization of the pyrene core; we have found that formylation/acetylation or bromination of pyrene can selectly lead to functionalization at K-region by Lewis acid catalysis. Herein, this Minireview highlights the direct synthetic approaches (such as formylation, bromination, oxidation, and de-tert-butylation reactions, etc.) to functionalize the pyrene in order to advance research on luminescent materials for organic electronic applications. Further, this article demonstrates that the future direction of pyrene chemistry is asymmetric functionalization of pyrene for organic semiconductor applications and highlights some of the classical asymmetric pyrenes, as well as the latest breakthroughs. In addition, the photophysical properties of pyrene-based molecules are briefly reviewed. To give a current overview of the development of pyrene chemistry, the review selectively covers some of the latest reports and concepts from the period covering late 2011 to the present day.

A cross-coupling-annulation cascade from peri-dibromonaphthalimide to pseudo-rylene bisimides

A novel synthetic strategy based on cascade C–C cross-coupling and C–H arylation afforded structurally unique polycyclic aromatics with desirable optical and redox properties.

Putting corannulene in its place. Reactivity studies comparing corannulene with other aromatic hydrocarbons

Reactivity studies have been used to order a series of polycyclic aromatic hydrocarbons, demonstrating that the curved species corannulene has comparable reactivity to triphenylene.

Deep-blue emitting pyrene–benzimidazole conjugates for solution processed organic light-emitting diodes

Pyrene–benzimidazole hybrids have been demonstrated as deep blue emitters for organic light-emitting diodes.

Synthesis and characterization of ultraviolet light-emitting organic acids

Three ultraviolet light-emitting organic acids of 3,3'-(4-phenyl-4H-1,2,4-triazole-3,5-diyl)dibenzoic acid (Tz-1), 4,4',4″-(4H-1,2,4-triazole-3,4,5-triyl)tribenzoic acid (Tz-2), and 4,4'-(4-(4'-carboxy-[1,1'-biphenyl]-4-yl)-4H-1,2,4-triazole-3,5-diyl)dibenzoic acid (Tz-3) were successfully synthesized and fully characterized by the (1)H NMR, the IR absorption spectra, and the X-ray single crystal diffraction. It was found that Tz-1, Tz-2, and Tz-3 could give out the ultraviolet photoluminescent spectra centered at 369 nm, 365 nm and 350 nm, respectively. The luminescence quantum yields of Tz-1 and Tz-2 were measured to be 0.20 and 0.14, respectively. Additionally, the density functional theory (DFT) and the time-dependent DFT calculations were also carried out for Tz-1, Tz-2, and Tz-3.