More Like this

1. D -Mannosamine hydrochloride (2-amino-2-deoxy- D -mannose hydrochloride): ionic hydrogen bonding in saccharides involving chloride and aminium ions

   https://doi.org/10.1107/S2053229622002121  

   Lin, Jieye; Oliver, Allen G.; Serianni, Anthony S. (April 2022, Acta Crystallographica Section C Structural Chemistry)

   D-Mannosamine hydrochloride (2-amino-2-deoxy-D-mannose hydrochloride), C 6 H 14 NO 5 + ·Cl − , (I), crystallized from a methanol/ethyl acetate/ n -hexane solvent mixture at room temperature in a 4 C 1 chair conformation that is slightly distorted towards the C3,O5 B form. A comparison of the structural parameters of (I) with the corresponding parameters in α-D-glucosamine hydrochloride, (II), and β-D-galactosamine hydrochloride, (III)/(III′), was undertaken to evaluate the effects of ionic hydrogen bonding on structural properties. Three types of ionic hydrogen bonds are present in the crystals of (I)–(III)/(III′), i.e. N + —H...O, N + —H...Cl − , and O—H...Cl − . The exocyclic structural parameters in (I), (II), and (III)/(III′) appear to be most influenced by this bonding, especially the exocyclic hydroxy groups, which adopt eclipsed conformations enabled by ionic hydrogen bonding to the chloride anion. Anomeric disorder was observed in crystals of (I), with an α:β ratio of 37:63. However, anomeric configuration appears to exert minimal structural effects; that is, bond lengths, bond angles, and torsion angles are essentially identical in both anomers. The observed disorder at the anomeric C atom of (I) appears to be caused by the presence of the chloride anion and atom O3 or O4 in proximal voids, which provide opportunities for hydrogen bonding to atom O1 in both axial and equatorial orientations. 

   more » « less
2. Preserving the symmetry of cis -1,2-difluoroethylene in the gas-phase heterodimer with hydrogen chloride: A microwave rotational study revealing a novel structure

   https://doi.org/10.1063/5.0231236  

   Leung, Helen O; Marshall, Mark D (September 2024, The Journal of Chemical Physics)

   The microwave spectra of three isotopologues of the gas-phase heterodimer formed between cis-1,2-difluoroethylene and hydrogen chloride are obtained in the 5–21 GHz region using Fourier transform microwave spectroscopy. The molecular structure, determined from the analysis of the spectra and supported by quantum chemistry calculations, has the hydrogen atom of the hydrogen chloride molecule interacting with both fluorine atoms of the fluoroethylene and no interaction between the chlorine atom and the olefin. Although the equilibrium structure has two inequivalent H⋯F interactions, zero-point motion averages over the two equivalent choices for these interactions, rendering the pairs of like atoms (C, H, and F) of the fluoroethylene equivalent, retaining the C2v symmetry of the olefin. This results in only one unique singly substituted 13C isotopologue and in the observed effects on transition intensities due to nuclear spin statistics. The heterodimer structure allows for a strong, linear hydrogen bond between the HCl donor and the fluoroethylene acceptor that is more important here than in the analogous acetylene containing complex, where the interaction between the π electrons of acetylene and an electrophilic hydrogen atom on the olefin compensates for the loss of linearity required for binding to a geminal F/H pair. 

   more » « less
3. Crystal structure of 4-methyl- N -(4-methylbenzyl)benzenesulfonamide

   https://doi.org/10.1107/S2056989020000535  

   Stenfors, Brock A.; Staples, Richard J.; Biros, Shannon M.; Ngassa, Felix N. (February 2020, Acta Crystallographica Section E Crystallographic Communications)

   null (Ed.)

   The title compound, C 15 H 17 NO 2 S, was synthesized via a substitution reaction between 4-methylbenzylamine and p -toluenesulfonyl chloride. In the crystal, N—H...O hydrogen bonds link the molecules, forming ribbons running along the b -axis direction. One of the aromatic rings hosts two intermolecular C—H...π interactions that link these hydrogen-bonded ribbons into a three-dimensional network. 

   more » « less
4. Geometrical variations of two manganese(II) complexes with closely related quinoline-based tripodal ligands

   https://doi.org/10.1107/S2056989021009786  

   Frey, Steven T.; Ballot, Jasper G.; Hands, Allison; Cirka, Haley A.; Rinaolo, Katheryn C.; Phalkun, Nich N.; Kaur, Manpreet; Jasinski, Jerry P. (October 2021, Acta Crystallographica Section E Crystallographic Communications)

   Structural analyses of the compounds di-μ-acetato-κ 4 O : O ′-bis{[2-methoxy- N , N -bis(quinolin-2-ylmethyl)ethanamine-κ 4 N , N ′, N ′′, O ]manganese(II)} bis(tetraphenylborate) dichloromethane 1.45-solvate, [Mn 2 (C 23 O 2 ) 2 (C 23 H 23 N 3 O) 2 ](C 24 H 20 B)·1.45CH 2 Cl 2 or [Mn(DQMEA)(μ-OAc) 2 Mn(DQMEA)](BPh 4 ) 2 ·1.45CH 2 Cl 2 or [1] (BPh 4 ) 2 ·1.45CH 2 Cl 2 , and (acetato-κ O )[2-hydroxy- N , N -bis(quinolin-2-ylmethyl)ethanamine-κ 4 N , N ′, N ′′, O ](methanol-κ O )manganese(II) tetraphenylborate methanol monosolvate, [Mn(CH 3 COO)(C 22 H 21 N 3 O)(CH 3 OH)](C 24 H 20 B)·CH 3 OH or [Mn(DQEA)(OAc)(CH 3 OH)]BPh 4 ·CH 3 OH or [2] BPh 4 ·CH 3 OH, by single-crystal X-ray diffraction reveal distinct differences in the geometry of coordination of the tripodal DQEA and DQMEA ligands to Mn II ions. In the asymmetric unit, compound [1] (BPh 4 ) 2 ·(CH 2 Cl 2 ) 1.45 crystallizes as a dimer in which each manganese(II) center is coordinated by the central amine nitrogen, the nitrogen atom of each quinoline group, and the methoxy-oxygen of the tetradentate DQMEA ligand, and two bridging-acetate oxygen atoms. The symmetric Mn II centers have a distorted, octahedral geometry in which the quinoline nitrogen atoms are trans to each other resulting in co-planarity of the quinoline rings. For each Mn II center, a coordinated acetate oxygen participates in C—H...O hydrogen-bonding interactions with the two quinolyl moieties, further stabilizing the trans structure. Within the crystal, weak π – π stacking interactions and intermolecular cation–anion interactions stabilize the crystal packing. In the asymmetric unit, compound [2] BPh 4 ·CH 3 OH crystallizes as a monomer in which the manganese(II) ion is coordinated to the central nitrogen, the nitrogen atom of each quinoline group, and the alcohol oxygen of the tetradentate DQEA ligand, an oxygen atom of OAc, and the oxygen atom of a methanol ligand. The geometry of the Mn II center in [2] BPh 4 ·CH 3 OH is also a distorted octahedron, but the quinoline nitrogen atoms are cis to each other in this structure. Hydrogen bonding between the acetate oxygen atoms and hydroxyl (O—H...O) and quinolyl (C—H...O and N—H...O) moieties of the DQEA ligand stabilize the complex in this cis configuration. Within the crystal, dimerization of complexes occurs by the formation of a pair of intermolecular O3—H3...O2 hydrogen bonds between the coordinated hydroxyl oxygen of the DQEA ligand of one complex and an acetate oxygen of another. Additional hydrogen-bonding and intermolecular cation–anion interactions contribute to the crystal packing. 

   more » « less
5. Crystal structures of three salts of the triphenylsulfonium ion

   https://doi.org/10.1107/S2056989025000118  

   Artis, Rylan; Callaway, Waylan; Heyward, Elizabeth; Reyes, Naomi; Roberts, Gavin; Van_Ostenbridge, Kaitlyn; Padgett, Clifford W; Lynch, Will E (February 2025, Acta Crystallographica Section E Crystallographic Communications)

   The reactions of triphenylsulfonium chloride ([TPS][Cl]) with various acids in methanol yield the corresponding salts triphenylsulfonium triiodide, C₁₈H₁₅S⁺·I₃⁻or [TPS][I₃] (I), triphenylsulfonium perchlorate, C₁₈H₁₅S⁺·ClO₄⁻or [TPS][ClO₄] (II), and triphenylsulfonium hexafluorophosphate, C₁₈H₁₅S⁺·PF₆⁻or [TPS][PF₆] (III), as crystalline products. These crystals were structurally characterized by single-crystal X-ray diffraction. In all three compounds, the sulfur atom in the triphenylsulfonium cation adopts a distorted trigonal–pyramidal geometry. [TPS][I₃] (I) and [TPS][PF₆](III) both crystallize in the space groupP2₁/n, while [TPS][ClO₄] (II) crystallizes inP2₁. The S—C bond lengths are comparable across the three salts, and the S—C—S bond angles are consistently between 102 and 106°. Hirshfeld surface analyses reveal that each structure is dominated by hydrogen-based intermolecular contacts, supplemented by anion-specific interactions such as I...H in (I), O...H in (II), and F...H in (III). These contacts organize the ions into mono-periodic ribbon- or chain-like arrangements. No significant π–π stacking is observed. 

   more » « less