scholarly journals Crystal structures and hydrogen bond analysis of five amino acid conjugates of terephthalic and benzene-1,2,3-tricarboxylic acids

CrystEngComm ◽  
2014 ◽  
Vol 16 (35) ◽  
pp. 8243-8251 ◽  
Author(s):  
Anirban Karmakar ◽  
Clive L. Oliver ◽  
Ana E. Platero-Prats ◽  
Elina Laurila ◽  
Lars Öhrström

This amino acid derived (red&blue) π-stacked (green) hydrogen bonded (striped) dimer forms a pcu-net with water molecules in the narrow channels. Four related molecules are also presented and all were subjected to graph set and Hirshfeld surface analyses.

2000 ◽  
Vol 56 (1) ◽  
pp. 142-154 ◽  
Author(s):  
Feng Xue ◽  
Thomas C. W. Mak

New crystalline adducts of tetraalkylammonium terephthalate/trimesate with urea and water molecules result from hydrogen-bond directed assembly of complementary acceptors and donors, and the anionic host lattices are described using the graph-set notation to identify distinct hydrogen-bonding motifs and patterns. Tetra-n-butylammonium terephthalate–urea–water (1/6/2), C46H104N14O12 (1), triclinic, space group P1¯, a = 8.390 (2), b = 9.894 (2), c = 18.908 (3) Å, α = 105.06 (2), β = 94.91 (1), γ = 93.82 (2)°, Z = 1, is composed of hydrogen-bonded terephthalate–urea layers, which are intersected by urea layers to generate a three-dimensional network containing large channels for accommodation of the cations. Tetraethylammonium terephthalate–urea–water (1/1/5), C25H58N4O10 (2), triclinic, P1¯, a = 9.432 (1), b = 12.601 (1), c = 14.804 (1) Å, α = 79.98 (1), β = 79.20 (1), γ = 84.18 (1)°, Z = 2, has cations sandwiched between hydrogen-bonded anionic layers. Tetraethylammonium trimesate–urea–water (1/2/7.5), C35H86N7O15.5 (3), triclinic, P1¯, a = 13.250 (1), b = 14.034 (1), c = 15.260 (1) Å, α = 72.46 (1), β = 78.32 (1), γ = 66.95 (1)°, Z = 2, manifests a layer-type structure analogous to that of (2). Tetra-n-propylammonium hydrogen trimesate–urea–water (1/2/5), C35H78N6O13 (4), orthorhombic, Pna21, a = 16.467 (3), b = 33.109 (6), c = 8.344 (1) Å, Z = 4, features hydrogen trimesate helices in a three-dimensional host architecture containing nanoscale channels each filled by a double column of cations.


2018 ◽  
Vol 74 (8) ◽  
pp. 1159-1162
Author(s):  
Ramalingam Sangeetha ◽  
Kasthuri Balasubramani ◽  
Kaliyaperumal Thanigaimani ◽  
Savaridasson Jose Kavitha

In the title molecular salt, C9H10N5 +·C7H7O3S−, the asymmetric unit consists of a 2,4-diamino-6-phenyl-1,3,5-triazin-1-ium cation and a 4-methylbenzenesulfonate anion. The cation is protonated at the N atom lying between the amine and phenyl substituents. The protonated N and amino-group N atoms are involved in hydrogen bonding with the sulfonate O atoms through a pair of intermolecular N—H...O hydrogen bonds, giving rise to a hydrogen-bonded cyclic motif with R 2 2(8) graph-set notation. The inversion-related molecules are further linked by four N—H...O intermolecular interactions to produce a complementary DDAA (D = donor, A = acceptor) hydrogen-bonded array, forming R 2 2(8), R 4 2(8) and R 2 2(8) ring motifs. The centrosymmetrically paired cations form R 2 2(8) ring motifs through base-pairing via N—H...N hydrogen bonds. In addition, another R 3 3(10) motif is formed between centrosymetrically paired cations and a sulfonate anion via N—H...O hydrogen bonds. The crystal structure also features weak S=O...π and π–π interactions. Hirshfeld surface and fingerprint plots were employed in order to further study the intermolecular interactions.


2003 ◽  
Vol 59 (1) ◽  
pp. 132-140 ◽  
Author(s):  
Henning Osholm Sørensen ◽  
Sine Larsen

The structural and thermodynamic backgrounds for the crystallization behaviour of racemates have been investigated using 2-phenoxypropionic acid (PPA) as an example. The racemate of PPA behaves normally and forms a racemic compound that has a higher melting point and is denser than the enantiomer. Low-temperature crystal structures of the pure enantiomer, the enantiomer cocrystallized with n-alkanes and the racemic acid showed that hydrogen-bonded dimers that form over crystallographic symmetry elements exist in all but the structure of the pure enantiomer. A database search for optically pure chiral mono-carboxylic acids revealed that the hydrogen-bonded cyclic dimer is the most prevalent hydrogen-bond motif in chiral mono-carboxylic acids. The conformation of PPA depends on the hydrogen-bond motif; the antiplanar conformation relative to the ether group is associated with a catemer hydrogen-bonding motif, whereas the more abundant synplanar conformation is found in crystals that contain cyclic dimers. Other intermolecular interactions that involve the substituent of the carboxylic group were identified in the crystals that contain the cyclic dimer. This result shows how important the nature of the substituent is for the crystal packing. The differences in crystal packing have been related to differences in melting enthalpy and entropy between the racemic and enantiomeric acids. In a comparison with the equivalent 2-(4-chlorophenoxy)-propionic acids, the differences between the crystal structures of the chloro and the unsubstituted acid have been identified and related to thermodynamic data.


2021 ◽  
Vol 8 ◽  
Author(s):  
Lorenzo Di Rienzo ◽  
Mattia Miotto ◽  
Leonardo Bò ◽  
Giancarlo Ruocco ◽  
Domenico Raimondo ◽  
...  

Assessing the hydropathy properties of molecules, like proteins and chemical compounds, has a crucial role in many fields of computational biology, such as drug design, biomolecular interaction, and folding prediction. Over the past decades, many descriptors were devised to evaluate the hydrophobicity of side chains. In this field, recently we likewise have developed a computational method, based on molecular dynamics data, for the investigation of the hydrophilicity and hydrophobicity features of the 20 natural amino acids, analyzing the changes occurring in the hydrogen bond network of water molecules surrounding each given compound. The local environment of each residue is complex and depends on the chemical nature of the side chain and the location in the protein. Here, we characterize the solvation properties of each amino acid side chain in the protein environment by considering its spatial reorganization in the protein local structure, so that the computational evaluation of differences in terms of hydropathy profiles in different structural and dynamical conditions can be brought to bear. A set of atomistic molecular dynamics simulations have been used to characterize the dynamic hydrogen bond network at the interface between protein and solvent, from which we map out the local hydrophobicity and hydrophilicity of amino acid residues.


2013 ◽  
Vol 69 (2) ◽  
pp. o282-o283
Author(s):  
Stephen J. Evans ◽  
C. Alicia Renison ◽  
D. Bradley G. Williams ◽  
Alfred Muller

In the title compound, C30H48BNOP2·0.5H2O, the water molecule is disordered about an inversion centre. Both phosphorus atoms shows distortions in their tetrahedral environments with the cyclohexyl substituents disordered over two orientations in a 0.851 (3):0.149 (3) occupancy ratio. The crystal structure is assembledviaO—H...O interactions between pairs of phosphininc amide molecules and water molecules, creating hydrogen-bonded dimers with graph-setR24(8) along [001]. Weak C—H...O interactions are also observed.


2016 ◽  
Vol 72 (10) ◽  
pp. 720-723 ◽  
Author(s):  
Xiao-Qing Cai ◽  
Bei Tian ◽  
Jian-Nan Zhang ◽  
Zhi-Min Jin

A fixed hydrogen-bonding motif with a high probability of occurring when appropriate functional groups are involved is described as a `supramolecular hydrogen-bonding synthon'. The identification of these synthons may enable the prediction of accurate crystal structures. The rare chiral hydrogen-bonding motifR53(10) was observed previously in a cocrystal of 2,4,6-trichlorophenol, 2,4-dichlorophenol and dicyclohexylamine. In the title solvated salt, 2C4H12N+·C6H3Cl2O−·(C6H3Cl2O−·C6H4Cl2O)·2C4H8O, five components, namely twotert-butylammonium cations, one 2,4-dichlorophenol molecule, one 2,4-dichlorophenolate anion and one 2,6-dichlorophenolate anion, are bound by N—H...O and O—H...O hydrogen bonds to form a hydrogen-bonded ring, with the graph-set motifR53(10), which is further associated with two pendant tetrahydrofuran molecules by N—H...O hydrogen bonds. The hydrogen-bonded ring has internal symmetry, with a twofold axis running through the centre of the 2,6-dichlorophenolate anion, and is isostructural with a previous and related structure formed from 2,4-dichlorophenol, dicyclohexylamine and 2,4,6-trichlorophenol. In the title crystal, helical columns are built by the alignment and twisting of the chiral hydrogen-bonded rings, along and across thecaxis, and successive pairs of rings are associated with each other through C—H...π interactions. Neighbouring helical columns are inversely related and, therefore, no chirality is sustained, in contrast to the previous case.


2018 ◽  
Vol 74 (11) ◽  
pp. 1420-1426
Author(s):  
Grzegorz Dutkiewicz ◽  
Edward Dutkiewicz ◽  
Maciej Kubicki

The crystal structures of four cocrystals of pyrazine with benzene polycarboxylic acids were determined, namely pyrazine–phthalic (benzene-1,2-dicarboxylic) acid (1/1), C4H4N2·C8H6O4 (1), pyrazine–hemimellitic (benzene-1,2,3-tricarboxylic) acid (1/1), C4H4N2·C9H6O6 (2), pyrazine–hemimellitic acid–water (1/2/2), C4H4N2·2C9H6O6·2H2O (2a), and pyrazine–pyromellitic (benzene-1,2,4,5-tetracarboxylic) acid (3/1), 3C4H4N2·C10H6O8 (3). In all cases, infinite chains of alternating acid and base molecules, bonded by O—H...N hydrogen bonds, are formed. However, the details of the supramolecular structures are different. The additional carboxylic acid groups in the tri- and tetracarboxylic acids participate in hydrogen bonding with neighbouring acid molecules (in 2), water molecules, which makes the structure more complicated (in 2a), or with additional pyrazine molecules (in 3). π–π interactions between aromatic rings help organize the crystal architectures in all cases except for hydrate 2a. In that case, the hydrogen-bond-enriched structure enforces a disposition of the rings in which no stacking is observed. The Hirshfeld surface analysis allows better visualization of the differences between the structures by fingerprint plots in particular.


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