Synthesis and characterization of water-soluble C₆₀–peptide conjugates

• Yue Ma,
• Lorenzo Persi and
• Yoko Yamakoshi

Beilstein J. Org. Chem. 2024, 20, 777–786, doi:10.3762/bjoc.20.71

• example, as a photosensitizer in photodynamic therapy. Keywords: biomaterial; fullerene; peptide; water-soluble; Introduction Since the seminal discovery in 1985 by Kroto, Smalley, Curl, and co-workers [1], fullerenes, specifically buckminsterfullerene C60, have intrigued the scientific community. The

• unique structure of fullerenes, characterized by a fully conjugated closed-cage structure, containing a mixture of hexagonal and pentagonal rings, have been recognized for the unique electronic [2][3][4], optical [5][6], and mechanical properties [7][8]. Despite the notable achievements in fullerene

• either 1) covalent functionalization of the fullerene surface with polar moieties or 2) complexation with water-soluble host molecules or polymers. Related to the former approach, the Nakamura group [11], Wudl group [12], and Hirsch group [13] reported initial work in the early 1990s on water-soluble C60

Organic electron transport materials

• Joseph Cameron and
• Peter J. Skabara

Beilstein J. Org. Chem. 2024, 20, 672–674, doi:10.3762/bjoc.20.60

• , meaning organic materials can be used effectively in a range of applications. For example, while a non-fullerene acceptor material might not be suitable as an electron transport layer in OPVs due to dissolution of layers, it can used in perovskite solar cells where it can be successfully deposited through

• , materials might be modified with polar side chains [9], instead of the use of alkyl groups [10], and this allows for improved ion transport. A similar strategy has been used to improve the doping of n-type thermoelectric materials, where polar side chains on fullerene materials allow for better miscibility

• overcome in developing materials for emerging technologies, researchers working on these issues should take inspiration from the rapid progress that was achieved in the development of non-fullerene acceptor materials as a replacement for PC61BM and PC71BM in organic solar cells which revitalised the

Enhanced reactivity of Li⁺@C₆₀ toward thermal [2 + 2] cycloaddition by encapsulated Li⁺ Lewis acid

• Hiroshi Ueno,
• Yu Yamazaki,
• Hiroshi Okada,
• Fuminori Misaizu,
• Ken Kokubo and
• Hidehiro Sakurai

Beilstein J. Org. Chem. 2024, 20, 653–660, doi:10.3762/bjoc.20.58

• , Graduate School of Science, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai 980-8578, Japan Division of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan 10.3762/bjoc.20.58 Abstract Lithium ion-endohedral fullerene (Li+@C60), a member of

• experimental and theoretical approaches, we clarified the range of applicable substrates for the thermal [2 + 2] cycloaddition of Li+@C60, highlighting the expanded scope of this straightforward and selective functionalization method. Keywords: electron transfer; fullerene; ion-endohedral fullerene; Lewis

• acid catalyst; thermal [2 + 2] cycloaddition; Introduction Chemical functionalization of fullerenes is a fascinating and extensively studied approach, playing a pivotal role in fullerene-based materials science to introduce various characteristic functionalities [1][2][3][4][5][6][7]. Significant

Switchable molecular tweezers: design and applications

• Pablo Msellem,
• Maksym Dekthiarenko,
• Nihal Hadj Seyd and
• Guillaume Vives

Beilstein J. Org. Chem. 2024, 20, 504–539, doi:10.3762/bjoc.20.45

• fullerene complexation in the cavity, thus enabling an allosteric regulation of the complexation properties of the system by a Pd(II) stimulus. An example of direct utilization of the rotation around the single bond of the bipyridine unit was reported by Caltagirone and co-workers in tweezers 29 (Figure 16a

• bipyridine-based molecular tweezers 30 (Figure 16b) with corannulene recognition units on positions 4 and 4’ (open-by-default) for fullerene complexation [63]. The bipyridine can be switched from s-trans to s-cis-conformation by the addition of copper(II) and one equivalent of 1,2-bis(diphenylphosphino

• upon oxidation. As expected, the preorganized rigid form presents stronger binding affinities to fullerenes than the freely rotating dithiol form [64]. Recently, similar bipyridine-based tweezers with Zn–porphyrin functional units for fullerene binding were reported, using different stimuli for

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

• developed by Murata, Komatsu et al. [80]. In this approach, C60 or C70 fullerenes are modified stepwise towards an open-cage derivative in order to encapsulate small molecules such as H2 [81][82]. Eventually, the chemical modifications are reversed to close the hole and give an endohedral fullerene. As

• depicted in Scheme 14, the 12-membered ring orifice of fullerene 51 was first enlarged by electrophilic addition of sulfur. After encapsulation of H2 molecule(s) (n = 1 or 2), four synthetic steps were required to reduce the hole size and ultimately obtain cage-closed compound (H2)n@54. In order to remove

• % yield. At that stage, the initial ring size of precursor 51 was recovered, and two further steps including a McMurry reaction and a thermolysis were then necessary to obtain endohedral fullerene (H2)n@54. As seen in the two first parts of this review, synthetic strategies involving a late-stage ring

Unveiling the regioselectivity of rhodium(I)-catalyzed [2 + 2 + 2] cycloaddition reactions for open-cage C₇₀ production

• Cristina Castanyer,
• Anna Pla-Quintana,
• Anna Roglans,
• Albert Artigas and
• Miquel Solà

Beilstein J. Org. Chem. 2024, 20, 272–279, doi:10.3762/bjoc.20.28

• opening. Keywords: cycloadditions; DFT calculations; [70]fullerene; open-cage fullerenes; rhodium; Introduction The discovery of C60 (buckminsterfullerene) in 1985 [1] initiated the search for possible technological applications of fullerenes. Nowadays, applications for these carbon-based molecules have

• cages. However, in other cases, some of the bonds between the C atoms of the cage are broken and the cage is opened. The first example of an open-cage fullerene was reported in 1995 by Hummelen, Prato, and Wudl [21] through the reaction of C60 with azides followed by photooxygenation. Since then, many

• open-cage C60 derivatives have been reported. These open-cage fullerenes can act as molecular containers. Of special interest is the procedure called molecular surgery designed by Murata et al. [22][23][24][25] in which a hole in the fullerene is opened, an atom or small molecule is introduced and then

Perspectives on push–pull chromophores derived from click-type [2 + 2] cycloaddition–retroelectrocyclization reactions of electron-rich alkynes and electron-deficient alkenes

• Michio Yamada

Beilstein J. Org. Chem. 2024, 20, 125–154, doi:10.3762/bjoc.20.13

• to posit that the phenyl rings possess a degree of rotational freedom, thereby circumventing steric repulsions. The steric congestion surrounding TCBD moieties can also induce further skeletal rearrangement. For instance, the spatial constraints proximal to the surface of fullerene derivatives lead

• , upon refluxing in chlorobenzene, a rearrangement ensued, yielding tetrakis-substituted fullerene derivatives 33 [112]. During this rearrangement, it was postulated that a zwitterionic intermediate was formed from the nucleophilic attack of the carbon of the dicyanomethylidene adjacent to the DMA group

• on the fullerene sphere. This was followed by a nucleophilic attack of the fullerene carbanion on one of the cyano groups, ultimately yielding 33. Computational calculations also suggested that the rearrangement was facilitated by the destabilization of the reactant due to steric interactions

Electron-beam-promoted fullerene dimerization in nanotubes: insights from DFT computations

• Laura Abella,
• Gerard Novell-Leruth,
• Josep M. Ricart,
• Josep M. Poblet and
• Antonio Rodríguez-Fortea

Beilstein J. Org. Chem. 2024, 20, 92–100, doi:10.3762/bjoc.20.10

• (CIIAE), FUNDECYT-PCTEx, Polytechnic School of Caceres Building, Office CIIAE-C7, Av. Universidad s/n, 10003 Cáceres, Spain 10.3762/bjoc.20.10 Abstract Fullerene dimerization inside a peapod is analyzed at DFT level by characterizing the stationary points and deriving the energy profile of the initial

• metadynamics simulations provide hints on structures for the initial steps of the irreversible phase 2 where bond formation and breaking lead to important structural reorganizations within the coalescence process. Keywords: DFT; dimerization; fullerene; molecular dynamics; peapods; Introduction Transmission

• have been published that record the dynamic behavior of a wide range of molecules and chemical reactions. One such process was the dimerization of C60 fullerene in a carbon nanotube peapod, i.e., hybrid structures consisting of fullerene molecules encapsulated in single-walled carbon nanotubes (SWCNT

Facile access to pyridinium-based bent aromatic amphiphiles: nonionic surface modification of nanocarbons in water

• Lorenzo Catti,
• Shinji Aoyama and
• Michito Yoshizawa

Beilstein J. Org. Chem. 2024, 20, 32–40, doi:10.3762/bjoc.20.5

• )2–Y (Y = OCH3, OH, and imidazole)). The new amphiphiles quantitatively self-assemble into ≈2 nm-sized aromatic micelles in water independent of the side-chain. Importantly, efficient water-solubilization and nonionic surface modification of various nanocarbons (e.g., fullerene C60, carbon nanotubes

• of the side-chain present. Importantly, efficient water-solubilization and nonionic surface modification of nanocarbons (i.e., fullerene C60 (C60), single/multi-walled carbon nanotubes (s/m-CNT), and graphene nanoplatelets (GN)) can be achieved through noncovalent encircling with the present

• via their encircling by the present amphiphiles in water. For example, utilizing the imidazole-functionalized amphiphile, an aqueous fullerene-based host–guest composite with pH-responsive surface charge was generated. In addition, water-solubilization of graphitic carbon nitride and subsequent

Anion–π catalysis on carbon allotropes

• M. Ángeles Gutiérrez López,
• Mei-Ling Tan,
• Giacomo Renno,
• Augustina Jozeliūnaitė,
• J. Jonathan Nué-Martinez,
• Javier Lopez-Andarias,
• Naomi Sakai and
• Stefan Matile

Beilstein J. Org. Chem. 2023, 19, 1881–1894, doi:10.3762/bjoc.19.140

• ][56][57]. Anion–π catalysis on fullerenes has been introduced in 2017 [12]. Fullerene anion–π catalysts were developed with the benchmark reaction introduced two years earlier (Figure 2) [2]. In this reaction, at the beginning of all biosynthesis, finetuned malonic acid half thioesters 4 [58][59][60

• to C60 fullerenes [12]. These amines function as bases, their position next to the aromatic surface is essential to turn on anion–π interactions as soon as substrate 4 is deprotonated. Fullerene derivatization with the Bingel reaction installs a cyclopropane that continues with one or two acid

• derivatives. In fullerene 8, this is an amide with a short ethylene tether for the tertiary amine (Figure 3). Fullerene 8 catalyzed the formation of the addition product 6 with high selectivity over the decarboxylation product 7 [12]. The experimental product ratio A/D8 was divided by the product ratio A/D9

Controlling the reactivity of La@C₈₂ by reduction: reaction of the La@C₈₂ anion with alkyl halide with high regioselectivity

• Yutaka Maeda,
• Saeka Akita,
• Mitsuaki Suzuki,
• Michio Yamada,
• Takeshi Akasaka,
• Kaoru Kobayashi and
• Shigeru Nagase

Beilstein J. Org. Chem. 2023, 19, 1858–1866, doi:10.3762/bjoc.19.138

• , the third carbon allotrope, have unique spherical molecular structures and exhibit high reactivity as electron-deficient polyolefins. The excellent redox properties of fullerenes are useful for their chemical derivatization and practical applications [1][2][3][4][5]. Fullerene anions can be easily

• transfer, followed by bimolecular nucleophilic substitution (SN2) reaction [8]. Endohedral metallofullerenes, wherein one or more metal atoms are encapsulated inside a fullerene cage, have garnered research interest [12][13][14][15]. The encapsulation of metal atoms can result in electron transfer from the

• metal atoms to the fullerene cage. Because of this intramolecular electron transfer, the characteristic properties of metallofullerenes, such as their redox potentials, are significantly different from those of empty fullerenes. For example, La@C82 has paramagnetic properties, and its formal electronic

Quinoxaline derivatives as attractive electron-transporting materials

• Zeeshan Abid,
• Liaqat Ali,
• Sughra Gulzar,
• Faiza Wahad,
• Raja Shahid Ashraf and
• Christian B. Nielsen

Beilstein J. Org. Chem. 2023, 19, 1694–1712, doi:10.3762/bjoc.19.124

• ), organic field-effect transistors (OFETs), organic-light emitting diodes (OLEDs) and other organic electronic technologies. Notably, the potential of quinoxaline derivatives as non-fullerene acceptors in OSCs, auxiliary acceptors and bridging materials in DSSCs, and n-type semiconductors in transistor

• transport applications. Furthermore, ongoing research efforts aimed at enhancing their performance and addressing key challenges in various applications are presented. Keywords: electron transport materials; non-fullerene acceptors; n-type semiconductors; organic electronics; quinoxalines; Introduction

• high electron mobility and efficient charge transfer. In particular, Qx derivatives find use as non-fullerene acceptors (NFAs) in OSCs and as essential building blocks in sensitizers for DSSCs. The significance of Qx extends beyond to thermally activated delayed fluorescence (TADF) emitters and

Benzoimidazolium-derived dimeric and hydride n-dopants for organic electron-transport materials: impact of substitution on structures, electrochemistry, and reactivity

• Swagat K. Mohapatra,
• Khaled Al Kurdi,
• Samik Jhulki,
• Georgii Bogdanov,
• John Bacsa,
• Maxwell Conte,
• Tatiana V. Timofeeva,
• Seth R. Marder and
• Stephen Barlow

Beilstein J. Org. Chem. 2023, 19, 1651–1663, doi:10.3762/bjoc.19.121

• oxidized than [RuCp*(1,3,5-Me3C6H3)]2 (−1.09 V) [61] and, like [RuCp*(1,3,5-Me3C6H3)]2, can still be handled in air. Reactivity To compare the reactivity of the new compounds towards relevant organic semiconductors (SC), we have examined the reactions of the 1H derivatives with the solubilized fullerene

Tying a knot between crown ethers and porphyrins

• Maksym Matviyishyn and
• Bartosz Szyszko

Beilstein J. Org. Chem. 2023, 19, 1630–1650, doi:10.3762/bjoc.19.120

• applications [43][44][78]. Fullerene-based crown ether-appended porphyrins developed by Diederich and co-workers were used as polymeric material films [79]. Intriguing supramolecular systems capable of electron transfer were developed by D'Souza, Ito and co-workers, showing selective multitopic receptors

A series of perylene diimide cathode interlayer materials for green solvent processing in conventional organic photovoltaics

• Kathryn M. Wolfe,
• Shahidul Alam,
• Eva German,
• Fahad N. Alduayji,
• Maryam Alqurashi,
• Frédéric Laquai and
• Gregory C. Welch

Beilstein J. Org. Chem. 2023, 19, 1620–1629, doi:10.3762/bjoc.19.119

• ], where the BHJ used was PM6:Y6 and PCEs were found to be comparable to that of PFN-Br with PCEs of over ≈13%. Results and Discussion Design strategy Previously, the benzyl-annulated dimers of the ethyl propyl perylene diimide (tPDI2-N-R; Figure 2) were reported as non-fullerene acceptors for OPVs

CuAAC-inspired synthesis of 1,2,3-triazole-bridged porphyrin conjugates: an overview

• Dileep Kumar Singh

Beilstein J. Org. Chem. 2023, 19, 349–379, doi:10.3762/bjoc.19.29

• -induced applications. Similar to porphyrins, fullerene C60 also possesses superior acceptor properties, low reduction potential and low reorganization energy [48][49]. Thus, keeping the diverse properties of fullerene in mind, de Miguel et al. [50] successfully prepared and characterized the triazole

• -linked porphyrin-fullerene dyads 100a–d and 104a,b. Firstly, meso-triazole-linked porphyrin conjugates 99a–d and 103a,b were synthesized from porphyrins 97a,b and 101, as shown in Scheme 20. For the click reaction between porphyrin 101 and alkyne 102a,b, one equivalent of tris(benzotriazolylmethyl)amine

• conjugates (99a–d, 103a,b) were utilized for the preparation of porphyrin-fullerene dyads 100a–d and 104a,b in 30–70% yield by the reaction with C60 and sarcosine in toluene under microwave conditions. The photophysical and computational studies of these ZnP-Tri-C60 conjugates revealed that the 1,2,3

Introducing a new 7-ring fused diindenone-dithieno[3,2-b:2',3'-d]thiophene unit as a promising component for organic semiconductor materials

• Valentin H. K. Fell,
• Joseph Cameron,
• Alexander L. Kanibolotsky,
• Eman J. Hussien and
• Peter J. Skabara

Beilstein J. Org. Chem. 2022, 18, 944–955, doi:10.3762/bjoc.18.94

• evaporation, average mobilities of 14.20 ± 2.55 cm2 V−1 s−1, with a maximum value of 17.2 cm2 V−1 s−1 were achieved. In recent years, fused thiophene molecules also achieved outstanding performances in OPVs. This was especially driven by recent developments in non-fullerene acceptors (NFA) [29]. One prominent

• 2021, Hou et al. reported a ternary OPV, using a mixture of the novel PBQx-TF (16) donor polymer and the non-fullerene acceptor eC9-2Cl (17), shown in Figure 7. In addition, a third material, F-BTA3 (18) was blended in [32]; all three materials are fused thiophene systems. The resulting OPV achieved a

• polymer 11, also featuring a fused thiophene system, showed a remarkable PCE of 6.80%, the then best value for non-fullerene acceptor organic solar cells [17]. The fluorinated derivative of ITIC, IT-4F, achieved, with donor polymer 13, PCEs in OPVs up to 17% [8]. The non-fullerene acceptor Y6 (14) [30

Recent advances in the application of isoindigo derivatives in materials chemistry

• Andrei V. Bogdanov and
• Vladimir F. Mironov

Beilstein J. Org. Chem. 2021, 17, 1533–1564, doi:10.3762/bjoc.17.111

• containing a short n-butyl substituent at the isoindigo nitrogen atoms and the longest and most branched alkyl radical in the p-phenylene fragment (Scheme 18). Sun et al. showed that such a combination of substituents provides the best miscibility of the polymer with the acceptor fullerene component, which

• may be due to the low hole conductivity, a decrease in the HOMO level of the polymer, and a narrower band gap of visible light absorption [51]. Within the framework of the study of the prospects for polymer derivatives of isoindigo in organic photovoltaics and avoiding the use of the fullerene

[2 + 1] Cycloaddition reactions of fullerene C₆₀ based on diazo compounds

• Yuliya N. Biglova

Beilstein J. Org. Chem. 2021, 17, 630–670, doi:10.3762/bjoc.17.55

• Yuliya N. Biglova Department of Chemistry, Bashkir State University, 450076, Ufa, Russian Federation 10.3762/bjoc.17.55 Abstract The most common variant of fullerene core functionalization is the [2 + 1] cycloaddition process. Of these, reactions leading to methanofullerenes are the most

• universe), the discovery in 1985 of its new allotropic modification, fullerene, has resulted in an avalanche-like expansion of studies in this area [1]. The exceptional physicochemical properties of the fullerene family and, above all, its main representative, C60, predetermine the broad practical interest

• ], have already been discovered among functionalized fullerenes. Bearing in mind the fact that numerous fullerene derivatives with a wide range of biological activity have been synthesized to date, the idea of using functionalized fullerenes in the field of medical chemistry, especially for the treatment

Insight into functionalized-macrocycles-guided supramolecular photocatalysis

• Minzan Zuo,
• Krishnasamy Velmurugan,
• Kaiya Wang,
• Xueqi Tian and
• Xiao-Yu Hu

Beilstein J. Org. Chem. 2021, 17, 139–155, doi:10.3762/bjoc.17.15

• + and crown ether, leading to the formation of cyclobutane in a high yield. D’Souza et al. constructed a photosynthetic triad 4 to mimic the photosynthetic reaction center [19]. A BODIPY, an ammonium-functionalized fullerene, and a zinc porphyrin functioned as the energy donor, electron acceptor, and

• electron donor, respectively (Figure 3). A benzo-18-crown-6 derivative was connected to the porphyrin ring, which could form a supramolecular complex with fullerene through dipole interactions. The formed supramolecular self-assembly resulted in a high energy-transmission efficiency (over 97%) between the

• BODIPY and the zinc porphyrin. The excited zinc porphyrin further transferred the electron to the fullerene, yielding a charge-separated state, with a long lifetime of 23 µs, indicating the charge stabilization of the supramolecular assembly. Thus, an artificial photocatalytic system that can mimic the

Using multiple self-sorting for switching functions in discrete multicomponent systems

• Amit Ghosh and
• Michael Schmittel

Beilstein J. Org. Chem. 2020, 16, 2831–2853, doi:10.3762/bjoc.16.233

• . Interestingly, the fullerene C60 was not taken up as a guest by the tetramer (6)4 in chlorinated solvents. For a more defined self-sorting, the authors switched the solvent from CDCl3 to [d8]-toluene. Now, a 2-fold completive self-sorting delivered the homoleptic inclusion complexes [(5)4(C60)] and [(6)4(C60

Water-soluble host–guest complexes between fullerenes and a sugar-functionalized tribenzotriquinacene assembling to microspheres

• Si-Yuan Liu,
• Xin-Rui Wang,
• Man-Ping Li,
• Wen-Rong Xu and
• Dietmar Kuck

Beilstein J. Org. Chem. 2020, 16, 2551–2561, doi:10.3762/bjoc.16.207

• -fullerene in co-organic solvents and aqueous solution was investigated by fluorescence spectroscopy and ultraviolet-visible spectroscopy. The association stoichiometry of the complexes TBTQ-(OG)6 with C60 and TBTQ-(OG)6 with C70 was found to be 1:1 with binding constants of Ka = (1.50 ± 0.10) × 105 M−1 and

• of this host with C60 and C70-fullerene was investigated in co-organic solvents and in aqueous solution. The hydrophobic surface simulation of this host indicated the formation of a supra-amphiphilic system, which, as shown by scanning electron microscopy, further self-assembles into microspheres in

• affinity of C70-fullerene may be attributed to its larger size and surface area as compared to C60-fullerene [50]. The complexation between TBTQ-(OG)6 and fullerenes was also examined by UV–vis spectroscopy in both toluene/DMSO 1:1 (v/v) and water. Figure 3a shows the UV–vis spectra of TBTQ-(OG)6, C60 and

Synthetic approaches to bowl-shaped π-conjugated sumanene and its congeners

• Shakeel Alvi and
• Rashid Ali

Beilstein J. Org. Chem. 2020, 16, 2212–2259, doi:10.3762/bjoc.16.186

• twentieth century when for the first time corannulene was reported by Barth et al. [10] at the University of Michigan (USA) in 1966 (crystal structure 1971) [11]. On the other hand, since the discovery of fullerene (C60) in 1985 [12] by Sir Harry Kroto and the first synthesis of sumanene in 2003 by Sakurai

Easy, efficient and versatile one-pot synthesis of Janus-type-substituted fullerenols

• Marius Kunkel and
• Sebastian Polarz

Beilstein J. Org. Chem. 2019, 15, 901–905, doi:10.3762/bjoc.15.87

• substituted fullerenol with five substituents on one pole of the fullerene and polyhydroxylation moieties, mostly ether and hydroxy groups, on the rest of the fullerene core. As substituents a broad variety of primary amines can be used to obtain Janus-type amphiphilic fullerenols in good to excellent yield

• . These fullerenol amphiphiles can serve as suitable precursors for further reactions resulting in new applications for fullerenols. Keywords: amphiphile; C60Cl6; fullerene; fullerenol; one-pot; Introduction The roman god Janus, who is typically depicted with two faces, metaphorically stands for duality

• there are not many spherical molecules known. Examples are the giant polyoxometalates reported by Müller et al. [3] and, more importantly for the current paper, fullerene C60. Because of the high symmetry of those compounds asymmetric modification is tedious with multiple synthesis and purification

Adhesion, forces and the stability of interfaces

• Robin Guttmann,
• Johannes Hoja,
• Christoph Lechner,
• Reinhard J. Maurer and
• Alexander F. Sax

Beilstein J. Org. Chem. 2019, 15, 106–129, doi:10.3762/bjoc.15.12