Synthesis, X-ray crystallography, vibrational spectroscopy, thermal and DFT studies of (E)-6-(4-methylstyryl)-4,5-dihydropyridazin-3(2H)-one

DFT insights into assembling [8]MCPP with [14]pyridine nanobelts for amino acid sensing

The progress in designing nanoscale electronic sensors for detecting amino acids (AAs) has attracted considerable interest due to their ability to enable label-free and real-time detection. In this study, the [14]pyridine@[8]MCPP system formed by assembling [8]cycloparaphenylene ([8]MCPP) with [14]pyridine methylene-bridged nanobelts was investigated using density functional theory (DFT) calculations as a potential sensor for five amino acids: glycine (Gly), alanine (Ala), threonine (Thr), leucine (Leu), and aspartic acid (Asp). The sensing capabilities of the assembled structure were evaluated through various analyses, including frontier molecular orbital (FMO), density of states (DOS), quantum theory of atoms in molecules (QTAIM), non-covalent interactions (NCI), and electron density difference (EDD). The energy gap of the [14]pyridine@[8]MCPP assembly was influenced by the presence of amino acids, with the most significant change (-8.75 %) observed in the [14]pyridine@[8]MCPP/Asp complex. Furthermore, QTAIM and NCI analyses indicated that the interactions between AAs and the [14]pyridine@[8]MCPP assembly are primarily governed by van der Waals (vdW) forces. The short recovery times (3.47 × 10-10 to 1.27 × 10-6 s) and favorable sensor responses (0.09-0.17) of the [14]pyridine@[8]MCPP/AA complexes at 298 K suggest that this assembly could serve as an effective material for detecting amino acids. These findings underscore the potential of assembled nanostructures as valuable candidates for amino acid sensing applications.

The interaction mechanism of papain and bromelain with apigenin and luteolin in binary and ternary systems

In this study, the interaction mechanism of papain and bromelain with apigenin and luteolin in binary and ternary systems was compared and analyzed by spectroscopic methods, molecular docking, and molecular dynamics simulation. Additionally, the effects of apigenin and/or luteolin on the conformational changes and enzymatic activity of papain and bromelain were investigated. The results show that apigenin and/or luteolin exhibit a moderate binding affinity with papain/bromelain, with the binding constants Ka in the range of 104-105 L mol-1. The order of addition of apigenin and luteolin significantly influenced their binding affinities to the enzymes. The main non-covalent forces of the papain-luteolin (first)-apigenin ternary system are hydrogen bonds and Van der Waals forces. Hydrophobic interactions, electrostatic forces and hydrogen bonds are the main non-covalent forces of other binary and ternary systems. These systems differentially alter the microenvironment of Trp and Tyr residues, secondary and tertiary structures, and enzymatic activity. Molecular docking and dynamics simulations identified specific binding sites of apigenin and/or luteolin on papain/bromelain, corroborating experimental findings. Notably, the ternary system exhibits a stronger inhibitory effect on papain activity compared to binary systems.

Synthesis, crystal structure, DFT, Hirshfeld surface analysis, energy framework, docking and molecular dynamic simulations of (E)-4-(4-methylbenzyl)-6-styrylpyridazin-3(2H)-one as anticancer agent

In this work, a novel crystal, (E)-4-(4-methylbenzyl)-6-styrylpyridazin-3(2H)-one (E-BSP) was synthesized via Knoevenagel condensation of benzaldehyde and (E)-6-(4-methoxystyryl)-4,5-dihydropyridazin-3(2H)-one. The molecular structure of E-BSP was confirmed by using FT-IR, 1H-NMR, 13C-NMR, UV-vis, ESI-MS, TGA/DTA thermal analyses and single crystal X-ray diffraction. The DFT/B3LYP methods with the 6-311++G(d,p) basis set were used to determine the vibrational modes over the optimized structure. Potential energy distribution (PED) and the VEDA 4 software were used to establish the theoretical mode assignments. The same approach was used to compute the energies of frontier molecular orbitals (HOMO-LUMO), global reactivity descriptors, and molecular electrostatic potential (MEP). Additionally, experimental and computed UV spectral parameters were determined in methanol and the obtained outputs were supported by FMO analysis. Molecular docking and molecular dynamics (MD) simulation analyses of the E-BSP against six proteins obtained from different cancer pathways were carried out. The proteins include; epidermal growth factor receptor (EGFR), Estrogen receptor (ERα), Mammalian target of rapamycin (mTOR), Progesterone receptor (PR) (Breast cancer), Human cyclin-dependent kinase 2 (CDK2) (Colorectal cancer), and Survivin (Squamous cell carcinoma/Non-small cell lung cancer). The results of the analyses showed that the compound had less binding energies ranging between -6.30 to -9.09 kcal/mol and formed stable complexes at the substrate-binding site of the proteins after the 50 ns MD simulation. Therefore, E-BSP was considered a potential inhibitor of different cancer pathways and should be used for the treatment of cancer after experimental validation and clinical trial.Communicated by Ramaswamy H. Sarma.

Crystal structure and Hirshfeld surface analysis of 6-((E)-2-{4-[2-(4-chloro-phen-yl)-2-oxoeth-oxy]phen-yl}ethen-yl)-4,5-di-hydro-pyridazin-3(2H)-one

The pyridazine ring in the title compound, C20H17ClN2O3, adopts a screw-boat conformation. The whole mol-ecule is flattened, the dihedral angles subtended by the least-squares plane of the central aromatic ring with those of the terminal benzene and pyridazine rings being 15.18 (19) and 11.23 (19)°, respectively. In the crystal, the mol-ecules are linked by pairs of N-H⋯O bonds into centrosymmetric dimers and by C-H⋯π contacts into columns. The results of the Hirshfeld surface analysis show that the most prominent inter-actions are H⋯H, accounting for 36.5% of overall crystal packing, and H⋯O/O⋯H (18.6% contribution) contacts.

Crystal structure and Hirshfeld surface analysis of 4-(2,6-di-chloro-benz-yl)-6-[(E)-2-phenyl-ethen-yl]pyridazin-3(2H)-one

The title pyridazinone derivative, C19H14Cl2N2O, an important pharmacophore with a wide variety of biological applications is not planar, the chloro-phenyl and pyridazinone rings being almost perpendicular, subtending a dihedral angle of 85.73 (11)°. The phenyl ring of the styryl group is coplanar with the pyridazinone ring [1.47 (12)°]. In the crystal, N-H⋯O hydrogen bonds form inversion dimers with an R 2 2(8) ring motif and C-H⋯Cl hydrogen bonds also occur. The roles of the inter-molecular inter-actions in the crystal packing were clarified using Hirshfeld surface analysis, and two-dimensional fingerprint plots indicate that the most important contributions to the crystal packing are from H⋯H (37.9%), C⋯H/H⋯C (18.7%), Cl⋯H/ H⋯Cl (16.4%) and Cl⋯C/C⋯Cl (6.7%) contacts.