We show increased dynamic nuclear polarization by adding a low dosage of a S = 15/2 Gd based endohedral metallofullerene (EMF) to DNP samples. By adding 60 μM Gd@CN, the nuclear polarization of H and C spins from 40 mM 4-oxo-TEMPO increases by approximately 40% and 50%, respectively, at 5 T and 1.2 K. Electron-electron double resonance (ELDOR) measurements show that the high spin EMF shortens the electron relaxation times and increases electron spectral diffusion leading to the increased DNP enhancement.
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http://dx.doi.org/10.1039/c7cc09765d | DOI Listing |
J Phys Chem Lett
January 2025
MOE Key Laboratory for Non-equilibrium Synthesis and Modulation of Condensed Matter, School of Physics, Xi'an Jiaotong University, Xi'an 710049, China.
The ultrafast excited-state dynamics of endohedral fullerenes are crucial in their photophysical and photochemical processes when they are employed as photovoltaic devices, photocatalytic devices, and single-molecule devices. In this study, by employing the non-adiabatic molecular dynamics simulations based on the time-dependent Kohn-Sham (TD-KS) method, we theoretically studied the size effect on ultrafast excited-state decay dynamics of the photoexcited Be electron in endohedral fullerenes Be@C (2 = 60, 70, and 80). These excited-state decay dynamics, which involve the charge-transfer process, occur in an ultrafast time scale of about 3 ps.
View Article and Find Full Text PDFJ Mol Model
January 2025
Institute of Molecular Science, Shanxi University, Taiyuan, 030006, China.
Context: Inspired by the newly synthesized endohedral fullerene T CH@C (1) and based on extensive density functional theory calculations, we predict herein a series of endohedral borafullerenes C CH@BC (4), T BH@BC (5), C HO@BC (6), C NH@BC (7), and T C@BC (8) which possess a BC (3) shell isovalent with C, with the neutral D C@BC (9) obtained from C@BC (8) by symmetric C─B substitutions. Detailed adaptive natural density partitioning (AdNDP) bonding analyses and iso-chemical shielding surfaces (ICSSs) calculations indicate that these core-shell species are spherically aromatic in nature, rendering high stability to the systems. More interestingly, based on the calculated effective donor-acceptor interaction between LP(O) → LV(B@BC) in HO@BC (6), we propose the concept of boron bond (BB) in chemistry which is defined as the in-phase orbital overlap between an electronegative atom A as lone-pair (LP) donor and an electron-deficient boron atom with a lone vacant (LV) orbital as LP acceptor.
View Article and Find Full Text PDFNanoscale
January 2025
Technical University of Darmstadt, Eduard-Zintl-Institute, Peter-Grünberg-Straße 8, 64287 Darmstadt, Germany.
The magnetic behavior of endohedrally transition-metal-doped tetrel clusters SnTM (TM = Cr, Mn, Fe) was investigated using a combined experimental and theoretical approach. Based on an improved experimental setup, the magnetic deflection was measured over a wide temperature range of = 16-240 K. From a Curie analysis of the experimentally observed single-sided shift at high nozzle temperatures, the spin multiplicities and -factors were determined.
View Article and Find Full Text PDFJ Chem Phys
January 2025
MOE Key Laboratory for Non-Equilibrium Synthesis and Modulation of Condensed Matter, School of Physics, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China.
Endohedral and exohedral fullerenes have both been employed as electron acceptors in polymer solar cells (PSCs). However, their differences in hot-electron relaxation dynamics remain unclear. Previous studies have shown that the location of a single atom, whether inside or outside the fullerene cage, results in significant differences in charge distribution.
View Article and Find Full Text PDFChem Commun (Camb)
December 2024
MOE Key Laboratory of Cluster Science, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 102488, China.
Endohedral metallofullerenes (EMFs) are constructed by fullerene cages encapsulating various metal atoms or metal clusters, which usually exhibit some motion. However, due to the fact that the elusive endohedral dynamics are related to many factors, it remains a challenge to image the motion of internal species. Recently, the electron spin was found to be a sensitive probe to detect the motion of internal species in EMFs.
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