Sm@<i>C</i>_2<i>v</i>(19138)‑C₇₆: A Non-IPR Cage Stabilized by a Divalent Metal Ion

Although a non-IPR fullerene cage is common for endohedral cluster fullerenes, it is very rare for conventional endofullerenes M@C_2<i>n</i>, probably because of the minimum geometry fit effect of the endohedral single metal ion. In this work, we report on a new non-IPR endofullerene Sm@<i>C</i>_2<i>v</i>(19138)-C₇₆, including its structural and electrochemical features. A combined study of single-crystal X-ray diffraction and DFT calculations not only elucidates the non-IPR cage structure of <i>C</i>_2<i>v</i>(19138)-C₇₆ but also suggests that the endohedral Sm²⁺ ion prefers to reside along the C₂ cage axis and close to the fused pentagon unit in the cage framework, indicative of a significant metal–cage interaction, which alone can stabilize the non-IPR cage. Furthermore, electrochemical studies reveal the fully reversible redox behaviors and small electrochemical gap of Sm@<i>C</i>_2<i>v</i>(19138)-C₇₆, which are comparable to those of IPR species Sm@<i>D</i>_3<i>h</i>-C₇₄

Popular C₈₂ Fullerene Cage Encapsulating a Divalent Metal Ion Sm²⁺: Structure and Electrochemistry

Two Sm@C₈₂ isomers have been well characterized for the first time by means of ¹³C NMR spectroscopy, and their structures were unambiguously determined as Sm@<i>C</i>_<i>2v</i><i>(9)</i>-C₈₂ and Sm@<i>C</i>_<i>3v</i><i>(7)</i>-C₈₂, respectively. A combined study of single crystal X-ray diffraction and theoretical calculations suggest that in Sm@<i>C</i>_<i>2v</i><i>(9)</i>-C₈₂ the preferred Sm²⁺ ion position shall be located in a region slightly off the <i>C</i>₂ axis of <i>C</i>_<i>2v</i><i>(9)</i>-C₈₂. Moreover, the electrochemical surveys on these Sm@C₈₂ isomers reveal that their redox activities are mainly determined by the properties of their carbon cages

High-Level Secretion of Pregnancy Zone Protein Is a Novel Biomarker of DNA Damage-Induced Senescence and Promotes Spontaneous Senescence

Identification of unique and specific biomarkers to better detect and quantify senescent cells remains challenging. By a global proteomic profiling of senescent human skin BJ fibroblasts induced by ionizing radiation (IR), the cellular level of pregnancy zone protein (PZP), a presumable pan-protease inhibitor never been linked to cellular senescence before, was found to be decreased by more than 10-fold, while the level of PZP in the conditioned medium was increased concomitantly. This observation was confirmed in a variety of senescent cells induced by IR or DNA-damaging drugs, indicating that high-level secretion of PZP is a novel senescence-associated secretory phenotype. RT-PCR examination verified that the transcription of the PZP gene is enhanced in various cells at senescence or upregulated following DNA damage treatment in a p53-independent manner. Moreover, pretreatment with late pregnancy serum containing a high level of PZP led to inhibition of doxorubicin-induced senescence in A549 cells, and depletion of PZP in the pregnancy serum could enhance such inhibition. Finally, the addition of immuno-precipitated PZP complexes into tissue culture attenuated the growth of A549 cells and promoted the spontaneous senescence. Therefore, we revealed that high-level secretion of PZP is a novel and unique feature associated with DNA damage-induced senescence, and secreted PZP is a positive regulator of cellular senescence, particularly during the late stage of gestation

Endohedral Metallofullerene as Molecular High Spin Qubit: Diverse Rabi Cycles in Gd₂@C₇₉N

An anisotropic high-spin qubit with long coherence time could scale the quantum system up. It has been proposed that Grover’s algorithm can be implemented in such systems. Dimetallic aza[80]­fullerenes M₂@C₇₉N (M = Y or Gd) possess an unpaired electron located between two metal ions, offering an opportunity to manipulate spin(s) protected in the cage for quantum information processing. Herein, we report the crystallographic determination of Gd₂@C₇₉N for the first time. This molecular magnet with a collective high-spin ground state (<i>S</i> = 15/2) generated by strong magnetic coupling (<i>J</i>_Gd‑Rad = 350 ± 20 cm^–1) has been unambiguously validated by magnetic susceptibility experiments. Gd₂@C₇₉N has quantum coherence and diverse Rabi cycles, allowing arbitrary superposition state manipulation between each adjacent level. The phase memory time reaches 5 μs at 5 K by dynamic decoupling. This molecule fulfills the requirements of Grover’s searching algorithm proposed by Leuenberger and Loss