Synthesis, structural characterization, and biological studies of new antimony(III) complexes with thiones. The influence of the solvent on the geometry of the complexes

Five new antimony(III) complexes with the heterocyclic thiones 2-mercapto-benzimidazole (MBZIM), 5-ethoxy-2-mercapto-benzimidazole (EtMBZIM), and 2-mercapto-thiazolidine (MTZD) of formulas {[SbCl(2)(MBZIM)4]+.Cl-.2H(2)O. (CH(3)OH)} (1), {[SbCl(2)(MBZIM)4]+.Cl-.3H(2)O.(CH3CN)} (2), [SbCl(3)(MBZIM)2] (3), [SbCl(3)(EtMBZIM)(2)] (4), and [SbCl(3)(MTZD)2] (5) have been synthesized and characterized by elemental analysis, FT-IR, far-FT-IR, differential thermal analysis-thermogravimetry, X-ray diffraction, and conductivity measurements. Complex {[SbCl2(tHPMT)(2)]+Cl-}, (tHPMT = 2-mercapto-3,4,5,6-tetrahydro-pyrimidine), already known, was also prepared, and its X-ray crystal structure was solved. It is shown that the complex is better described as {[SbCl3(tHPMT)(2)]} (6). Crystal structures of all other complexes (1-5) have also been determined by X-ray diffraction at ambient conditions. The crystal structure of the hydrated ligand, EtMBZIM.H2O is also reported. Compound [C(28)H(24)Cl(2)N(8)S(4)Sb.2H(2)O.Cl.(CH(3)OH)] (1) crystallizes in space group P2(1), with a = 7.7398(8) A, b = 16.724(3) A, c = 13.717(2) A, beta = 98.632(11) degrees, and Z = 2. Complex [C(28)H(24)Cl(2)N(8)S(4)S(b).Cl.3H(2)O.(CH(3)CN)] (2) corresponds to space group P2(1), with a = 7.8216(8) A, b = 16.7426(17) A, c = 13.9375(16) A, beta = 99.218(10) degrees , and Z = 2. In both 1 and 2 complexes, four sulfur atoms from thione ligands and two chloride ions form an octahedral (Oh) cationic [SbS(4)Cl(2)]+ complex ion, where chlorides lie at axial positions. A third chloride counteranion neutralizes it. Complexes 1 and 2 are the first examples of antimony(III) compounds with positively charged Oh geometries. Compound [C(14)H(12)Cl(3)N(4)S(2)S(b)] (3) crystallizes in space group P, with a = 7.3034(5) A, b = 11.2277(7) A, c = 12.0172(8) A, alpha = 76.772(5) degrees, beta = 77.101(6) degrees, gamma = 87.450(5) degrees, and Z = 2. Complex [C(18)H(20)Cl(3)N(4)O(2)S(2)S(b)] (4) crystallizes in space group P1, with a = 8.6682(6) A, b = 10.6005(7) A, c = 13.0177(9) A, alpha = 84.181(6) degrees, beta = 79.358(6) degrees, gamma = 84.882(6) degrees, and Z = 2, while complex [C(6)H(10)Cl(3)N(2)S(4)S(b)] (5) in space group P2(1)/c shows a = 8.3659(10) A, b = 14.8323(19) A, c = 12.0218(13) A, beta = 99.660(12) degrees, and Z = 4 and complex [C(8)H(16)Cl(3)N(4)S(2)S(b)] (6) in space group P1 shows a = 7.4975(6) A, b = 10.3220(7) A, c = 12.1094(11) A, alpha = 71.411(7) degrees, beta = 84.244(7) degrees, gamma = 73.588(6) degrees, and Z = 2. Crystals of complexes 3-6 grown from acetonitrile solutions adopt a square-pyramidal (SP) geometry, with two sulfur atoms from thione ligands and three chloride anions around Sb(III). The equatorial plane is formed by two sulfur and two chloride atoms in complexes 3-5, in a cis-S, cis-Cl arrangement in 3 and 5 and a trans-S, trans-Cl arrangement in 4. Finally, in the case of 6, the equatorial plane is formed by three chloride ions and one sulfur from the thione ligand while the second sulfur atom takes an axial position leading to a unique SP conformation. The complexes showed a moderate cytostatic activity against tumor cell lines.     

The reaction OF N‐dichlorophosphoryl‐ P‐trichlorophosphazene with alkyl grignard reagents

The reactions of N‐dichlorophosphoryl‐P‐trichlorophosphazene Cl₃PN P(O)Cl₂ ( 1 ) with benzylmagnesium bromide, 2‐phenylethylmagnesium bromide, trimethylsilylmethylmagnesium chloride, n‐butylmagnesium bromide, cyclohexylmagnesium bromide, cyclopentylmagnesium bromide, tert‐butylmagnesium bromide, iso‐propylmagnesium bromide, and ethylmagnesium bromide were studied. Tri‐ and pentaalkyl phosphazenes were obtained in very poor yield from trimethylsilylmethylmagnesium chloride and cyclohexylmagnesium bromide, respectively. Trialkylphosphoryl compounds formed from benzyl‐, 2‐phenylethyl‐, and n‐butylmagnesium bromide. No phosphorus compound could be isolated from the reaction of 1 with t‐butyl‐, cyclopentyl‐, iso‐propyl‐, and ethylmagnesium bromide. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:413–416, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10153     

Phenolic acid contents, essential oil compositions and antioxidant activities of two varieties of Salvia euphratica from Turkey

This study was designed to evaluate the in vitro antioxidant activities of n-hexane (Hex), dichloromethane (DCM), methanol (MeOH) and essential oils (EO) extracts obtained from Salvia euphratica var. euphratica and Salvia euphratica var. leiocalycina and to determine their essential oil and phenolic acid compositions. The samples were screened for their antioxidant activity by using DPPH and β-carotene/linoleic acid assays. Methanol extracts of both varieties exhibited strong antioxidant activities. Our results showed that rosmarinic acid was dominant phenolic acid of MeOH extracts (39.4 and 55.8?μg?mg?1, respectively). The chemical compositions of essential oils of two varieties were analysed and their main components were determined as eucalyptol (18.4%) and trans-pinocarvyl acetate (24.9%), respectively. It can be said that these varieties could be used as natural antioxidant.     

Which Extraction Solvents and Methods Are More Effective in Terms of Chemical Composition and Biological Activity of Alcea fasciculiflora from Turkey?

The bioactive content, antioxidant properties, and enzyme inhibition properties of extracts of Alcea fasciculiflora from Turkey prepared with different solvents (water, methanol, ethyl acetate) and extraction methods (maceration, soxhlet, homogenizer assisted extraction, and ultrasound assisted extraction) were examined in this study. UHPLC-HRMS analysis detected or annotated a total of 50 compounds in A. fasciculiflora extracts, including 18 hydroxybenzoic and hydroxycinnamic acids, 7 Hexaric acids, 7 Coumarins, 15 Flavonoids, and 3 hydroxycinnamic acid amides. The extracts had phenolic and flavonoid levels ranging from 14.25 to 24.87 mg GAE/g and 1.68 to 25.26 mg RE/g, respectively, in the analysis. Both DPPH and ABTS tests revealed radical scavenging capabilities (between 2.63 and 35.33 mg TE/g and between 13.46 and 76.27 mg TE/g, respectively). The extracts had reducing properties (CUPRAC: 40.38–78 TE/g and FRAP: 17.51–42.58 TE/g). The extracts showed metal chelating activity (18.28–46.71 mg EDTAE/g) as well as total antioxidant capacity (phosphomolybdenum test) (0.90–2.12 mmol TE/g). DPPH, ABTS, FRAP, and metal chelating tests indicated the water extracts to be the best antioxidants, while the ethyl acetate extracts had the highest overall antioxidant capacity regardless of the extraction technique. Furthermore, anti-acetylcholinesterase activity was identified in all extracts (0.17–2.80 mg GALAE/g). The water extracts and the ultrasound-assisted ethyl acetate extract were inert against butyrylcholinesterase, but the other extracts showed anti-butyrylcholinesterase activity (1.17–5.80 mg GALAE/g). Tyrosine inhibitory action was identified in all extracts (1.79–58.93 mg KAE/g), with the most effective methanolic extracts. Only the ethyl acetate and methanolic extracts produced by maceration and homogenizer aided extraction showed glucosidase inhibition (0.11–1.11 mmol ACAE/g). These findings showed the overall bioactivity of the different extracts of A. fasciculiflora and provided an overview of the combination of solvent type and extraction method that could yield bioactive profile and pharmacological properties of interest and hence, could be a useful reference for future studies on this species.     

Statistically boundedness and statistical core of double sequences

The concept of statistical convergence was presented by Steinhaus in 1951. This concept was extended to the double sequences by Mursaleen and Edely in 2003. Throughout this paper we will present multidimensional analogues of the results presented by Fridy and Orhan in 1997. To achieve this goal multidimensional analogues of the definition for bounded statistically sequences, statistical inferior and statistical superior will be presented. In addition to these results we will investigate statistical core for double sequences and study an inequality related to the statistical and P-cores of bounded double sequences.     

Estimating Motion From MRI Data

Magnetic resonance imaging (MRI) is an ideal imaging modality to measure blood flow and tissue motion. It provides excellent contrast between soft tissues, and images can be acquired at positions and orientations freely defined by the user. From a temporal sequence of MR images, boundaries and edges of tissues can be tracked by image processing techniques. Additionally, MRI permits the source of the image signal to be manipulated. For example, temporary magnetic tags displaying a pattern of variable brightness may be placed in the object using MR saturation techniques, giving the user a known pattern to detect for motion tracking. The MRI signal is a modulated complex quantity, being derived from a rotating magnetic field in the form of an induced current. Well-defined patterns can also be introduced into the phase of the magnetization, and could be thought of as generalized tags. If the phase of each pixel is preserved during image reconstruction, relative phase shifts can be used to directly encode displacement, velocity and acceleration. New methods for modeling motion fields from MRI have now found application in cardiovascular and other soft tissue imaging. In this review, we shall describe the methods used for encoding, imaging, and modeling motion fields with MRI.     

Many Sources Asymptotics for Networks with Small Buffers

In this paper, we obtain the overflow asymptotics in a network with small buffers when the resources are accessed by a large number of stationary independent sources. Under the assumption that the network is loop-free with respect to source–destination routes, we identify the precise large deviations rate functions for the buffer overflow at each node in terms of the external input characteristics. It is assumed that each type of source requires a Quality of Service (QoS) defined by bounds on the fraction of offered work lost. We then obtain the admissible region for sources which access the network based on these QoS requirements. When all the sources require the same QoS, we show that the admissible region asymptotically corresponds to that which is obtained by assuming that flows pass through each node unchanged.     

Adsorption of Cu(II) ions from aqueous solution by hazelnut husk activated carbon prepared with potassium acetate

Hazelnut husk (HH), an agricultural waste, was converted to carbonaceous material by chemical activation using potassium acetate. The produced activated carbon (KAHHAC) was characterized by FTIR, SEM, N₂ adsorption–desorption experiments, CHN elemental analysis, and determination of moisture, ash, and point of zero charge. KAHHAC was used for the batch adsorption of Cu(II) ions from aqueous solutions. Optimum pH and contact time were found to be 5.0 and 240 minutes, respectively. The adsorption equilibrium data were described well by the Langmuir equation providing 105.3?mg?g^?1 Cu(II) adsorption capacity. The pseudo-second-order model successfully described the kinetic of Cu(II) adsorption by KAHHAC. The adsorbed Cu(II) onto KAHHAC was completely desorbed by 0.5?M nitric acid. In conclusion, HH activated carbon (AC) produced by the potassium acetate activation method is a very useful and efficient sorbent material for the removal of Cu(II) from aqueous solution.