Salts of purine alkaloids caffeine and theobromine with 2,6-dihydroxybenzoic acid as coformer: structural, theoretical, thermal and spectroscopic studies

2021 ◽  
Vol 77 (11) ◽  
Author(s):  
Mateusz Gołdyn ◽  
Anna Komasa ◽  
Mateusz Pawlaczyk ◽  
Aneta Lewandowska ◽  
Elżbieta Bartoszak-Adamska
Keyword(s):  
Hydrogen Bonds ◽  
Water Solubility ◽  
Theoretical Calculations ◽  
Spectroscopic Studies ◽  
X Ray Diffraction ◽  
Dihydroxybenzoic Acid ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Purine Alkaloids ◽  
Vis Spectroscopy

The study of various forms of pharmaceutical substances with specific physicochemical properties suitable for putting them on the market is one of the elements of research in the pharmaceutical industry. A large proportion of active pharmaceutical ingredients (APIs) occur in the salt form. The use of an acidic coformer with a given structure and a suitable pK a value towards purine alkaloids containing a basic imidazole N atom can lead to salt formation. In this work, 2,6-dihydroxybenzoic acid (26DHBA) was used for cocrystallization of theobromine (TBR) and caffeine (CAF). Two novel salts, namely, theobrominium 2,6-dihydroxybenzoate, C7H9N4O2 +·C7H5O4 − (I), and caffeinium 2,6-dihydroxybenzoate, C8H11N4O2 +·C7H5O4 − (II), were synthesized. Both salts were obtained independently by slow evaporation from solution, by neat grinding and also by microwave-assisted slurry cocrystallization. Powder X-ray diffraction measurements proved the formation of the new substances. Single-crystal X-ray diffraction studies confirmed proton transfer between the given alkaloid and 26DHBA, and the formation of N—H...O hydrogen bonds in both I and II. Unlike the caffeine cations in II, the theobromine cations in I are paired by noncovalent N—H...O=C interactions and a cyclic array is observed. As expected, the two hydroxy groups in the 26DHBA anion in both salts are involved in two intramolecular O—H...O hydrogen bonds. C—H...O and π–π interactions further stabilize the crystal structures of both compounds. Steady-state UV–Vis spectroscopy showed changes in the water solubility of xanthines after ionizable complex formation. The obtained salts I and II were also characterized by theoretical calculations, Fourier-transform IR spectroscopy (FT–IR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and elemental analysis.

Two new CdII MOFs of 1,4-bis(1H-benzimidazol-1-yl)butane and flexible dicarboxylate ligands: luminescence sensing towards Fe3+

2020 ◽  
Vol 76 (11) ◽  
pp. 1024-1033
Author(s):  
Fang-Hua Zhao ◽  
Shi-Yao Li ◽  
Wen-Yu Guo ◽  
Zi-Hao Zhao ◽  
Xiao-Wen Guo ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Solid State ◽  
Hydrogen Bonds ◽  
Layer Structure ◽  
Three Dimensional ◽  
Supramolecular Network ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
X Ray ◽  
Vis Spectroscopy

Two new CdII MOFs, namely, two-dimensional (2D) poly[[[μ2-1,4-bis(1H-benzimidazol-1-yl)butane](μ2-heptanedioato)cadmium(II)] tetrahydrate], {[Cd(C7H10O4)(C18H18N4)]·4H2O} n or {[Cd(Pim)(bbimb)]·4H2O} n (1), and 2D poly[diaqua[μ2-1,4-bis(1H-benzimidazol-1-yl)butane](μ4-decanedioato)(μ2-decanedioato)dicadmium(II)], [Cd2(C10H16O4)2(C18H18N4)(H2O)2] n or [Cd(Seb)(bbimb)0.5(H2O)] n (2), have been synthesized hydrothermally based on the 1,4-bis(1H-benzimidazol-1-yl)butane (bbimb) and pimelate (Pim2−, heptanedioate) or sebacate (Seb2−, decanedioate) ligands. Both MOFs were structurally characterized by single-crystal X-ray diffraction. In 1, the CdII centres are connected by bbimb and Pim2− ligands to generate a 2D sql layer structure with an octameric (H2O)8 water cluster. The 2D layers are further connected by O—H...O hydrogen bonds, resulting in a three-dimensional (3D) supramolecular structure. In 2, the CdII centres are coordinated by Seb2− ligands to form binuclear Cd2 units which are linked by bbimb and Seb2− ligands into a 2D hxl layer. The 2D layers are further connected by O—H...O hydrogen bonds, leading to an 8-connected 3D hex supramolecular network. IR and UV–Vis spectroscopy, thermogravimetric analysis and solid-state photoluminescence analysis were carried out on both MOFs. Luminescence sensing experiments reveal that both MOFs have good selective sensing towards Fe3+ in aqueous solution.

Exploring concomitant/conformational dimorphism in a difluoro-substituted phosphoramidate derivative

2019 ◽  
Vol 75 (4) ◽  
pp. 451-461 ◽  
Author(s):  
Avantika Hasija ◽  
Deepak Chopra
Keyword(s):  
Hydrogen Bonds ◽  
Intermolecular Interactions ◽  
Crystallization Process ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Dispersion Energy ◽  
Torsion Angles ◽  
X Ray ◽  
Electrostatic Contribution ◽  
Distinguished Contribution

The concomitant occurrence of dimorphs of diphenyl (3,4-difluorophenyl)phosphoramidate, C18H14F2NO3P, was observed via a solution-mediated crystallization process with variation in the symmetry-free molecules (Z′). The existence of two forms, i.e. Form I (block, Z′ = 1) and Form II (needle, Z′ = 2), was characterized by single-crystal X-ray diffraction, differential scanning calorimetry and powder X-ray diffraction. Furthermore, a quantitative analysis of the energetics of the different intermolecular interactions was carried out via the energy decomposition method (PIXEL), which corroborates with inputs from the energy framework and looks at the topology of the various intermolecular interactions present in both forms. The unequivocally distinguished contribution of strong N—H...O hydrogen bonds along with other interactions, such as C—H...O, C—H...F, π–π and C—H...π, mapped on the Hirshfeld surface is depicted by two-dimensional fingerprint plots. Apart from the major electrostatic contribution from N—H...O hydrogen bonds, the crystal structures are stabilized by contributions from the dispersion energy. The closely related melting points and opposite trends in the calculated lattice energies are interesting to investigate with respect to the thermodynamic stability of the observed dimorphs. The significant variation in the torsion angles in both forms helps in classifying them in the category of conformational polymorphs.

scholarly journals Investigations on the Solubility of Vortioxetine Based on X-ray Structural Data and Crystal Contacts

Crystals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 536
Author(s):  
Xian-Rui Zhang ◽  
Lei Gao ◽  
Gui-Yuan He ◽  
Chao-Jie Chen
Keyword(s):  
Hydrogen Bonds ◽  
Structural Data ◽  
Pharmaceutical Chemistry ◽  
X Ray Diffraction ◽  
Dihydroxybenzoic Acid ◽  
X Ray ◽  
Crystal Contacts ◽  
Poorly Soluble ◽  
Xrd Techniques ◽  
Solid Form

Investigation on the solid-state pharmaceutical chemistry has been known as an intriguing strategy to not only modify the physicochemical properties of drugs but also expand the solid form landscape. Vortioxetine (VOT) is an effective but poorly soluble antidepressant. To improve the solubility of vortioxetine and expand possible solid forms, in this paper, four novel solid forms of vortioxetine with dihydroxybenzoic acids (VOT-23BA, VOT-24BA-TOL, VOT-25BA, and VOT-26BA, 23BA = 2,3-dihydroxybenzoic acid, 24BA = 2,4-dihydroxybenzoic acid, 25BA = 2,5-dihydroxybenzoic acid, 26BA = 2,6-dihydroxybenzoic acid, and TOL = toluene) were synthesized first by a solvent evaporation method and then characterized by single-crystal X-ray diffraction (SCXRD), thermal, and XRD techniques. VOT-24BA-TOL, VOT-25BA, and VOT-26BA, showed similar [2+2] tetrameric R 4 4 (12) hydrogen bonds by acid-piperazine heterosynthon. In the VOT-23BA-H2O salt, the VOT cation and 23BA anion interacted through protonated piperazine-hydroxyl N-H···O hydrogen bonds, not protonated piperazine-deprotonated carboxylic acid N-H···O hydrogen bonds. Solubility studies were carried out in purified water and it was found that the VOT-23BA-H2O, VOT-25BA, and VOT-26BA salts exhibited an increase in water compared to pure VOT. The solubility of the stabilized salt formations followed the order of VOT-25BA > VOT-26BA > VOT-23BA-H2O in purified water.

Synthesis, crystal structure and physicochemical characterization of a Hg(II) complex with 6-methoxyquinoline as ligand

2015 ◽  
Vol 70 (10) ◽  
pp. 719-725 ◽  
Author(s):  
Cristian Villa-Pérez ◽  
Isabel C. Ortega ◽  
Angélica M. Payán-Aristizábal ◽  
Gustavo Echeverría ◽  
Gloria C. Valencia-Uribe ◽  
...  
Keyword(s):  
Molecular Oxygen ◽  
Theoretical Calculations ◽  
Physicochemical Characterization ◽  
Spectroscopic Studies ◽  
Monoclinic Space Group ◽  
Oxygen Production ◽  
X Ray Diffraction ◽  
Singlet Molecular Oxygen ◽  
X Ray

AbstractA new complex of Hg(II) with 6-methoxyquinoline (C10H9NO-6MQ) has been synthesized and characterized. The structure of the complex Hg(6MQ)Cl2 was determined by single crystal X-ray diffraction. It crystallizes in the monoclinic space group P21/c with a = 3.9139(3), b = 26.3400(2), c = 10.9090(9) Å, β = 89.833(6)°, V = 1124.6(1) Å3 and Z = 4 molecules per unit cell. The coordination geometry of the mercury(II) center can be described as a distorted square pyramid formed by one nitrogen atom of the 6MQ and four chlorine atoms. Fourier transform infrared, Raman and UV/Vis spectroscopic studies have been carried out to characterize the compound, using theoretical calculations for the assignment of the experimentally observed bands. The thermal behavior was investigated by thermogravimetric analysis. The quantum yield of singlet molecular oxygen production ΦΔ was measured with steady-state methods in ethanol, using 9,10-dimethylanthracene (DMA) as actinometer and Bengal rose as reference photosensitizer. The resultant singlet molecular oxygen was detected indirectly by photooxidation reactions of DMA. The luminescence properties have also been studied.

Structure and hydrogen bonding in 2,4-dihydroxybenzoic acid at 90, 100, 110 and 150 K; a theoretical and single-crystal X-ray diffraction study

2007 ◽  
Vol 63 (2) ◽  
pp. 303-308 ◽  
Author(s):  
Andrew Parkin ◽  
Martin Adam ◽  
Richard I. Cooper ◽  
Derek S. Middlemiss ◽  
Chick C. Wilson
Keyword(s):  
Hydrogen Bonding ◽  
Solid State ◽  
Hydrogen Bonds ◽  
X Ray Diffraction ◽  
Dihydroxybenzoic Acid ◽  
X Ray ◽  
Hydrogen Bond System ◽  
Proton Disorder ◽  
Intramolecular Hydrogen ◽  
Carboxylic Acid Dimer

A new polymorph of 2,4-dihydroxybenzoic acid is reported. The structure was characterized by multiple-temperature X-ray diffraction and solid-state DFT computations. The material shows a geometric pattern of hydrogen bonding consistent with cooperativity between the intermolecular carboxylic acid dimer and intramolecular hydrogen bonds. The presence of proton disorder within this hydrogen-bond system, which would support such a cooperative model, was not fully ruled out by the initial X-ray studies. However, solid-state calculations on the three possible end-point tautomers indicate that the dominant crystallographically observed configuration is substantially lower in energy than the other tautomers (by at least 9 kJ mol−1), indicating that no disorder should be expected. It is therefore concluded that no disorder is observed either in the intra- or intermolecular hydrogen bonds of the title compound and that the cooperativity between the hydrogen bonds is not present within the temperature range studied.

Structural and spectroscopic studies of dipotassium 3,3,3′,3′-tetramethylcystinate trihydrate, K2[C10H18N2O4S2]3H2O

1984 ◽  
Vol 62 (6) ◽  
pp. 1127-1133 ◽  
Author(s):  
Romolo Faggiani ◽  
Helen Elaine Howard-Lock ◽  
Colin James Lyne Lock ◽  
Maria Lurdes Martins ◽  
Philip Stuart Smalley
Keyword(s):  
Hydrogen Bonds ◽  
Single Crystal ◽  
Spectroscopic Studies ◽  
The Other ◽  
Ionic Interactions ◽  
Water Molecules ◽  
Torsional Angle ◽  
X Ray Diffraction ◽  
Standard Methods ◽  
X Ray

The compound dipotassium 3,3,3′,3′-tetramethylcystinate trihydrate, K2[C10H18O4N2S2]3H2O, has been prepared and characterized by single crystal X-ray diffraction. Crystals were monoclinic, P21a = 6.160(1), b = 26.473(8), c = 6.193(1) Å, β = 113.94(1)°, with two formula units in the unit cell. Intensities were measured on a Syntex P21, diffractometer with use of MoKα radiation. The structure was solved by standard methods and refined to R1 = 0.0469, R2 = 0.0472 based on 2303 independent observed reflections. The C—S bonds (1.877(6), 1.891(6) Å) are longer than in many similar compounds although the S—S bond (2.040(2) Å) is not. The C—S—S—C torsional angle (108.7(3)°) is larger than normal in dithiol compounds. Other distances and angles are normal. Two types of potassium coordination are present, one a distorted octahedron, the other a distorted trigonal prism. In addition to the ionic interactions, hydrogen bonds involving the water molecules are important in stabilizing the structure.

Hydrogen bonds in Na2S·9D2O: Neutron diffraction, X-ray diffraction and vibrational spectroscopic studies

1982 ◽  
Vol 57 ◽  
pp. 237-246 ◽  
Author(s):  
A. Preisinger ◽  
K. Mereiter ◽  
O. Baumgartner ◽  
G. Heger ◽  
W. Mikenda ◽  
...  
Keyword(s):  
Hydrogen Bonds ◽  
Neutron Diffraction ◽  
Spectroscopic Studies ◽  
X Ray Diffraction ◽  
X Ray

Unprecedented transformation of [I−·I3−] to [I42−] polyiodides in the solid state: structures, phase transitions and characterization of dipyrazolium iodide triiodide

2015 ◽  
Vol 44 (42) ◽  
pp. 18447-18458 ◽  
Author(s):  
M. Węcławik ◽  
P. Szklarz ◽  
W. Medycki ◽  
R. Janicki ◽  
A. Piecha-Bisiorek ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Phase Transitions ◽  
Solid State ◽  
Dielectric Measurements ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Vis Spectroscopy ◽  
Solid State Structures

Dipyrazolium iodide triiodide, [C3N2H5+]2[I−·I3−], has been synthesized and studied by means of X-ray diffraction, differential scanning calorimetry, dielectric measurements, and UV-Vis spectroscopy.

scholarly journals Molecular and Crystal Structure of a Chitosan−Zinc Chloride Complex

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1407
Author(s):  
Toshifumi Yui ◽  
Takuya Uto ◽  
Kozo Ogawa
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Theoretical Calculations ◽  
Chloride Complex ◽  
Fiber Axis ◽  
X Ray Diffraction ◽  
Intermolecular Hydrogen Bonds ◽  
Chain Packing ◽  
X Ray ◽  
Packing Structure

We determined the molecular and packing structure of a chitosan–ZnCl2 complex by X-ray diffraction and linked-atom least-squares. Eight D-glucosamine residues—composed of four chitosan chains with two-fold helical symmetry, and four ZnCl2 molecules—were packed in a rectangular unit cell with dimensions a = 1.1677 nm, b = 1.7991 nm, and c = 1.0307 nm (where c is the fiber axis). We performed exhaustive structure searches by examining all of the possible chain packing modes. We also comprehensively searched the positions and spatial orientations of the ZnCl2 molecules. Chitosan chains of antiparallel polarity formed zigzag-shaped chain sheets, where N2···O6, N2···N2, and O6···O6 intermolecular hydrogen bonds connected the neighboring chains. We further refined the packing positions of the ZnCl2 molecules by theoretical calculations of the crystal models, which suggested a possible coordination scheme of Zn(II) with an O6 atom.

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