2D Fingerprint Research Articles

Crystal engineering of Pb(II)-salen coordination polymer enforced for the selective fluorescence NACs sensing activity in a dispersed aqueous medium: A combined experimental and theoretical DFT monologue

A new 1D coordination polymer (CP), [(SCN)Cd(L1)Pb(NCS)]n (1) was synthesized using N2O4-based Scaffold (H2L1 = N, N’-bis(3-methoxysalicylidenimino)-1,3-diaminopropane) and structurally characterized using various analytical instruments. X-ray structure disclosed complex (1) crystallize in the Orthorhombic space group P212121 with Z=4. The crystal structure contains heteronuclear units of [(SCN)Cd(L1)Pb(NCS)]n, linked by a μ1,1,3 thiocyanate (SCN−) bridging. Here weak S···S chalcogen, Pb···S tetrel bonding with two C-H···π(SCN) and one C-H···π(arene) like interactions are vividly observed. The QTAIM/NCI diagram successfully explains the nature of these contacts. Hirshfeld surface (HS) and 2D fingerprint plots analysis has described the non-covalent supramolecular features. The H…H interactions dominate the solid-state crystal structure. The complex fluorescence behaviour is eventually quenched in the presence of explosive nitroaromatic compounds. Complex (1) retained high fluorescence sensitivity and selectivity only for organo-toxin trinitrophenol (TNP). The Stern-Volmer equation evaluated the enhancement of the fluorescence mechanism, the limit of detection (LOD), and the quenching constant (KSV), which for TNP is 6.92 × 104 M−1. The turn-off fluorescence sensing mechanism is explained by (a) AIM/RDG surface interactions energy, (b) Charge-transfer complex, (b) Photo-induced electron transfer (PET) through the HOMO-LUMO approach, (c) Fluorescence resonance energy transfer (FRET), and (d) 1H NMR titration. Notably, the active dynamic sensing is due to a decrease in fluorescence lifetime after the successive addition of TNP with the polymer. Finally, the title complex (1) is employed as a quenched fluorescence response sensor for detecting TNP in a dispersed aqueous medium.

2,6-disubstituted imidazothiadiazole 5-carbaldehyde: Synthesis, crystal structure elucidation and in-silico studies

The synthesis of novel imidazo[2,1-b][1,3,4]thiadiazole derivatives through the reaction of 3,4 dimethoxy phenylacetic acid with various 2 bromo acetophenones is been presented. Further all the derivates were performed for formylation reaction for the introduction of the aldehyde functional group at C-4 position of the target molecule. The Structure of these compounds were well characterized by various spectroscopic techniques such as 1 H and 13 C NMR, mass spectroscopy and FT-IR. X-ray crystallographic study confirmed the structure of imidazothiadiazole and the title compound. The CCDC and ORTEP has been presented. Hirshfeld surface analysis and calculations were carried out to explore intermolecular interactions present in the molecule. The analysis of 2D fingerprint plot gives the quantitative contributions of molecular contacts to the total Hirshfeld surface. in-silico molecular docking studies were performed to check their binding affinities with antimicrobial E. coli MurBenzyme receptor in comparison with the standard ciprofloxacin. Docking scores obtained predicts that two of the novel molecules are potent antimicrobial agents.

Growth, structural, vibrational, characterization and DFT investigations of 2-methylimidazolium hydrogen oxalate dihydrate (2MIO) single crystal-towards third order NLO applications

We report the studies conducted on the single crystal of 2-methyimidazolium hydrogen oxalate dihydrate (2MIO) which was achieved by employing the solution growth technique of conventional slow evaporation wherein the solvent used was deionized water. The confirmation of the grown 2MIO crystal's lattice parameters were accomplished by the analysis of single-crystal X-ray diffraction (SCXRD). The powder sample was utilized for the studies of identifying its crystalline phase, composition, and NLO efficiency. The UV–Vis-NIR studies show that the 2MIO crystal has a better transmittance in the region of entire visible and the lower cut-off wavelength is 280 nm. The decomposition and dissociation points of the 2MIO were studied by employing thermal measurements. The nonlinear optical parameters were computed for 2MIO from the performed Z-scan study. Additionally, quantum chemical studies were carried out on 2MIO molecule which was performed by making use of density functional theory (DFT) at the B3LYP/6–311 G (d.p) method. The optimized geometrical parameters, the bond length and bond angles were compared with the observed experimental XRD data. Hirshfeld surface analysis featuring 2D fingerprint plots were analysed by using Crystal Explorer 3.1 such that it could confirm the intermolecular and weak interactions. Natural bond orbital (NBO) analysis was undertaken to evaluate the donor-accepter interactions and stabilization energies of the molecule. The HOMO-LUMO energy was analysed whereby the energy gap (ΔE) and other related properties of the molecules present in 2MIO were calculated. The first-order hyperpolarizability of 2MIO was measured from the computational studies with which it is established that the obtained value is 4.95 times than that of standard urea.

Experimental and Theoretical Studies of the Optical Properties of the Schiff Bases and Their Materials Obtained from o-Phenylenediamine.

Two macrocyclic Schiff bases derived from o-phenylenediamine and 2-hydroxy-5-methylisophthalaldehyde L1 or 2-hydroxy-5-tert-butyl-1,3-benzenedicarboxaldehyde L2, respectively, were obtained and characterized by X-ray crystallography and spectroscopy (UV-vis, fluorescence and IR). X-ray crystal structure determination and DFT calculations for compounds confirmed their geometry in solution and in the solid phase. Moreover, intermolecular interactions in the crystal structure of L1 and L2 were analyzed using 3D Hirshfeld surfaces and the related 2D fingerprint plots. The 3D Hirschfeld analyses show that the most numerous interactions were found between hydrogen atoms. A considerable number of such interactions are justified by the presence of bulk tert-butyl groups in L2. The luminescence of L1 and L2 in various solvents and in the solid state was studied. In general, the quantum efficiency between 0.14 and 0.70 was noted. The increase in the quantum efficiency with the solvent polarity in the case of L1 was observed (λex = 350 nm). For L2, this trend is similar, except for the chloroform. In the solid state, emission was registered at 552 nm and 561 nm (λex = 350 nm) for L1 and L2, respectively. Thin layers of the studied compounds were deposited on Si(111) by the spin coating method or by thermal vapor deposition and studied by scanning electron microscopy (SEM/EDS), atomic force microscopy (AFM), spectroscopic ellipsometry and fluorescence spectroscopy. The ellipsometric analysis of thin materials obtained by thermal vapor deposition showed that the band-gap energy was 3.45 ± 0.02 eV (359 ± 2 nm) and 3.29 ± 0.02 eV (377 ± 2 nm) for L1/Si and L2/Si samples, respectively. Furthermore, the materials of the L1/Si and L2/Si exhibited broad emission. This feature can allow for using these compounds in LED diodes.

Convolutional Neural Network Model Based on 2D Fingerprint for Bioactivity Prediction.

Determining and modeling the possible behaviour and actions of molecules requires investigating the basic structural features and physicochemical properties that determine their behaviour during chemical, physical, biological, and environmental processes. Computational approaches such as machine learning methods are alternatives to predicting the physiochemical properties of molecules based on their structures. However, the limited accuracy and high error rates of such predictions restrict their use. In this paper, a novel technique based on a deep learning convolutional neural network (CNN) for the prediction of chemical compounds' bioactivity is proposed and developed. The molecules are represented in the new matrix format Mol2mat, a molecular matrix representation adapted from the well-known 2D-fingerprint descriptors. To evaluate the performance of the proposed methods, a series of experiments were conducted using two standard datasets, namely the MDL Drug Data Report (MDDR) and Sutherland, datasets comprising 10 homogeneous and 14 heterogeneous activity classes. After analysing the eight fingerprints, all the probable combinations were investigated using the five best descriptors. The results showed that a combination of three fingerprints, ECFP4, EPFP4, and ECFC4, along with a CNN activity prediction process, achieved the highest performance of 98% AUC when compared to the state-of-the-art ML algorithms NaiveB, LSVM, and RBFN.

Robust Identification and Segmentation of the Outer Skin Layers in Volumetric Fingerprint Data.

Despite the long history of fingerprint biometrics and its use to authenticate individuals, there are still some unsolved challenges with fingerprint acquisition and presentation attack detection (PAD). Currently available commercial fingerprint capture devices struggle with non-ideal skin conditions, including soft skin in infants. They are also susceptible to presentation attacks, which limits their applicability in unsupervised scenarios such as border control. Optical coherence tomography (OCT) could be a promising solution to these problems. In this work, we propose a digital signal processing chain for segmenting two complementary fingerprints from the same OCT fingertip scan: One fingerprint is captured as usual from the epidermis ("outer fingerprint"), whereas the other is taken from inside the skin, at the junction between the epidermis and the underlying dermis ("inner fingerprint"). The resulting 3D fingerprints are then converted to a conventional 2D grayscale representation from which minutiae points can be extracted using existing methods. Our approach is device-independent and has been proven to work with two different time domain OCT scanners. Using efficient GPGPU computing, it took less than a second to process an entire gigabyte of OCT data. To validate the results, we captured OCT fingerprints of 130 individual fingers and compared them with conventional 2D fingerprints of the same fingers. We found that both the outer and inner OCT fingerprints were backward compatible with conventional 2D fingerprints, with the inner fingerprint generally being less damaged and, therefore, more reliable.

A new copper hybrid compound based on 3,3'-diaminodiphenylsulfone as ligand: Growth, crystal structure, spectroscopic analysis, and thermal behavior

A new copper compound with general formula [H2L]2(CuCl4(H2O)2).2Cl·2H2O [L = 3,3′-diaminodiphenylsulfone] was synthesized, at room temperature, by slow evaporation method. The morphology was observed by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscope (EDS). The single crystal X-ray analysis indicates that the studied compound crystallizes in the P-1 triclinic space group. The packing pattern is characterized by organic and inorganic layers alternation stabilized by means of hydrogen interactions. Hirshfeld Surface analysis in combination with 2D fingerprint plots reveal the quantitatively relative contributions of these intermolecular interactions. Infrared and Raman spectroscopic analysis were performed to distinguish the different chemical functional groups and their environments in this compound. Additionally, the optical study was inspected by UV–visible and photoluminescence measurements. The compound exhibits three optical absorption bands at 245, 308 and 554 nm, with 1.54 and 1.64 eV indirect and direct gap energies values, respectively. Thermal analysis (TGA and DSC) was also investigated.

Structural characterization, molecular docking assessment, drug-likeness study and DFT investigation of 2-(2-{1,2-dibromo-2-[3-(4-chloro-phenyl)-[1,2,4]oxadiazol-5-yl]-2-fluoro-ethyl1}-phenyl)-methyl 3-methoxy-acrylic ester

The structure of 2-(2-{1,2 dibromo-2-[3-(4-chloro-phenyl)- [1,2,4]oxadiazol-5-yl]-2-fluoro-ethyl1}-phenyl)-methyl 3-methoxy-acrylic ester (BCOD) was determined using X-ray single-crystal diffraction and theoretical. The BCOD compound crystallizes in the P-1 space group of the triclinic crystallographic system. The absolute structure has been refined to the final R of 5% for 3356 observed reflections. The evaluation of the theoretical parameters was performed using density functional theory (DFT) along with B3LYP and HSEH1PBE functionals at 6–311++G (d,p) basis set in the ground state. The theoretical geometries reproduce well the X-ray structural parameters. The 3D structure was analyzed through distances, bond and dihedral angles exposing that the BCOD molecule is non-planar. The HOMO and LUMO energy values, and reactivity descriptors were also studied and the molecular electrostatic surface potential (MEP) was calculated and mapped to highlight the positive and negative regions in the molecule. Furthermore, intermolecular interactions and their contributions in the crystal were analyzed by exploring Hirshfeld surface and 2D fingerprint results. The H⋅⋅⋅H and O⋅⋅⋅H intercontacts represent the main intermolecular interactions with contributions of 30.7% and 14%, respectively. Moreover, reduced density gradient was used to investigate non-bonded and weak interactions. The biological activity of this compound was extensively studied using molecular docking to identify the hydrogen bonds and binding energy with different proteins.

A new 3D HoIII-organic framework constructed from 1,3,5-tris(4-carboxyphenyl)benzene and 1,10-phenanthroline: Crystal structure, morphological and solid state luminescence properties

A new polynuclear LnIII coordination compound (1) with the stoichiometric formula {[Ho(BTB)(phen)]·(DMF)}n, (H3BTB ​= ​1,3,5-Tris(4-carboxyphenyl)benzene, phen ​= ​1,10 –phenanthroline monohydrate and DMF ​= ​N, N – dimethylformamide) has been synthesized by the solvothermal method and characterized by the infrared spectroscopy, thermogravimetric analysis, single-crystal X-ray diffraction studies, elemental analysis and solid-state electronic absorption properties and solid-state photoluminescence measurements. The XRD analyses indicate that 1 crystallizes in a monoclinic system with space group P21/c and also each HoIII ion has eight coordination, forming a distorted square antiprismatic geometry. For all the coordinated oxygen atoms, six of them belong to five carboxylate groups from different BTB3−ligands, while two nitrogen atoms from only one phen ligand were involved in the coordination. Two crystallographically equivalent HoIII ions are bridged to a dimeric unit as secondary unit buildings (SUBs) by four carboxyl groups in different directions, which also form typical 1D hexagonal channels with BTB3− ligands, these channels are connected in a three-dimensional (3D) framework. Also, these open channels were occupied by two different BTB3− ligands. According to the 3D Hirshfeld surface and 2D fingerprint plots analysis, H⋯H intermolecular interactions are the dominant interactions in the HoIII. Additionally, the π⋯π stacking information determined by the shape index and curvedness plots coincides with the crystal structure analysis. Moreover, photoluminescence properties of 1 were recorded and investigated at room temperature in the Vis-NIR region. Under the excitation of UV light, 1 exhibited strong yellowish-orange emission with CIE chromaticity coordinates (0.480, 0.430). 1 emits at 521, 575 and 653 ​nm correspond to 5F3 → 5I8, 5S2 +5F4→ 5I8 and 5F5→ 5I8 in the visible region, whereas only one weakly peak at 761 ​nm originated to 5S2 +5F4→ 5I7 in the NIR region. This polymeric complex can potentially be applied to luminescent probes or OLEDs.

Synthesis, characterization, Hirshfeld surface analysis and molecular docking studies of 3-(cyclohexylthio)-4-hydroxy-6-methyl-2H-chromen-2-one

The 3-(cyclohexylthio)-4-hydroxy-6-methyl-2H-chromen-2-one (mf. C16H18O3S), a biologically relevant new version of organo-sulfur compounds, has been synthesized Its detailed spectral properties and X-ray crystal structure are studied. The crystal structure was solved by direct method and refined by full matrix least squares procedure to final R value of 0.0468. The crystal structure is stabilized by elaborate system of O-H···O, C-H···O, O-H···S hydrogen bonds to form supramolecular structures. 3D Hirshfeld surfaces and allied 2D fingerprint plots were analyzed for molecular interactions. The Hirshfeld surface analysis of the crystal structure indicates H…H and C···H/H···C interactions as the most important contributors to the crystal packing. Theoretical (DFT) studies on the molecular structure, HOMO, LUMO, MESP surfaces have been performed at B3LYP/6-311 + G(d,p) level of theory. The molecular docking studies have been performed to get insights into the inhibition nature of this molecule against CDKS protein, and search for new anticancer agents. Pharmacological analysis was carried out inorder to check the bioactive nature of the synthesized compound.

Synthesis, crystal structure elucidation and interactions in 1,2,4,5-tetraazaspiro[5.5]undecane-3-thione:Hirshfeld surface analysis, 2d fingerprint plots and 3D energy framework calculations

• 1,2,4,5-tetraazaspiro[5.5]undecane-3-thione was synthesized and characterized by Spectroscopic techniques ( 1 H, 13 C NMR, FT-IR, UV). • Crystal structure elucidation of 1,2,4,5-tetraazaspiro[5.5]undecane-3-thione was done using single crystal X-ray crystallography. • Intermolecular interactions were quantified and located by 2D fingerprint plots via Hirshfeld surface analysis. • 3D energy framework calculations for intermolecular interaction energies were estimated. In this research, crystals of 1,2,4,5-tetraazaspiro[5.5]undecane-3-thione were synthesized and crystallized by slow evaporation solution technique. Synthesized compound was characterized by various physicochemical and modern spectroscopic techniques (FT-IR spectroscopy, 1 H, 13 C NMR and UV-Vis absorption) as well as single crystal X-ray crystallography. Single crystal X-ray diffraction analysis reveals that crystal belongs to monoclinic system with cell dimensions: a = 10.9818 (11) Å, b = 7.0629 (7) Å, c = 12.0194 (12) Å, α = 90°, β = 104.189° (3), γ = 90° and V = 903.82 (16) Å 3 . The empty space and intermolecular connections in crystal lattices were analysed using void mapping and Hirshfeld surface analysis respectively. Percent contribution of some important intermolecular interactions such as H•••H, S•••H/H•••S and N•••H/H•••N and their impact on crystal packing are shown in 2D fingerprint plots. The 3D-topology of crystal packing was analysed and shown using 3D energy framework analysis.

Can 3D fingerprint scanning beat facial ID?

IDloop's Tom Michalsky reviews how well the latest contactless 3D fingerprint scanning systems perform, compared to other contactless and contact-based biometric ID technologies.

Penta-coordinated Cr(II) and Cu(II) complexes appended with 4′-(4-quinolyl)-2,2′:6′,2″-terpyridine: Crystal structure, Hirshfeld surface analysis, luminescence and thermal properties

Two new chromium and copper complexes containing 4′-(4-quinolyl)-2,2′:6′,2′'-terpyridine (qtpy) have been synthesized and characterized using elemental analysis, IR and X-ray crystal structure determination. The reaction of CrCl3.6H2O with qtpy in presence of granulated zinc as a reducing agent has been resulted in the formation of the new terpyridine chromium(II) complex [Cr(qtpy)Cl2] (1). Moreover, the reaction of CuBr2 with qtpy affords the new complex [Cu(qtpy)Br2] (2). Recrystallization of 1 from DMF and recrystallization of 2 from DMSO yield the respective solvates, [Cr(qtpy)Cl2].DMF (1.DMF) and [Cu(qtpy)Br2].2DMSO (2.2DMSO), confirmed by X-ray single crystal analysis. The crystal structures of isostructural complexes [Cr(qtpy)Cl2].DMF (1.DMF) and [Cu(qtpy)Br2].2DMSO (2.2DMSO) reveal that chromium(II) and copper(II) adopt the penta-coordinated square pyramidal geometry in which Cr and Cu are coordinated by three nitrogen atoms of qtpy and two Cl- for 1.DMF, and two Br- for 2.2DMSO. As well, the crystal packings of complex 1.DMF, and 2.2DMSO clearly show the formation of supramolecular structures through C-H…X (X = N, O, halide) hydrogen bond interactions. The 3D Hirshfeld surface analysis and 2D fingerprint maps were used for quantitative mapping out of the intermolecular interactions for 1.DMF, and 2.2DMSO. Luminescence properties of 1 and 2 displayed the ligand-based π–π* emission bands in solution. Thermal properties of 1 and 2 show that they undergo thermal decomposition and the corresponding metal oxide formed in each case.

Deciphering the importance of MD descriptors in designing Vitamin D Receptor agonists and antagonists using machine learning

The Vitamin D Receptor (VDR) ligand-binding domain undergoes conformation change upon the binding of VDR agonists/antagonists. Helix 12 ((H)12) is one of the important helices at VDR ligand binding and its conformational changes are controlled by the binding of agonists and antagonists molecules. Various molecular modeling studies are available to explain the agonistic and antagonistic activity of vitamin D analogs. In this work, for the first time, we attempted to generate a machine learning model with fingerprints, 2D, 3D and MD descriptors that are specific to Vitamin D analogs and VDR. Initially, 2D and 3D descriptors and fingerprints of 1003 vitamin D analogs were calculated using CDK and RDKit. The machine learning model was generated using descriptors and fingerprints. Further, 80 Vitamin D analogs (40 VDR agonists + 40 VDR antagonists) were docked in the VDR active site. 50ns MD simulation was performed for each protein-ligand complex. Different MD descriptors such as Solvent Accessible Surface Area (SASA), radius of gyration, PC1 and PC2 were calculated and considered along with CDK and RDKit descriptors as features for machine learning calculations. A few other descriptors that are related to VDR conformational changes such as conformation of the (H)12, the angle at kink were considered for machine learning model generation. It was observed that the descriptors calculated from VDR conformational changes i) were able to distinguish between agonists and antagonists ii) provide key and comprehensive information about the unique binding characteristics of agonists and antagonists iii) provide a strong basis for the machine learning model generation. Overall, this study attempts the utilization of descriptors that are specific to a protein conformation will be helpful for the generation of an efficient machine learning model.

Structural investigations and theoretical insights of a polymethoxy chalcone derivative: Synthesis, crystal structure, 3D energy frameworks and SARS CoV-2 docking studies

Chalcone derivatives with various functional groups have shown potent pharmacological and non-linear optical properties. A multi‑methoxy substituted (E)-1-(3,4-dimethoxyphenyl)-3-(3,4,5-trimethoxyphenyl) prop‑2-en-1-one, chalcone derivative has been synthesized and spectroscopically characterized by 1H and 13C NMR, LC-MS and FT-IR techniques. A pale yellow colored rectangular shaped single crystals of the compound were obtained by slow evaporation method and the three dimensional structure was confirmed using X-ray diffraction studies. The compound crystallized in the monoclinic crystal system with P21/a space group. The crystal and molecular structure is stabilized by CH···O inter and intra molecular hydrogen bond interactions apart from the prominent CH···π and π···π stacking interactions. These interactions were studied using Hirshfeld surface analysis to understand the nature and strength of interactions; the 2D fingerprint plot quantifies each individual intermolecular contact and revealed that the H…H (49.2%) interactions have the major contribution to the molecular surface. The analysis of 3D molecular energy frameworks revealed that the dispersion energy (-208.16 kJ mol−1) dominates all other energies and their visualization identifies the packing order of the molecules in the crystalline environment. The lattice energy of the compound is found to be -398.1 kJ mol−1. The electronic properties of the compound were quantified using theoretical quantum chemical computations with DFT-B3LYP/6–311+G (d, p) level basis set. The electronic energy band gap of the chalcone molecule is found to be 3.6961 eV. The NBO and Mulliken atomic charges were computed and the molecular electrostatic potential map was plotted to identify the chemical reactive sites on the molecular surface. The second-order nonlinear optical properties of the molecule based on the first static hyperpolarizability (β) have been investigated. Further, the molecular docking studies of the chalcone derivative against corona virus 2 (SARS-CoV-2) protein have been carried out to shed light on the possible significant molecular interactions.

Supramolecular association of (1,4-phenylenedimethanaminium) bis(perchlorate) monohydrate: A combined experimental and theoretical study

This paper deals with the crystal structure of the new material (1,4-phenylenedimethanaminium) bis(perchlorate) monohydrate, (C8H14N2)(ClO4)2·H2O that was prepared in crystalline form by solvent evaporation method at room temperature. Single crystal X-ray diffraction analysis shows that this compound crystallizes in the monoclinic system, with the space group P21/c. The title structure benefits from extensive intermolecular interactions such as C-H… π interactions and hydrogen bonds which are the major forces to make it more stable in the solid-state.The interactions in the solid-state have been also studied using Hirshfeld surface analyses (dnorm, curvedness, and shape index), as well as its 2D fingerprint plots. To reinforce experimental results, DFT calculations have been performed via the B3LYP/LanL2DZ method. HOMO-LUMO energies and the chemical quantum descriptors were taken into account. AIM and RDG analysis has been explored to reveal the steadiness of the molecule. Molecular electrostatic potential inspection has also been submitted in the study.

Self-assembly of new cobalt complexes based on [Co (SCN)4], synthesis, empirical, antioxidant activity, and quantum theory investigations

The cobalt (II) complexes have been synthesized from the reaction of the cationic entities (3,4-dimethylaniline (1) and histamine (2)) with metallic salt CoCl2⋅6H2O and thiocyanate ion (SCN−) as a ligand in H2O/ethanolic solution and processing by the evaporation crystal growth method at room temperature to get crystals. The synthesized complex has been fully characterized by single-crystal X-ray diffraction. UV–Visible, FTIR spectroscopy, TGA analysis, and DFT circulations were also performed. The crystal structural analysis reveals that the solid (1) {[Co(SCN)4] (C8H12N)3}·Cl crystallizes in the monoclinic system with the space group P21/n and the solid (2) {[Co(SCN)4](C5H11N3)2}·2Cl crystallizes in the monoclinic space group P21/m. Metal cations are joined into corrugated chains parallel to the b-axis direction in (1) and (2) by four thiocyanate anions. The crystal structures of (1) and (2) were calculated using XRPD data, indicating that they are closely connected to the DRX mono-crystal results. Different interactions pack the system into a ring formed by N–H⋯Cl and N–H⋯S hydrogen bonds. C–H⋯π and the π⋯π stacking of anilinuim ring for (1) and N–H⋯S intermolecular interactions for (1) and (2) increase the crystals' robustness. Hirshfeld surface analysis cum 2D fingerprint plots visualize the main intermolecular interactions with their contributions in the solid-state phase. The molecular geometries of both complexes obtained from the crystal structure were used for quantum chemical calculation. Here, frontier orbital analysis and electrostatic potential illustrate the chemical reactivities of metal–organic complexes. QTAIM and NCI analysis reveal the strength of interactions at the electronic level.

Energy transfer mechanism of Eu2+, Mn2+Doped lithium aluminate phosphor: Synthesis, Hirshfeld surface analysis and optical study

The LiAlO2 phosphor doped with Eu2+ sensitizer ions and Mn2+ ions activator were synthesized by employing microwave-assisted solution combustion synthesis method (SCS), and structural correlation investigations were elaborated. The host material was characterized by XRD, FT-IR, SEM, TEM analysis and their spectroscopic studies by photoluminescence study. The structural correlation i.e., 3D Hirshfeld surface analysis and 2D fingerprint plots of the LiAlO2 phosphor were generated using crystal explorer-17 software in order to discuss strength of different bonds and their inter-contacts. The energy transfer from Eu2+ to Mn2+ ions through exchange interactions was explained by Dexter's exchange interactions. The energy transfer interactions are possibly due to dipole-dipole transitions was best demonstrated by linear fitting with n: 6 (R2 = 0.987). The chromaticity diagram explains the nature of the color spectrum of phosphor-based on their particular wavelengths. The energy transfer from Eu2+ ions to Mn2+ ions leads to wavelength tunable ability of the phosphor suitable for the development of warm white light LEDs.

Structural and Energetic Properties of Weak Noncovalent Interactions in Two Closely Related 3,6-Disubstituted-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazole Derivatives: In Vitro Cyclooxygenase Activity, Crystallography, and Computational Investigations.

Two 3,6-disubstituted-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazole derivatives, namely, 3-(adamantan-1-yl)-6-(2-chloro-6-fluorophenyl)-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazole 1 and 6-(2-chloro-6-fluorophenyl)-3-phenyl-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazole 2, were prepared, and the detailed analysis of the weak intermolecular interactions responsible for the supramolecular self-assembly was performed using X-ray diffraction and theoretical tools. Analyses of Hirshfeld surface and 2D fingerprint plot demonstrated the effect of adamant-1-yl/phenyl moieties on intermolecular interactions in solid-state structures. The effect of these substituents on H···H/Cl/N contacts was more specific. The CLP-PIXEL and density functional theory methods provide information on the energetics of molecular dimers observed in these compounds. The crystal structure of compound 1 stabilizes with a variety of weak intermolecular interactions, including C–H···N, C–H···π, and C–H···Cl hydrogen bonds, a directional C–S···π chalcogen bond, and unconventional short F···C/N contacts. The crystal structure of compound 2 is stabilized by π-stacking interactions, C–H···N, C–H···π, and C–H···Cl hydrogen bonds, and highly directional attractive σ–hole interactions such as the C–Cl···N halogen bond and the C–S···N chalcogen bond. In addition, S(lp)···C(π) and short N···N contacts play a supportive role in the stabilization of certain molecular dimers. The final supramolecular architectures resulting from the combination of different intermolecular interactions are observed in both the crystal packing. The molecular electrostatic potential map reveals complementary electrostatic potentials of the interacting atoms. The quantum theory of atoms in molecules approach was used to delineate the nature and strength of different intermolecular interactions present in different dimers of compounds 1 and 2. The in vitro experiments suggest that both compounds showed selectivity against COX-2 targets rather than COX-1. Molecular docking analysis showed the binding pose of the compounds at the active sites of COX-1/2 enzymes.

Synthesis, crystal structures, spectroscopic characterization and in vitro evaluation of the 4-sulfono-3-methoxycinnamaldehydes as potential α-glucosidase and/or α-amylase inhibitors

The 4-sulfono-3-methoxycinnamaldehyde derivatives 2a–e were synthesized by sulfonation of 4-hydroxy-3-methoxycinnamaldehyde 1 with alkyl or phenyl sulfonyl chlorides. Both single crystal X-ray diffraction (XRD) and 1H NMR spectroscopic techniques provided proof of the trans stereochemistry of the α,β-unsaturated carbonyl arm of these molecular constructs. XRD method confirmed the trans isomer to exist exclusively in the solid state. NOESY experiment, on the other hand, confirmed the presence in the solution phase of also a conformer with cis alkenyl moiety and a trans orientation of the aldehyde group. This observation was corroborated by density functional theory studies which predicted the coexistence of both cis and trans isomers in the gas phase. The Hirshfeld surface and 2D fingerprint plots were used to understand the intermolecular interactions responsible for the molecular packing in the crystal lattices of these compounds. Their potential to inhibit α-glucosidase and/or α-amylase activities were evaluated through enzymatic assays in vitro complemented with molecular docking studies. 4-(Methoxyphenyl)sulfono-3-methoxycinnamaldehyde (2d) exhibited increased inhibitory effect against α-glucosidase (IC50 = 0.68 ± 1.36 µM) and α-amylase (IC50 = 22.99 ± 0.45 µM) compared to substrate 1 (IC50 = 1.70 ± 1.77 µM & 30.45 ± 0.30 µM, respectively) and acarbose (IC50 = 4.46 ± 1.52 µM & 25.48 ± 0.80 µM, respectively). The experimental results were complemented with data from molecular docking of the most active derivatives and molecular dynamics simulation study of derivatives with highest binding energies against α-glucosidase and α-amylase.