Synthesis of Some Novel N-Substituted Phthalazinone and Pyridopyridazinone Derivatives

Phthalazinone and pyridopyridazinone derivatives 3, 5, and 9 were prepared via reaction ofappropriate lactams 2 and 8 with 2-bromoethylphthalimide, N-tosylaziridine, and N,O-ditosyl derivatives of N-methylethanolamine in a two-step process in the presence of MeONa/MeOH or NaH/dimethylformamide (DMF). Starting compounds 2 and 8 were obtained by reaction of hydrazine hydrate with isoindolinones 1 or azaisoindolinones 6. Selected N-(2-phthalimidoethyl)-phthalazinones were converted into corresponding 2-[2-(methylamino) ethyl]- derivatives in satisfactory yields by treatment with hydrazine.     

The Analysis of Hyperfine Shifts of Mono-Ligand High-Spin Cobalt(II) Pyrazolylborate Complexes

In this paper, we present the detailed study on the correlation of the nuclear magnetic resonance (NMR) parameters with the results of density functional theory calculations performed for paramagnetic high-spin cobalt(II) complexes with trispyrazolylborate ligands. This work focuses on estimation of dipolar and contact shifts in mono-ligand high-spin cobalt(II) pyrazolylborate systems along with discussion on ¹H NMR properties of the mentioned tetra-, penta- and hexacoordinate complexes. The calculation results show frontier molecular orbitals that may be responsible for contact shift. The calculated contact shift values are compared with the dipolar shift and hyperfine ones.     

Quantum Evolution beyond the Markovian Semigroup — Generalizing the Stenholm–Barnett Approach

We provide conditions for the memory kernel governing the time-nonlocal quantum master equation which guarantee that the corresponding dynamical map is completely positive and trace-preserving. This approach gives rise to the new parametrization of dynamical maps in terms of two completely positive maps – so-called legitimate pair. In fact, these new parameterizations are a natural generalization of Markovian semigroup. Interestingly our class contains recently studied models like semi-Markov evolution and collision models.     

Calix[4]arene phosphonates - recognition of amino alcohols in water

The water-soluble calix[4]arenes based cavitands were obtained in good yield by introduction of phosphonic acids groups at the upper rim; we describe the design, synthesis, and formation of the complexes with ephedrine, norephedrine, and noradrenaline hydrochloride in the phosphate buffer at pD 7.3. © 2004 Wiley Periodicals, Inc. Heteroatom Chem 15:155–161, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10229     

Physiological and Biochemical Parameters of Common Duckweed Lemna minor after the Exposure to Tetracycline and the Recovery from This Stress

In this study, the ability of Lemna minor L. to recover to normal growth, after being degraded in a tetracycline-containing medium, was extensively investigated. The plants were exposed to tetracycline (TC) at concentrations of 1, 2.5, and 10 mM. Subsequently, their physiological status was analysed against the following criteria: rate of plant growth; free radical accumulation; antioxidant enzyme activity; chlorophyll content; HSP70 protein content; cell membrane permeability, and mitochondrial activity. The study showed that duckweed can considerably recover from the damage caused by antibiotics, within a week of cessation of stress. Of the plant properties analysed, mitochondrial activity was the most sensitive to antibiotic-induced disturbances. After transferring the plants to a tetracycline-free medium, all plant parameters improved significantly, except for the mitochondrial activity in the plants grown on the medium containing the highest dose of tetracycline. In the plants treated with this antibiotic at the concentration of 10 mM, the proportion of dead mitochondria increased and was as high as 93% after one week from the beginning of the recovery phase, even after the transfer to the tetracycline-free medium.     

Assessment of Anti-Inflammatory and Antimicrobial Potential of Ethanolic Extract of Woodfordia fruticosa Flowers: GC-MS Analysis

Currently, the potential utilization of natural plant-derived extracts for medicinal and therapeutic purposes has increased remarkably. The current study, therefore, aimed to assess the antimicrobial and anti-inflammatory activity of modified solvent evaporation-assisted ethanolic extract of Woodfordia fruticosa flowers. For viable use of the extract, qualitative analysis of phytochemicals and their identification was carried out by gas chromatography–mass spectroscopy. Analysis revealed that phenolic (65.62 ± 0.05 mg/g), flavonoid (62.82 ± 0.07 mg/g), and ascorbic acid (52.46 ± 0.1 mg/g) components were present in high amounts, while β-carotene (62.92 ± 0.02 µg/mg) and lycopene (60.42 ± 0.8 µg/mg) were present in lower amounts. The antimicrobial proficiency of modified solvent-assisted extract was evaluated against four pathogenic bacterial and one fungal strain, namely Staphylococcus aureus (MTCC 3160), Klebsiella pneumoniae (MTCC 3384), Pseudomonas aeruginosa (MTCC 2295), and Salmonella typhimurium (MTCC 1254), and Candida albicans (MTCC 183), respectively. The zone of inhibition was comparable to antibiotics streptomycin and amphotericin were used as a positive control for pathogenic bacterial and fungal strains. The extract showed significantly higher (p < 0.05) anti-inflammatory activity during the albumin denaturation assay (43.56–86.59%) and HRBC membrane stabilization assay (43.62–87.69%). The extract showed significantly (p < 0.05) higher DPPH (2,2-diphenyl-1-picrylhydrazyl) scavenging assay and the obtained results are comparable with BHA (butylated hydroxyanisole) and BHT (butylated hydroxytoluene) with percentage inhibitions of 82.46%, 83.34%, and 84.23%, respectively. Therefore, the obtained results concluded that ethanolic extract of Woodfordia fruticosa flowers could be utilized as a magnificent source of phenols used for the manufacturing of value-added food products.     

Zinc(II) Tri‐tert‐butoxysilanethiolates. Synthesis,Properties, Crystal and Molecular Structures of [Zn{SSi(OBut)3}2(NH3)L] (L = 2‐Picoline or 2,4‐Lutidine) and [Zn{SSi(OBut)3}2(NH3)2] · MeCN Complexes

[Zn{SSi(OBu^t)₃}₂(NH₃)]₂ ( 1 ) reacts with 2‐picoline or 2,4‐lutidine (L) without elimination of ammonia giving stable monometallic complexes [Zn{SSi(OBu^t)₃}₂(NH₃)L] ( 3 and 4 ), with two different nitrogen ligands bonded to the metal center. Reaction of (Bu^tO)₃SiSH with zinc di(acetylacetonate) in ammonia atmosphere leads to the complex with two ammine ligands [Zn{SSi(OBu^t)₃}₂(NH₃)₂] · MeCN ( 5 ). Molecular and crystal structures of 3 , 4 and 5 have been determined by the single crystal X‐ray structural analysis. All have distorted tetrahedral geometry. The presence of ammonia gives rise to hydrogen bonds, different in all three cases. 3 , 4 , and 5 are the first examples of structurally characterized ammine ligated zinc thiolates.     

Ternary Rare Earth (RE) Gold Compounds REAuCd and RE2Au2Cd

New intermetallic rare earth compounds REAuCd (RE = Y, La–Nd, Sm–Yb) and RE₂Au₂Cd (RE = La, Pr, Nd, Sm) were prepared by reaction of the elements in sealed tantalum tubes in a high‐frequency furnace. The compounds were investigated by X‐ray diffraction both on powders and single crystals. The equiatomic REAuCd compounds with RE = Y, La–Nd, Sm, and Gd–Tm adopt the ZrNiAl type structure with space group P62m. Single crystal X‐ray data yielded a = 786.2(2), c = 415.9(1) pm, wR2 = 0.0337, 402 F² values for LaAuCd and a = 782.91(9), c = 410.01(5) pm, wR2 = 0.0653, 395 F² values for CeAuCd with 14 parameters for each refinement. Geometrical motifs in CeAuCd are two types of gold centered tricapped trigonal prisms: [Au1Cd₃Ce₆] and [Au2Cd₆Ce₃]. The gold and cadmium atoms form a three‐dimensional [AuCd] polyanion in which the cerium atoms fill distorted hexagonal channels. EuAuCd and YbAuCd crystallize with a TiNiSi type structure, space group Pnma: a = 755.2(1), b = 450.59(5), c = 878.6(1) pm, wR2 = 0.0904, 500 F² values for EuAuCd, and a = 731.64(3), b = 432.94(2), c = 875.80(4) pm, wR2 = 0.1192, 457 F² values for YbAuCd with 20 parameters for each refinement. In these structures the europium(ytterbium) and cadmium atoms form zig‐zag chains of egde‐ and face‐sharing trigonal prisms which are centered by the gold atoms. Also in EuAuCd and YbAuCd a three‐dimensional [AuCd] polyanion occurs in which the europium(ytterbium) atoms are embedded. Europium and ytterbium are divalent in EuAuCd and YbAuCd. Susceptibility measurements show Pauli paramagnetism for YbAuCd and Curie‐Weiss behavior above 100 K for EuAuCd with an experimental magnetic moment of 7.86(6) μ_B/Eu. Ferromagnetic ordering is detected at 28 K. The saturation magnetic moment is 7.1(1) μ_B/Eu at 1.9 K. ¹⁵¹Eu Mössbauer spectra show an isomer shift of –9.2(2) mm/s and full magnetic hyperfine field splitting at 4.2 K with an internal hyperfine field of 19.5(4) T at the europium nuclei. The RE₂Au₂Cd compounds crystallize with the Mo₂FeB₂ structure, a ternary ordered version of the U₃Si₂ type. These structures may be considered as an intergrowth of distorted CsCl and AlB₂ related slabs of compositions RECd and REAu₂. Chemical bonding in REAuCd and RE₂Au₂Cd is briefly discussed.     

Symmetry‐Breaking Transitions in HoCuAs2–xPx and ErCuAs2–xPx (x = 0–2): Crystal Structure,Application of Landau Theory,Magnetic and Electrical Properties

Crystal structures of compounds undergoing symmetry‐breaking transitions have been investigated by the X‐ray single crystal and powder methods. While the phases HoCuAs₂ through HoCuAs_1.33P_0.67 and ErCuAs₂ through ErCuAsP retain the tetragonal HfCuSi₂ structure (P4/nmm space group), the compounds HoCuAsP through HoCuAs_0.33P_1.67 and ErCuAs_0.67P_1.33 through ErCuAs_0.33P_1.67 undergo orthorhombic distortions to the GdCuAs_1.15P_0.85 structure (Pmmn space group). Further distortions follow in the phosphides: HoCuP₂ adopts a larger orthorhombic cell (Cmma, a = 5.273(3), b = 5.305(3), c = 9.645(5) Å) and ErCuP₂ has a monoclinic cell with a doubled parameter, the b parameter in the monoclinic cell (P2₁/n, a = 3.737(3), b = 19.239(15), c = 3.728(3) Å, β = 90.09(1)°). Zigzag chains are formed in the phosphorus layer of ErCuP₂. According to Landau theory the transitions from HoCuAs_1.33P_0.67 to HoCuAsP and from ErCuAsP to ErCuAs_0.67P_1.33 can be continuous, and the transitions from HoCuAs_0.33P_1.67 to HoCuP₂ and from ErCuAs_0.33P_1.67 to ErCuP₂ are necessarily first‐order. The results of magnetic and electrical measurements for HoCuAs₂ and HoCuP₂ are reported. Due to the magnetic moments localized on Ho atoms both compounds order antiferromagnetically at low temperatures. They exhibit metallic conductivity.