A Metallofullerene Electron Donor that Powers an Efficient Spin Flip in a Linear Electron Donor–Acceptor Conjugate

The dream target of artificial photosynthesis is the realization of long-lived radical ion pair states that power catalytic centers and, consequently, the production of solar fuels. Notably, magnetic field effects, especially internal magnetic field effects, are rarely employed in this context. Here, we report on a linear Lu₃N@<i>I</i>_<i>h</i>-C₈₀–PDI electron donor–acceptor conjugate, in which the presence of the Lu₃N cluster exerts an appreciable electron nuclear hyperfine coupling on the charge transfer dynamics. As such, a fairly efficient radical ion pair intersystem crossing converts the initially formed singlet radical ion pair state, ¹[(Lu₃N@<i>I</i>_<i>h</i>-C₈₀)^•+–PDI^•–], to the corresponding triplet radical ion pair state, ³[(Lu₃N@<i>I</i>_<i>h</i>-C₈₀)^•+–PDI^•–]. Most notably, the radical ion pair state lifetime of the latter is nearly 1000 times longer than that of the former

The enunciation of 'terrorism' as a kind of power and its distribution in the West

This paper is motivated by the assumption that ‘terrorism’ is a loaded and politically significant term, the use of which exudes and produces power relations. It acknowledges this, and also argues that not everyone has an equal right to use the term. This leads to an examination into the kind of power that is manifested in the use of the term, by putting the social constructivist framework to work and placing the semantic field of terrorism within that framework. It identifies a kind of power attached to the enunciation of the term ‘terrorism’ and argues that it is unequally distributed between perceived potential victims of terrorism and perceived potential perpetrators of terrorism. Drawing on Nietzsche’s genealogical analysis of morality, I argue that it is counterproductive to deny potential perpetrators the power of enunciation around the term ‘terrorism’ on the basis that this leads to a kind of slave revolt in terrorism. Redistributing the power of enunciation around the term ‘terrorism’ might remove the line that separates potential victims from potential perpetrators of terrorism and work towards reducing the threat of terrorism itself by allowing those potential perpetrators to exercise this capability within mainstream society, as opposed to seeking alternative communities to do so outside of it

Single-Crystal X‑ray Diffraction Study of Three Yb@C₈₂ Isomers Cocrystallized with Ni^II(octaethylporphyrin)

Single crystals of three soluble Yb@C₈₂ isomers, namely, Yb@<i>C</i>₂(5)-C₈₂, Yb@<i>C</i>_<i>s</i>(6)-C₈₂, and Yb@<i>C</i>_2<i>v</i>(9)-C₈₂, cocrystallized with Ni^II(octaethylporphyrin), allowed accurate crystallographic elucidation of their molecular structures in terms of both cage symmetry and metal location. Multiple metal positions were found in all these isomers, but the major metal sites were found in some specific regions within these cages. Specifically, the Yb²⁺ ion prefers to reside close to a hexagonal ring in Yb@<i>C</i>₂(5)-C₈₂ and Yb@<i>C</i>_2<i>v</i>(9)-C₈₂ but a [5,6,6]-junction carbon atom in Yb@<i>C</i>_<i>s</i>(6)-C₈₂. Theoretical calculations at the B3LYP level revealed that these metal positions all correspond to energy minima from the electrostatic potential maps and give rise to the most stable configurations of these Yb@C₈₂ isomers. Furthermore, it is noteworthy that this is the first report on X-ray crystallographic studies of such metallofullerenes with the popular <i>C</i>_2<i>v</i>(9)-C₈₂ encapsulating a divalent metal ion, described as M²⁺@[<i>C</i>_2<i>v</i>(9)-C₈₂]^2–

Single-Crystal X‑ray Diffraction Study of Three Yb@C₈₂ Isomers Cocrystallized with Ni^II(octaethylporphyrin)

Single crystals of three soluble Yb@C₈₂ isomers, namely, Yb@<i>C</i>₂(5)-C₈₂, Yb@<i>C</i>_<i>s</i>(6)-C₈₂, and Yb@<i>C</i>_2<i>v</i>(9)-C₈₂, cocrystallized with Ni^II(octaethylporphyrin), allowed accurate crystallographic elucidation of their molecular structures in terms of both cage symmetry and metal location. Multiple metal positions were found in all these isomers, but the major metal sites were found in some specific regions within these cages. Specifically, the Yb²⁺ ion prefers to reside close to a hexagonal ring in Yb@<i>C</i>₂(5)-C₈₂ and Yb@<i>C</i>_2<i>v</i>(9)-C₈₂ but a [5,6,6]-junction carbon atom in Yb@<i>C</i>_<i>s</i>(6)-C₈₂. Theoretical calculations at the B3LYP level revealed that these metal positions all correspond to energy minima from the electrostatic potential maps and give rise to the most stable configurations of these Yb@C₈₂ isomers. Furthermore, it is noteworthy that this is the first report on X-ray crystallographic studies of such metallofullerenes with the popular <i>C</i>_2<i>v</i>(9)-C₈₂ encapsulating a divalent metal ion, described as M²⁺@[<i>C</i>_2<i>v</i>(9)-C₈₂]^2–

Single-Crystal X‑ray Diffraction Study of Three Yb@C₈₂ Isomers Cocrystallized with Ni^II(octaethylporphyrin)

Single crystals of three soluble Yb@C₈₂ isomers, namely, Yb@<i>C</i>₂(5)-C₈₂, Yb@<i>C</i>_<i>s</i>(6)-C₈₂, and Yb@<i>C</i>_2<i>v</i>(9)-C₈₂, cocrystallized with Ni^II(octaethylporphyrin), allowed accurate crystallographic elucidation of their molecular structures in terms of both cage symmetry and metal location. Multiple metal positions were found in all these isomers, but the major metal sites were found in some specific regions within these cages. Specifically, the Yb²⁺ ion prefers to reside close to a hexagonal ring in Yb@<i>C</i>₂(5)-C₈₂ and Yb@<i>C</i>_2<i>v</i>(9)-C₈₂ but a [5,6,6]-junction carbon atom in Yb@<i>C</i>_<i>s</i>(6)-C₈₂. Theoretical calculations at the B3LYP level revealed that these metal positions all correspond to energy minima from the electrostatic potential maps and give rise to the most stable configurations of these Yb@C₈₂ isomers. Furthermore, it is noteworthy that this is the first report on X-ray crystallographic studies of such metallofullerenes with the popular <i>C</i>_2<i>v</i>(9)-C₈₂ encapsulating a divalent metal ion, described as M²⁺@[<i>C</i>_2<i>v</i>(9)-C₈₂]^2–

Single-Crystal X‑ray Diffraction Study of Three Yb@C₈₂ Isomers Cocrystallized with Ni^II(octaethylporphyrin)

Single crystals of three soluble Yb@C₈₂ isomers, namely, Yb@<i>C</i>₂(5)-C₈₂, Yb@<i>C</i>_<i>s</i>(6)-C₈₂, and Yb@<i>C</i>_2<i>v</i>(9)-C₈₂, cocrystallized with Ni^II(octaethylporphyrin), allowed accurate crystallographic elucidation of their molecular structures in terms of both cage symmetry and metal location. Multiple metal positions were found in all these isomers, but the major metal sites were found in some specific regions within these cages. Specifically, the Yb²⁺ ion prefers to reside close to a hexagonal ring in Yb@<i>C</i>₂(5)-C₈₂ and Yb@<i>C</i>_2<i>v</i>(9)-C₈₂ but a [5,6,6]-junction carbon atom in Yb@<i>C</i>_<i>s</i>(6)-C₈₂. Theoretical calculations at the B3LYP level revealed that these metal positions all correspond to energy minima from the electrostatic potential maps and give rise to the most stable configurations of these Yb@C₈₂ isomers. Furthermore, it is noteworthy that this is the first report on X-ray crystallographic studies of such metallofullerenes with the popular <i>C</i>_2<i>v</i>(9)-C₈₂ encapsulating a divalent metal ion, described as M²⁺@[<i>C</i>_2<i>v</i>(9)-C₈₂]^2–

Chemical Understanding of Carbide Cluster Metallofullerenes: A Case Study on Sc₂C₂@<i>C</i>_2<i>v</i>(5)–C₈₀ with Complete X-ray Crystallographic Characterizations

Little is known about the chemical properties of carbide cluster metallofullerenes (CCMFs). Here we report the photochemical reaction of a newly assigned CCMF Sc₂C₂@<i>C</i>_2<i>v</i>(5)–C₈₀ with 2-adamantane-2,3-[3<i>H</i>]-diazirine (AdN₂, <b>1</b>), which provides a carbene reagent under irradiation. Five monoadduct isomers (<b>2a</b>–<b>2e</b>), with respective abundances of 20%, 40%, 25%, 5%, and 10%, were isolated and characterized with a combination of experimental techniques including unambiguous single-crystal X-ray crystallography. Results show that the two Sc atoms of the bent Sc₂C₂ cluster tend to move in most cases, whereas the C₂-unit is almost fixed. Accordingly, it is difficult to explain the addition patterns by considering the strain and charge density on the cage with a fixed cluster, and thus a moving cluster may account for the addition patterns. These results show that the situation of CCMFs is more complicated than those in other metallofullerenes. Furthermore, a thermal isomerization process from <b>2b</b> to <b>2c</b> was observed, confirming that the most abundant isomer <b>2b</b> is a kinetically favored adduct. Finally, it is revealed that the electronic and electrochemical properties of pristine Sc₂C₂@<i>C</i>_2<i>v</i>(5)–C₈₀ have been markedly altered by exohedral modification

Unexpected Formation of a Sc₃C₂@C₈₀ Bisfulleroid Derivative

The reaction of tetrazine <b>1</b> with Sc₃C₂@C₈₀ exclusively affords the open-cage derivative <b>2</b> instead of the expected C₂-inserted derivative <b>3</b> bearing a four-membered ring, as previously obtained for C₆₀. The structure of <b>2</b> has been firmly established by NMR spectroscopy and theoretical calculations. EPR spectroscopy shows that a single Sc atom of the Sc₃C₂ cluster gets located within the bulge created by the bridging addend, which is a first step toward release of the internal metal atoms

Where Does the Metal Cation Stay in Gd@<i>C</i>_2<i>v</i>(9)-C₈₂? A Single-Crystal X-ray Diffraction Study

Metal positions in endohedral metallofullerenes (EMFs) are of special importance because their molecular symmetry and intrinsic properties are strongly influenced by the location and motion of the encapsulated metals. X-ray analyses of the cocrystals of Gd@<i>C</i>_2<i>v</i>(9)-C₈₂ with nickel^II octaethylporphyrin [Ni^II(OEP)] reveal that the Gd³⁺ cation is off-center, being located under a hexagonal ring along the 2-fold axis of the <i>C</i>_2<i>v</i>(9)-C₈₂ cage. This result is in sharp contrast to that of a previous study, showing that Gd@<i>C</i>_2<i>v</i>(9)-C₈₂ has an anomalous endohedral structure, with the metal being positioned over a [6,6] bond, which is opposite to the hexagonal ring along the C₂ axis (<i>Phys. Rev. B</i> <b>2004</b>, <i>69</i>, 113412). In agreement with theoretical calculations and related studies, it is conclusive that the single rare-earth metal in M@<i>C</i>_2<i>v</i>(9)-C₈₂ always tends to coordinate with the hexagonal ring along the 2-fold axis, instead of interacting with the [6,6] bond on the other end, regardless of the type of metal atom

Chemical Understanding of Carbide Cluster Metallofullerenes: A Case Study on Sc₂C₂@<i>C</i>_2<i>v</i>(5)–C₈₀ with Complete X-ray Crystallographic Characterizations

Little is known about the chemical properties of carbide cluster metallofullerenes (CCMFs). Here we report the photochemical reaction of a newly assigned CCMF Sc₂C₂@<i>C</i>_2<i>v</i>(5)–C₈₀ with 2-adamantane-2,3-[3<i>H</i>]-diazirine (AdN₂, <b>1</b>), which provides a carbene reagent under irradiation. Five monoadduct isomers (<b>2a</b>–<b>2e</b>), with respective abundances of 20%, 40%, 25%, 5%, and 10%, were isolated and characterized with a combination of experimental techniques including unambiguous single-crystal X-ray crystallography. Results show that the two Sc atoms of the bent Sc₂C₂ cluster tend to move in most cases, whereas the C₂-unit is almost fixed. Accordingly, it is difficult to explain the addition patterns by considering the strain and charge density on the cage with a fixed cluster, and thus a moving cluster may account for the addition patterns. These results show that the situation of CCMFs is more complicated than those in other metallofullerenes. Furthermore, a thermal isomerization process from <b>2b</b> to <b>2c</b> was observed, confirming that the most abundant isomer <b>2b</b> is a kinetically favored adduct. Finally, it is revealed that the electronic and electrochemical properties of pristine Sc₂C₂@<i>C</i>_2<i>v</i>(5)–C₈₀ have been markedly altered by exohedral modification