One pot synthesis of two potent Ag(I) complexes with quinoxaline ligand, X-ray structure, Hirshfeld analysis, antimicrobial, and antitumor investigations.

In one pot, the self-assembly of AgNO3 and 2-chloroquinoxaline (2Cl-quinox) in water-ethanol mixture afforded two novel crystalline Ag(I) complexes. The major product is the polymeric complex [Ag(2Cl-quinox)(NO3)]n; (1), while the minor product (2) comprises two molecules which are the monomeric [Ag(2Cl-quinox)2(NO3)]; (2a) and polymeric [Ag(2Cl-quinox)(NO3)]n; (2b) complexes. The single crystal X-ray structure revealed that 1 and 2b are made up of two-dimensional infinite sheets. In contrast, 2a is a monomeric complex which has a highly distorted tetrahedral geometry around Ag(I) center. In all cases, the 2Cl-quinox molecule acts as a terminal monodentate ligand. Complexes 1 and 2b have similar molecular structures and also have almost similar crystal packing. Using Hirshfeld surface analysis, the O…H hydrogen bonds and π-π stacking interactions contributed significantly to the molecular packing. Both complexes have broad-spectrum action towards multi drug-resistance bacteria. The most effective function of 2 is against Proteus morganii, with a MIC value of 8 µg/mL. Complex 2 (IC50 = 5.93 ± 0.52 µg/mL) has remarkably greater cytotoxic effect against lung carcinoma (A-549) than cis-platin (IC50 = 7.5 ± 0.69 µg/mL) and AgNO3 (IC50 = 14.7 ± 0.53 µg/mL). The higher Ag-content in 2 could be the main reason for its higher cytotoxicity than 1.

Synthesis, X-ray Structure, Hirshfeld, DFT and Biological Studies on a Quinazolinone-Nitrate Complex.

The reaction of 4-hydroxyquinazoline (4HQZ) with aqueous solution of nitric acid afforded the corresponding quinazolinone-nitrate (4HQZN) complex in very good yield. The crystal structure of 4HQZN was determined and its structural and supramolecular structural aspects were analyzed. 4HQZN crystallized in the space group P21/c and monoclinic crystal system with one [4HQZ-H]+[NO3]- formula and Z = 4. Its supramolecular structure could be described as a 2D infinite layers in which the 4HQZN molecules are connected via N-H…O and C-H…O hydrogen bridges. Using DFT calculations, the relative stability of five suggested isomers of 4HQZN were predicted. It was found that the medium effects have strong impact not only on the isomers' stability but also on the structure of the 4HQZN. It was found that the structure of 4HQZN in DMSO and methanol matched well with the reported X-ray structure which shed the light on the importance of the intermolecular interactions on the isomers' stability. The structure of 4HQZN could be described as a proton transfer complex in which the nitrate anion acting as an e-donor whiles the protonated 4HQZ is an e-acceptor. In contrast, the structure of the isolated 4HQZN in gas phase and in cyclohexane could be described as a 4HQZ…HNO3 hydrogen bonded complex. Biological screening of the antioxidant, anticancer and antimicrobial activities of 4HQZ and 4HQZN was presented and compared. It was found that, 4HQZN has higher antioxidant activity (IC50 = 36.59 ± 1.23 µg/mL) than 4HQZ. Both of 4HQZ and 4HQZN showed cell growth inhibition against breast (MCF-7) and lung (A-549) carcinoma cell lines with different extents. The 4HQZ has better activity with IC50 of 178.08 ± 6.24 µg/mL and 119.84 ± 4.98 µg/mL, respectively. The corresponding values for 4HQZN are 249.87 ± 9.71 µg/mL and 237.02 ± 8.64 µg/mL, respectively. Also, the antibacterial and antifungal activities of 4HQZN are higher than 4HQZ against all studied microbes. The most promising result is for 4HQZN against A. fumigatus (MIC = 312.5 µg/mL).

Fe(III) Complexes Based on Mono- and Bis-pyrazolyl-s-triazine Ligands: Synthesis, Molecular Structure, Hirshfeld, and Antimicrobial Evaluations.

The self-assembly of iron(III) chloride with three pyrazolyl-s-triazine ligands, namely 2,4-bis(3,5-dimethyl-1H-pyrazol-1-yl)-6-(piperidin-1-yl)-1,3,5-triazine (PipBPT), 4-(4,6-bis(3,5-dimethyl-1H-pyrazol-1-yl)-1,3,5-triazin-2-yl)morpholine (MorphBPT), and 4,4'-(6-(3,5-dimethyl-1H-pyrazol-1-yl)-1,3,5-triazine-2,4-diyl)dimorpholine (bisMorphPT) afforded [Fe(PipBPT)Cl2][FeCl4] (1), [Fe(MorphBPT)Cl2][FeCl4] (2), and [H(bisMorphPT)][FeCl4]. bisMorphPT.2H2O (3), respectively, in good yield. In complexes 1 and 2, the Fe(III) is pentacoordinated with three Fe-N interactions from the pincer ligand and two coordinated chloride anions in the inner sphere, and FeCl4¯ in the outer sphere. Complex 3 is comprised of one protonated ligand as cationic part, one FeCl4¯ anion, and one neutral bisMorphPT molecule in addition to two crystallized water molecules. Analysis of molecular packing using Hirshfeld calculations indicated that H…H and Cl…H are the most important in the molecular packing. They comprised 40.1% and 37.4%, respectively in 1 and 32.4% and 37.8%, respectively in 2. Complex 1 exhibited the most bioactivity against the tested microbes while 3 had the lowest bioactivity. The bisMorphPT and MorphBPT were inactive towards the tested microbes while PipBPT was active. As a whole, the Fe(III) complexes have enhanced antibacterial and antifungal activities as compared to the free ligands.

Unexpected formation of polymeric silver(I) complexes of azine-type ligand via self-assembly of Ag-salts with isatin oxamohydrazide.

Isatin oxamohydrazide (L) reacted with the aqueous solution of silver nitrate at room temperature afforded the polymeric silver(I) nitrato complex, [Ag2L'(NO3)2] n , (1) of the azine ligand (L'). Similarly, the reaction of L with silver(I) perchlorate gave the [Ag2L'2(ClO4)2] n , (2) coordination polymer. Careful inspection of the crystals from the nitrato complex preparation showed the presence of another crystalline product which is found to be [Ag(Isatin-3-hydrazone)NO3], (3) suggesting that the reaction between silver(I) nitrate and L proceeds first by the hydrolysis of L to the isatin hydrazone which attacks another molecule of L to afford L'. Testing metal salts such as Ni2+, Co2+, Mn2+, Cu2+ and Cd2+ did not undergo any reaction with L either under the same reaction conditions or with heating under reflux up to 24 h. Treatment of the warm alcoholic solution of L with few drops of 1 : 1 (v/v) hydrochloric acid gave the free ligand (L') in good yield. The [Ag2L'(NO3)2] n complex forms a two-dimensional infinite coordination polymer, while the [Ag2L'2(ClO4)2] n forms one-dimensional infinite chains with an alternating silver-azine backbone. Quantitative analysis of the intermolecular interactions in their crystals is made using Hirshfeld surface analysis. Density functional theory studies were performed to investigate the coordination bonding in the studied complexes.

Chemical delithiation and exfoliation of [Formula: see text].

Progressive chemical .delithiation of commercially available lithium cobalt oxide ([Formula: see text]) showed consecutive changes in the crystal properties. Rietveld refinement of high resolution X-ray and neutron diffraction revealed an increased lattice parameter c and a reduced lattice parameter a for chemically delithiated samples. Using electron microscopy we have also followed the changes in the texture of the samples towards what we have found is a critical layer stoichiometry of about [Formula: see text] with x=1/3 that causes the grains to exfoliate. The pattern of etches by delithiation suggests that unrelieved strain fields may produce chemical activity.

Preparation and characterization of core-shell battery materials for Li-ion batteries manufactured by substrate induced coagulation.

In this work Substrate Induced Coagulation (SIC) was used to coat the cathode material LiCoO(2), commonly used in Li-ion batteries, with fine nano-sized particulate titania. Substrate Induced Coagulation is a self-assembled dip-coating process capable of coating different surfaces with fine particulate materials from liquid media. A SIC coating consists of thin and rinse-prove layers of solid particles. An advantage of this dip-coating method is that the method is easy and cheap and that the materials can be handled by standard lab equipment. Here, the SIC coating of titania on LiCoO(2) is followed by a solid-state reaction forming new inorganic layers and a core-shell material, while keeping the content of active battery material high. This titania based coating was designed to confine the reaction of extensively delithiated (charged) LiCoO(2) and the electrolyte. The core-shell materials were characterized by SEM, XPS, XRD and Rietveld analysis.

Pyridine as trigger for chloride isomerisation in chelated ruthenium benzylidene complexes: implications for olefin metathesis.

The cationic pyridine adduct of a ruthenium complex bearing a chelating benzylidene and an N-heterocyclic carbene was identified as an intermediate during the activation of cis dichloro species and a novel triggering concept for olefin metathesis catalysts based on cationic species was disclosed.

Halide exchanged Hoveyda-type complexes in olefin metathesis.

The aims of this contribution are to present a straightforward synthesis of 2(nd) generation Hoveyda-type olefin metathesis catalysts bearing bromo and iodo ligands, and to disclose the subtle influence of the different anionic co-ligands on the catalytic performance of the complexes in ring opening metathesis polymerisation, ring closing metathesis, enyne cycloisomerisation and cross metathesis reactions.

P-C bond formation via P-H addition of a fluoroaryl phosphinic acid to ketones.

The synthesis, structure and reactivity of the fluoroaryl phosphinic acid HF(4)C(6)-P(O)HOH is reported and compared to a sterically comparable yet non-fluorinated analog with similar size. The fluoroaryl phosphinic acid undergoes reversible P-H addition to the carbonyl functionality of ketones under formation of a P-C bond which is retained in the resulting α-hydroxy phosphinic acid. The latter shows an extended 2D hydrogen bonded network in the solid state.

Optimized synthesis of tetrafluoroterephthalic acid: a versatile linking ligand for the construction of new coordination polymers and metal-organic frameworks.

Pure 2,3,5,6-tetrafluoroterephthalic acid (H(2)tfBDC) is obtained in high yields (95%) by reacting 1,2,4,5-tetrafluorobenzene with a surplus (>2 equiv) of n-butyllithium in tetrahydrofuran (THF) and subsequent carbonation with CO(2) without any extensive purification procedure. A single crystal X-ray structure analysis of H(2)tfBDC (1) confirms former data obtained for a deuterated sample (P1, Z = 1). Recrystallization from water/acetone leads to single crystals of H(2)tfBDC·2H(2)O (2, P2(1)/c, Z = 2), where an extensive hydrogen bonding network is found. By reacting H(2)tfBDC with an aqueous ammonia solution, single crystals of (NH(4))(2)tfBDC (3, C2/m, Z = 2) are obtained. 3 is thermally stable up to 250 °C and shows an enhanced solubility in water compared to H(2)tfBDC. Monosubstituted 2,3,5,6-tetrafluorobenzoic acid (H(2)tfBC, 4) is obtained by reacting 1,2,4,5-tetrafluorobenzene with stoichiometric amounts (1 equiv) of n-butyllithium in THF. Its crystal structure (Fdd2, Z = 16) shows dimeric units as characteristic structural feature.