New Hydrazone Derivatives Based on Pyrazolopyridothiazine Core as Cytotoxic Agents to Colon Cancers: Design, Synthesis, Biological Evaluation, and Molecular Modeling.

In this research, a series of novel hydrazone derivatives based on pyrazolopyridothiazinylacetohydrazide were designed, synthesized, and evaluated for their in vitro cytotoxic potency on several human colon cancer cells (HTC116, HT-29, and LoVo). After MTT and SRB assays four of the most active derivatives: hydrazide GH and hydrazones GH7, GH8, and GH11, were chosen for further investigation. Hydrazone GH11 had the highest cytotoxic activity (IC50 values of c.

Consequences of the Pb-S Bond Formation for Lead Halide Perovskites.

Lead halide perovskites are structurally not stable due to their ionic bonds. Using sulfur agents in the crystal growth improves the stability and performance of the photovoltaic and light-emitting devices. In this theoretical work, we use a small toy S-radical in place of A cation in the bulk of lead iodide perovskite, and highlight the significance of the Pb-S covalent-double-bond formation for: the charge redistribution on the neighboring bonds that also turn to be covalent, phase transformation to a stable non-perovskite structure, and superior optoelectronic properties.

Very Strong Hydrogen Bond in Nitrophthalic Cocrystals.

This work presents the studies of a very strong hydrogen bond (VSHB) in biologically active phthalic acids. Research on VSHB comes topical due to its participation in many biological processes. The studies cover the modelling of intermolecular interactions and phthalic acids with 2,4,6-collidine and N,N-dimethyl-4-pyridinamine complexes with aim to obtain a VSHB.

Renewed spectroscopic and theoretical research of hydrogen bonding in ascorbic acid.

The studies of two isomers of ascorbic acid and their deuteroanalogues, presented in the paper, have been accomplished by vibrational spectroscopy methods and quantum-chemical simulations. The spectroscopic research of L-ascorbic and D-isoascorbic acids have been carried out by the infrared (IR) and Raman (R) techniques. On the basis of the obtained results the spectral interpretation of the hydrogen bonded groups of ascorbic acids has been performed.

Photochemical Transformations of Peptides Containing the -(2-Selenoethyl)glycine Moiety.

The diselenide bond has attracted considerable attention due to its ability to undergo the metathesis reaction in response to visible light. In our previous study, we demonstrated visible-light-induced diselenide metathesis of selenocysteine-containing linear peptides, allowing for the convenient generation of peptide libraries. Here, we investigated the transformation of linear and cyclic peptides containing the -(2-selenoethyl)glycine moiety.

Partial Methane Oxidation to Methanol on Ru-Porphyrins - on the Role of Non-Innocent Ligands and Spin Crossover.

The partial oxidation reaction of CH led to the formation of CH OH in the presence of Ru-porphyrin oxo complexes (denoted as POR, POR-O and POR-OH where in the case of the last two, oxygen atom and the OH group were attached to the active site, respectively), in which Ru was present on different oxidation states. The simulations were performed based on Density Functional Theory (DFT) with extended geometric and electronic structure analyses of each reaction step. Moreover, the reaction pathways were investigated in different spin states.

Pd and Pt metal atoms as electron donors in σ-hole bonded complexes.

Quantum calculations provide a systematic assessment of the ability of Group 10 transition metals M = Pd and Pt to act as an electron donor within the context of pnicogen, chalcogen, and halogen bonds. These M atoms are coordinated in a square planar geometry, attached to two N atoms of a modified phenanthrene unit, as well as two ligand atoms Cl, Br, or I. As the Lewis acid, a series of AF molecules were chosen, which could form a pnicogen bond (A = P, As, Sb), chalcogen bond (A = S, Se, Te) or halogen bond (A = Cl, Br, I) with M.

The Malaprade reaction mechanism for ethylene glycol oxidation by periodic acid based on density functional theory (DFT).

A general mechanism of the Malaprade oxidative carbon-carbon bond cleavage reaction of α-glycol in the presence of periodic acid has been proposed on the basis of density functional theory (DFT) computations. Ethylene glycol and periodic acid, both in their neutral forms, have been studied as noble substrate representatives in model reactions. The proposed reaction mechanism has been constructed based on and compared with previously published experimental kinetic, spectroscopic and temperature and pH-dependent studies.

Heterobimetallic 21,23-dimetallaporphyrin: activation of metal-metal interactions within the porphyrinoid macrocycle.

Two core-modified porphyrins containing metal atoms, namely platinum(II) or platinum(IV) and rhodium(III), in place of two NH units, have been obtained by a post-synthetic modification of the 21,23-ditelluraporphyrin. The products of the tellurium-to-metal exchange, 21-platina-23-rhodaporphyrins, incorporate rhodacyclopentadiene and platinacyclopentadiene units with the metal atoms facing each other. The two molecules exhibit different degrees of metal-metal interaction depending on the oxidation state of platinum, with the NBO bond order being 0.

Static and Dynamical Quantum Studies of CX-AlX and CSiX-BX (X = F, Cl, Br) Complexes with Hydrocyanic Acid: Unusual Behavior of Strong π-Hole at Triel Center.

The set of TX-TrX (T = C, Si, Ge; Tr = B, Al, Ga; X = F, Cl, Br) molecules offers a rather unique opportunity to study both σ-hole and π-hole dimerization on the tetrel and triel ends, respectively. According to the molecular electrostatic potential (MEP) distribution, the π-hole extrema (acidic sites) were more intense than their σ-hole counterparts. The molecules owning the most (CX-AlX) and least (SiX-BX) intense π-holes were chosen to evaluate their capacities to attract one and two HCN molecules (Lewis bases).

Role of Non-Covalent Interactions in Carbonic Anhydrase I-Topiramate Complex Based on QM/MM Approach.

Carbonic anhydrase (CA) I with a Topiramate (TPM) complex was investigated on the basis of a Quantum Mechanics/Molecular Mechanics (QM/MM) approach. The QM part was treated using Density Functional Theory (DFT) while the MM was simulated using Amberff14SB and GAFF force fields. In addition, the TIP3P model was applied to reproduce the polar environment influence on the studied complex.

Inter- vs. Intra-Molecular Hydrogen Bond in Complexes of Nitrophthalic Acids with Pyridine.

This study covers the analysis of isomeric forms of nitrophthalic acids with pyridine. This work dwells on the complementary experimental (X-ray, IR and Raman) and theoretical (Car-Parrinello Molecular Dynamics (CPMD) and Density Functional Theory (DFT)) studies of the obtained complexes. The conducted studies showed that steric repulsion between the nitro group in ortho-position and the carboxyl group causes significant isomeric changes.

Unraveling the Nature of Hydrogen Bonds of "Proton Sponges" Based on Car-Parrinello and Metadynamics Approaches.

The nature of intra- and intermolecular non-covalent interactions was studied in four naphthalene derivatives commonly referred to as "proton sponges". Special attention was paid to an intramolecular hydrogen bond present in the protonated form of the compounds. The unsubstituted "proton sponge" served as a reference structure to study the substituent influence on the hydrogen bond (HB) properties.

Exploring the Dynamical Nature of Intermolecular Hydrogen Bonds in Benzamide, Quinoline and Benzoic Acid Derivatives.

The hydrogen bonds properties of 2,6-difluorobenzamide, 5-hydroxyquinoline and 4-hydroxybenzoic acid were investigated by Car-Parrinello and path integral molecular dynamics (CPMD and PIMD), respectively. The computations were carried out in vacuo and in the crystalline phase. The studied complexes possess diverse networks of intermolecular hydrogen bonds (N-H…O, O-H…N and O-H…O).

Chalcogen Bond as a Factor Stabilizing Ligand Conformation in the Binding Pocket of Carbonic Anhydrase IX Receptor Mimic.

It is postulated that the overexpression of Carbonic Anhydrase isozyme IX in some cancers contributes to the acidification of the extracellular matrix. It was proved that this promotes the growth and metastasis of the tumor. These observations have made Carbonic Anhydrase IX an attractive drug target.

Comprehensive Empirical Model of Substitution-Influence on Hydrogen Bonding in Aromatic Schiff Bases.

In this work, over 500 structures of tri-ring aromatic Schiff bases with different substitution patterns were investigated to develop a unified description of the substituent effect on the intramolecular hydrogen bridge. Both proximal and distal effects were examined using Density Functional Theory (DFT) in the gas phase and with solvent reaction field (Polarizable Continuum Model (PCM) and water as the solvent). In order to investigate and characterize the non-covalent interactions, a topological analysis was performed using the Quantum Theory of Atoms In Molecules (QTAIM) theory and Non-Covalent Interactions (NCI) index.

Synthesis, Anticancer Activity and Molecular Docking Studies of Novel -Mannich Bases of 1,3,4-Oxadiazole Based on 4,6-Dimethylpyridine Scaffold.

Cancer is one of the greatest challenges in modern medicine today. Difficult and long-term treatment, the many side effects of the drugs used and the growing resistance to treatment of neoplastic cells necessitate new approaches to therapy. A very promising targeted therapy is based on direct impact only on cancer cells.

Affinities to Oxaliplatin: Vitamins from B Group vs. Nucleobases.

Oxaliplatin, similar to Cisplatin, exhibits anticancer activity by interacting with DNA and inducing programmed cell death. It is biotransformed through a number of spontaneous and non-enzymatic processes. In this way, several transient reactive species are formed, including dichloro-, monochloro-, and diaqua-DACH platin, which can complex with DNA and other macromolecules.

A new mixed-valence Cu/Cu three-dimensional coordination polymer constructed with an N,O-donor ligand generated via solvothermal synthesis: structural features and magnetic properties.

A new mixed-valence Cu/Cu three-dimensional coordination polymer, poly[[diaquabis[μ-2-(pyrazin-2-yl)quinoline-4-carboxylato]dicopper(I)copper(II)] bis(tetrafluoridoborate)], {[Cu(CHNO)(HO)](BF)}, was synthesized and characterized, with 2-(pyrazin-2-yl)quinoline-4-carboxylic acid being employed as a linker ligand. The ligand was isolated as its hydrochloride salt, 4-carboxy-2-(pyrazin-2-yl)quinolin-1-ium chloride dihydrate, CHNO·Cl·2HO. The compounds show luminescence at 550 nm for the ligand and at 565 nm for the polymer at 297 K.

Revealing Intra- and Intermolecular Interactions Determining Physico-Chemical Features of Selected Quinolone Carboxylic Acid Derivatives.

The intra- and intermolecular interactions of selected quinolone carboxylic acid derivatives were studied in monomers, dimers and crystals. The investigated compounds are well-recognized as medicines or as bases for further studies in drug design. We employed density functional theory (DFT) in its classical formulation to develop gas-phase and solvent reaction field (PCM) models describing geometric, energetic and electronic structure parameters for monomers and dimers.

Inside out Approach to Rotator State in Hydrogen-Bonded System-Experimental and Theoretical Cross-Examination in n-Octanol.

The experimental and theoretical description of premelting behavior is one of the most challenging tasks in contemporary material science. In this paper, n-octanol was studied using a multi-method approach to investigate it at macroscopic and molecular levels. The experimental infrared (IR) spectra were collected in the solid state and liquid phase at temperature range from -84∘C to -15 ∘C to detect temperature-related indicators of pretransitional phenomena.

Intermolecular Interactions and Spectroscopic Signatures of the Hydrogen-Bonded System-n-Octanol in Experimental and Theoretical Studies.

n-Octanol is the object of experimental and theoretical study of spectroscopic signatures and intermolecular interactions. The FTIR measurements were carried out at 293 K for n-octanol and its deuterated form. Special attention was paid to the vibrational features associated with the O-H stretching and the isotope effect.

Exploring Intra- and Intermolecular Interactions in Selected -Oxides-The Role of Hydrogen Bonds.

Intra- and intermolecular interactions have been explored in selected -oxide derivatives: 2-(N,N-dimethylamino-N-oxymethyl)-4,6-dimethylphenyl () and 5,5'-dibromo-3-diethylaminomethyl-2,2'-biphenol -oxide (). Both compounds possess intramolecular hydrogen bonding, which is classified as moderate in and strong in , and resonance-assisted in both cases. Density Functional Theory (DFT) in its classical formulation as well as Time-Dependent extension (TD-DFT) were employed to study proton transfer phenomena.

Biological Evaluation and Molecular Docking Studies of Novel 1,3,4-Oxadiazole Derivatives of 4,6-Dimethyl-2-sulfanylpyridine-3-carboxamide.

To date, chronic inflammation is involved in most main human pathologies such as cancer, and autoimmune, cardiovascular or neurodegenerative disorders. Studies suggest that different prostanoids, especially prostaglandin E, and their own synthase (cyclooxygenase enzyme-COX) can promote tumor growth by activating signaling pathways which control cell proliferation, migration, apoptosis, and angiogenesis. Non-steroidal anti-inflammatory drugs (NSAIDs) are used, alongside corticosteroids, to treat inflammatory symptoms particularly in all chronic diseases.

How Substitution Combines with Non-Covalent Interactions to Modulate 1,4-Naphthoquinone and Its Derivatives Molecular Features-Multifactor Studies.

Substitution is well-known to modulate the physico-chemical properties of molecules. In this study, a combined, multifactor approach was employed to determine a plethora of substitution patterns using -Br and -O-H in 1,4-naphthoquinone and its derivatives. On the basis of classical Density Functional Theory (DFT), 25 models divided into three groups were developed.