In the asymmetric unit of the title co-crystal, C(7)H(5)NO(4)·C(12)H(14)N(4)O(2)S, there are two independent but conformationally similar heterodimers, which are formed through inter-molecular N-H⋯O(carb-oxy) and carbox-yl-pyrimidine O-H⋯N hydrogen-bond pairs, giving a cyclic motif [graph set R(2) (2)(8)]. The dihedral angles between the rings in the sulfonamide molecules are 78.77 (8) and 82.33 (9)° while the dihedral angles between the ring and the CO(2)H group in the acids are 2.19 (9) and 7.02 (10)°. A two-dimensional structure parallel to the ab plane is generated from the heterodimer units through hydrogen-bonding associations between NH(2) and sulfone groups. Between neighbouring two-dimensional arrays there are two types of aromatic π-π stacking inter-actions involving either one of the pyrimidine rings and a 4-nitro-benzoic acid mol-ecule [minimum ring centroid separation = 3.5886 (9) Å] or two acid mol-ecules [minimum ring centroid separation = 3.7236 (10) Å].
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http://dx.doi.org/10.1107/S1600536812019563 | DOI Listing |
J 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.
View Article and Find Full Text PDFChem Asian J
January 2025
Department of Chemistry, University at Albany, State University of New York, Albany, NY, 12222, USA.
The two-fold reduction of tetrabenzo[a,c,e,g]cyclooctatetraene (TBCOT, or tetraphenylene, 1) with K, Rb, and Cs metals reveals a distinctive core transformation pathway: a newly formed C-C bond converts the central eight-membered ring into a twisted core with two fused five-membered rings. This C-C bond of 1.589(3)-1.
View Article and Find Full Text PDFLangmuir
January 2025
Applied Systems Analysis & Research, Sandia National Laboratories, Albuquerque, New Mexico 87123, United States.
Salt formations have been explored for the permanent isolation of spent nuclear fuel based on their high thermal conductivity, self-healing nature, and low hydraulic permeability to brine flow. Vacancy defect concentrations in salt complicate fracture mechanics not driven by dislocation dynamics and can influence the resulting surface structure. Classical molecular dynamic simulations were used to simulate tensile testing of salt crystals (halite) with vacancy defect concentrations of up to 0.
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