Steering LuN clusters in C cages: cluster configuration dominated by cage transformation.

While the strong interaction between the internal unit and the fullerene cage inside metallofullerenes is widely acknowledged, how the cage transformation interacts with the cluster configuration remains elusive. For this purpose, we herein synthesized three metallofullerene molecules with an easy-to-compare cluster configuration and cage arrangement, namely LuN@(17 490)-C, LuN@(22 010)-C, and LuN@(5)-C. The three lutetium-based nitride clusterfullerenes (NCFs) with small C carbon cages were synthesized by a modified arc-discharge method and their structures were unambiguously confirmed by X-ray crystallography.

Regioselective Radical Reaction of Monometallofullerene Y@C(9)-C With N-arylbenzamidine Mediated by Silver Carbonate.

A novel radical reaction of monometallofullerene Y@C(9)-C with N-arylbezamidine () is successfully conducted through catalysis with silver carbonate. The high-performance liquid chromatographic and mass spectrum results demonstrate that the reaction is highly regioselective to afford only one monoadduct () with an imidazoline group added on C cage, and computations through density functional theory reveal the addition group is attached to a specific [5, 6]-bond (C20-C76) near the Y atom. Furthermore, the analysis of prymidalization angle of the carbon atoms demonstrates the geometry of carbon cage is in favor of the regioselective formation of isomer (20, 76).

Three-Dimensional Cubic and Dice-Like Microstructures of Higher Fullerene C with Enhanced Photoelectrochemical and Photoluminescence Properties.

The single-crystal micro/nanostructures of fullerene species, namely C and C , have been previously studied, but studies on the morphology and properties of higher fullerenes have rarely been reported due to the limited amount of samples and their ellipsoidal isomeric structures. Herein, we report the formation of three-dimensional (3D) micro-cubes and micro-dice of a higher fullerene (C ) via a facile liquid-liquid interfacial precipitation (LLIP) method. The micro-cubes were prepared by regulating the concentration of C in trimethylbenzene (TMB) and the volume ratio of TMB and isopropanol.

Crystallographic Characterization of TiC@(5)-C, TiC@(8)-C, and TiC@(6)-C: Identification of Unsupported TiC Cluster with Cage-Dependent Configurations.

Fullerene cages are ideal hosts to encapsulate otherwise unstable metallic clusters to form endohedral metallofullerenes (EMFs). Herein, a novel TiC cluster with two titanium atoms bridged by a C-unit has been stabilized by three different fullerene cages to form TiC@(5)-C, TiC@(8)-C, and TiC@(6)-C, representing the first examples of unsupported titanium carbide clusters. Crystallographic results show that the configuration of the TiC cluster changes upon cage variation.

Trapping an unprecedented TiC unit inside the icosahedral C fullerene: a crystallographic survey.

The sub-nanometer cavity of fullerene cages is an ideal platform to accommodate otherwise unstable species for accurate structural characterization with, for example, rather accurate single crystal X-ray diffraction (XRD) crystallography. Herein, we report the successful entrapment of an isolated TiC moiety inside the icosahedral-C cage to form TiC@I-C an arc-evaporation process in the gas phase. The single crystal XRD crystallographic results unambiguously reveal that the C-unit adopts an unprecedented cyclopropane-like structure which coordinates with the three titanium atoms in an unexpected fashion where the triangular C-unit is nearly perpendicular to the Ti-plane.

Preferential Formation of Mono-Metallofullerenes Governed by the Encapsulation Energy of the Metal Elements: A Case Study on Eu@C (2n=74-84) Revealing a General Rule.

Encapsulating one to three metal atoms or a metallic cluster inside fullerene cages affords endohedral metallofullerenes (EMFs) classified as mono-, di-, tri-, and cluster-EMFs, respectively. Although the coexistence of various EMF species in soot is common for rare-earth metals, we herein report that europium tends to prefer the formation of mono-EMFs. Mass spectroscopy reveals that mono-EMFs (Eu@C ) prevail in the Eu-containing soot.

Crystallographic characterization of ErN@C (2n = 80, 82, 84, 88): the importance of a planar ErN cluster.

A series of Er-based nitride clusterfullerenes (NCFs), ErN@C, have been successfully synthesized and isolated. In particular, ErN@I(7)-C, ErN@D(6)-C, ErN@C(9)-C, ErN@C(51365)-C, and ErN@D(35)-C have been characterized by single-crystal X-ray diffraction (XRD) for the first time. The planar configuration of the inserted ErN cluster is identified unambiguously and the Er-N distances increase in accordance with cage expansion to maintain strong metal-cage interactions.

Highly regioselective complexation of tungsten with Eu@C/Eu@C: interplay between endohedral and exohedral metallic units induced by electron transfer.

Interactions between the inner and outer units through a fullerene cage are of fundamental importance for the creation of molecular spintronics and machines, but the mechanism of such through-cage interplay is still unclear. In this work, we have designed and synthesized two prototypical compounds which contain only a single europium atom inside the cage and merely a tungsten atom coordinating outside to clarify the interactions between the endohedral and exohedral metallic units. They are obtained by reacting a tungsten complex W(CO)(PhPCHPPh) () with the corresponding metallofullerenes in a highly regioselective manner ( for Eu@ (5)-C and for Eu@ (13)-C).

Intermolecular packing and charge transfer in metallofullerene/porphyrin cocrystals.

Charge transfer in metallofullerene/porphyrin cocrystals is revealed for the first time. Originated from the different solvents for crystallization, distinct stacking manners are presented in the two types of cocrystals. It is demonstrated that intermolecular packing, next to the nature of the corresponding electron donors and acceptors, dominates the charge transfer processes.

Crystallographic identification of Eu@C (2 = 88, 86 and 84): completing a transformation map for existing metallofullerenes.

Revealing the transformation routes among existing fullerene isomers is key to understanding the formation mechanism of fullerenes which is still unclear now because of the absence of typical key links. Herein, we have crystallographically identified four new fullerene cages, namely, (27)-C, (7)-C, (13)-C and (11)-C, in the form of Eu@C , which are important links to complete a transformation map that contains as many as 98% (176 compounds in total) of the reported metallofullerenes with clear cage structures (C , 2 = 86-74). Importantly, the mutual transformations between the metallofullerene isomers included in the map require only one or two well-established steps (Stone-Wales transformation and/or C insertion/extrusion).