Ultrasound-assisted synthesis of two novel [CuBr(diamine)2·H2O]Br complexes: Solvatochromism, crystal structure, physicochemical, Hirshfeld surface thermal, DNA/binding, antitumor and antibacterial activities

Cu(II)(PhOMe-Salophen) Complex: Greener Pasture Biological Study, XRD/HAS Interactions, and MEP

PhOMe-salophen (1b) (salophen is N,N-bis(salycilidene)-1,2-phenylenediamine with two tert-butyl on each ring) and Cu(II) complex with PhOMe-salophen (1c) have been synthesized and characterized using various tools, including X-ray diffraction for the Cu(II)-complex (1c, C₄₃H₅₂CuN₂O₃)). The copper complex has been obtained by Cu²⁺ templated approach using 1b. PhOMe-salophen (1b) has been obtained in reasonably high yield using a mixture of the Schiff-base, 1a, Pd(OAc)₂, PPh₃, Na₂CO₃, 4-methoxyphenylboronic acid in benzene. We focus in this research work on the electronic and structural properties of the Cu–Schiff base complex. The tetra-coordinate τ₄ index was calculated, indicating almost a perfect square planner in agreement with X-ray diffraction results. MEP reveals the maximum positive regions in 1/-associated with the azomethine and methoxyphenyl C–H bonds with an average value of 0.03 a.u. Hirshfeld surface analysis (HSA) was also studied to highlight the significant inter-atomic contacts and their percentage contribution through 2D Fingerprint plot. In a fair comparative molecular docking study, 1b and 1c were docked together with N-[{(5-methylisoxazol-3-yl)-carbonyl}alanyl}-l-valyl]-N1-((1R,2Z)-4-(benzyloxy)-4-oxo-1-[{(3R)-2-oxopyrrolidin-3-yl}methyl]but-2-enyl)-l-leucinamide, N3 against main protease M^pro, (PDB code 7BQY) using the same parameters and conditions. Interesting here to use the free energy, in silico, molecular docking approach, which aims to rank our molecules with respect to the well-known inhibitor, N3. The binding scores of 1b, 1c, N3 are –7.8, –9.0, and –8.4 kcal/mol, respectively. These preliminary results propose that ligands deserve additional study in the context of possible remedial agents for COVID-19.

One-Pot Microwave-Assisted Synthesis of Water-Soluble Pyran-2,4,5-triol Glucose Amine Schiff Base Derivative: XRD/HSA Interactions, Crystal Structure, Spectral, Thermal and a DFT/TD-DFT

The(3R,4R,6R)-3-(((E)-2-hydroxybenzylidene)amino)-6-(hydroxymethyl)tetrahydro-2H-pyran-2,4,5-triol water-soluble Glucose amine Schiff base (GASB-1) product was made available by condensation of 2-hydroxybenzaldehyde with (3R,6R)-3-amino-6-(hydroxymethyl)-tetra-hydro-2H-pyran-2,4,5-triol under mono-mode microwave heating. A one-pot 5-minute microwave-assisted reaction was required to complete the condensation reaction with 90% yield and without having byproducts. The 3D structure of GASB-1 was solved from single crystal X-ray diffraction data and computed by DFT/6-311G(d,p). The Hirshfeld surface analysis (HSA), molecular electronic potential (MEP), Mulliken atomic charge (MAC), and natural population analysis (NPA) were performed. The IR and UV-Vis spectra were matched to their density functional theory (DFT) relatives and the thermal behavior was resolved in an open-room condition via thermogravimetry/Derivative thermogravimetry (TG/DTG) and differential scanning calorimetry (DSC). The highest occupied molecular orbital/lowest unoccupied molecular orbital (HOMO/LUMO), density of state (DOS), and time-dependence TD-DFT computations were correlated to the experimental electron transfer in water and acrylonitrile solvents.

Exo⇔Endo Isomerism, MEP/DFT, XRD/HSA-Interactions of 2,5-Dimethoxybenzaldehyde: Thermal, 1BNA-Docking, Optical, and TD-DFT Studies

The exo⇔endo isomerization of 2,5-dimethoxybenzaldehyde was theoretically studied by density functional theory (DFT) to examine its favored conformers via sp²–sp² single rotation. Both isomers were docked against 1BNA DNA to elucidate their binding ability, and the DFT-computed structural parameters results were matched with the X-ray diffraction (XRD) crystallographic parameters. XRD analysis showed that the exo-isomer was structurally favored and was also considered as the kinetically preferred isomer, while several hydrogen-bonding interactions detected in the crystal lattice by XRD were in good agreement with the Hirshfeld surface analysis calculations. The molecular electrostatic potential, Mulliken and natural population analysis charges, frontier molecular orbitals (HOMO/LUMO), and global reactivity descriptors quantum parameters were also determined at the B3LYP/6-311G(d,p) level of theory. The computed electronic calculations, i.e., TD-SCF/DFT, B3LYP-IR, NMR-DB, and GIAO-NMR, were compared to the experimental UV–Vis., optical energy gap, FTIR, and ¹H-NMR, respectively. The thermal behavior of 2,5-dimethoxybenzaldehyde was also evaluated in an open atmosphere by a thermogravimetric–derivative thermogravimetric analysis, indicating its stability up to 95 °C.

Synthesis of Novel Tetra(µ3-Methoxo) Bridged with [Cu(II)-O-Cd(II)] Double-Open-Cubane Cluster: XRD/HSA-Interactions, Spectral and Oxidizing Properties

A new double-open-cubane core Cd(II)-O-Cu(II) bimetallic ligand mixed cluster of type [Cl2Cu4Cd2(NNO)6(NN)2(NO3)2].CH3CN was made available in EtOH/CH3CN solution. The 1-hydroxymethyl-3,5-dimethylpyrazole (NNOH) and 3,5-dimethylpyrazole (NNH) act as N,O-polydentate anion ligands in coordinating the Cu(II) and Cd(II) centers. The structure of the cluster in the solid state was proved by XRD study and confirmed in the liquid state by UV-vis analysis. The XRD result supported the construction of two octahedral and one square pyramid geometries types around the four Cu(II) centers and only octahedral geometry around Cd(II) two centers. Interestingly, NNOH ligand acts as a tetra-µ3-oxo and tri-µ2-oxo ligand; meanwhile, the N-N in NNH acts as classical bidentate anion/neutral ligands. The interactions in the lattice were detected experimentally by the XRD-packing result and computed via Hirschfeld surface analysis (HSA). The UV-vis., FT-IR and Energy Dispersive X-ray (EDX), supported the desired double-open cubane cluster composition. The oxidation potential of the desired cluster was evaluated using a 3,5-DTB-catechol 3,5-DTB-quinone as a catecholase model reaction.

Synthesis and amide imidic prototropic tautomerization in thiophene-2-carbohydrazide: XRD, DFT/HSA-computation, DNA-docking, TG and isoconversional kinetics via FWO and KAS models

Thiophene-2-carbohydrazide as a novel small-molecule amide tautomer has been synthesized with an acceptable yield under microwave radiation (MW) conditions. The amide imidic thiophene-2-carbohydrazide prototropic tautomerization via single proton intramigration was computed using the DFT B3LYP/6-311G(d,p) level of theory. The endo-isomer amide structure of thiophene-2-carbohydrazide was proved by XRD and is considered to be the kinetically favored isomer. The DFT-structure parameters were compared to their corresponding XRD-experimental parameters. Several H-bond interactions were detected in the crystal lattice experimentally using the XRD-packing model then correlated to MEP and HSA calculations. The manual and calculated electronic parameters such as, frontier molecular orbital energies, excitation energy, absorption, dipole moment, DOS, GRD quantum parameters and TD-SCF/B3LYP were DFT computed. The thiophene-2-carbohydrazide isomers together with their prototropic (E)/(Z)-thiophene-2-carbohydrazonic acid tautomers were docked against 1BNA DNA. FWO and KAS isoconversional kinetic methods were applied, and the thermal behavior and estimated E_a–α relations were determined.

Thiophene-2-carbohydrazide as a novel small-molecule amide tautomer has been synthesized with an acceptable yield under microwave radiation (MW) conditions.

Ultrasonic synthesis of Oct. trans-Br2Cu(N ∩ N)2 Jahn-Teller distortion complex: XRD-properties, solvatochromism, thermal, kinetic and DNA-binding evaluations

Under mode of ultrasonic vibration, the neutral octahedral mononuclear [trans-CuBr₂(N ∩ N)₂]·3H₂O complex with N ∩ N = 2,2-dimethylpropane-1,3-diamine was obtained. The structure of the desired complex was characterized by UV-Vis. spectroscopy, FT-IR, EDX, MS, SEM, TG/DTA and CHN-analysis. The octahedral-structure of the desired Cu(II) complex was proven via XRD single-crystal diffraction and its molecular interactions were computed by Hirschfeld surface analysis. Alcohol (as solvent) and short ultrasonic vibration dose period played a critical role in sonochemistry synthesis of octahedral neutral trans-CuBr₂(N ∩ N)₂ complex instead of trigonal bi-pyramidal monocation [CuBr(N ∩ N)₂]Br one. Due to the Jahn-Teller effect, the complex exhibited a trans bonds elongation along Br-Cu-Br axis originating a distorted-octahedral Cu(II), as revealed by the XRD measurements (Br-Cu = 3.04 Å). Therefore, the Solvatochromic behavior of the complex was successfully performed since the trans di-bromide ions are loosely coordinated to Cu(II) center, the change in complex solutions colors by using different solvents which can be detected even by naked-eye supported atypical Jahn-Teller elongation effect formation. TG/DTA and Flynn Wall Ozawa (FWO) isoconversional kinetic methods were applied for the complex to figure out the thermal behavior, kinetic of the ligands de-structured and estimate its Ea/α relation. The complex binding mode to the CT-DNA was examined by UV-vis. spectroscopic, melting curve, CV and viscosity tests. The complex exhibited very strong DNA binding via an intercalation mode of coordination with K_b = 6.5 × 10⁵ value.