Photochemically assisted synthesis of phenacenes fluorinated at the terminal benzene rings and their electronic spectra

• Yuuki Ishii,
• Minoru Yamaji,
• Fumito Tani,
• Kenta Goto,
• Yoshihiro Kubozono and
• Hideki Okamoto

Beilstein J. Org. Chem. 2025, 21, 670–679, doi:10.3762/bjoc.21.53

• due to the angular annelation. These series are known as one-dimensional graphene ribbons. As has been commonly recognized, acene molecules have been intensively and extensively studied in the organic functional materials field [5][6][7]. By contrast, phenacenes had been hardly applied as functional

Deep-blue emitting 9,10-bis(perfluorobenzyl)anthracene

• Long K. San,
• Sebastian Balser,
• Brian J. Reeves,
• Tyler T. Clikeman,
• Yu-Sheng Chen,
• Steven H. Strauss and
• Olga V. Boltalina

Beilstein J. Org. Chem. 2025, 21, 515–525, doi:10.3762/bjoc.21.39

• , bulky fluorinated substituents, such as perfluoroalkyls and perfluoroaryls, have been predicted by DFT [16] and shown experimentally [17], to improve the air- and photostability of acene-containing materials, by increasing their electron affinity and/or by sterically blocking reactive sites

• -step reactions with anthraquinone starting materials [24], or by Ullman coupling reactions of acene bromides with perfluoroalkyl iodides [25]. Notably, direct UV photoinduced reactions between anthracene and perfluoroalkyl iodides in the presence of a reducing agent, Na2S2O3, yielded perfluoroalkylated

Oxidation of [3]naphthylenes to cations and dications converts local paratropicity into global diatropicity

• Abel Cárdenas,
• Zexin Jin,
• Yong Ni,
• Jishan Wu,
• Yan Xia,
• Francisco Javier Ramírez and
• Juan Casado

Beilstein J. Org. Chem. 2025, 21, 277–285, doi:10.3762/bjoc.21.20

• ] reported a stable heptacene dication in concentrated sulfuric acid, a stability attributed to the intermolecular Coulomb repulsion between the charged molecules, which prevents the dimerization of the acene. This exciting finding suggests possible modes of kinetic stabilization of oxidized species of π

Kinetically stabilized 1,3-diarylisobenzofurans and the possibility of preparing large, persistent isoacenofurans with unusually small HOMO–LUMO gaps

• Qian Liu and
• Glen P. Miller

Beilstein J. Org. Chem. 2024, 20, 1099–1110, doi:10.3762/bjoc.20.97

• Qian Liu Glen P. Miller Department of Chemistry, University of New Hampshire, 23 Academic Way, Durham, New Hampshire 03864-3598, USA 10.3762/bjoc.20.97 Abstract DFT calculations demonstrate that an isoacenofuran of any size possesses a smaller HOMO–LUMO gap than the corresponding acene bearing an

• gaps is achievable. As such, these molecules deserve increased attention as potential p-type organic semiconductors. Keywords: acene; DFT calculation; highly delocalized π-system; isoacenofuran; isobenzofuran; kinetically stabilized; organic semiconductor; small HOMO–LUMO gap; synthesis; Introduction

• aromatic sextet in any neutral, closed-shell resonance form (Figure 2). Thus, compared to the corresponding acene, an isoacenofuran could possess a more highly delocalized π-system and an even smaller HOMO–LUMO gap. For example, consider pentacene and isotetracenofuran. Pentacene can be drawn in several

Synthesis of π-conjugated polycyclic compounds by late-stage extrusion of chalcogen fragments

• Aissam Okba,
• Pablo Simón Marqués,
• Kyohei Matsuo,
• Naoki Aratani,
• Hiroko Yamada,
• Gwénaël Rapenne and
• Claire Kammerer

Beilstein J. Org. Chem. 2024, 20, 287–305, doi:10.3762/bjoc.20.30

• pristine acene with a dienophile to transiently form a cycloadduct with increased solubility for processing purposes, and unmasking it afterwards via a retro-Diels–Alder reaction [16][17][18][19]. In parallel to retro-Diels–Alder reactions, another efficient strategy for the in situ aromatization of target

• , in matrices [22][23][24][25] or in a single crystal [26]. This strategy has also been extended to the synthesis of dyads involving an acene moiety combined with a chromophore [27]. Alternatively, when inserting a monoketone bridging fragment, i.e., a norbornadien-7-one moiety, in the soluble

• transposed to the synthesis of hexacene [84], decacene [85] and ultimately dodecacene [86], which is the longest acene prepared to date. The related soluble precursors 58–60 incorporate 3 to 5 oxabicyclo moieties in their hydrocarbon scaffold (Scheme 16), and are sufficiently stable and soluble to undergo

Biphenylene-containing polycyclic conjugated compounds

• Cagatay Dengiz

Beilstein J. Org. Chem. 2023, 19, 1895–1911, doi:10.3762/bjoc.19.141

• exhibit significant stability problems when their conjugation enhances. Various approaches have been developed to address this stability concern. Among these strategies, one involves the incorporation of the biphenylene unit into acene frameworks, limiting the electron delocalization through the

• can be attributed to Clar's rule, which considers the increasing number of non-sextet rings throughout the acene series as a contributing factor (Figure 1) [5][6]. Numerous approaches have been developed to address the challenges arising from the instability and solubility issues encountered in acenes

• . These include the incorporation of heteroatoms within the acene backbone [7][8], stabilization of the acene core structure through the integration of diverse units [9][10], and the introduction of bulky substituents [11]. These approaches aim to maintain the desirable electronic properties of acenes

Preparation of β-cyclodextrin-based dimers with selectively methylated rims and their use for solubilization of tetracene

• Konstantin Lebedinskiy,
• Volodymyr Lobaz and
• Jindřich Jindřich

Beilstein J. Org. Chem. 2022, 18, 1596–1606, doi:10.3762/bjoc.18.170

• functionalizing these molecules, for example, by inserting some protecting groups. Substituted heptacenes demonstrate remarkable stability and exceptional electric properties. Nevertheless, studying the properties of unsubstituted acenes is also essential. We guessed that some increase in solubility of acene

Recent advances in the syntheses of anthracene derivatives

• Giovanni S. Baviera and
• Paulo M. Donate

Beilstein J. Org. Chem. 2021, 17, 2028–2050, doi:10.3762/bjoc.17.131

• /water in the first step and trimethylamine in the next reaction step [56]. Other procedures In 2008, Lin et al. reported a homo-elongation protocol to obtain acene diesters and dinitriles starting from dialdehydes (Scheme 23) [57]. This methodology was based on a Wittig reaction between substituted [n

• ]acene-2,3-dicarbaldehydes 91 and the Wittig reagents 92; DBU was employed to produce the corresponding substituted [n+1]acene-2,3-diethyl diesters 93. Then, in two steps (reduction and Swern oxidation), the authors converted the diesters 93 to the dialdehydes 94, which could be transformed into the

• corresponding [n+2]acene-2,3-diethyl diesters 95 by the procedure described above. The scope of the reaction included five examples of substituted anthracene-2,3-dicarboxylates bearing Cl or alkoxy groups (43–86% yield). Lin et al. also applied the same approach to synthesize acene-2,3-dinitriles 96 by using

Synthesis, structural characterization, and optical properties of benzo[f]naphtho[2,3-b]phosphoindoles

• Mio Matsumura,
• Takahiro Teramoto,
• Masato Kawakubo,
• Masatoshi Kawahata,
• Yuki Murata,
• Kentaro Yamaguchi,
• Masanobu Uchiyama and
• Shuji Yasuike

Beilstein J. Org. Chem. 2021, 17, 671–677, doi:10.3762/bjoc.17.56

• is known that λmax of [n]helicenes generally has a shorter wavelength than for the corresponding linear poly(acene)s [25]. The λmax of benzo[e]naphtho[2,1-b]phosphindole (A), 358 nm [16], is the same as that of parent 2. In contrast, the corresponding oxide B has a λmax wavelength that is

Synthesis of C₇₀-fragment buckybowls bearing alkoxy substituents

• Yumi Yakiyama,
• Shota Hishikawa and
• Hidehiro Sakurai

Beilstein J. Org. Chem. 2020, 16, 681–690, doi:10.3762/bjoc.16.66

• that with C60 fragment because most of them consists of acene and/or pyrene units, which might give unique photochemical and electrochemical properties. Recently, we synthesized a buckybowl C28H14 1, which is corresponding to a 40% fragment of C70, from C60-fragment sumanene (2) in three steps via ring

Molecular recognition using tetralactam macrocycles with parallel aromatic sidewalls

• Dong-Hao Li and
• Bradley D. Smith

Beilstein J. Org. Chem. 2019, 15, 1086–1095, doi:10.3762/bjoc.15.105

• acene guests Rotaxane template 18 in Scheme 2 is a squaraine dye whose central core has two oxygen atoms that can form hydrogen bonds with the tetralactam NH residues. Squaraine rotaxanes were first prepared by the Smith group in 2005 using the Leigh-type clipping method [44]. As a general trend the

• crystal structures of acene and azaacene guests inside tetralactam B with the surrounding macrocycle in chair or boat conformations [25]. Recent work has shown that water-soluble versions of anthracene tetralactam B can be threaded by water soluble squaraine dyes with very high affinities (Ka ≈ 109 M−1

• are omitted for clarity. Selected X-ray structures of [2]rotaxanes with tetralactam A as the surrounding macrocycle reported by groups led by Leigh, Smith, Cooke, and Berná [37][39][50][52][53][54][55][56]. (a) Chemical structures of squaraine, thiosquaraine, croconaine, and acene guests that can bind

Steric “attraction”: not by dispersion alone

• Ganna Gryn’ova and
• Clémence Corminboeuf

Beilstein J. Org. Chem. 2018, 14, 1482–1490, doi:10.3762/bjoc.14.125

• the recent years, perception of the vaguely defined ‘steric’ interactions as categorically repulsive has shifted towards recognizing the crucial role of attractive dispersion in the bulky systems [1]. London dispersion was shown to be capable of bending σ-bonded acene dimers (2 in Figure 1A) [2] and

Interactions between photoacidic 3-hydroxynaphtho[1,2-b]quinolizinium and cucurbit[7]uril: Influence on acidity in the ground and excited state

• Jonas Becher,
• Daria V. Berdnikova,
• Darinka Dzubiel,
• Heiko Ihmels and
• Phil M. Pithan

Beilstein J. Org. Chem. 2017, 13, 203–212, doi:10.3762/bjoc.13.23

• derivative 7 (Kb = 3 × 104 M−1) [36]. Although a comparison of binding constants from different studies has to be done carefully due to the different experimental conditions, it appears that linear acene-type quinolizinium derivatives fit better into the binding site of CB[7] with highly favorable energetic

Anionic sigmatropic-electrocyclic-Chugaev cascades: accessing 12-aryl-5-(methylthiocarbonylthio)tetracenes and a related anthra[2,3-b]thiophene

• Laurence Burroughs,
• John Ritchie,
• Mkhethwa Ngwenya,
• Dilfaraz Khan,
• William Lewis and
• Simon Woodward

Beilstein J. Org. Chem. 2015, 11, 273–279, doi:10.3762/bjoc.11.31

• , substituted phenyl, 2-thienyl) to ortho-C6H4(CHO)2 undergo cascades to tetracenes on simple admixture of LiHDMS, CS2 and MeI. Acene formation proceeds by [3,3]-sigmatropic rearrangement of xanthate anions followed by 6π electrocyclisations. The reactions are terminated by E2 or anionic Chugaev-type

• , attaining such derivatives rapidly through simple chemistry is often problematic [5][6]. Cross-coupling approaches (formally an excellent approach for acene library preparation) [7][8][9][10][11][12][13] are often hindered by the insolubility, or poor availability, of the parent haloacenes. Conversely

• , stepwise synthesis of a family of acene derivatives from various acyclic precursors is normally very step intensive. The prevalence of these issues in the synthesis of substituted tetracenes caused Lin [14], building on the anthracycline natural product work of Saá [15], to introduce a 1,2-bis-allene

Scalable synthesis of 5,11-diethynylated indeno[1,2-b]fluorene-6,12-diones and exploration of their solid state packing

• Bradley D. Rose,
• Peter J. Santa Maria,
• Aaron G. Fix,
• Chris L. Vonnegut,
• Lev N. Zakharov,
• Sean R. Parkin and
• Michael M. Haley

Beilstein J. Org. Chem. 2014, 10, 2122–2130, doi:10.3762/bjoc.10.219

• pentacene, as it, along with numerous other acene derivatives, has been substituted with trialkylsilylethynyl groups of varying size to study the effect on the solid state packing in single crystals [17]. This was shown to have a large effect on the OFET performance as slight changes in the geometry can

Aryl substitution of pentacenes

• Andreas R. Waterloo,
• Anna-Chiara Sale,
• Dan Lehnherr,
• Frank Hampel and
• Rik R. Tykwinski

Beilstein J. Org. Chem. 2014, 10, 1692–1705, doi:10.3762/bjoc.10.178

• positions of the acene core are the 6- and 13-positions [27][28][29], and these positions can be effectively blocked by different trialkylsilylethynyl units [30]. Inspired by previous studies in which we [18][31], and others [32][33][34], observed promising solid-state arrangement and properties of aryl

Crystal design using multipolar electrostatic interactions: A concept study for organic electronics

• Peer Kirsch,
• Qiong Tong and
• Harald Untenecker

Beilstein J. Org. Chem. 2013, 9, 2367–2373, doi:10.3762/bjoc.9.272

• experimentally observed charge carrier mobilities, e.g., in pentacene based OFETs, remain far below the theoretically predicted limit of several tens of cm2·V−1s−1 [8]. In order to overcome this obstacle, it would be ideal to have acene-like organic semiconductors which pack in the crystal not in one-dimensional

• ]. However, the price to pay for this optimized morphology is the presence of bulky silyl groups which do not electronically contribute to the charge transport. For this reason we set out to execute an alternative concept to achieve a brick-like, slipped stacking in planar, acene-based organic semiconductors

• slightly tilted around their long axis (only ca. 5.2° relative to the sheet plane) (Figure 4). The reason why 1 does not display the acene-typical herring bone arrangement appears to be the distribution of the electrostatic potentials dominating the packing completely. However, a drawback of the