Synthesis, crystal structure and photophysical properties of a dinuclear MnII complex with 6-(di-ethyl-amino)-4-phenyl-2-(pyridin-2-yl)quinoline.

A new quinoline derivative, namely, 6-(di-ethyl-amino)-4-phenyl-2-(pyridin-2-yl)quinoline, C24H23N3 (QP), and its MnII complex aqua-1κO-di-µ-chlorido-1:2κ4 Cl:Cl-di-chlorido-1κCl,2κCl-bis-[6-(di-ethyl-amino)-4-phenyl-2-(pyridin-2-yl)quinoline]-1κ2 N 1,N 2;2κ2 N 1,N 2-dimanganese(II), [Mn2Cl4(C24H23N3)2(H2O)] (MnQP), were synthesized. Their compositions have been determined with ESI-MS, IR, and 1H NMR spectroscopy. The crystal-structure determination of MnQP revealed a dinuclear complex with a central four-membered Mn2Cl2 ring. Both MnII atoms bind to an additional Cl atom and to two N atoms of the QP ligand. One MnII atom expands its coordination sphere with an extra water mol-ecule, resulting in a distorted octa-hedral shape. The second MnII atom shows a distorted trigonal-bipyramidal shape. The UV-vis absorption and emission spectra of the examined compounds were studied. Furthermore, when investigating the aggregation-induced emission (AIE) properties, it was found that the fluorescent color changes from blue to green and eventually becomes yellow as the fraction of water in the THF/water mixture increases from 0% to 99%. In particular, these color and intensity changes are most pronounced at a water fraction of 60%. The crystal structure contains disordered solvent mol-ecules, which could not be modeled. The SQUEEZE procedure [Spek (2015 ▸). Acta Cryst. C71, 9-18] was used to obtain information on the type and qu-antity of solvent mol-ecules, which resulted in 44 electrons in a void volume of 274 Å3, corresponding to approximately 1.7 mol-ecules of ethanol in the unit cell. These ethanol mol-ecules are not considered in the given chemical formula and other crystal data.

Performance of ferrite nanoparticles in inductive heating swing adsorption (IHSA): how tailoring material properties can circumvent the design limitations of a system.

Inductive heating swing adsorption (IHSA) using hybrid adsorbents incorporating a porous material and ferrite nanoparticles holds promise to be a performant, electrified alternative for conventional gas separation. Successful implementation of hybrid adsorbents in IHSA depends on achieving a maximal specific absorption rate (SAR) in the conditions and at the frequency of the induction setup. This paper outlines and demonstrates successful strategies for optimization of the particle composition, tailoring the coercivity and susceptibility of the ferrite particles to optimal performance in a given alternating magnetic field.

Synthesis and crystal structures of three organoplatinum(II) complexes bearing natural aryl-olefin and quinoline derivatives.

Three organoplatinum(II) complexes bearing natural aryl-olefin and quinoline derivatives, namely, [4-meth-oxy-5-(2-meth-oxy-2-oxoeth-oxy)-2-(prop-2-en-1-yl)phen-yl](quinolin-8-olato)platinum(II), [Pt(C13H15O4)(C9H6NO)], (I), [4-meth-oxy-5-(2-oxo-2-propoxyeth-oxy)-2-(prop-2-en-1-yl)phen-yl](quinoline-2-carboxy-l-ato)platinum(II), [Pt(C15H19O4)(C10H6NO2)], (II), and chlorido-[4-meth-oxy-5-(2-oxo-2-propoxyeth-oxy)-2-(prop-2-en-1-yl)phen-yl](quinoline)-plat-inum(II), [Pt(C15H19O4)Cl(C9H7N)], (III), were synthesized and structurally characterized by IR and 1H NMR spectroscopy, and by single-crystal X-ray diffraction. The results showed that the cyclo-platinated aryl-olefin coordinates with PtII via the carbon atom of the phenyl ring and the C=Colefinic group. The deprotonated 8-hy-droxy-quinoline (C9H6NO) and quinoline-2-carb-oxy-lic acid (C10H6NO2) coordinate with the PtII atom via the N and O atoms in complexes (I) and (II) while the quinoline (C9H7N) coordinates via the N atom in (III). Moreover, the coordinating N atom in complexes (I)-(III) is in the cis position compared to the C=Colefinic group. The crystal packing is characterized by C-H⋯π, C-H⋯O [for (II) and (III)], C-H⋯Cl [for (III) and π-π [for (I)] inter-actions.

Synthesis, crystal structure and anti-cancer activity of the complex chlorido-(η2-ethyl-ene)(quinolin-8-olato-κ2N,O)platinum(II) by experimental and theoretical methods.

The complex [Pt(C9H6NO)Cl(C2H4)], (I), was synthesized and structurally characterized by ESI mass spectrometry, IR, NMR spectroscopy, DFT calculations and X-ray diffraction. The results showed that the deprotonated 8-hy-droxy-quinoline (C9H6NO) coordinates with the PtII atom via the N and O atoms while the ethyl-ene coordinates in the η2 manner and in the trans position compared to the coordinating N atom. The crystal packing is characterized by C-H⋯O, C-H⋯π, Cl⋯π and Pt⋯π inter-actions. Complex (I) showed high selective activity against Lu-1 and Hep-G2 cell lines with IC50 values of 0.8 and 0.4 µM, respectively, 54 and 33-fold more active than cisplatin. In particular, complex (I) is about 10 times less toxic to normal cells (HEK-293) than cancer cells Lu-1 and Hep-G2. Furthermore, the reaction of complex (I) with guanine at the N7 position was proposed and investigated using the DFT method. The results indicated that replacement of the ethyl-ene ligand with guanine is thermodynamically more favorable than the Cl ligand and that the reaction occurs via two consecutive steps, namely the replacement of ethyl-ene with H2O and the water with the guanine mol-ecule.

Palladium-Catalyzed Arylations towards 3,6-Diaryl-1,3a,6a-triazapentalenes and Evaluation of Their Fluorescence Properties.

Methyl 4-(1,3a,6a-triazapentalen-3-yl)benzoate (TAP1) shows interesting properties as a small molecule fluorophore. In the search for post-functionalization methods, palladium-catalyzed arylation reactions were demonstrated. Direct CH arylation reactions of TAP1 with various aryl halides resulted in 3,6-diaryltriazapentalenes TAP4, although mostly in poor yields. Bromination of TAP1 followed by Suzuki coupling, on the other hand, requires a more delicate procedure, but gave arylated products with the same regiochemistry (TAP4) in moderate to good yields. The structure of 6-phenyltriazapentalene TAP4a was confirmed by crystallographic analysis. In addition, the effect of the C6 arylation on the fluorescent properties of 3-aryl-1,3a,6a-triazapentalenes was studied in dichloromethane at room temperature and in 2-methyltetrahydrofuran at 77 K, while the photophysical properties of two saponified derivatives were measured in acetonitrile.

Synthesis of a 3,7-Disubstituted Isothiazolo[4,3-b]pyridine as a Potential Inhibitor of Cyclin G-Associated Kinase.

Disubstituted isothiazolo[4,3-b]pyridines are known inhibitors of cyclin G-associated kinase. Since 3-substituted-7-aryl-isothiazolo[4,3-b]pyridines remain elusive, a strategy was established to prepare this chemotype, starting from 2,4-dichloro-3-nitropyridine. Selective C-4 arylation using ligand-free Suzuki-Miyaura coupling and palladium-catalyzed aminocarbonylation functioned as key steps in the synthesis. The 3-N-morpholinyl-7-(3,4-dimethoxyphenyl)-isothiazolo[4,3-b]pyridine was completely devoid of GAK affinity, in contrast to its 3,5- and 3,6-disubstituted congeners. Molecular modeling was applied to rationalize its inactivity as a GAK ligand.

Synthesis, crystal structure and Hirshfeld surface analysis of 2-({5-[(naphthalen-1-yl)meth-yl]-4-phenyl-4H-1,2,4-triazol-3-yl}sulfan-yl)-1-(4-nitro-phen-yl)ethanone.

The title compound, C27H20N4O3S, crystallizes in the monoclinic system, space group P21/n, with Z = 4. The global shape of the mol-ecule is determined by the orientation of the substituents on the central 4H-1,2,4-triazole ring. The nitro-phenyl ring, phenyl ring, and naphthalene ring system are oriented at dihedral angles of 82.95 (17), 77.14 (18) and 89.46 (15)°, respectively, with respect to the triazole ring. The crystal packing features chain formation in the b-axis direction by S⋯O inter-actions. A Hirshfeld surface analysis indicates that the highest contributions to surface contacts arise from contacts in which H atoms are involved.

An Extrusion Strategy for On-Demand SF5Cl Gas Generation from a Commercial Disulfide.

Herein we report a novel methodology for the ex situ generation of SF5Cl by employing 4,4'-dipyridyl disulfide as a safe commercial reagent, obviating the need for lecture bottles. The method is applicable to certain SF5Cl-involving transformations by using a two-chamber reactor. Moreover, easily applying SF5Cl in different solvents is rendered feasible, while avoiding the use of glovebox techniques. This report also suggests 1H-19F HOESY as a simple and fast stereochemistry indication for chloropentafluorosulfanylated olefins.

Unusual reaction of (E)-2-[(benzo[d]thia-zol-2-yl-imino)-meth-yl]-5-(di-ethyl-amino)-phenol with tri-phenyl-borane: crystal structures and optical properties.

The mol-ecular and crystal structure of (E)-2-[(benzo[d]thia-zol-2-yl-imino)-meth-yl]-5-(di-ethyl-amino)-phenol (C18H19N3O2S, Et2N-Bz) and its unexpected reaction product with tri-phenyl-borane, 2,2-diphenyl-1,3-dioxa-2-borata-1,2-di-hydro-naphthalene [systematic name: N,N-diethyl-2,2-diphenyl-2H-1,3λ3,2λ4-ben-zodioxaborinin-7-amine, C23H24BNO2, (I)] are described. For Et2N-Bz, the hydroxyl group is involved in an intra-molecular hydrogen bond with the imino nitro-gen atom and the C=N bond displays an E configuration. The crystal packing is characterized by layers of inversion dimers parallel to the (10) plane and chains of mol-ecule in the a-axis direction formed through C-H⋯O inter-actions. Complex (I) crystallizes with two mol-ecules (A and B) in the asymmetric unit, which differ in the orientation of the ethyl groups. The 1,3-dioxa-2-borata-1,2,3,4-tetra-hydro-naphthalene ring displays a slight envelope conformation with the boron atom as the flap. In the crystal packing, chains of alternating A and B mol-ecules formed by C-H⋯O hydrogen bonds run in the b-axis direction. The UV-vis absorption and emission properties of the compounds are discussed and their aggregation-induced emission properties are further investigated.

Synthesis, crystal structure, DFT, Hirshfeld surface analysis, energy frameworks and in-Silico drug-targeting PFKFB3 kinase of novel triazolequinoxalin derivative (TZQ) as a therapeutic Strategy against cancer.

Overall, drug design is a dynamic and evolving field, with researchers constantly working to improve their understanding of molecular interactions, develop new computational methods, and explore innovative techniques for creating effective and safe medications. The process can involve steps such as the identification of targets, the discovery of lead compounds, lead optimization, preliminary testing, human trials, regulatory approval and finally post-marketing surveillance, all aimed at bringing a new drug from concept to market. In this article, the synthesis of the novel triazolequinoxalin (TZQ) 1-((1-hexyl-1H-1,2,3-triazol-5-yl)methyl)-3-phenylquinoxalin-2(1H)-one (4) is reported. The structure has been identified with a variety of spectroscopic methods (1H, 13C NMR, and LC-MS) and finally, the structure has been determined by X-ray diffraction (XRD) studies. The TZQ molecule has crystallized in the monoclinic space C2/c group with unit cell dimensions a = 41.201(2) Å, b = 10.6339(6) Å, c = 9.4997(4) Å, ß = 93.904(4). The crystal structure is stabilized by intermolecular interactions (N-H ⋯ O and N-H … Cg) occurring within the molecule. The presence of these intermolecular interactions is evaluated through analysis of Hirshfeld surfaces (HS) and two-dimensional (2D) chemical fingerprints map. Additionally, energy frameworks were employed to identify the prevailing interaction energy influencing the molecular arrangement. Density Functional Theory (DFT) calculations were computed to establish concurrence between theoretical and experimental results. Furthermore, the HOMO-LUMO energy levels were determined using the B3LYP/6-31+G(d, p) level of theory. Finally, molecular docking was used to predict the anti-cancer activity of the compound (4) against PFKFB3 kinase and presented noticeable hydrophilic and hydrophobic interactions at the active site region.

Ex situ Generation of Thiazyl Trifluoride (NSF3 ) as a Gaseous SuFEx Hub.

Sulfur(VI)-fluoride exchange (SuFEx) chemistry, an all-encompassing term for substitution events that replace fluoride at an electrophilic sulfur(VI), enables the rapid and flexible assembly of linkages around a SVI core. Although a myriad of nucleophiles and applications works very well with the SuFEx concept, the electrophile design has remained largely SO2 -based. Here, we introduce S≡N-based fluorosulfur(VI) reagents to the realm of SuFEx chemistry. Thiazyl trifluoride (NSF3 ) gas is shown to serve as an excellent parent compound and SuFEx hub to efficiently synthesize mono- and disubstituted fluorothiazynes in an ex situ generation workflow. Gaseous NSF3 was evolved from commercial reagents in a nearly quantitative fashion at ambient conditions. Moreover, the mono-substituted thiazynes could be extended further as SuFEx handles and be engaged in the synthesis of unsymmetrically disubstituted thiazynes. These results provide valuable insights into the versatility of these understudied sulfur functionalities paving the way for future applications.

Crystal structure and Hirshfeld surface analysis of N-{N-[amino-(di-methyl-amino)-meth-yl]carbamimido-yl}-3-bromo-benzene-sulfonamide.

The title compound, C10H14BrN5O2S, is the bromo-benzene-sulfonamide derivative of the type 2 diabetes drug metformin. The asymmetric unit contains two mol-ecules with almost identical conformations but a different orientation of the bromo-phenyl moiety. Both mol-ecules exhibit intra-molecular N-H⋯N and N-H⋯O hydrogen bonds. The mol-ecular packing features chain formation in the a-axis direction by alternating N-H⋯N and N-H⋯O inter-actions. In addition, ring motifs consisting of four mol-ecules and π-π inter-actions between the phenyl rings contribute to the three-dimensional architecture. A Hirshfeld surface analysis shows that the largest contributions to surface contacts arise from contacts in which H atoms are involved.

Fine-tuning non-covalent interactions between hybrid metal-oxo clusters and proteins.

Interactions between the protein Hen Egg White Lysozyme (HEWL) and three different hybrid Anderson-Evans polyoxometalate clusters - AE-NH2 (δ-[MnMo6O18{(OCH2)3CNH2}2]3-), AE-CH3 (δ-[MnMo6O18{(OCH2)3CCH3}2]3-) and AE-Biot (δ-[MnMo6O18{(OCH2)3CNHCOC9H15N2OS}2]3-) - were studied via tryptophan fluorescence spectroscopy and single crystal X-ray diffraction. Quenching of tryptophan fluorescence was observed in the presence of all three hybrid polyoxometalate clusters (HPOMs), but the extent of quenching and the binding affinity were greatly dependent on the nature of the organic groups attached to the cluster. Control experiments further revealed the synergistic effect of the anionic polyoxometalate core and organic ligands towards enhanced protein interactions. Furthermore, the protein was co-crystallised with each of the three HPOMs, resulting in four different crystal structures, thus allowing for the binding modes of HPOM-protein interactions to be investigated with near-atomic precision. All crystal structures displayed a unique mode of binding of the HPOMs to the protein, with both functionalisation and the pH of the crystallisation conditions influencing the interactions. From the crystal structures, it was determined that HPOM-protein non-covalent complexes formed through a combination of electrostatic attraction between the polyoxometalate cluster and positively charged surface regions of HEWL, and direct and water-mediated hydrogen bonds with both the metal-oxo inorganic core and the functional groups of the ligand, where possible. Hence, functionalisation of metal-oxo clusters shows great potential in tuning their interactions with proteins, which is of interest for several biomedical applications.

Three-Step Synthetic Pathway toward Fully Decorated [1,2,3]Triazolo[4,5-d]pyrimidine (8-Azapurine) Derivatives.

[1,2,3]Triazolo[4,5-d]pyrimidines (8-azapurines) are known bioisosteres of the purine nucleus. A step-efficient synthesis of 8-azapurines, in particular 6-alkyl derivatives, is currently unavailable. This work focuses on a three-step synthetic pathway for the synthesis of fully decorated 8-azapurines, with special attention on 6-alkyl-8-azapurines. A diverse library of 8-azapurines was obtained starting from various alkynes, azides, and amidines, involving interrupted CuAAC, oxidation, and cyclization reactions. Additionally, postfunctionalization reactions were demonstrated for a selected number of substrates.

Oxygen-induced chromophore degradation in the photoswitchable red fluorescent protein rsCherry.

Reversibly switchable monomeric Cherry (rsCherry) is a photoswitchable variant of the red fluorescent protein mCherry. We report that this protein gradually and irreversibly loses its red fluorescence in the dark over a period of months at 4 °C and a few days at 37 °C. We also find that its ancestor, mCherry, undergoes a similar fluorescence loss but at a slower rate. X-ray crystallography and mass spectrometry reveal that this is caused by the cleavage of the p-hydroxyphenyl ring from the chromophore and the formation of two novel types of cyclic structures at the remaining chromophore moiety. Overall, our work sheds light on a new process occurring within fluorescent proteins, further adding to the chemical diversity and versatility of these molecules.

An unusual disulfide-linked dimerization in the fluorescent protein rsCherryRev1.4.

rsCherryRev1.4 has been reported as one of the reversibly photoswitchable variants of mCherry, and is an improved version with a faster off-switching speed and lower switching fatigue at high light intensities than its precursor rsCherryRev. However, rsCherryRev1.4 still has some limitations such as a tendency to dimerize as well as complex photophysical properties. Here, the crystal structure of rsCherryRev1.4 was determined at a resolution of 2 Šand it was discovered that it forms a dimer that shows disulfide bonding between the protomers. Mutagenesis, gel electrophoresis and size-exclusion chromatography strongly implicate Cys24 in this process. Replacing Cys24 in rsCherryRev1.4 resulted in a much lower tendency towards dimerization, while introducing Cys24 into mCherry correspondingly increased its dimerization. In principle, this finding opens the possibility of developing redox sensors based on controlled dimerization via disulfide cross-linking in fluorescent proteins, even though the actual application of engineering such sensors still requires additional research.

Visible-Light-Induced Cascade Difunctionalization of Indoles Enabled by the Synergy of Photoredox and Photoexcited Ketones: Direct Access to Alkylated Pyrrolophenanthridones.

Herein, we describe a methodology to construct polycyclic pyrrolophenanthridones with an (amino)alkyl side chain that involves visible-light-induced decarboxylative radical addition for the intermolecular dearomatization of indoles and subsequent photoinduced C(sp2)-X bond activation via photoexcited ketones for an intramolecular cyclization cascade. Carboxylic acids serve both as a radical source toward indole dearomatization and as reductants to initiate an electron transfer with photoexcited N-acylindole derivatives in the reaction toward pyrrolophenantridone skeletons, which occurs under mild reaction conditions with good functional group tolerance.

Gold(I)-Catalyzed Intramolecular Bicyclization: Divergent Construction of Quinazolinone and Ampakine Analogues.

A gold(I)-catalyzed cascade intramolecular cyclization of Ugi adducts for the divergent construction of quinazolinone and ampakine analogues has been developed in a rapid, highly efficient and step-economical manner. This protocol shows high yields, excellent functional-group tolerance, broad substrate scope and excellent chemo- and regioselectivity. The practicality of this strategy is further demonstrated by a scale-up reaction. Diverse oligopeptides are also found to be well tolerated, affording polycyclic products decorated with a peptide chain.

Experimental and theoretical studies on the synthesis of 1,4,5-trisubstituted pyrrolidine-2,3-diones.

Substituted 4-acetyl-3-hydroxy-3-pyrroline-2-ones have been prepared via three-component reactions and the tautomerism of these 3-pyrroline-2-ones is due to the slight difference of energy, and the significantly large rate constant of transformation between two tautomers. 1,4,5-Trisubstituted pyrrolidine-2,3-dione derivatives were prepared from the above mentioned 2-pyrrolidinone derivatives and aliphatic amines, which exist in enamine form and are stabilized by an intramolecular hydrogen bond. A possible reaction mechanism between 3-pyrroline-2-one and aliphatic amine (CH3NH2) was proposed based on computational results and the main product is formed favorably following the PES via the lowest ΔG # pathway in both the gas-phase and an ethanol solvent model. DFT calculations showed that kinetic selectivity is more significant than thermodynamic selectivity for forming main products.

Classroom experiments with artificial sweeteners: growing single crystals and simple calorimetry.

An easily accessible experimental set-up to grow large single crystals of two sweeteners readily available in supermarkets, erythritol and xylitol, is described. The crystallization of these compounds illustrates the principles of crystallization by evaporation. As these artificial sweeteners are also known to induce a cool sensation in the mouth, the crystal-growing experiment is complemented with a simple calorimetric set-up to demonstrate the endothermic nature of the dissolution of the selected sweeteners in a more qu-anti-tative approach by measuring the heat of dissolution (ΔH diss). The choice of these two sweeteners also allows use of the freely available WebCSD and Mercury tools to visualize their three-dimensional structure, crystal packing and powder diffractograms, and to deepen stereochemical concepts such as stereoisomers and meso compounds.