scholarly journals Comparing C2=O and C2=S Barbiturates: Different Hydrogen-Bonding Patterns of Thiobarbiturates in Solution and the Solid State

2021 ◽  
Vol 22 (23) ◽  
pp. 12679
Author(s):  
Chenming Li ◽  
Philipp Hilgeroth ◽  
Nazmul Hasan ◽  
Dieter Ströhl ◽  
Jörg Kressler ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Association Constants ◽  
Langmuir Films ◽  
Brewster Angle Microscopy ◽  
Temperature Dependent ◽  
Model Compounds ◽  
Hydrophobic Polymer ◽  
Hydrogen Bonding Strength ◽  
Bonding Patterns

Carbonyl-centered hydrogen bonds with various strength and geometries are often exploited in materials to embed dynamic and adaptive properties, with the use of thiocarbonyl groups as hydrogen-bonding acceptors remaining only scarcely investigated. We herein report a comparative study of C2=O and C2=S barbiturates in view of their differing hydrogen bonds, using the 5,5-disubstituted barbiturate B and the thiobarbiturate TB as model compounds. Owing to the different hydrogen-bonding strength and geometries of C2=O vs. C2=S, we postulate the formation of different hydrogen-bonding patterns in C2=S in comparison to the C2=O in conventional barbiturates. To study differences in their association in solution, we conducted concentration- and temperature-dependent NMR experiments to compare their association constants, Gibbs free energy of association ∆Gassn., and the coalescence behavior of the N-H‧‧‧S=C bonded assemblies. In Langmuir films, the introduction of C2=S suppressed 2D crystallization when comparing B and TB using Brewster angle microscopy, also revealing a significant deviation in morphology. When embedded into a hydrophobic polymer such as polyisobutylene, a largely different rheological behavior was observed for the barbiturate-bearing PB compared to the thiobarbiturate-bearing PTB polymers, indicative of a stronger hydrogen bonding in the thioanalogue PTB. We therefore prove that H-bonds, when affixed to a polymer, here the thiobarbiturate moieties in PTB, can reinforce the nonpolar PIB matrix even better, thus indicating the formation of stronger H-bonds among the thiobarbiturates in polymers in contrast to the effects observed in solution.

scholarly journals Temperature-Dependent Solid-State NMR Proton Chemical-Shift Values and Hydrogen Bonding

2021 ◽  
Author(s):  
Alexander A. Malär ◽  
Laura A. Völker ◽  
Riccardo Cadalbert ◽  
Lauriane Lecoq ◽  
Matthias Ernst ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Hydrogen Bonding ◽  
Solid State ◽  
Chemical Shift ◽  
Hydrogen Bonds ◽  
Solid State Nmr ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
Proton Chemical Shift ◽  
Temperature Dependent

Temperature-dependent NMR experiments are often complicated by rather long magnetic-field equilibration times, for example occurring upon a change of sample temperature. We demonstrate that the fast temporal stabilization of the magnetic field can be achieved by actively stabilizing the temperature which allows to quantify the weak temperature dependence of the proton chemical shift which can be diagnostic for the presence of hydrogen bonds. Hydrogen bonding plays a central role in molecular recognition events from both fields, chemistry and biology. Their direct detection by standard structure determination techniques, such as X-ray crystallography or cryo-electron microscopy, remains challenging due to the difficulties of approaching the required resolution, on the order of 1 Å. We herein explore a spectroscopic approach using solid-state NMR to identify protons engaged in hydrogen bonds and explore the measurement of proton chemical-shift temperature coefficients. Using the examples of a phosphorylated amino acid and the protein ubiquitin, we show that fast Magic-Angle Spinning (MAS) experiments at 100 kHz yield sufficient resolution in proton-detected spectra to quantify the rather small chemical-shift changes upon temperature variations.<br>

Hydrogen-bonding patterns in the cocrystal 2,4-diamino-6-phenyl-1,3,5-triazine–sorbic acid (1/1)

2007 ◽  
Vol 63 (11) ◽  
pp. o4450-o4451 ◽  
Author(s):  
Kaliyaperumal Thanigaimani ◽  
Packianathan Thomas Muthiah ◽  
Daniel E. Lynch
Keyword(s):  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Sorbic Acid ◽  
Carboxyl Group ◽  
Amino Group ◽  
Acid Molecule ◽  
Asymmetric Unit ◽  
Graph Set ◽  
Bonding Patterns

In the title cocrystal, C9H9N5·C6H8O2, the asymmetric unit contains one 2,4-diamino-6-phenyl-1,3,5-triazine molecule and a sorbic acid molecule. The triazine molecules are base-paired [with a graph set of R 2 2(8)] on either side via N—H...N hydrogen bonds, forming a supramolecular ribbon along the c axis. Each triazine molecule interacts with the carboxyl group of a sorbic acid molecule via N—H...O and O—H...N hydrogen bonds, generating R 2 2(8) motifs. The supramolecular ribbons are interlinked by N—H...O hydrogen bonds involving the 2-amino group of the triazine molecules and the carboxyl O atom of the sorbic acid molecule.

N—H...S and N—H...O hydrogen bonds: `pure' and `mixed'R22(8) patterns in the crystal structures of eight 2-thiouracil derivatives

2014 ◽  
Vol 70 (2) ◽  
pp. 241-249 ◽  
Author(s):  
Wilhelm Maximilian Hützler ◽  
Ernst Egert
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Dimethyl Sulfoxide ◽  
Crystal Structures ◽  
Thiouracil Derivatives ◽  
Bonding Patterns

The preferred hydrogen-bonding patterns in the crystal structures of 5-propyl-2-thiouracil, C7H10N2OS, (I), 5-methoxy-2-thiouracil, C5H6N2O2S, (II), 5-methoxy-2-thiouracil–N,N-dimethylacetamide (1/1), C5H6N2O2S·C4H9NO, (IIa), 5,6-dimethyl-2-thiouracil, C6H8N2OS, (III), 5,6-dimethyl-2-thiouracil–1-methylpyrrolidin-2-one (1/1), C6H8N2OS·C5H9NO, (IIIa), 5,6-dimethyl-2-thiouracil–N,N-dimethylformamide (2/1), 2C6H8N2OS·C3H7NO, (IIIb), 5,6-dimethyl-2-thiouracil–N,N-dimethylacetamide (2/1), 2C6H8N2OS·C4H9NO, (IIIc), and 5,6-dimethyl-2-thiouracil–dimethyl sulfoxide (2/1), 2C6H8N2OS·C2H6OS, (IIId), were analysed. All eight structures containR22(8) patterns. In (II), (IIa), (III) and (IIIa), they are formed by two N—H...S hydrogen bonds, and in (I) by alternating pairs of N—H...S and N—H...O hydrogen bonds. In contrast, the structures of (IIIb), (IIIc) and (IIId) contain `mixed'R22(8) patterns with one N—H...S and one N—H...O hydrogen bond, as well asR22(8) motifs with two N—H...O hydrogen bonds.

scholarly journals Hydrogen-bonding patterns in 2-amino-4,6-dimethoxypyrimidine–4-aminobenzoic acid (1/1)

2006 ◽  
Vol 62 (7) ◽  
pp. o2976-o2978 ◽  
Author(s):  
Kaliyaperumal Thanigaimani ◽  
Packianathan Thomas Muthiah ◽  
Daniel E. Lynch
Keyword(s):  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Carboxyl Group ◽  
Acid Molecule ◽  
Aminobenzoic Acid ◽  
Graph Set ◽  
Supramolecular Chain ◽  
Bonding Patterns ◽  
Hydrogen Bonded

In the title cocrystal, C6H9N3O2·C7H7NO2, the 2-amino-4,6-dimethoxypyrimidine molecule interacts with the carboxyl group of the 4-aminobenzoic acid molecule through N—H...O and O—H...N hydrogen bonds, forming a cyclic hydrogen-bonded motif [R 2 2(8)]. This motif further self-organizes through N—H...O hydrogen bonds to generate an array of six hydrogen bonds with the rings having the graph-set notation R 2 3(6), R 2 2(8), R 4 2(8), R 2 2(8) and R 2 3(6). The 4-aminobenzoic acid molecules self-assemble via N—H...O hydrogen bonds to form a supramolecular chain along the c axis.

Hydrogen-bonding patterns in 4-[(5-methylisoxazol-3-yl)aminosulfonyl]anilinium chloride

2007 ◽  
Vol 63 (11) ◽  
pp. o4312-o4313 ◽  
Author(s):  
Annamalai Subashini ◽  
Packianathan Thomas Muthiah ◽  
Gabriele Bocelli ◽  
Andrea Cantoni
Keyword(s):  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Benzene Ring ◽  
Title Compound ◽  
Crystal Packing ◽  
Tetrahedral Geometry ◽  
Compound C ◽  
Bonding Patterns

In the title compound, C10H12O3N3S+·Cl−, 4-amino-N-(5-methyl-3-isoxazolyl)benzenesulfonamide is protonated on the amine N atom which is connected to the benzene ring. The geometry around the S atom is considerably distorted from ideal tetrahedral geometry. The crystal packing is stabilized by intermolecular N—H...N, N—H...Cl, N—H...O and C—H...O hydrogen bonds.

Comparison of hydrogen bonds and diverse weak interactions of the nitro group in 2-methyl-4-nitroanilinium nitrate, bisulfate and two hexafluoridosilicates: elementary graph-set approach

2016 ◽  
Vol 72 (6) ◽  
pp. 916-926 ◽  
Author(s):  
Marek Daszkiewicz ◽  
Agnieszka Mielcarek
Keyword(s):  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Crystal Structures ◽  
Nitro Group ◽  
Weak Interactions ◽  
Gradual Expansion ◽  
Graph Set ◽  
Mathematical Relations ◽  
Elementary Graph ◽  
Bonding Patterns

Crystal structures of (H2m4na)NO3(1), (H2m4na)HSO4(2), (H2m4na)2SiF6(3) and (H2m4na)2SiF6·2H2O (4), where 2m4na = 2-methyl-4-nitroaniline, are presented. Two layers of interactions occur in the structures, N—H...O/F hydrogen bonds and interactions with the nitro group. Although diverse, hydrogen-bonding patterns are compared with each other by means of interrelations among elementary graph-set descriptors and descriptors of hydrogen-bonding patterns. Using mathematical relations, the gradual expansion of the ring patterns was shown in the crystal structures. Parallel and perpendicular arranged nitro groups form weak π(N)NO2...π(O)NO2and π(N)NO2...ONO2interactions, respectively. The πNO2...πringinteraction has an impact to the stabilization of parallel oriented nitro groups. Generally, weak interactions constructed by the nitro group occur in the studied crystals as follows: π(N)NO2...π(O)NO2, πring...πring, C—H...O (1); π(N)NO2...π(O)NO2, π(N)NO2...ONO2(2); π(N)NO2...π(O)NO2, π(N)NO2...ONO2(3); C—H...O (4).

scholarly journals Crystal structure and hydrogen-bonding patterns in 5-fluorocytosinium picrate

2017 ◽  
Vol 73 (3) ◽  
pp. 361-364 ◽  
Author(s):  
Marimuthu Mohana ◽  
Packianathan Thomas Muthiah ◽  
Colin D. McMillen
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Dihedral Angle ◽  
Title Compound ◽  
Two Dimensional ◽  
Π Interactions ◽  
Sheet Structure ◽  
Bonding Patterns

In the crystal structure of the title compound, 5-fluorocytosinium picrate, C4H5FN3O+·C6H2N3O7−, one N heteroatom of the 5-fluorocytosine (5FC) ring is protonated. The 5FC ring forms a dihedral angle of 19.97 (11)° with the ring of the picrate (PA−) anion. In the crystal, the 5FC+cation interacts with the PA−anion through three-centre N—H...O hydrogen bonds, forming two conjoined rings havingR21(6) andR12(6) motifs, and is extended by N—H...O hydrogen bonds and C—H...O interactions into a two-dimensional sheet structure lying parallel to (001). Also present in the crystal structure are weak C—F...π interactions.

Secondary ligands and the intramolecular hydrogen bonds drive photoluminescence quantum yields from aminopyrazine coordination polymers

2020 ◽  
Vol 44 (46) ◽  
pp. 20259-20266
Author(s):  
Maykon Alves Lemes ◽  
José Antônio do Nascimento Neto ◽  
Freddy Fernandes Guimarães ◽  
Lauro June Queiroz Maia ◽  
Ricardo Costa de Santana ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Coordination Polymers ◽  
Quantum Yields ◽  
Intramolecular Hydrogen Bonds ◽  
Intramolecular Hydrogen ◽  
Bonding Patterns

Here the role of secondary ligands and their hydrogen bonding patterns in determining the photoluminescence quantum yields of aminopyrazine (ampyz) coordination polymers was probed.

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