In this study, a novel diacylhydrazone Schiff base butanedihydrazide-bridged bis(4-methoxysalicylaldehyde) ligand (HL) was synthesized by the condensation of 2-hydroxy-4-methoxybenzaldehyde and succinic dihydrazide. UV-vis and fluorescence spectroscopy were used to methodically examine how HL binds to common monovalent, divalent, and trivalent metal ions. According to the results, HL showed strong interaction with the majority of divalent and trivalent ions and indicated clear fluorescence selectivity toward Fe(iii), while demonstrating minimal interaction with monovalent metal ions (Li(i), Na(i), and K(i)). The HL ligand displayed excellent Fe(iii) recognition ability, as evidenced by its low detection limit (0.76 mu M) and relatively strong binding constant (2.74 x 105 M-1), underscoring its potential as an effective Fe(iii) sensing probe. Fe(iii) is detected by the HL ligand using a fluorescence quenching method. The Mn-L complex crystallizes in the monoclinic crystal system with space group C2/c, as proven by single-crystal X-ray diffraction analysis, which also provides structural support for the stable coordination framework of the complex. C-H & ctdot;pi contacts and pi & ctdot;pi stacking interactions enhance the Mn-L crystal packing, improving structural stability. The optical band gap of the Mn-L complex was determined to be 2.55 eV from Tauc plot analysis, in excellent agreement with the DFT calculated value of 2.50 eV, highlighting the strong consistency between experimental and theoretical results. Photophysical studies revealed that HL and its Mn-L complex are highly luminescent, emitting violet light upon excitation at 365 nm and exhibiting fluorescence quantum yields of 0.66 and 0.61, respectively, indicating that coordination to Mn only marginally reduces the emissive efficiency of the ligand.

The diazotization reaction of o-trifluoromethyl aniline from aromatic amines with 5,5-dimethylcyclohexane-1,3-dione was studied, as a result, 2-(2-(o-trifluoromethylphenyl)hydrazono)-5,5-dimethylcyclohexane-1 ,3-dione (THDCD) was synthesized and its structure was confirmed by X-ray diffraction analysis. The solid state assembly is stabilized by numerous intermolecular interactions which are deeply probed by Hirshfeld surface analysis. The enrichment ratio was computed for getting the contact with the highest propensity to form crystal packing interaction. The mechanical response of the crystal is predicted by voids analysis. Moreover, interaction energy calculations were performed at HF/3-21G electron density model to further inspect the supramolecular assembly of the crystal. DFT calculation was conducted using B3LYP level with 6–311++G(d, p) basic set with the help of Gaussian 09W and GaussView 6.0 packages. MEP surface, HOMO-LUMO orbitals, and NBO theory were analyzed via DFT approach. Theoretical method confirms the proposed geometry of THDCD by X-ray analysis.

Metal(II)-carboxylate frameworks are an important class of MOF materials finding applications in gas storage, separation, sensing, catalysis, etc. Recently, their design, synthesis and characterization have been established at a very fast pace. Here two novel MOFs based on 5,5 '-(([1,1 '-biphenyl]-4,4 '-dicarbonyl) bis(azanediyl))diisophthalic acid (H4L, an amide containing ligand) and transition metals (copper and zinc) are reported. Several characterization tools e.g., FT-IR, XRD, SEM, TGA, and XPS are used to characterize these MOFs. Single -crystal X-ray diffraction and Hirshfeld surface analyses are used to characterize the 3D structural framework. The void and cavity analysis revealed the strength of the crystal packing. Both MOFs followed multistage thermogravimetric disintegration profiles. The solvent molecules escaped around 200 degrees C and the structural changes due to decompositions in the frameworks continued till 500 degrees C. The morphological analysis for Zn-MOF and Cu-MOF showed uniform wedge-shaped rectangular blocks and spherical balls with dimensions around 100 and 50 mu m, respectively. The amide functionalized Zn(II)- carboxylate framework exhibited high catalytic activity (85->99%) towards the solvent -free cycloaddition of CO2 to different epoxides e.g., epichlorohydrin, propylene oxide, allyl glycidyl ether and glycidyl isopropyl ether with 100% selectivity under ambient conditions (i.e., 1 bar at 40 degrees C for 24 h) at very low catalyst loading. By adjusting the reaction conditions (T, P, and co -catalyst), the catalytic conversion reached 100% within only 2 hours. The results showed Zn-MOF as a superior and efficient catalyst compared to other reported MOFs. Additionally, the catalyst can be easily recovered and regenerated for repeated use without performance loss.

The current research work is about the synthesis of the novel Schiff base obtained by the condensation reaction of 2-hydroxy-5-nıtrobenzaldehyde with 3-fluoroaniline. The synthesized compound is characterized by IR spectroscopy and single crystal X-rays diffraction (SC-XRD) technique. SC-XRD inferred that C–H⋯O and off-set π⋯π stacking interactions are the main features of the supramolecular assembly. Hirshfeld surface analysis is performed to shield more light on the intermolecular interactions. Mechanical strength of the crystal is predicted by the void analysis. Moreover, the interaction energy between molecular pairs and energy frameworks are computed by using B3LYP/6-31G(d,p) electron density model in order to understand the topology of the crystal.

It has been found that CF3COOH catalyzes the Knoevenagel condensation reaction of 5-bromo-2-hydroxybenzaldehyde and ethyl cyanoacetate. Consequently, the 6-bromo-2-oxo-2H-chromene-3-carbonitrile (BOCC) compound has been synthesized. The structure was proved by single crystal X-rays diffraction analysis. The asymmetric unit contained two identical molecules A and B which are different with respect to crystallography. The crystal packing is mainly stabilized by C–H⋯N and C–H⋯O bonding which is further stabilized by C–N⋯π and off-set π⋯π stacking interactions. Hirshfeld surface analysis is employed for the further exploration of the intermolecular interactions. Enrichment ratio is computed for the interatomic contacts to find the tendency of the contacts to form the crystal packing interactions. The void analysis is performed to predict the mechanical behaviour. Furthermore, the computational study is performed for finding the interaction energy between molecular pair by using B3LYP/6-31G(d,p) electron density model. The study inferred the role of various types of interaction energies in stabilizing the molecular pair.

The three-component condensation reaction of 4-methylbenzaldehyde with acetophenone and urea in the presence of CF3COOH was investigated and as a result, 4-phenyl-6-(p-tolyl)pyrimidin-2(1H)-one (PPTP) was synthesized. The structure was determined by single crystal X-rays diffraction analysis which inferred that the PPTP crystallized in monoclinic crystal system with space group P21/c. The dihedral angles between the aromatic rings indicate that the molecule is non-planar. The crystal packing is mainly stabilized by N–H⋯O and C–H⋯O bonding which is further stabilized by off-set π⋯π stacking interactions. The supramolecular assembly is further investigated by Hirshfeld surface analysis. The mechanical behaviour is predicted by the void analysis Moreover, the computational study is carried out for finding the interaction energy between molecular pair by using B3LYP/6-31G(d,p) electron density model. The study inferred the role of various types of interaction energies in stabilizing the crystal packing.

Herein, a new Ni(II) carboxylate polymer, [Ni(Pyr)·4H2O]Phth, is synthesized by the reaction of NiSO4·7H2O with equimolar amounts of phthalic acid (PhthH2) as the counter-anion and pyrazine (Pyr) as an ancillary ligand in aqueous media. The crystal structure of [Ni(Pyr)·4H2O]Phth is investigated by single crystal X-rays diffraction analysis, which inferred the ionic nature of the complex. In cation, the Ni-center is coordinated by two pyrazine rings and four water molecules to form an octahedral coordination geometry. The crystal structure exists as a one-dimensional polymeric structure. The crystal packing is stabilized by O–H⋯O and C–H⋯O bonding. The non-covalent interactions are investigated by Hirshfeld surface analysis. The enrichment ratio delivers the tendency of the interaction of the pair of chemical moieties, which are involved in the packing of crystals. Moreover, void analysis is executed to look at the packing efficiency, which helps in predicting the mechanical response of the compound.

The diazotization reaction of p -fluoroaniline from aromatic amines with 5,5-dimethylcyclohexane-1,3-dione was studied, as a result 2-(2-( p -fluorophenyl)hydrazone)-5,5-dimethylcyclohexane-1,3-dione ( FHDCD ) was synthesized and its structure was confirmed by single crystal X-ray diffraction (XRD) technique. The crystal packing was governed by various intermolecular interactions which was inspected by Hirshfeld surface analysis. 2D fingerprint plots were formed to find the contact that has most significant contribution in crystal packing. Enrichment ratio was calculated in order to find the contact that has highest propensity to form crystal packing interaction. Void analysis was carried out to predict the mechanical response of the crystal. Moreover, interaction energy calculations were performed at HF/3-21G electron density model to further inspect the supramolecular assembly of the crystal.

A pyranopyrimidine derivative named as 10-amino-7-(2,4-diamino-6-oxidopyrimidin-1-ium-5-yl)-7H-benzo[7,8]chromeno[2,3-d]pyrimidin-9-ium-8-olate dimethylformamide acetic acid hydrate (ADCP) is synthesized by the reaction of 2-hydroxy-1-naphthaldehyde and 2,6-diaminopyrimidin-4-ol in the presence of ethanol and dimethylformamide. The synthesized compound is characterized by single crystal X-ray diffraction technique. The molecule exists as a doubly zwitterion ion and the supramolecular assembly is stabilized by N–H⋯N, N–H⋯O and O–H⋯N bonding interactions. These intermolecular interactions are further investigated and justified by Hirshfeld Surface Analysis. Void analysis is carried out in order to check the response of the crystal to an applied stress. Quantum chemical calculations are carried out at B3LYP/6-31G(d,p) electron density model for finding the interaction energies between molecular pairs.

Herein, a new Schiff base copper complex named as of bis{(E)-5-(diethylamino)-2-(((3-iodo-4-methylphenyl)imino)methyl)phenol}copper(II) (DIMP-Cu) is synthesized by the reaction of (E)-5-(diethylamino)-2-(((3-iodo-4-methylphenyl)imino)methyl)phenol with copper(II)acetate monohydrate in ethanol. The complex is characterized by FTIR, UV-visible, 1H NMR and 13C NMR. Moreover, the crystal structure is determined by single crystal X-rays diffraction analysis (SC-XRD) which showed that the coordination geometry around Cu-atom is distorted square planar. The supramolecular assembly is mainly stabilized by C–H⋯I bonding. The non-covalent interactions are further inspected by Hirshfeld surface analysis. Mechanical response of the crystal is predicted by void analysis. Computational study is carried out by using HF/3-21G electron density model in order to find the interaction energy between molecular pairs.

Binuclear zinc(II) Schiff base complexes were synthesized through the reaction of ONNO tetradentate Schiff base ligands derived from the condensation of 2,2-dimethyl-1,3-propanediamine and 5-chlorosalicylaldehyde or 5bromosalicylaldehyde with zinc acetylacetonate salt. The structures of synthesized products were explored spectroscopically through the FT-IR, 1H NMR and elemental analysis. Structural analysis of the complexes revealed that the compound is a centrosymmetric dimer in which the five coordinated Zn(II) atoms are linked to the opposite metal center by making mu-phenoxo bridges through one of the phenolic oxygen atoms of Schiff base ligands. The nature and types of non-covalent interactions present among the sample molecules were also investigated by using the quantum theory of atoms in molecules and non-covalent interactions calculations. The theoretical calculations, performed by density functional theory using the B3LYP/Def2-TZVP level of theory, direct that the intended outcomes are in compliance with the actual consequences. Furthermore, from antimicrobial screenings it was revealed that the zinc complexes are more active as compared to the ligands.

Schiff base complexes of new palladium(II) and nickel(II) are prepared through the treatment of symmetrical Schiff base ligand which are derivative of 4,5-dimethyl-o-phenylenediamine with Ni(OAc)(2).4H(2)O and Pd(OAc)(2) salts. Elemental analysis, as well as spectroscopic methods like FT-IR and H-1 NMR, were employed to investigate the molecular structure of the produced ligand and its associated metal complexes. The crystal structure investigation confirms that the coordination environment of the nickel in the NiL complex is tetra-coordinate occupied by ONNO sets of the coordinated ligand in slightly distorted square planar geometry. A Hirshfeld surface investigation is carried out for further exploration and understanding of the intermolecular interactions and a comparative study with some relevant crystal structures. The DFT's theoretical calculations, which used the B3LYP/Def2-TZVP level of theory, showed that the theoretical conclusions corresponded to the actual findings. (C) 2021 Elsevier B.V. All rights reserved.

The effective preparation of pyrimethamine based co-crystal salts with substituted benzoic acids (4-nitrobenzoic acid 1 and 5-chlorosalicylic acid 2) in methanol has been reported. The crystal structure of salt 1 and 2 is acquired through the x-rays diffraction technique. Hirshfeld surface analysis elaborates the comparative study of the non-covalent interactions in salt 1 and 2. In order to theoretically evaluate the non-covalent interactions between molecular ions in salts 1 and 2, DFT and TD-DFT calculations of molecular salts were performed. FMO and GRD analyses were performed to evaluate the reactivity of molecular ions. While, NBO, AIM and NCI analyses were performed to explore the non-covalent interactions between cation and anions of molecular salts 1 and 2. The calculations demonstrated that salt 1 has H-bond slightly stronger than salt 2 due to the withdrawing effect of -NO2 substituent group. The molecular anions reactivity allows different patterns of non-covalent interactions that affect the salts arrangement in the crystal.

The current research work is about the efficient synthesis of three crystalline Schiff bases derived from benzene sulfonamides named as (E)-4-((3-ethoxy-2-hydroxybenzylidene)amino)benzenesulfonamide ( ASES ), (E)-4-((3-ethoxy-2-hydroxybenzylidene)amino)-N-(5-methylisoxazol-3-yl)benzenesulfonamide ( SMB ), (E)-4-((2-hydroxy-3-methoxybenzylidene)amino)-N-(5-methylisoxazol-3-yl)benzenesulfonamide ( SES ) and their characterization by single-crystal X-rays diffraction (SC-XRD) studies. The molecular configuration of ASES and SMB is stabilized by intramolecular O-H center dot center dot center dot N bonding, whereas C-H center dot center dot center dot O intramolecular H-bonding is responsible for the stabilization of the molecular configuration of SES . The N-H center dot center dot center dot O intermolecular H-bonding is the main aspect of the supramolecular behaviour of ASES , while the N-H center dot center dot center dot O and C-H center dot center dot center dot O intermolecular H-bonding are the major features of the supramolecular behaviour of SMB and SES , respectively. The S-O center dot center dot center dot zr interaction performs a significant role in the stabilization of the molecular assembly of the SMB , whereas the C-H center dot center dot center dot zr interaction stabilizes the molecular assembly of SES . The role of weak off-set zr center dot center dot center dot zr interaction in all three compounds is also explored. The non-covalent interactions of strong as well as comparatively weak nature are further comprehensively explored by Hirshfeld surface (HS) analysis for the further exploration of the molecular assembly. Furthermore, we have also applied quantum chemical methods to calculate the linear and nonlinear optical (NLO) properties of synthesized compounds. The average linear polarizability values for ASES, SMB , and SES are found to be 34.83 x 10 -24 esu, 40.14 x 10 -24 esu, and 42.67 x 10 -24 esu, respectively, while the third-order NLO average polarizability amplitudes of ASES, SMB , and SES are found to be reasonably larger, amounting to 58.89 x 10 -36 esu, 83.35 x 10 -36 esu, and 69.69 x 10 -36 esu at the M06-2X/6-311G * levels of theory, respectively. A comparison of average NLO polarizabilities shows that the amplitudes of SMB and SES are 41% and 18% larger than that of ASES , respectively, which are also 3 and 2.5 times larger than that of para -nitroaniline ( p -NA) as calculated using the same methodology. We believe that the above-synthesized compounds will have decent potential to be used as NLO materials. (c) 2022 Elsevier B.V. All rights reserved.

In present work, two novel adamantyl based thiazoles were synthesized via simple cyclization reaction of 1-(substitutedbenzylidene)thiosemicarbazides (2) and 1-adamantyl bromomethyl ketone. The structures of resulting compounds 3a and 3b were established with the help of spectro-analytical techniques like; FTIR, H-1-, C-13-NMR and mass spectrometry. The final confirmation of the structures was done with single crystal XRD. All spectroscopic properties of the compounds were further investigated with Density Functional Theory (DFT). The quantum chemical calculations were performed through B3LYP method with 6-311G(d,p), ccPVTZ and ccPVDZ as basis sets to determine bond lengths, bond angles, dihedral angles, frontier molecular orbitals (FMOs) and molecular electrostatic potential (MEP), which revealed that the molecule 3b is strong electrophile while molecule 3a is moderate one. We have also compared the theoretical molecular vibrations and chemical shifts of the compounds with experimental data and results were in good agreement with each other. On the basis of respective correlation co-efficient (sigma(2)) of calculation methods (6-311G(d,p), ccPVTZ and ccPVDZ) it is revealed that ccPVTZ basis sets gave the best results. The MEP analysis revealed that electronegative elements in structure possess the maximum electronic cloud. (C) 2022 Elsevier B.V. All rights reserved.

In search of achieving some specific fluorescent and biological applications, azo-based compounds 1 and 2 with robust H-bonding and strong peptide properties were synthesized and characterized by essential spectroscopic techniques such as UV-Vis, FT-IR, 1 H NMR, and single-crystal X-ray crystallographic studies. The intermolecular interactions in compounds 1 and 2 are elaborated by Hirshfeld surface analysis. Both compounds exhibit maximum absorption between 250 and 400 nm in the trans configuration with allowed transitions. Irradiating the solution of compound 1 with UV light, the intensity of the peaks around 285 and 339 nm changed with time indicating the isomerization from trans to cis state. The antioxidant activity of compounds 1 and 2 was studied by using the DPPH free radical scavenging assay with fixed reaction time and steady-state measurements. The results indicate that the azo compounds exhibit moderate scavenging activity compared to ascorbic acid. As a result of DNA interactions, a hypochromic shift was observed in the UV-Vis spectra of compounds 1 and 2 at different concentrations of DNA. The values of binding constant (K b ) and Gibbs free energy ( AG o ) for compounds 1 and 2 were found to be 1.5 x 10 4 M -1 , -23.8 kJ/mol and 1.9 x 10 4 M -1 and -22.8 kJ/mol, respectively. Additionally, compounds 1 and 2 were docked with different DNA fragments to get structure-property insights by studying the intermolecular interactions of their respective complexes. The binding interaction energies of compounds 1 and 2 are found to be -8.40 and -7.70 kcal/mol for 1BNA (DNA) fragment and -8.50 and -7.90 kcal/mol for 1D29 (DNA), respectively. To get molecular-level structural insights, the frontier molecular orbitals (FMOs) and molecular electrostatic potentials (MEPs) were also calculated and explained for the optimized molecular geometries of compounds 1 and 2 . The current combined experimental and computational study highlights the importance of our synthesized compounds which may evoke the scientific interest of the chemical community to further explore their potential in-vivo and in-vitro applications. (c) 2022 Elsevier B.V. All rights reserved.

Metal-organic frameworks (MOFs) are porous coordination polymers with interesting structural frameworks, properties, and a wide range of applications. A novel 3D cadmium(II)-carboxylate framework, CdMOF ([Cd2(L)(DMF)(H2O)2]n), was synthesized by the solvothermal method using a tetracarboxylic bridging linker having amide functional moieties. The CdMOF crystal structure exists in the form of a 3D layer structure. Based on the single-crystal X-ray diffraction studies, the supramolecular assembly of CdMOF is explored by Hirshfeld surface analysis. The voids and cavities analysis is performed to check the strength of the crystal packing in CdMOF. The CdMOF followed a multistage thermal degradation pattern in which the solvent molecules escaped around 200 °C and the structural framework remained stable till 230 °C. The main structural framework collapsed (>60 wt.%) into organic volatiles between 400–550 °C. The SEM morphology analyses revealed uniform wedge-shaped rectangular blocks with dimensions of 25–100 μm. The catalytic activity of CdMOF for the solvent and cocatalyst-free cycloaddition of CO2 into epichlorohydrin was successful with 100% selectivity. The current results revealed that this 3D CdMOF is more active than the previously reported CdMOFs and, more interestingly, without using a co-catalyst. The catalyst was easily recovered and reused, having the same performance.

This investigation is focused on the synthesis of two halo-functionalized crystalline Schiff base (imine) compounds: (E)-2-methoxy-6-(((3-(trifluoromethyl)phenyl)imino)methyl)phenol (MFIP) and (E)-1-(((2-fluorophenyl)imino)methyl)naphthalen-2-ol (FPIN) by the condensation reaction of substituted benzaldehydes and substituted aniline. The crystal structures of MFIP and FPIN were determined unambiguously by single-crystal X-ray diffraction (SC-XRD) studies. Intermolecular interactions and the role of fluorine atoms in the stabilization of the crystal packing are explored for both compounds using Hirshfeld surface analysis. Accompanied with experimental studies, quantum chemical calculations were also performed for comprehensive structure elucidation at the M06/6-311G(d,p) level of theory. A comparison of experimental and density functional theory results for geometrical parameters exhibited excellent agreement. Interestingly, Frontier molecular orbitals and natural bond orbital (NBO) findings revealed that intramolecular charge transfer and hyper-conjugation interactions had played a significant role to stabilize the molecules. Both compounds exhibited a relatively larger value of hardness with a smaller global softness, which, as proposed by the SC-XRD and NBO study, shows a higher stability. Nonlinear optical (NLO) findings showed that FPIN manifested a larger value of linear polarizability ( = 293.06 a.u.) and second-order hyperpolarizability (<γ> = 3.31 × 105 a.u.) than MFIP ( = 252.42 and <γ> = 2.08 × 105 a.u.) due to an extended conjugation. The above-mentioned findings of the entitled compounds may play a crucial role in NLO applications.

Two imine compounds named as (E)-2-(((3,4-dichlorophenyl)imino)methyl)phenol (DC2H) and (E)-4-(((2,4-dimethylphenyl)imino)methyl)phenol (DM4H) are synthesized, and their crystal structures are verified using the single-crystal X-ray diffraction (XRD) technique. The crystal structures of the compounds are compared with the closely related crystal structures using the Cambridge Structural Database (CSD). The crystal packing in terms of intermolecular interactions is fully explored by Hirshfeld surface analysis. Void analysis is carried out for both compounds to check the strength of the crystal packing. Furthermore, a state-of-the-art dual computational technique consisting of quantum chemical and molecular docking methods is used to shed light on the molecular structure, optoelectronic properties, and bioactivity of indigenously synthesized compounds. The optimized molecular geometries are compared with their counterpart experimental values. Based on previous reports of biofunctions of the indigenously synthesized imine derivatives, they are explored for their potential inhibition properties against two very crucial proteins (main protease (Mpro) and nonstructural protein 9 (NSP9)) of SARS-CoV-2. The calculated interaction energy values of DC2H and DM4H with Mpro are found to be -6.3 and -6.6 kcal/mol, respectively, and for NSP9, the calculated interaction energy value is found to be -6.5 kcal/mol. We believe that the current combined study through experiments and computational techniques will not only pique the interest of the broad scientific community but also evoke interest in their further in vitro and in vivo investigations.

This work reports the synthesis, X-ray characterization and theoretical study of dichlorophenyl substituted 3-hydroxy-chromenones focusing on the low prevalence of halogen bonds and in vitro and in silico lipoxygenase inhibition (LOX) studies.