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Herein, we performed the reactions of M3N@Ih-C80(M = Sc and Lu) with the methanol (CH3OH) solution of TBAOH (note that both CH3O–and OH–are nucleophiles) in benzonitrile (PhCN) and dimethylformamide, respectively. It is found that OH–ions rather than CH3O–ions selectively attacked the fullerene cage to form the M3N@C80––O–intermediate. Although the fullerene cage is initially attacked by OH–in both PhCN and DMF solvents, the products are quite different. In PhCN, two isomeric Sc3N@Ih-C80fullerooxazoline heterocyclic products (1and 2) were synthesized. Whereas, in DMF, an epoxide of Lu3N@Ih-C80(3) was obtained. The preference for fullerooxazoline formation over that of fullerene epoxy in PhCN is well explained by density functional theory calculations. Plausible reaction mechanisms for the formation of metallofullerene oxazoline and epoxide were proposed based on the experimental and theoretical results.

Azafullerenes derived from nitrogen substitution of carbon cage atoms render direct modifications of the cage skeleton, electronic, and physicochemical properties of fullerene. Gas-phase ionized monometallic endohedral azafullerene (MEAF) [La@C81N]+formed via fragmentation of a La@C82monoadduct was detected in 1999, but the pristine MEAF has never been synthesized. Here, we report the synthesis, isolation, and characterization of the first pristine MEAF La@C81N, tackling the two-decade challenge. Single-crystal X-ray diffraction study reveals that La@C81N has an 82-atom cage with a pseudo C3v(8) symmetry. According to DFT computations, the nitrogen substitution site within the C82cage is proposed to locate at a hexagon/hexagon/pentagon junction far away from the encapsulated La atom. La@C81N exists in stable monomer form with a closed-shell electronic state, which is drastically different from the open-shell electronic state of the original La@C82. Our breakthrough in synthesizing a new type of azafullerene offers a new insight into the skeletal modification of fullerenes.

Despite their multifaceted advantages, inverted perovskite solar cells (PSCs) still suffer from lower power conversion efficiencies (PCEs) than their regular counterparts, which is largely due to recombination energy losses (Eloss) that arise from the chemical, physical, and energy level mismatches, especially at the interfaces between perovskites and fullerene electron transport layers (ETLs). To address this problem, we herein introduce an aminium iodide derivative of a buckybowl (aminocorannulene) that is molecularly layered at the perovskite–ETL interface. Strikingly, besides passivating the PbI2-rich perovskite surface, the aminocorannulene enforces a vertical dipole and enhances the surface n-type character that is more compatible with the ETL, thus boosting the electron extraction and transport dynamics and suppressing interfacial Eloss. As a result, the champion PSC achieves an excellent PCE of over 22%, which is superior compared to that of the control device (∼20%). Furthermore, the device stability is significantly enhanced, owing to a lock-and-key-like grip on the mobile iodides by the buckybowls and the resultant increase of the interfacial ion-migration barrier. This work highlights the potential of buckybowls for the multifunctional surface engineering of perovskite toward high-performance and stable PSCs.

Monometallic cyanide clusterfullerenes (CYCFs) represent a unique branch of endohedral clusterfullerenes with merely one metal atom encapsulated, offering a model system for elucidating structure–property correlation, while up to now only C82and C76cages have been isolated for the pristine CYCFs. C84is one of the most abundant fullerenes and has 24 isomers obeying the isolated pentagon rule (IPR), among which 14 isomers have been already isolated, whereas the C2v(17)-C84isomer has lower relative energy than several isolated isomers but never been found for empty and endohedral fullerenes. Herein, four novel C84-based pristine CYCFs with variable encapsulated metals and isomeric cages, including MCN@C2(13)-C84(M = Y, Dy, Tb) and DyCN@C2v(17)-C84, have been synthesized and isolated, fulfilling the first identification of the missing C2v(17)-C84isomer, which can be interconverted from the C2(13)-C84isomer through two steps of Stone–Wales transformation. The molecular structures of these four C84-based CYCFs are determined unambiguously by single-crystal X-ray diffraction. Surprisingly, although the ionic radii of Y3+, Dy3+, and Tb3+differ slightly by only 0.01 Å, such a subtle difference leads to an obvious change in the metal–cage interactions, as inferred from the distance between the metal atom and the nearest hexagon center of the C2(13)-C84cage. On the other hand, upon altering the isomeric cage from DyCN@C2(13)-C84to DyCN@C2v(17)-C84, the Dy–cage distance changes as well, indicating the interplay between the encapsulated DyCN cluster and the outer cage. Therefore, we demonstrate that the metal–cage interactions within CYCFs can be steered via both internal and external routes.

A general one-step synthesis of symmetrical or unsymmetrical 1,4-di(organo)fullerenes from organo(hydro)fullerenes (RC60H) is realized by direct oxidative arylation. The new combination of catalytic trifluoromethanesulfonic acid (TfOH) and stoichiometric o-chloranil is the first to be used to directly generate an R-C60+intermediate from common RC60H. Unexpectedly, the in situ generated R-C60+intermediate is shown to be quite stable in whole 13C NMR spectroscopy characterization in the absence of cation quenching reagents. Because the direct oxidation of common RC60H to form the corresponding R-C60+has never been realized, the present combination of TfOH and o-chloranil solves the challenges associated with the formation of stable RC60+cations from common RC60H without any coordination of an R group.

The combustion has long been applied for industrial synthesis of carbon materials such as fullerenes as well as carbon particles (known as carbon black), but the components and structures of the carbon soot are far from being clarified. Herein, we retrieve an unprecedented hydrofullerene C66H4from a soot of a low-pressure combustion of benzene–acetylene–oxygen. Unambiguously characterized by single-crystal X-ray diffraction, the C66H4renders a nonclassical geometry incorporating two heptagons and two pairs of fused pentagons in a C2vsymmetry. The common vertexes of the fused pentagons are bonded with four hydrogen atoms to convert the hydrogen-linking carbon atoms from sp2to sp3hybridization, which together with the adjacent heptagons essentially releases the sp2-bond strains on the abutting-pentagon sites of the diheptagonal fused pentagon C66(dihept-C66). DFT computations suggest the possibility for an in situhydrogenation process leading to stabilization of the dihept-C66. In addition, the experiments have been carried out to study heptagon-dependent properties of dihept-C66H4, indicating the key responsibility of the heptagon for changing hydrocarbon activity and electronic properties. The present work with the unprecedented double-heptagon-containing hydrofullerene successfully isolated and identified as one of the low-pressure combustion products shows that the heptagon is a new building block for constructing fullerene products in addition to pentagons and hexagons in low-pressure combustion systems.

Herein, an adenosine triphosphate (ATP)-induced enzyme-catalyzed cascade reaction system based on metal–organic framework/alkaline phosphatase (MOF/ALP) nanocomposites was designed to establish a surface-enhanced Raman spectroscopy (SERS) biosensor for use in rapid, sensitive ATP detection. Numerous ALP molecules were first encapsulated using ZIF-90 to temporarily deactivate the enzyme activity, similar to a lock. Au nanostars (AuNSs), as SERS-enhancing substrates, were combined with o-phenylenediamine (OPD) to form AuNSs@OPD, which could significantly improve the Raman signal of OPD. When the target ATP interacted with the MOF/ALP nanocomposites, ATP could act as a key to open the MOF structure, releasing ALP, which should further catalyze the conversion of OPD to oxOPD with the aid of ascorbic acid 2-phosphate. Therefore, with the increasing concentrations of ATP, more ALP was released to catalyze the conversion of OPD, resulting in the reduced intensity of the Raman peak at 1262 cm–1, corresponding to the level of OPD. Based on this principle, the ATP-induced enzyme-catalyzed cascade reaction SERS biosensor enabled the ultrasensitive detection of ATP, with a low detection limit of 0.075 pM. Consequently, this study provides a novel strategy for use in the ultrasensitive, rapid detection of ATP, which displays considerable potential for application in the fields of biomedicine and disease diagnosis.

A molecular containerfor a single water molecule was obtained by chemical transformation of a [60]fullerene cage. A phosphate moiety acts as an effective “stopper” in the orifice (see picture).

Ein molekularer Behälterfür ein einzelnes Wassermolekül wurde durch chemische Umwandlung eines [60]Fulleren‐Käfigs erhalten. Eine Phosphatgruppe dient als ein effektiver Behälterverschluss.

Herein, a nitrogen-embedded quintuple [7]helicene (N-Q7H) with an azapentabenzocorannulene core, which can be considered to be a helicene/azacorannulene hybrid π-system, was synthesized from azapentabenzocorannulene in a three-step process. N-Q7His the first example of a multiple helicene with an azabuckybowl core. Single-crystal X-ray diffractometry unambiguously confirmed the structure of the propeller-shaped hybrid π-system. Owing to nitrogen-atom doping in the multiple helicenes and effective hybridization between the helicene and azacorannulene, N-Q7Hexhibits considerably redshifted absorption and emission (yellow-to-green color change and green-to-near-infrared fluorescence change) relative to the azapentabenzocorannulene core. The broad absorption from the ultraviolet–visible to the NIR region is ascribable to the allowed transition between the highest occupied molecular orbital and the lowest unoccupied molecular orbital after symmetry breaking, as revealed by density functional theory calculations. Compared to previous propeller-shaped multiple helicenes with corannulene or hexabenzocoronene (etc.) as cores, N-Q7Hdemonstrates a significantly higher NIR fluorescence quantum efficiency of 28%. Additionally, the chiral-resolution and redox properties of N-Q7Hwere investigated. The excellent photophysical and inherent chiral properties of N-Q7Hsuggest that azapentabenzocorannulene can be used as an outstanding nitrogen-embedded core to construct novel multiple helicenes with wide application potential, including as NIR fluorescent bio-probes.

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ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.