Search

Comprehensive Summary: Efficient charge transport and defect passivation are essential for high efficiency of organic–inorganic hybrid perovskite solar cells (PSCs). Functionalized fullerenes featuring high electron affinity and mobility as well as small reorganization energy have been extensively applied in PSCs toward facilitated electron transport and passivated trap states, leading to improvements of both device efficiency and stability. Herein, we summarize the recent advances, especially in the last three years, in applications of functionalized fullerenes including fullerene derivatives and endohedral metallofullerenes in PSCs. Their functions in trap state passivation, electron transport promotion, crystalline modulation, water/oxygen erosion inhibition, and so on, are discussed in details. In particular, we emphasize novel functions of fullerenes beyond trap state passivation, as well as the synergy of multifunction of fullerenes in improving PSC device performance and stability. Finally, we present an outlook on designing novel multifunctionalized fullerenes toward highly efficient and stable PSC devices. [ABSTRACT FROM AUTHOR]

Because of the limitations of traditional refrigerants, the application of trans-critical CO2 technology in domestic gas conditioners and other fields is becoming increasingly popular. This paper proposes a new CO2 trans-critical refrigeration system. Combining the internal heat exchanger and expander components, as well as the two-stage compression cycle, we analyzed the effectiveness of the expander, internal heat exchanger, and intercooling on system performance under various operating conditions in terms of energy, exergy analysis, and optimal discharge pressure. The system performance can be changed by changing the cycle conditions and internal heat exchanger effectiveness, which reduces system power consumption and the percentage of exergy losses of gas cooler components. Compared to the single-stage compression with expander cycle, the systems cycle power consumption is reduced by 2–15.7% and the maximum system COP is increased by 2.93–6.93%. From the view of energy effectiveness, the system's maximum COP increases by 3.9% and the percentage of exergy losses of gas cooler decreases by 22.5% with the effectiveness of internal heat exchanger varying. The addition of an internal heat exchanger has resulted in improved system performance, which is important for providing a relevant cycle model for the application. [ABSTRACT FROM AUTHOR]

Herein, we report the selective synthesis, characterization, and photophysical properties of two novel chiral carbon macrocycles. Non-planar (S)-2,2′-bis(methoxymethoxy)-1,1′-binaphthalene was introduced into the scaffold of oligo-paraphenylenes to achieve the chirality in these macrocycles. Their photophysical properties were investigated by steady-state and time-resolved spectroscopies, as well as circular dichroism and circularly polarized luminescence spectroscopies. We demonstrate that the emission maxima of the chiral macrocycles are redshifted compared to chiral binaphthyl units and that macrocycles show chiroptical properties (‖glum‖ > 1.0 × 10−3). [ABSTRACT FROM AUTHOR]

The high-regioselective synthesis of bisadducts based on low-symmetry C70 has been a challenging work due to the large amount of formed regioisomers, which require tedious separation procedures for isomeric purity and block their application in different fields. Herein, we successfully obtained a novel 1, 2, 3, 4-bis(triazolino)fullerene[C70] 2 with high regioselectivity by the rigid tether-directed regioselective synthesis strategy and the corresponding molecular structure was unambiguously confirmed by single-crystal X-ray crystallography characterization. The crystal data clearly show that the addition occurs at the domain of corannulene moiety at the end of ellipse C70 as well as the 1, 2, 3, 4-addition sites located at one hexagonal ring with a [6,6]-closed addition pattern. Furthermore, 2 was applied as an additive of perovskite layer to construct MAPbI3-based regular (n-i-p) perovskite solar cells, affording the power conversion efficiency (PCE) of 18.59%, which is a 7% enhancement relative to that of control devices without additive. [ABSTRACT FROM AUTHOR]

Endohedral clusterfullerenes exhibit unique chemical properties due to intramolecular electron transfer of the encaged metal cluster to the outer fullerene cages. We report the synthesis of two Sc3N@D3h‐C78 monoadducts 2 a and 2 b through the 1,3‐dipolar reaction of Sc3N@D3h‐C78 with carbonyl ylide bearing anomalous cis‐conformation regioselectivity. The molecular structures of these monoadducts are unambiguously confirmed by single‐crystal X‐ray crystallography, revealing that both 2 a and 2 b have cis‐conformations with the furan moiety grafted via [6,6]‐closed addition patterns. Under the same conditions, the control reaction of C60 with carbonyl ylide affords two monoadducts 3 a and 3 b, which exhibit cis‐ and trans‐conformations, respectively, with [6,6]‐closed addition patterns. According to theoretical calculations, the exclusive formation of the cis‐only Sc3N@D3h‐C78 monoadducts is a consequence of conjunct effects of thermodynamic stability of adducts, the reactivity of the addition site, and the cis‐dipole intermediate from trans1. [ABSTRACT FROM AUTHOR]

Endohedral clusterfullerenes exhibit unique chemical properties due to intramolecular electron transfer of the encaged metal cluster to the outer fullerene cages. We report the synthesis of two Sc3N@D3h‐C78 monoadducts 2 a and 2 b through the 1,3‐dipolar reaction of Sc3N@D3h‐C78 with carbonyl ylide bearing anomalous cis‐conformation regioselectivity. The molecular structures of these monoadducts are unambiguously confirmed by single‐crystal X‐ray crystallography, revealing that both 2 a and 2 b have cis‐conformations with the furan moiety grafted via [6,6]‐closed addition patterns. Under the same conditions, the control reaction of C60 with carbonyl ylide affords two monoadducts 3 a and 3 b, which exhibit cis‐ and trans‐conformations, respectively, with [6,6]‐closed addition patterns. According to theoretical calculations, the exclusive formation of the cis‐only Sc3N@D3h‐C78 monoadducts is a consequence of conjunct effects of thermodynamic stability of adducts, the reactivity of the addition site, and the cis‐dipole intermediate from trans1. [ABSTRACT FROM AUTHOR]

According to the isolated pentagon rule (IPR), for stable fullerenes, the 12 pentagons should be isolated from one another by hexagons, otherwise the fused pentagons will result in an increase in the local steric strain of the fullerene cage. However, the successful isolation of more than 100 endohedral and exohedral fullerenes containing fused pentagons over the past 20 years has shown that strain release of fused pentagons in fullerene cages is feasible. Herein, we present a general overview on fused‐pentagon‐containing (i.e. non‐IPR) fullerenes through an exhaustive review of all the types of fused‐pentagon‐containing fullerenes reported to date. We clarify how the strain of fused pentagons can be released in different manners, and provide an in‐depth understanding of the role of fused pentagons in the stability, electronic properties, and chemical reactivity of fullerene cages. [ABSTRACT FROM AUTHOR]

Ein Übersichtsartikel, der sich speziell mit der Stabilisierung kondensierter Fünfringe bei vor 2009 isolierten Fullerenen befasst, wurde von Xie et al. 2009 veröffentlicht. In diesem Aufsatz geben wir nun einen allgemeinen Überblick über Fullerene, die kondensierte Fünfringe enthalten, wobei wir uns auf die hochinteressanten neuen Fortschritte auf diesem Themengebiet seit 2009 konzentrieren. Anhand einer vollständigen Auflistung aller bisher beschrieben Arten von Fullerenen mit kondensierten Fünfringen werden wir verdeutlichen, wie die Spannung kondensierter Fünfringe auf unterschiedliche Weise freigesetzt werden kann. Wir werden außerdem die Auswirkungen der kondensierten Fünfringe auf die Stabilität, die elektronischen Eigenschaften und die chemische Reaktivität des Fullerenkäfigs diskutieren und damit ein tiefgehendes Verständnis der Rolle kondensierter Fünfringe ermöglichen. Am Schluss werden wir die Perspektiven von Fullerenen mit kondensierten Fünfringen erörtern, insbesondere ungeklärte Fragen wie die Stabilität reiner, leerer Nicht‐IPR‐Fullerene und deren Bildungsmechanismen. [ABSTRACT FROM AUTHOR]

We herein demonstrate for the first time the unexpected oxygen-involving reaction between M3N@Ih(7)-C80 (M = Sc, Lu) and 1,3-bis(diisopropylphenyl)imidazol-2-ylene (1). By introducing a tiny amount of oxygen into the reaction, unprecedented products (2a for Sc3N@C80 and 3a for Lu3N@C80) with the normal carbene center C2 singly bonded to a triple hexagonal junction (THJ) cage carbon together with an oxygen atom bridging the same THJ carbon atom and a neighboring carbon atom forming an epoxy structure are obtained. In situ mechanism study, in combination with theoretical calculations, reveals that the bond-breaking peroxidation facilitates the formation of the unexpected products 2a and 3a, providing new insight into fullerene chemistry. [ABSTRACT FROM AUTHOR]

Labile bis-triazoline adducts of C60 are supposed to be the precursors of bis-azafulleroids, but the formation mechanism is still unclear because of the incomplete isolation of the thermolized products and the lack of X-ray structures. A rigid-tethered reagent 1,2-bis(azidomethyl)benzene ( 1) was used to regioselectively synthesize the labile 1,2,3,4-bis(triazolino)[60]-fullerene ( 2), the structure of which was determined by single-crystal X-ray crystallography. Further thermolysis of 2 produces four products (3 a- 3 d), which were all characterized by X-ray crystallography. Although 3 a and 3 b have traditional bis-azafulleroid structures, as proposed previously, 3 c and 3 d show unprecedented structures with either the coexistence of [5,6]-open and [6,6]-closed patterns or an oxidized structure with an 11-membered ring on the cage. A thermolysis mechanism is proposed to clarify long-term confusion about the transformation process from bis-triazoline adducts to bis-azafulleroids of C60. [ABSTRACT FROM AUTHOR]

Labile bis-triazoline adducts of C60 are supposed to be the precursors of bis-azafulleroids, but the formation mechanism is still unclear because of the incomplete isolation of the thermolized products and the lack of X-ray structures. A rigid-tethered reagent 1,2-bis(azidomethyl)benzene ( 1) was used to regioselectively synthesize the labile 1,2,3,4-bis(triazolino)[60]-fullerene ( 2), the structure of which was determined by single-crystal X-ray crystallography. Further thermolysis of 2 produces four products (3 a- 3 d), which were all characterized by X-ray crystallography. Although 3 a and 3 b have traditional bis-azafulleroid structures, as proposed previously, 3 c and 3 d show unprecedented structures with either the coexistence of [5,6]-open and [6,6]-closed patterns or an oxidized structure with an 11-membered ring on the cage. A thermolysis mechanism is proposed to clarify long-term confusion about the transformation process from bis-triazoline adducts to bis-azafulleroids of C60. [ABSTRACT FROM AUTHOR]

Endohedral metallofullerenes (EMFs) have novel structures and properties that are closely associated with the internal metallic species. Benzyl radical additions have been previously shown to form closed-shell adducts by attaching an odd number of addends to open-shell EMFs (such as Sc3C2@ Ih-C80) whereas an even number of groups are added to closed-shell EMFs (for example Sc3N@ Ih-C80). Herein we report that benzyl radical addition to the closed-shell La2@ Ih-C80 forms a stable, open-shell monoadduct instead of the anticipated closed-shell bisadduct. Single-crystal X-ray diffraction results show the formation of a stable radical species. In this species, the La−La distance is comparable to the theoretical value of a La−La covalent bond and is shorter than reported values for other La2@ Ih-C80 derivatives, providing unambiguous evidence for the formation of direct La−La bond. [ABSTRACT FROM AUTHOR]

Endohedral metallofullerenes (EMFs) have novel structures and properties that are closely associated with the internal metallic species. Benzyl radical additions have been previously shown to form closed-shell adducts by attaching an odd number of addends to open-shell EMFs (such as Sc3C2@ Ih-C80) whereas an even number of groups are added to closed-shell EMFs (for example Sc3N@ Ih-C80). Herein we report that benzyl radical addition to the closed-shell La2@ Ih-C80 forms a stable, open-shell monoadduct instead of the anticipated closed-shell bisadduct. Single-crystal X-ray diffraction results show the formation of a stable radical species. In this species, the La−La distance is comparable to the theoretical value of a La−La covalent bond and is shorter than reported values for other La2@ Ih-C80 derivatives, providing unambiguous evidence for the formation of direct La−La bond. [ABSTRACT FROM AUTHOR]

We have made a systematic investigation of the regioselective reaction between triethylamine and C60 under thermal conditions, presenting X-ray crystallographic results of the pentane-fused adduct for the first time. In addition to finding the reaction conditions which gave the highest yield and the best regioselectivity, we captured with GC-MS the acetaldehyde and diethylamine intermediates that were involved in the reaction, thus clarifying the reaction mechanism. [ABSTRACT FROM AUTHOR]

Accelerating the charge separation and transfer as well as increasing the visible light absorption is of great importance for photocatalysts to realize efficient photocatalytic hydrogen evolution via water splitting. Herein, for the first time, we fabricated in-plane graphited nanocarbon-conjugated polymeric carbon nitride (GNC-C 3 N 4) nanosheet heterostructure photocatalyst from melamine and hexaketocyclohexane octahydrate mixture via an amino-carbonyl reaction. The incorporation of GNC into conjugate network of C 3 N 4 can not only dramatically enhance the light harvesting but also significantly promote the charge separation and transfer by the built-in electric field and intimate interface in the coplanar GNC-C 3 N 4 heterostructure. Accordingly, the optimal GNC-C 3 N 4 photocatalyst demonstrates a more than 15-fold enhancement for photocatalytic hydrogen evolution from water under visible light irradiation, compared to C 3 N 4. • Novel nanocarbon-conjugated g-C 3 N 4 (GNC-C 3 N 4) nanosheet heterostructure is synthesized. • The graphited nanocarbon improves charge separation and charge transfer processes. • Photocatalytic performance of the GNC-C 3 N 4 nanosheet is 15 times higher than pristine g-C 3 N 4. [ABSTRACT FROM AUTHOR]

The chemical properties of carbide-cluster metallofullerenes (CCMFs) remain largely unexplored, although several new members of CCMFs have been discovered recently. Herein, we report the reaction between Sc2C2@ C3 v(8)-C82, which is viewed as a prototypical CCMF because of its high abundance, and 3-triphenylmethyl-5-oxazolidinone ( 1) to afford the corresponding pyrrolidino derivative Sc2C2@ C3 v(8)-C82(CH2)2NTrt ( 2; Trt=triphenylmethyl). Single-crystal X-ray crystallography studies of 2 revealed that the reaction takes place at a [6,6]-bond junction, which is directly over the encapsulated C2 unit and is far from either of the two scandium atoms. On the basis of theoretical calculations and by considering previously reports, we have found that a hexagonal carbon ring on the cage of Sc2C2@ C3 v(8)-C82 is highly reactive toward different reagents due to the overlap of high p-orbital axis vector (POAV) angles and large LUMO coefficients. We propose that this highly concentrated area of reactivity is generated by the encapsulation of the Sc2C2 cluster because this region is absent from the empty fullerene C3 v(8)-C82. Moreover, the absorption and electrochemical results confirm that derivative 2 is more stable than pristine Sc2C2@ C3 v(8)-C82, thus illuminating its potential applications. [ABSTRACT FROM AUTHOR]

2D perovskites possess superior humidity stability but inferior power conversion efficiency (PCE) compared with 3D perovskites due to their typically insulating spacers. Size of the spacer cation is determinative for the formation of 2D perovskite, and fullerene is believed not to be capable of templating 2D perovskite structure because of its larger size than the width of the lead‐halide octahedron despite its well‐known strong electron‐accepting ability. Herein, a novel amino‐functionalized fullerene derivative (abbreviated as C60‐BPAM) is developed and an 'improbable' spacer for 2D/3D hybrid perovskite solar cells (PSCs), achieving enhanced electron transport is applied. Unlike most of the reported alkylammonium spacers that are based on insulating organic tails, the incorporation of a highly conductive fullerene tail within C60‐BPAM2+ leads to increased electron density in 2D/3D perovskite and induces an additional built‐in electric field, facilitating electron transport in PSCs. Besides, the 2D/3D hybrid structure helps to passivate both of the shallow‐ and deep‐level defects within perovskite. As a result, the PCE of 2D/3D PSCs improves from 19.36% (3D MAPbI3 PSCs) to 20.21%. Moreover, the 2D/3D PSCs show significant improvement in the humidity stability compared to the 3D counterparts. [ABSTRACT FROM AUTHOR]

2D layered MXene‐based materials are applied as cation‐intercalation electrode materials for sodium‐ion batteries (SIBs) due to their layered structures but suffer from spontaneous restacking during Na+ insertion and deintercalation processes, resulting in sluggish reaction kinetics and poor cycling stability. Herein, fullerene C60 is intercalated covalently into the interlayer of Ti3C2Tx MXene nanosheets by using a low‐temperature hydrothermal reaction between a water‐soluble C60 derivative and hydrophilic MXene nanosheets, resulting in enlarged interlayer spacing of MXene nanosheets from 12.8 to 14.1 Å and consequently retarded self‐restacking. Moreover, the strong electron extraction ability of C60 facilitates electron transfer from MXene to C60, enabling faster charge transport during Na+ transportation. The as‐prepared C60@MXene hybrid is applied as a novel anode of SIBs, exhibiting outstanding electrochemical performance and super‐long cycling stability. C60@MXene‐based SIB delivers a specific capacity of 226.8 mAh g−1 at 0.1 A g−1 after 300 cycles, which surpasses that obtained from the pristine MXene anode, and retains 94.5% capacity at 1 A g−1 after 10 000 cycles. DFT simulations confirm that C60‐induced enlarged interlayer spacing benefits Na+ migrations, which is responsible for improved electrochemical performance and cycling stability. [ABSTRACT FROM AUTHOR]

Fullerene has a definite 0D closed‐cage molecular structure composed of merely sp2‐hybridized carbon atoms, enabling it to serve as an important building block that is useful for constructing supramolecular assemblies and micro/nanofunctional materials. Conversely, graphene has a 2D layered structure, possessing an exceptionally large specific surface area and high carrier mobility. Likewise, other emerging graphene‐analogous 2D nanomaterials, such as graphitic carbon nitride (g‐C3N4), transition‐metal dichalcogenides (TMDs), hexagonal boron nitride (h‐BN), and black phosphorus (BP), show unique electronic, physical, and chemical properties, which, however, exist only in the form of a monolayer and are typically anisotropic, limiting their applications. Upon hybridization with fullerenes, noncovalently or covalently, the physical/chemical properties of 2D nanomaterials can be tailored and, in most cases, improved, significantly extending their functionalities and applications. Here, an exhaustive review of all types of hybrids of fullerenes and 2D nanomaterials, such as graphene, g‐C3N4, TMDs, h‐BN, and BP, including their preparations, structures, properties, and applications, is presented. Finally, the prospects of fullerene‐2D nanomaterial hybrids, especially the opportunity of creating unknown functional materials by means of hybridization, are envisioned. An exhaustive review of the hybrids of fullerenes with 2D materials including graphene, graphitic carbon nitride, transition‐metal dichalcogenides, hexagonal boron nitride, and black phosphorus is presented, focused on their preparations, structures, properties, and applications. Upon hybridization with fullerenes noncovalently or covalently, physical/chemical properties of 2D materials can be tailored and in most cases improved, significantly extending their functionalities and applications. [ABSTRACT FROM AUTHOR]

By hybridizing covalently or noncovalently fullerenes with 2D nanomaterials such as graphene, molybdenum disulfide (MoS2) and black phosphorus (BP), the unique properties of 2D nanomaterials can be tailored and improved, significantly extending their functionalities and applications. In article number 1800941, Shangfeng Yang and co‐workers exhaustively review all types of hybrids of fullerenes and 2D nanomaterials, emphasizing their versatile hybridization strategies and applications. [ABSTRACT FROM AUTHOR]

Herein, we report divergent additions of 2,2′‐diazidobiphenyls to C60 and Sc3N@Ih‐C80. In stark contrast to that of the previously reported bis‐azide additions, the unexpected cascade reaction leads to the dearomative formation of azafulleroids 2 fused with a 7‐6‐5‐membered ring system in the case of C60. In contrast, the corresponding reaction with Sc3N@Ih‐C80 switches to the C−H insertion pathway, thereby resulting in multiple isomers, including a carbazole‐derived [6,6]‐azametallofulleroid 3 and a [5,6]‐azametallofulleroid 4 and an unusual 1,2,3,6‐tetrahydropyrrolo[3,2‐c]carbazole‐derived metallofullerene 5, whose molecular structures have been unambiguously determined by single‐crystal X‐ray diffraction analyses. Among them, the addition type of 5 is observed for the first time in all reported additions of azides to fullerenes. Furthermore, unexpected isomerizations from 3 to 5 and from 4 to 5 have been discovered, providing the first examples of the isomerization of an azafulleroid to a carbazole‐derived fullerene rather than an aziridinofullerene. In particular, the isomerism of the [5,6]‐isomer 4 to the [5,6]‐isomer 5 is unprecedented in fullerene chemistry, contradicting the present understanding that isomerization generally occurs between [5,6]‐ and [6,6]‐isomers. Control experiments have been carried out to rationalize the reaction mechanism. Furthermore, representative azafulleroids have been applied in organic solar cells, thereby resulting in improved power conversion efficiencies. [ABSTRACT FROM AUTHOR]

Herein, we report divergent additions of 2,2′‐diazidobiphenyls to C60 and Sc3N@Ih‐C80. In stark contrast to that of the previously reported bis‐azide additions, the unexpected cascade reaction leads to the dearomative formation of azafulleroids 2 fused with a 7‐6‐5‐membered ring system in the case of C60. In contrast, the corresponding reaction with Sc3N@Ih‐C80 switches to the C−H insertion pathway, thereby resulting in multiple isomers, including a carbazole‐derived [6,6]‐azametallofulleroid 3 and a [5,6]‐azametallofulleroid 4 and an unusual 1,2,3,6‐tetrahydropyrrolo[3,2‐c]carbazole‐derived metallofullerene 5, whose molecular structures have been unambiguously determined by single‐crystal X‐ray diffraction analyses. Among them, the addition type of 5 is observed for the first time in all reported additions of azides to fullerenes. Furthermore, unexpected isomerizations from 3 to 5 and from 4 to 5 have been discovered, providing the first examples of the isomerization of an azafulleroid to a carbazole‐derived fullerene rather than an aziridinofullerene. In particular, the isomerism of the [5,6]‐isomer 4 to the [5,6]‐isomer 5 is unprecedented in fullerene chemistry, contradicting the present understanding that isomerization generally occurs between [5,6]‐ and [6,6]‐isomers. Control experiments have been carried out to rationalize the reaction mechanism. Furthermore, representative azafulleroids have been applied in organic solar cells, thereby resulting in improved power conversion efficiencies. [ABSTRACT FROM AUTHOR]

Patterned graphene‐functionalization with a tunable degree of functionalization can tailor the properties of graphene. Here, we present a new reductive functionalization approach combined with lithography rendering patterned graphene‐functionalization easily accessible. Two types of covalent patterning of graphene were prepared and their structures were unambiguously characterized by statistical Raman spectroscopy together with scanning electron microscopy/energy‐dispersive X‐ray spectroscopy (SEM‐EDS). The reversible defunctionalization processes, as revealed by temperature‐dependent Raman spectroscopy, enable the possibility to accurately modulate the degree of functionalization by annealing. This allows for the management of chemical information through complete write/store/erase cycles. Based on our strategy, controllable and efficient patterning graphene‐functionalization is no longer a challenge and facilitates the development of graphene‐based devices. [ABSTRACT FROM AUTHOR]

Patterned graphene‐functionalization with a tunable degree of functionalization can tailor the properties of graphene. Here, we present a new reductive functionalization approach combined with lithography rendering patterned graphene‐functionalization easily accessible. Two types of covalent patterning of graphene were prepared and their structures were unambiguously characterized by statistical Raman spectroscopy together with scanning electron microscopy/energy‐dispersive X‐ray spectroscopy (SEM‐EDS). The reversible defunctionalization processes, as revealed by temperature‐dependent Raman spectroscopy, enable the possibility to accurately modulate the degree of functionalization by annealing. This allows for the management of chemical information through complete write/store/erase cycles. Based on our strategy, controllable and efficient patterning graphene‐functionalization is no longer a challenge and facilitates the development of graphene‐based devices. [ABSTRACT FROM AUTHOR]

Carbon nanotubes (CNTs) have unusual physical properties that are valuable for nanotechnology and electronics, but the chemical synthesis of chirality‐ and diameter‐specific CNTs and π‐conjugated CNT segments is still a great challenge. Reported here are the selective syntheses, isolations, characterizations, and photophysical properties of two novel chiral conjugated macrocycles ([4]cyclo‐2,6‐anthracene; [4]CAn2,6), as (−)/(+)‐(12,4) carbon nanotube segments. These conjugated macrocyclic molecules were obtained using a bottom‐up assembly approach and subsequent reductive elimination reaction. The hoop‐shaped molecules can be directly viewed by a STM technique. In addition, chiral enantiomers with (−)/(+) helicity of the [4]CAn2,6 were successfully isolated by HPLC. The new tubular CNT segments exhibit large absorption and photoluminescence redshifts compared to the monomer unit. The carbon enantiomers are also observed to show strong circularly polarized luminescence (glum≈0.1). The results reported here expand the scope of materials design for bottom‐up synthesis of chiral macrocycles and enrich existing knowledge of their optoelectronic properties. [ABSTRACT FROM AUTHOR]

Carbon nanotubes (CNTs) have unusual physical properties that are valuable for nanotechnology and electronics, but the chemical synthesis of chirality‐ and diameter‐specific CNTs and π‐conjugated CNT segments is still a great challenge. Reported here are the selective syntheses, isolations, characterizations, and photophysical properties of two novel chiral conjugated macrocycles ([4]cyclo‐2,6‐anthracene; [4]CAn2,6), as (−)/(+)‐(12,4) carbon nanotube segments. These conjugated macrocyclic molecules were obtained using a bottom‐up assembly approach and subsequent reductive elimination reaction. The hoop‐shaped molecules can be directly viewed by a STM technique. In addition, chiral enantiomers with (−)/(+) helicity of the [4]CAn2,6 were successfully isolated by HPLC. The new tubular CNT segments exhibit large absorption and photoluminescence redshifts compared to the monomer unit. The carbon enantiomers are also observed to show strong circularly polarized luminescence (glum≈0.1). The results reported here expand the scope of materials design for bottom‐up synthesis of chiral macrocycles and enrich existing knowledge of their optoelectronic properties. [ABSTRACT FROM AUTHOR]

A few‐layer fullerene network possesses several advantageous characteristics, including a large surface area, abundant active sites, high charge mobility, and an appropriate band gap and band edge for solar water splitting. Herein, we report for the first time that the few‐layer fullerene network shows interesting photocatalytic performance in pure water splitting into H2 and H2O2 in the absence of any sacrificial reagents. Under optimal conditions, the H2 and H2O2 evolution rates can reach 91 and 116 μmol g−1 h−1, respectively, with good stability. This work demonstrates the novel application of the few‐layer fullerene network in the field of energy conversion. [ABSTRACT FROM AUTHOR]

A few‐layer fullerene network possesses several advantageous characteristics, including a large surface area, abundant active sites, high charge mobility, and an appropriate band gap and band edge for solar water splitting. Herein, we report for the first time that the few‐layer fullerene network shows interesting photocatalytic performance in pure water splitting into H2 and H2O2 in the absence of any sacrificial reagents. Under optimal conditions, the H2 and H2O2 evolution rates can reach 91 and 116 μmol g−1 h−1, respectively, with good stability. This work demonstrates the novel application of the few‐layer fullerene network in the field of energy conversion. [ABSTRACT FROM AUTHOR]

Metal cyanide clusterfullerenes (CYCFs) are formed via the encapsulation of a single metal atom and a cyanide unit inside fullerene cages, endowing them with excellent properties in various applications. In this work, we report the synthesis, isolation, and characterizations of the first cases of thulium (Tm)-based CYCFs with the popular C82 carbon cages. The structural elucidation of the two TmCN@C82 isomers was achieved via diverse analytical techniques, including mass spectrometry, Vis-NIR spectroscopy, single-crystal X-ray crystallography, and cyclic voltammetry. The crystallographic analyses unambiguously confirmed the molecular structures of the two TmCN@C82 isomers as TmCN@Cs(6)-C82 and TmCN@C2v(9)-C82. Both TmCN clusters adopt a well-established triangular configuration, with the Tm ion located on the symmetrical plane of the carbon cages. The electronic structures of both TmCN@C82 isomers adopt a Tm3+(CN)−@(C82)2− configuration, exhibiting characteristic spectral and electrochemical properties reminiscent of divalent endohedral metallofullerenes (EMFs). Intriguingly, unlike the divalent Tm2+ ion observed in the mono-metallofullerenes Tm@C2n, a higher oxidation state of Tm3+ is identified in the monometallic TmCN cluster due to bonding with the cyanide anion. This result provides valuable insight into the essential role of the non-metallic endo-units in governing the oxidation state of the metal ion and the electronic behaviors of EMFs. [ABSTRACT FROM AUTHOR]

Using a reductive sidewall functionalization concept, we prepared for the first time a covalent inter‐carbon‐allotrope hybrid consisting of single‐walled carbon nanotubes (SWCNTs) and the endohedral fullerene Sc3N@C80. The new compound type was characterized through a variety of techniques including absorption spectroscopy, Raman spectroscopy, TG‐MS, TG‐GC‐MS, and MALDI‐TOF MS. HRTEM investigations were carried out to visualize this highly integrated architecture. [ABSTRACT FROM AUTHOR]

Using a reductive sidewall functionalization concept, we prepared for the first time a covalent inter‐carbon‐allotrope hybrid consisting of single‐walled carbon nanotubes (SWCNTs) and the endohedral fullerene Sc3N@C80. The new compound type was characterized through a variety of techniques including absorption spectroscopy, Raman spectroscopy, TG‐MS, TG‐GC‐MS, and MALDI‐TOF MS. HRTEM investigations were carried out to visualize this highly integrated architecture. [ABSTRACT FROM AUTHOR]

Endohedral metallofullerenes (EMFs) are one type of intriguing metal/carbon hybrid molecule with the molecule configuration of sphere cavity-encapsulating metal ions/metal clusters due to their unique physicochemical properties and corresponding application in the fields of biological materials, single molecule magnet materials and energy conversion materials. Although the EMF family is growing, and versatile EMFs have been successfully synthesized and confirmed using crystal structures, some expected EMF members have not been observed using the conventional fullerene separation and purify strategy. These missing EMFs raise an interesting scientific issue as to whether this is due to the difficulty in separating them from the in situ formed carbon soot. Herein, we successfully captured a long-sought dysprosium-based EMF bearing a C2v(5)-C80 cage (Dy@C2v(5)-C80) in the form of Dy@C2v(5)-C80(CH2Ph)(Ph = −C6H5) from carbon soot containing versatile EMFs using simple benzyl radical functionalization and unambiguously confirmed the molecule structure using single crystal X-ray diffraction characterization. Meanwhile, the crystal structure of Dy@C2v(5)-C80(CH2Ph) showed that a single benzyl group was grafted onto the (5,6,6)-carbon, suggesting the open-shell electronic configuration of Dy@C2v(5)-C80. The theoretical calculations unveiled that the benzyl radical addition enables the modulation of the electronic configuration of Dy@C2v(5)-C80 and the corresponding stabilization of Dy@C2v(5)-C80 in conventional organic solvents. This facile stabilization strategy via benzyl radical addition exhibits the considerable capability to capture these missing EMFs, with the benefit of enriching the endohedral fullerene family. [ABSTRACT FROM AUTHOR]

In tin perovskite solar cells (PSCs), fullerene (C60) and fullerene derivative [6,6]‐phenyl‐C61‐butyric acid methyl ester (PCBM) are commonly utilized electron transport materials. However, the energetic disorder, inadequate passivation, and energy level mismatch of C60 and PCBM limit the improvement of power conversion efficiency (PCE) and lifespan of tin PSCs. In this work, a multifunctional interface manipulation strategy is developed by introducing a pyridine‐functionalized fullerene derivative, fullerene‐n‐butyl‐pyridine (C60‐BPy), into the interface between the tin perovskite and the electron transport layer (ETL) to improve the photovoltaic performance and stability of tin PSCs. The C60‐BPy can strongly anchor on the perovskite surface via coordination interactions between the pyridine moiety and the Sn2+ ion, which not only reinforces the passivation of the trap‐state within the tin perovskite film, but also regulates the interface energy level alignment to reduce non‐radiative recombination. Moreover, the improved interface binding and carrier transport properties of C60‐BPy contribute to superior device stability. The resulting devices have achieved the highest PCE of 14.14% with negligible hysteresis, and are maintained over 95% of their initial PCE under continuous one‐sun illumination for 1000 h. [ABSTRACT FROM AUTHOR]

Sonodynamic therapy (SDT) triggered by ultrasound represents an emerging tumor therapy approach with minimally invasive treatment featuring nontoxicity and deep tissue‐penetration, and its efficacy sensitively depends on the sonosensitizer which determines the generation of reactive oxygen species (ROS). Herein, for the first time covalently functionalized few‐layer black phosphorus nanosheets (BPNSs) are applied as novel sonosensitizers in SDT, achieving not only boosted SDT efficacy but also inhibited cytotoxicity relative to the pristine BPNSs. Three different covalently functionalized‐BPNSs are synthesized, including the first fullerene‐functionalized BPNSs with C60 covalently bonded onto the surface of BPNSs (abbreviated as C60‐s‐BP), surface‐functionalized BPNSs by benzoic acid (abbreviated as BA‐s‐BP), and edge‐functionalized BPNSs by C60 (abbreviated as C60‐e‐BP), and the role of covalent functionalization pattern of BPNSs on its SDT efficacy is systematically investigated. Except C60‐e‐BP, both surface‐functionalized BPNSs (C60‐s‐BP, BA‐s‐BP) exhibit higher SDT efficacies than the pristine BPNSs, while the highest SDT efficacy is achieved for BA‐s‐BP due to its strongest capability of generating the hydroxyl (·OH) radicals, which act as the dominant ROS to kill the tumor cells. [ABSTRACT FROM AUTHOR]

Direct π-extension by the Scholl reaction for solution-based growth of armchair edges in curved macrocyclic hydrocarbon nanostructures is a great challenge. To date, several attempts at direct π-extension of small highly strained macrocycles have failed. Herein, we report a fixed two-bond approach for direct functionalization of small strained macrocyclic nanorings. The reaction occurs selectively to produce large π-extended molecular crowns with high yields. The design of these precursors features two peripheral C–C bonds that are readily incorporated into the extended aromatic moiety to overcome strain-induced side reactions, such as 1,2-phenyl shift. The crown-shaped macrocycle 10 showed a significant redshift (∼100 nm for absorption) compared with its precursor. This synthesis strategy could pave the way towards the π-extension of strained conjugated macrocycles and their potential applications in electron-transport devices. [ABSTRACT FROM AUTHOR]

Edge-selectively passivated BP nanosheets with fullerene C 70 covalently grafted at the edge (BPNSs-C 70) is synthesized through a facile solid-state mechanochemical route, leading to dramatic enhancements of not only the ambient stability but also the antibacterial activities. BPNSs-C 70 exhibits superior in vitro and in vivo antibacterial efficacies against MRSA attributed to the synergistically improved singlet oxygen (1O 2) and hydroxyl radicals (•OH) generation originated from the intramolecular electron transfer from BPNSs to C 70. [Display omitted] • Few-layer BPNSs were covalently functionalized by edge-selectively grafting C 70. • Covalent P-C bonds between BPNSs and C 70 form within BPNSs-C 70 hybrid. • Upon grafting C 70 , the ambient stability of BPNSs is dramatically enhanced. • For the first time the covalently functionalized BPNSs is employed in disinfection. • BPNSs-C 70 exhibits boosted in vitro and in vivo antibacterial efficacies. In the fight against bacterial infection, conventional antibiotic treatment encounters the formidable challenges of drug resistance and sluggish development. Non-metallic two-dimensional (2D) nanomaterials such as black phosphorus (BP) have emerged as promising non-antibiotic antimicrobial candidates due to its peculiar physiochemical properties, but face hurdles including low ambient stability and limited antibacterial activity, hindering its widespread utilization in disinfection. Herein, few-layer BP nanosheets (BPNSs) were covalently passivated by edge-selectively grafting fullerene C 70 via a one-step solid-state mechanochemical route, and for the first time the covalently functionalized BPNSs is employed in disinfection. Fullerene edge-selective covalent passivation not only effectively overcomes the obstacles of poor ambient stability, but also substantially enhances the antibacterial activities of BPNSs. The BPNSs-C 70 hybrid (denoted as BPNSs-C 70) was applied as a novel non-metallic and non-antibiotic nano-antibacterial agent. Under 660 nm visible light irradiation, BPNSs-C 70 demonstrates high generation capacity of reactive oxygen species (ROS), resulting in boosted in vitro and in vivo antibacterial efficacies against methicillin-resistant Staphylococcus aureus (MRSA) relative to the pristine BPNSs with exceptional biocompatibility. The significantly enhanced antibacterial performance of BPNSs-C 70 is attributed to the synergistically improved singlet oxygen (1O 2) and hydroxyl radicals (•OH) generation originated from the intramolecular electron transfer from BPNSs to C 70. [ABSTRACT FROM AUTHOR]

Innenrücktitelbild: Highly Efficient and Reversible Covalent Patterning of Graphene: 2D-Management of Chemical Information (Angew. Keywords: Graphen; Kovalente Strukturierung; Raman-Spektroskopie; Strukturierte Funktionalisierung EN Graphen Kovalente Strukturierung Raman-Spektroskopie Strukturierte Funktionalisierung 5901 5901 1 03/23/20 20200327 NES 200327 B Die räumlich aufgelöste kovalente Strukturierung b von Graphen wurde durch die Anwendung dreier Reaktionsprinzipien erreicht: reduktive Aktivierung des Kohlenstoffgitters, antaratopische Bindung sowie klassische Lithographie. Wie A. Hirsch et al. in ihrer Zuschrift auf S. 5651 zeigen, ermöglicht die reversible Defunktionalisierung des strukturierten Graphens die Speicherung chemischer Information, wobei vollständige Schreib/Speicher/Lösch-Zyklen etabliert werden. [Extracted from the article]

Despite recent successes in preparing three‐dimensional crystals of empty fullerenes, such as C60 and C70, 3D endohedral fullerene crystals, and especially hollow nanostructures, have been scarcely reported. A universal approach has now been developed to prepare shape‐tunable 3D crystals of several metal nitride clusterfullerenes, including cubes and dice (hollow cubes with holes at the center of each face), which can be readily switched by changing the volume ratio of good (mesitylene) and poor (isopropanol) solvents. Synchrotron‐based soft X‐ray nano‐computed tomography was used to unambiguously identify the interior microstructure of the dice‐shaped crystals of Tb3N@C80, and especially the depth of the hole at each face, confirming that the dice has a solid center and the holes are not interconnected. Owing to the enhanced light absorption, the dice‐shaped crystals exhibit enhanced photoluminescence relative to that of the cubes. [ABSTRACT FROM AUTHOR]

Despite recent successes in preparing three‐dimensional crystals of empty fullerenes, such as C60 and C70, 3D endohedral fullerene crystals, and especially hollow nanostructures, have been scarcely reported. A universal approach has now been developed to prepare shape‐tunable 3D crystals of several metal nitride clusterfullerenes, including cubes and dice (hollow cubes with holes at the center of each face), which can be readily switched by changing the volume ratio of good (mesitylene) and poor (isopropanol) solvents. Synchrotron‐based soft X‐ray nano‐computed tomography was used to unambiguously identify the interior microstructure of the dice‐shaped crystals of Tb3N@C80, and especially the depth of the hole at each face, confirming that the dice has a solid center and the holes are not interconnected. Owing to the enhanced light absorption, the dice‐shaped crystals exhibit enhanced photoluminescence relative to that of the cubes. [ABSTRACT FROM AUTHOR]

Two‐dimensional (2D) black phosphorus (BP) has a unique band structure, but it suffers from low ambient stability owing to its high reactivity to oxygen. Covalent functionalization has been demonstrated to passivate the reactive BP effectively, however the reported covalent functionalization methods are quite limited to aryl diazonium and nucleophilic additions affording P−C and P−O−C single bonds, for which the retaining of one unpaired electron in the Group 15 phosphorus atom hampers the passivation effect. Now, covalent azide functionalization of BP nanosheets (BPNSs) is reported, leading to significant enhancement of the ambient stability of BP as confirmed by UV/Vis spectroscopic studies. The most stable configuration of the azide functionalized BPNSs (f‐BPNSs) is predicted by theoretical calculations, featuring the grafting of benzoic acid moiety onto BPNSs via the unprecedented P=N double bonds formed through in situ nitrene as a reactive intermediate. Stabilizing black phosphorus (BP) via azide passivation: Azide functionalization is developed as a new covalent functionalization approach of BP nanosheets (BPNSs), leading to the formation of unprecedented P=N double bonds. These passivate the reactive BPNSs effectively and contribute to a dramatic enhancement of the ambient stability of BPNSs, with the degradation ratio inhibited by about 12 times relative to the pristine BPNSs. [ABSTRACT FROM AUTHOR]

Two‐dimensional (2D) black phosphorus (BP) has a unique band structure, but it suffers from low ambient stability owing to its high reactivity to oxygen. Covalent functionalization has been demonstrated to passivate the reactive BP effectively, however the reported covalent functionalization methods are quite limited to aryl diazonium and nucleophilic additions affording P−C and P−O−C single bonds, for which the retaining of one unpaired electron in the Group 15 phosphorus atom hampers the passivation effect. Now, covalent azide functionalization of BP nanosheets (BPNSs) is reported, leading to significant enhancement of the ambient stability of BP as confirmed by UV/Vis spectroscopic studies. The most stable configuration of the azide functionalized BPNSs (f‐BPNSs) is predicted by theoretical calculations, featuring the grafting of benzoic acid moiety onto BPNSs via the unprecedented P=N double bonds formed through in situ nitrene as a reactive intermediate. [ABSTRACT FROM AUTHOR]

Abstract: Rare‐earth metals have been mostly entrapped into fullerene cages to form endohedral clusterfullerenes, whereas non‐Group‐3 transition metals that can form clusterfullerenes are limited to titanium (Ti) and vanadium (V), and both are exclusively entrapped within an Ih‐C80 cage. Non‐Group‐3 transition‐metal‐containing endohedral fullerenes based on a C80 cage with D5h symmetry, VxSc3−xN@D5h‐C80 (x=1, 2), have now been synthesized, which exhibit two variable cluster compositions. The molecular structure of VSc2N@D5h‐C80 was unambiguously determined by X‐ray crystallography. According to a comparative study with the reported Ti‐ and V‐containing clusterfullerenes based on a Ih‐C80 cage and the analogous D5h‐C80‐based metal nitride clusterfullerenes containing rare‐earth metals only, the decisive role of the non‐Group‐3 transition metal on the formation of the corresponding D5h‐C80‐based clusterfullerenes is unraveled. [ABSTRACT FROM AUTHOR]

Abstract: Rare‐earth metals have been mostly entrapped into fullerene cages to form endohedral clusterfullerenes, whereas non‐Group‐3 transition metals that can form clusterfullerenes are limited to titanium (Ti) and vanadium (V), and both are exclusively entrapped within an Ih‐C80 cage. Non‐Group‐3 transition‐metal‐containing endohedral fullerenes based on a C80 cage with D5h symmetry, VxSc3−xN@D5h‐C80 (x=1, 2), have now been synthesized, which exhibit two variable cluster compositions. The molecular structure of VSc2N@D5h‐C80 was unambiguously determined by X‐ray crystallography. According to a comparative study with the reported Ti‐ and V‐containing clusterfullerenes based on a Ih‐C80 cage and the analogous D5h‐C80‐based metal nitride clusterfullerenes containing rare‐earth metals only, the decisive role of the non‐Group‐3 transition metal on the formation of the corresponding D5h‐C80‐based clusterfullerenes is unraveled. [ABSTRACT FROM AUTHOR]

Fullerene derivatives especially [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) with strong electron-accepting abilities have been commonly implemented as indispensable cathode buffer layers (CBLs) of inverted (p-i-n) planar perovskite solar cells (iPSCs) to facilitate electron transport. However, only a single fullerene CBL is typically used in iPSC devices, resulting in interfacial energy offset between fullerene CBL and metal cathode and consequently insufficient electron transport. Herein, we synthesized a novel bis-dimethylamino-functionalized fullerene derivative (abbreviated as PCBDMAM) and applied it as an auxiliary fullerene interlayer atop of PCBM to form a PCBM/PCBDMAM double fullerene CBL, leading to dramatic enhancement of both efficiency and ambient stability of iPSC devices. Incorporation of PCBDMAM interlayer facilitates the formation of interfacial dipole layer between PCBM and Ag cathode, resulting in decrease of the work function of the Ag cathode. As a result, the CH 3 NH 3 PbI 3 (MAPbI 3) iPSC devices based on PCBM/PCBDMAM double fullerene CBL exhibit the highest power conversion efficiency (PCE) of 18.11%, which is drastically higher than that of the control device based on single PCBM CBL (14.21%) and represents the highest value reported for double fullerene CBL-based iPSC devices. Moreover, due to the higher hydrophobicity of PCBDMAM than PCBM, iPSC devices based on PCBM/PCBDMAM double fullerene CBL shows an enhanced ambient stability, retaining 67% of the initial PCE after storage 1440 h exposure under the ambient atmosphere without any encapsulation, whereas only 43% retaining was achieved for the control device based on single PCBM CBL. Two is better than one : A novel bis-dimethylamino-functionalized fullerene derivative (PCBDMAM) was synthesized and deposited atop of PCBM to construct PCBM/PCBDMAM double fullerene cathode buffer layers (CBLs) in inverted perovskite solar cells (iPSCs), leading to dramatic enhancements of both efficiency and ambient stability of iPSC devices owing to the minimized interfacial energy offset between PCBM CBL and Ag cathode resulted from decrease of the work function of the Ag cathode. Image 1 • Device with PCBM/PCBDMAM double fullerene CBLs exhibit dramatic enhancements of both efficiency and ambient stability. • The minimized interfacial energy offset between PCBM and Ag cathode resulted the decreased work function of Ag cathode. • A highest PCE of 18.11% was achieved for the iPSCs with PCBM/PCBDMAM double fullerene cathode buffer layers. [ABSTRACT FROM AUTHOR]

A novel polyethylene glycol-functionalized fullerene derivative (C 60 -PEGA) was synthesized by a facile one-step nucleophilic addition reaction. C 60 -PEGA possessed good solubility in methanol and was estimated as C 60 -(C 8 H 18 N) 13 H 13 O with average PEG moiety of 13 by 1H NMR, FT-IR and X-ray photoelectron spectroscopy (XPS). C 60 -PEGA was applied as an ETL to construct inverted bulk heterojunction polymer solar cells (inverted BHJ-PSCs) based on photoactive layers of poly[4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2- b :4,5- b ′]dithiophene-co-3-fluorothieno[3, 4-b]thiophene-2-carboxylate]: [6,6]-phenyl-C 71 -butyric acid methyl ester (PTB7-Th: PC 71 BM), which achieve the best PCE of 9.25%, surpassing that of reference device based on the ZnO ETL (8.61%). The higher ETL performance of C 60 -PEGA ETL in BHJ-iPSC device relative to that of the ZnO ETL was attributed to the increase of electron mobility and effective electron transport from the active layer to the ITO cathode because that the reduced work function (WF) of ITO via the modification of C 60 -PEGA leads to the increase of short-circuit current density (Jsc) and consequent PCE. A novel polyethylene glycol-functionalized fullerene derivative (C 60 -PEGA) was successfully achieved by one-step nucleophilic addition reaction and applied as electron transport layer (ETL) in inverted polymer solar cells with active layer of PTB7-Th: PC 71 BM, exhibiting superior ETL performance with PCE of 9.25% relative to that of ZnO-based device (8.61%) due to the promoted electron transport capability. Image 1 • Novel polyethylene glycol-functionalized fullerene derivative (C 60 -PEGA) was successfully synthesized via facile one-step reaction and was confirmed as C 60 -(C 8 H 18 N) 13 H 13 O. • C 60 -PEGA exhibits superior solubility in methanol and was speculated to act as electron transport layer (ETL) in inverted polymer solar cells. • C 60 -PEGA as ETL in inverted polymer solar cell achieves the power conversion efficiency (PCE) of 9.25%, surpassing that of reference device based on the ZnO ETL(8.61%). • C 60 -PEGA ETL in inverted polymer solar cells shows higher electron mobility than that of device with ZnO ETL. • C 60 -PEGA ETL enable the modification of ITO in inverted polymer solar cell, leading to the decrease of work function of ITO and corresponding improved electron transport. [ABSTRACT FROM AUTHOR]