Crystal structure and supramolecular features of O-ethyl pivaloylcarbamothioate: insights from Hirshfeld surface and energy framework analyses

The crystal structure of O-ethyl pivaloylcarbamothioate has been determined by single-crystal X-ray diffraction. The compound crystallizes in the orthorhombic crystal system, the space group Pbca, with unit-cell dimensions a = 10.144(9) Å, b = 10.230(6) Å, c = 19.934(19) Å. The unit-cell volume is 2069(3) Å3 with Z = 8 at 298.15(2) K. A crystal specimen of size 0.241 × 0.217 × 0.124 mm3 was used for data collection using CuKα radiation (λ = 1.54178 Å). The measured reflections (25,062 in total) covered the index ranges −12 ≤ h ≤ 12, −12 ≤ k ≤ 13, and −25 ≤ l ≤ 25, of which 2246 were unique (Rint = 0.1349, Rsigma = 0.0658). The refinement converged with the final values R1 = 0.0942 [I > 2σ(I)] and wR2 = 0.2485 (all data), giving a calculated density of 1.216 g/cm3 and the absorption coefficient μ = 2.506 mm-1. The crystal structure of the title compound is stabilized by a hierarchical supramolecular architecture involving both classical (N-H···O) and non-classical (C-H···O, C-H···N, C-H···S) hydrogen bonds, giving rise to triangular, zigzag, and cyclic motifs as well as  and  synthons. Hirshfeld surface and fingerprint analyses confirm that H···H contacts dominate the packing, whereas directional H···O and H···S interactions play a crucial role in lattice cohesion. Interaction energy calculations further reveal that electrostatic and dispersion forces are the main contributors to the stabilization of the three-dimensional framework

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Graphical Content

Di-aqua-di-isothiocyanato-tin(II)-bis(18-crown-6), Sn(NCS)2·2(18-crown-6)·2H2O – A supramolecular compound of a low-valent main group element with bent sandwich architecture

The crystal structure of the title compound, di-aqua-di-isothiocyanato-tin(II)-bis(18-crown-6), was determined by single crystal X-ray structure analysis. The compound crystallizes in the monoclinic space group C2/c with half a molecule of the point group C2 in the asymmetric unit. The supramolecular arrangement of the three different building blocks, a bent Sn(NCS)2 one, a water molecule, and an 18-crown-6 molecule exhibits a bent sandwich-like structure with an opening angle of 48.1(1)° referring to the least-squares planes through the oxygen atoms of the crown ether molecules. Bond lengths and angles within this aggregate indicate that the isothiocyanate groups bond to the central, bivalent tin atom via covalent 2e-2c-bonds based on two orthogonal p orbitals of the metal atom, and the oxygen atoms of the water molecules via a symmetrical 3c-4e bond by use of the third metal p orbital. The crown ether molecules do not have oxygen-tin contacts but are hydrogen-bonded to the water molecules. Their conformation has similarities with that of an ideal D3d conformation

Click chemistry in tuberculosis research: From drug design to therapeutic delivery - A systematic review

The molecular hybridization of 1,2,3-triazoles with various bioactive scaffolds has become a promising approach to the development of new antitubercular drugs, offering a versatile platform for improving drug efficacy and specificity. This review covers key advancements over the past decade in creating triazole-based hybrids that integrate azoles, coumarin/chromene, isoniazid, quinoline/dihydroquinoline, quinolone, ferrocene, isatin, furan, and other structures. These hybrid molecules generally show improved potency against both drug-sensitive and drug-resistant Mycobacterium tuberculosis strains while maintaining favorable toxicity profiles, making them particularly valuable in the current landscape of rising drug resistance. Structure-activity relationship (SAR) studies highlight that strategic substituent positioning and optimal linker selection are critical in enhancing antimycobacterial efficacy. Furthermore, modifications to the electronic and steric properties of the hybrids have been shown to influence their ability to bypass common resistance mechanisms, underscoring the potential of these compounds to overcome treatment barriers. In particular, several of these hybrids demonstrate promising activity against MDR-TB and XDR-TB strains, suggesting potential applications for immunocompromised patients, such as those with HIV co-infection. Collectively, these findings offer valuable insights for the rational design of next-generation antituberculosis agents that could transform tuberculosis (TB) treatment paradigms in both resistant and sensitive cases of TB

Study of solid residues obtained from the pyrolysis of commercial plastic waste bottles by FTIR and TG methods

The composition of solid residues-products of thermal pyrolysis of plastic waste (polyethylene terephthalate (PET), polypropylene (PP)) at 350-550 °C was studied by Fourier transform infrared spectroscopy (FT-IR) and differential thermal analysis (DTA) methods. On the basis of the transition band (T%) the absorption and Abs parameters were calculated. It was observed that the Abs parameters of the peaks observed in the initial samples appear to change depending on the pyrolysis temperature, with the appearance of new peaks at higher temperatures. It was observed that during the pyrolysis of PET polymer waste, a number of bands with wavenumber 1692, 1670, 1262, 755, 694, and 464 cm-1 occurred at above 450 °C. It would seem that the Abs parameters for the 2923, 1453, and 846 cm-1 peaks observed in the initial samples are equal to zero. It would appear that during the pyrolysis of the PET polymer waste at 550 °C, only three peaks with wavenumbers of 1686, 1062 and 707 cm-1 are observed. Similarly, during the pyrolysis of the PP polymer waste at the same temperature, only one new peak (1092 cm-1) is observed. The solid residues of the pyrolysis processes for the samples taken at 550 °C are calculated and are equal to 13.6 and 0.6%, respectively, for PET and PP. The data shows that solid residues from the pyrolysis of PP wastes have a structure similar to that of charcoal

Enhanced photoconversion efficiency in organic polymer solar cells: Synthesis, structural analysis and computational modelling of 4,8-dichlorobenzo[1,2-b]difuran-2,6-dicarboxylic acid-based composite

Improving the photoconversion efficiency (PCE) of organic polymer-based solar cells (SCs) is crucial to their competitiveness with conventional SCs. This study presents a novel approach to improve PCE of an organic composite solar cell incorporating 4,8-dichlorobenzo[1,2-b]difuran-2,6-dicarboxylic acid. The molecular composite was designed based on the photoactive donor-π-acceptor (D-π-A) architecture and computationally modeled to optimize its efficiency. The synthesized material was characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), and spectral analysis, confirming the formation of a perovskite lattice. Photovoltaic performance was evaluated using simulated device measurements, which produced a fill factor (FF) of 0.708, a short-circuit current density (JSC) of 12.8 mA/cm2, an open-circuit voltage (VOC) of 1.22 V, and an overall PCE of 12.78%. The active exciton diffusion path length was measured at < 9 Å, with a direct band gap of 2.05 eV. The stabilized Urbach energy of the material ranged from 110 to 220 meV. Furthermore, the active single-layer film was interfaced with both a small work function electrode (SWFE) and a long work function electrode (LWFE). The material exhibited high polarizability (αtot = 483.34×10-33 esu, Δα = 332.68×10-33 esu), indicating a strong potential for efficient photoconversion. This study demonstrates the feasibility of using 4,8-dichlorobenzo [1,2-b] difuran-2,6-dicarboxylic acid-based composite for high-performance organic solar cells, offering a promising alternative to conventional SCs

Crystallographic and Hirshfeld surface analysis of 10-(4-chlorophenyldiazenyl)-3-(3-chlorophenyl)-1-methyl-3,5a,6,11b-tetrahydro-5H-benzopyrano[4',3'-4,5]pyrano[2,3-c]pyrazole

The title compound, 10-(4-chlorophenyldiazenyl)-3-(3-chlorophenyl)-1-methyl-3,5a,6,11b-tetrahydro-5H-benzopyrano [4',3'-4,5]pyrano[2,3-c]pyrazole, crystallizes in the triclinic crystal system having the space group P-1 with the following unit cell parameters: a = 7.599(2), b = 11.596(3), c = 12.796(3) Å, α = 90.092(5), β = 94.810(5), γ = 90.583(5)°, Z = 2. The crystal structure was solved by direct methods using single-crystal X-ray diffraction data collected at 100 K and refined by full-matrix least-squares procedures to a final R-value of 0.0636 for 2578 observed reflections. All three phenyl rings A, B, and F are planar. The pyrazole ring E is also planar. Rings C and D are in half-chair conformation with asymmetry parameters: ΔC2(C7a-C11a) = 3.02 and ΔC2(C3a-C11c) = 4.02, respectively. Hirshfeld surface is a 3D boundary around a molecule/crystal structure based on electron density. The Hirshfeld surface analysis revealed dominant H···H (31.0%), H···Cl (26%), and H···C (18%) interactions, contributing to crystal stability and packing efficiency. Molecular docking studies further indicated a strong and stable ligand-enzyme interaction, highlighting its potential for small-molecule inhibitor development

Effects of solvents on the aromaticity and thermodynamic properties of azacalix[2]arene[2]pyrimidines: A computational study

The Harmonic Oscillator Model of Aromaticity (HOMA) indexes for the 2,4,6,8-tetraaza-1(2,4),5(4,2)-dipyrimidina-3,7(1,3)-dibenzenacyclooctaphane (TPB) molecule were calculated in gas, ethanol, n-octanol and water phase. Solvent effects were analyzed with the use of the Integral Equation Formalism Polarizable Continuum Model (IEFPCM) as the default in the self-consistent reaction field (SCRF) method in Gaussian09. The HOMA indexes indicate the presence of highly aromatic pyrimidine and benzyl rings while the parameters for pyrimidine rings slightly decrease and those for the benzyl ring slightly increase with increasing dielectric constant. According to the results, the pyrimidine ring shows the highest aromaticity in the gas phase and a slight decrease in more polar solvents. In contrast, the benzene ring shows an increase in aromaticity as the solvent polarity increases. The HOMO energy of the TPB shifts downward in more polar solvents and the most significant shift occurs in the water phase. The HOMO-LUMO energy gap increases in polar solvents, indicating higher chemical stability and decreased reactivity in these solvents. These findings provide insight into the stability and reactivity of TPB in different phases for potential applications. In addition, apparent thermodynamic properties such as the heat capacity, entropy, enthalpy, and Gibbs free energy of TBP in various solvents were calculated. Using computational simulations, we derive heat capacity equations that exhibit similar quadratic and linear terms in both phases, differing only in their constants. The negative quadratic term leads to a decrease in heat capacity at very low temperatures

Synthesis and crystal structure of [HexNH3]2[HC2O4]2·H2O: A novel hydrogen oxalate hydrate organic salt showing antimicrobial activity against Streptomyces

The new monohydrated n-hexylammonium hydrogen oxalate salt [HexNH3]2[HC2O4]2·H2O (1) (HexNH3 = C6H16N+) has been prepared at room temperature, by mixing dehydrated oxalic acid with n-hexylamine. Salt 1 isolated as single-crystals, crystallizes in the orthorhombic system (space group Pna21) with cell constants of a = 14.1534(8) Å, b = 5.6656(3) Å, c = 26.8153(16) Å, V = 2150.3(2) Å3 and Z = 4. Two n-hexylammonium cations, two hydrogen oxalate anions, and one water molecule compose the asymmetric unit. All components of salt 1 are linked through N-H···O and O-H···O hydrogen bonding interactions leading to an extended supramolecular self-assembly. Structural characterization of 1 was completed by infrared and UV-visible spectroscopy. Elemental analysis (C, H, and N) also corroborates the X-ray crystal structure. The antibacterial activity of salt 1 against a bacterial species of the genus Streptomyces, extracted from potatoes, was then investigated. The antibiotic susceptibility test revealed that the bacteria were highly sensitive to salt, from a concentration of 6 mg/mL, thus acting as an effective bactericide

Ibuprofen, a household pharmaceutical belonging to the racemic mimic class-chirality, diastereochemical details, packing and overlay of the pair within the (S)(+) crystals

We have discovered that enantiopure and racemic Ibuprofen crystallize with nearly the same cell constants, the former in space group P21, the latter in P21/c. As expected from a pair that belongs to the racemic mimic class, the values of Z’ are 2.0 and 1.0, respectively.  Interestingly, despite the fact that one is enantiopure and the other is a racemate, they form the classical dicarboxylate dimer one is familiar with in elemental chemistry and with nearly identical geometrical parameters, the enantiopure sitting at a true lattice inversion center, and the other one at a pseudo-inversion point located at 0.5000, 0.4458, and 0.5000. Packing diagrams are provided that show the remarkable degree to which they agree. Overlay diagrams generated with Mercury illustrate the extent to which the pair of enantiopure species resemble each other; the differences being largely small diastereoisomeric discrepancies and without a doubt the result of anisotropy in packing forces. Finally, within accepted limits for π-π bondings, there are no significant interactions between the phenyl rings in either crystalline form