We show that an ethylenic coupler provides a very strong intramolecular magnetic interaction. A recently synthesized nitronyl nitroxide derivative, D-NIT2, is investigated by ab initio quantum chemical methods. The broken symmetry approach yields a coupling constant -541 K that is in good agreement with the observed value in solid state.
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http://dx.doi.org/10.1021/jp0510286 | DOI Listing |
ACS Omega
December 2024
Department of Chemistry, Panskura Banamali College, Panskura RS, West Bengal 721152, India.
In this study, a tetradentate Schiff-base ligand (HL), synthesized by the condensation of ethylenediamine with 2-hydroxy-3-methoxy-5-methylbenzaldehyde, was reacted with either manganese salts or manganese salts in the presence of various pseudohalides in methanol. This reaction resulted in the formation of five mononuclear Mn complexes: [Mn(L)(HO)](NO)·1/2HO·1/2CHOH (), [Mn(L)(HO)](ClO)·HO (), [Mn(L)(N)(HO)]·1/3HO (), [Mn(L)(NCS)(HO)] (), and [Mn(L)(HO)](dca) () (where dca is dicyanamide ion). X-ray crystallography revealed that the Mn centers adopt a hexa-coordinate pseudo-octahedral geometry, where the equatorial plane is constructed with phenoxo oxygen and imine nitrogen atoms from the Schiff base ligand, while the axial positions are occupied by water molecules or a combination of water and pseudohalides.
View Article and Find Full Text PDFChem Soc Rev
December 2024
Hefei National Research Center for Physical Sciences at the Microscale, Key Laboratory of Precision and Intelligent Chemistry, School of Chemistry and Materials Science, and National Synchrotron Radiation Laboratory, School of Nuclear Science and Technology, University of Science and Technology of China, Hefei, Anhui 230026, China.
J Org Chem
December 2024
Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstrasse 5-13, 81377 Munich, Germany.
The reactions of diketene were investigated in the HF/MF and DF/MF (M = As or Sb) binary superacidic systems. Depending on the stoichiometric ratio of the Lewis acids and diketene, monoprotonated acetoacetyl fluoride and diprotonated acetoacetyl fluoride were obtained. The salts were characterized by low-temperature vibrational spectroscopy, nuclear magnetic resonance spectroscopy, and single-crystal X-ray diffraction.
View Article and Find Full Text PDFJ Mol Biol
December 2024
Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, PA, USA; Center for Computational and Genomic Medicine, Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA, USA. Electronic address:
Human interleukin-2 (IL-2) is a crucial cytokine for T cell regulation, with therapeutic potential in cancer and autoimmune diseases. However, IL-2's pleiotropic effects across different immune cell types often lead to toxicity and limited efficacy. Previous efforts to enhance IL-2's therapeutic profile have focused on modifying its receptor binding sites.
View Article and Find Full Text PDFSci Adv
December 2024
Laboratoire des Biomolécules, LBM, Département de Chimie, École Normale Supérieure, PSL University, Sorbonne Université, CNRS, 75005 Paris, France.
Dynamic nuclear polarization (DNP) enhances nuclear magnetic resonance (NMR) sensitivity by transferring polarization from unpaired electrons to nuclei, but nearby nuclear spins are difficult to detect or "hidden" due to strong electron-nuclear couplings that hypershift their NMR resonances. Here, we detect these hypershifted spins in a frozen glycerol-water mixture doped with TEMPOL at ~1.4 K using spin diffusion enhanced saturation transfer (SPIDEST), which indirectly reveals their spectrum.
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