Structural Chemistry最新文献

Herein, we synthesized novel 4-methyl coumarin-incorporated heterocyclic azo dyes, and structures were confirmed by analytical and spectroscopic approaches. Computational studies were performed using the DFT method with a B3LYP/ 6–31 G (d, p) basis set used to explore the molecular geometry, Mullikan atomic charges, global reactive descriptors, MEP, and RDG. Nonlinear optical (NLO) analysis revealed that the first-order hyperpolarizability of 1d was 18 times greater than that of urea. Natural bond orbital (NBO) analysis showed that all the compounds had greater stability due to internal charge transfer. Solvatochromic behavior was analyzed using UV–Vis spectroscopy, and the absorbance was observed in the range of 380–445 nm. The electrochemical behavior was determined by cyclic voltammetry, which exhibited two reduction peaks and was used to calculate the energy of the molecules (E_HOMO-E_LUMO). The antimicrobial activity was studied against different pathogens Viz., E. coli, S. aureus, and A. flavus, and the results showed that the compounds had good antimicrobial efficacy. “Furthermore, in silico molecular docking results revealed that compounds 1b and 1a have good binding site energies against the target enzymes DNA gyrase and O-methyltransferase, respectively”.

Four acridinium/acridine derivatives have been prepared by mechanochemical synthesis and their crystal structure, supramolecular framework, interaction energy calculation, thermal analysis, and photophysical properties are studied and presented in this manuscript. In the crystal structure, the one- and two-dimensional supramolecular framework is constructed via various strong and weak intermolecular interactions such as N‒H…Cl, O‒H…N, O‒H…Cl, C‒H…Cl, C‒H…O, C‒H…π, and π…π, respectively. The contribution of intermolecular interaction in the three-dimensional molecular packing is studied by the Hirshfeld surface analysis. The calculated total energy value of intermolecular interaction/contacts observed between the molecular pairs in the acridine compound is stronger than the energy value of intermolecular interaction/contacts of acridinium derivatives. The energy value of π…π contacts exhibited between the molecular pairs is significantly stronger than other weak interactions. The thermogravimetric analysis reveals that the acridinium derivatives degrade in three steps whereas the acridine compound undergoes a single-step degradation. Studies show that the acridinium derivatives exhibit a better photoluminescence quantum yield when compared to the acridine compound, and the acridine compound experiences a photoluminescence quenching due to charge transfer interactions.

The reaction of 1-phenyl-1,3-butanedione, also known as benzoylacetone (bzac), with adequate copper salts (sulfate/acetate) at a molar ratio of 2:1 in methanol led to two mononuclear complexes, trans-[Cu(bzac)₂] (I) and cis-[Cu(bzac)₂(CH₃OH)] (II). Both complexes crystallize in the monoclinic P2₁/c symmetry. The copper is four- and five-coordinate, exhibiting a square planar geometry and a distorted square-based pyramid in I and II, respectively. Their crystal structures form discrete supramolecular packing. Indeed, Hirshfeld surface analysis (HSA) with 2D fingerprint plots revealed short-range intermolecular contacts involving O—H···Ο hydrogen bonds and C—H···π interactions in both complexes, in addition to π···π interactions in I. The complexes were characterized by IR and UV‒Vis spectroscopic methods. Moreover, a thorough examination of I and II was conducted, focusing on their structural attributes, electronic characteristics, and both linear and nonlinear optical (NLO) responses through density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations. These quantum calculations were executed utilizing uωwb97xd/6-311G**/SDD. The results revealed that the β₀ value for II was approximately 23 times greater than that of urea. On the other hand, the static and dynamic second hyperpolarizabilities (γ(0; 0,0,0), γ(− 2ω; ω,0,0), and γ(− 2ω; ω,ω,0)) of I are approximately 33% higher than those of II. From this, we infer that the complexes under investigation have potential as outstanding materials for second- and third-order NLO applications. The interactions of I and II with tubulin (PDB ID: 4O2B) were evaluated by molecular docking studies. The results showed that both complexes can bind to many sites on the target and may inhibit its polymerization process. Furthermore, the antioxidant activity of both complexes was also determined and fully discussed.

The interaction of molecular iodine on Mg_n (n = 2–18) clusters has been investigated using first-principles calculations. Structural, adsorption energy and electronic properties of these systems are reported. After structure optimization, the iodine molecule undergoes dissociative adsorption, where the I–I covalent bond of molecular iodine is broken and the dissociative iodine atoms adsorb on the surfaces of the magnesium clusters. The adsorption energy ranging from − 4.335 to − 5.740 eV indicates the chemisorption of I on Mg_n clusters. In the same way, for n > 4, Mg-I compounds have bond lengths of 2.694 to 2.937 Å forming ionic bonds and the values of charge transfer in Mg_nI₂ reach − 0.829 to − 0.977 e. The projected density of states (PDOS) of Mg₇I₂, which has the highest absolute adsorption energy, and Mg₁₆I₂, which has the highest amount of charge transfer, demonstrate the strong hybridization between the Mg 3s and the I 5p orbitals. Overall, the change in electronic structure suggests that Mg_n clusters might serve as promising adsorbents for the removal of gaseous radioactive iodine.

λ-Cyhalothrin (CLT), a widely employed pyrethroid insecticide for pest control, is typically marketed as a racemate, akin to many other pesticides. It has been recognized that optical isomers may exhibit distinct biological activity and toxicity, prompting the burgeoning demand for more efficient separation methods to isolate these isomers. In this study, we employed a theoretical approach to unravel the chiral recognition mechanisms governing the interaction between a polysaccharide-derived stationary phase and the λ-cyhalothrin. Density functional theory calculations were utilized to glean structural and energetic information, enabling the elucidation of the observed chiral discrimination and enantiomeric elution order from prior HPLC experiments. Our analysis pinpointed the critical role of hydrogen bonding and π-π stacking interactions in dictating the relative stability of the diastereomeric complexes formed between the λ-cyhalothrin enantiomers and the chiral selector.