The 3-chloro-benzoate anion of the title salt, C(6)H(9)N(2) (+)·C(7)H(4)ClO(2) (-), is nearly planar with a dihedral angle of 2.44 (13)° between the benzene ring and the carboxyl-ate group. In the crystal, the protonated N atom and the 2-amino group of the cation are hydrogen bonded to the carboxyl-ate O atoms of the anion via a pair of N-H⋯O hydrogen bonds with an R(2) (2)(8) ring motif, forming an approximately planar ion pair with a dihedral angle of 7.92 (5)° between the pyridinium and benzene rings. The ion pairs are further connected via N-H⋯O and C-H⋯O hydrogen bonds, forming a two-dimensional network parallel to the bc plane.
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http://dx.doi.org/10.1107/S1600536812043231 | DOI Listing |
J Am Chem Soc
January 2025
Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055, China.
A small but growing set of radical SAM (-adenosyl-l-methionine) enzymes catalyze the radical mediated dehydration or dehydrogenation of 1,2-diol substrates. In some cases, these activities can be interchanged via minor structural perturbations to the reacting components raising questions regarding the relative importance of hyperconjugation, proton circulation and leaving group stability in determining the reaction outcome. The present work describes trapping and electron paramagnetic resonance (EPR) characterization of an α-hydroxyalkyl radical intermediate during dehydration and dehydrogenation of cytosylglucuronic acid and its derivatives catalyzed by the radical SAM enzyme BlsE and its Glu189Ala mutant from the blasticidin S biosynthetic pathway.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Universität Rostock, Institut für Chemie, Albert-Einstein-Str. 3a, 18059, Rostock, GERMANY.
The linkage of an imidazole-based N-heterocyclic olefin (NHO), containing a terminal CH2 donor group, with a phosphorus-centered diradical molecular fragment leads to an open-shell singlet diphospha-indenylide system, a new class of P-heterocycles, which can be interpreted both as a phosphorus-centered diradicaloid and as a zwitterion with a permanent, overall charge separation between the N- and P-heterocyclic ring systems. The rotation of the imidazole ring, which is thermally possible due to a central C-C bond with a weakened π-component, changes both the charge separation and diradical character depending on the dihedral angle, as quantum mechanical calculations indicate. By varying the bulkiness of substituents at the imidazole-based NHO, it was possible to obtain different diphospha-indenylide species with different rotation angles in the solid state and hence varying diradical character.
View Article and Find Full Text PDFJ Chem Theory Comput
January 2025
Institute of Physical Chemistry, RWTH Aachen University, Aachen 52074, Germany.
Exploring the conformational space of molecules remains a challenge of fundamental importance to quantum chemistry: identification of relevant conformers at ambient conditions enables predictive simulations of almost arbitrary properties. Here, we propose a novel approach, called TTConf, to enable conformational sampling of large organic molecules where the combinatorial explosion of possible conformers prevents the use of a brute-force systematic conformer search. We employ tensor trains as a highly efficient dimensionality reduction algorithm, effectively reducing the scaling from exponential to polynomial.
View Article and Find Full Text PDFJ Chem Phys
January 2025
Ideal Vacuum Products, LLC, 5910 Midway Park Blvd. NE, Albuquerque, New Mexico 87109, USA.
The hydroxysilylene (HSiOH) molecule has been spectroscopically identified in the gas phase for the first time. This highly reactive species was produced in a twin electric discharge jet using separate precursor streams of 16O2/18O2 and Si2H6/Si2D6, both diluted in high pressure argon. The strongest and most stable laser induced fluorescence (LIF) signals were obtained by applying an electric discharge to each of the precursor streams and then merging the discharge products just prior to expansion into vacuum.
View Article and Find Full Text PDFFront Genet
January 2025
College of Sciences, Inner Mongolia University of Technology, Hohhot, China.
Background: The realization of many protein functions requires binding with ligands. As a significant protein-binding ligand, ATP plays a crucial role in various biological processes. Currently, the precise prediction of ATP binding residues remains challenging.
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