Incoporation of Fe(Ⅲ) in framework of zeolite L

Zeolite L with Fe in lattice position is prepared from the gel with Fe/(Fe+Al) ratio up to 0.4 using ferric nitrate as Fe source. The incorporation of Fe(Ⅲ) in framework is characterized by XRD, IR, TG/DTA, BET and Mossbauer spectroscopy. Zeolite L is destabilized by Fe(Ⅲ) in framework and the reduction of Fe(Ⅲ) in framework of (Al,Fe )KL was first reported.     

Synthesis of optically active Zn(II) complexes with thiosemicarbazones of (+)-camphor (L) and (−)-carvone (L1). The crystal structures of L and [Zn(L)2Cl2]

The optically active complexes [Zn(L)₂Cl₂] (I) and [Zn(L¹)₂Cl₂] (II) (L and L¹ are thiosemicar-bazones of (+)-camphor and (?)-carvone, respectively) were obtained. The crystal structures of L and complex I were determined by X-ray diffraction. The structure of L consists of hydrogen-bonded molecules united into chains. The crystal structure of complex I is built from mononuclear molecules. The coordination polyhedron of the Zn atom is a distorted tetrahedron Cl₂S₂. The molecule L functions as a monodentate ligand. According to data from IR spectroscopy, complex II is structurally similar to complex I.     

Study on Roots of Firmiana plantanifolia (L.f.) Marsili

Firmiana plantanifolia (L.f.) Marsili is a Chinese medicine used in the treatment of numerous disorders such as rheumatism, asthma, fracture, and tumor etc.[1] In the course of a search for biological active compounds from medicinal plants,[2] we have examined the water extract of the root of this plant and succeeded in isolating three novel constituents named firmianones A, B and C (Scheme 1), along with 9 known compounds. Their UV, HRMS and NMR spectral data indicated that they are isoprenylated naphthoquinone dimmers. Firmianones A and B have a novel hexacyclo [14.8.0.02,7.06.15.099.14.018,23]tetracosa-1(16),3,9(14),10,12,7,19,21,23-nonaen-8-one skeleton and their absolute stereochemistry was determined by CD exciton-coupling experiments.     

Effect of γ-irradiation on the physicochemical and sensory properties of hazelnuts (Corylus avellana L.)

The present study evaluated the quality of hazelnuts as a function of irradiation dose to determine dose levels causing minimal undesirable changes to hazelnuts. Physicochemical (color, peroxide value (PV), hexanal content, fatty acid composition and volatile compounds) and sensory (color, texture, odor and taste) properties were determined.Results showed a twenty fold increase in peroxide value and twenty-eight fold increase in hexanal content after irradiation at a dose of 7 kGy. An increase was also observed in saturated fatty acids (10%–23%) with a parallel decrease in unsaturated fatty acids (90–77%). Volatile compounds such as ketones, alkanes, alcohols, aldehydes, furans, aromatic hydrocarbons, bicyclic monoterpenes and acids were produced mostly comprising secondary oxidation products of hazelnut lipids after irradiation. Color parameter b* increased (p<0.05) after irradiation at a dose of ⩾5 kGy, while color parameters L* and a* remained unchanged by irradiation. Sensory evaluation showed that texture and color were not affected by irradiation. Taste, the most sensitive sensory attribute showed that hazelnuts retain acceptable sensory quality when irradiated up to a dose of 1.5 kGy.     

Dependence of the chemical properties of macrocyclic [Ni(II)(2)L(μ-O(2)CR)](+) complexes on the basicity of the carboxylato coligands (L(2-) = macrocyclic N(6)S(2) ligand)

The dependence of the properties of mixed ligand [Ni(II)(2)L(μ-O(2)CR)](+) complexes (where L(2-) represents a 24-membered macrocyclic hexaamine-dithiophenolato ligand) on the basicity of the carboxylato coligands has been examined. For this purpose 19 different [Ni(II)(2)L(μ-O(2)CR)](+) complexes (2-20) incorporating carboxylates with pK(b) values in the range 9 to 14 have been prepared by the reaction of [Ni(II)(2)L(μ-Cl)](+) (1) and the respective sodium or triethylammonium carboxylates. The resulting carboxylato complexes, isolated as ClO(4)(-) or BPh(4)(-) salts, have been fully characterized by elemental analyses, IR, UV/vis spectroscopy, and X-ray crystallography. The possibility of accessing the [Ni(II)(2)L(μ-O(2)CR)](+) complexes by carboxylate exchange reactions has also been examined. The main findings are as follows: (i) Substitution reactions between 1 and NaO(2)CR are not affected by the basicity or the steric hindrance of the carboxylate. (ii) Complexes 2-20 form an isostructural series of bisoctahedral [Ni(II)(2)L(μ-O(2)CR)](+) compounds with a N(3)Ni(μ-SR)(2)(μ-O(2)CR)NiN(3) core. (iii) They are readily identified by their ν(as)(CO) and ν(s)(CO) stretching vibration bands in the ranges 1684-1576 cm(-1) and 1428-1348 cm(-1), respectively. (iv) The spin-allowed (3)A(2g) → (3)T(2g) (ν(1)) transition of the NiOS(2)N(3) chromophore is steadily red-shifted by about 7.5 nm per pK(b) unit with increasing pK(b) of the carboxylate ion. (v) The less basic the carboxylate ion, the more stable the complex. The stability difference across the series, estimated from the difference of the individual ligand field stabilization energies (LFSE), amounts to about 4.2 kJ/mol [Δ(LFSE)(2,18)]. (vi) The "second-sphere stabilization" of the nickel complexes is not reflected in the electronic absorption spectra, as these forces are aligned perpendicularly to the Ni-O bonds. (vii) Coordination of a basic carboxylate donor to the [Ni(II)(2)L](2+) fragment weakens its Ni-N and Ni-S bonds. This bond weakening is reflected in small but significant bond length changes. (viii) The [Ni(II)(2)L(μ-O(2)CR)](+) complexes are relatively inert to carboxylate exchange reactions, except for the formato complex [Ni(II)(2)L(μ-O(2)CH)](+) (8), which reacts with both more and less basic carboxylato ligands.     

Syntheses and Crystal Structures of [Ni(L)_2(NCS)_2] and [Co(L)_2(NCS)_2](L=Azobis(2-pyridine)

1 INTRODUCTION The synthesis of new organic-inorganic hybrid compounds is a relatively new research area that has developed rapidly in the last several years[1]. Bische- late ligand[2, 3], such as azobis(2-pyridine), is a novel tetradentate ligand expect…     

Spectroscopy studies on DNA binding of two ruthenium complexes [Ru(MeIm)4(L)]2+ (L = iip and tip)

Two ruthenium(II) complexes [Ru(MeIm)₄(L)]²⁺ (L?=?2-(imidazo-4-group)-1H-imidazo-[4,5-f][1,10]phenanthroline, 2-(thiophene-2-group)-1H-imidazo[4,5-f][1,10]phenanthroline, MeIm?=?1-methylimidazole) have been synthesized according to literature and structurally characterized. The interaction of the complexes with calf thymus DNA has been explored using electronic absorption titration, competitive binding experiment, circular dichroism, thermal denaturation, and viscosity measurements. The results show that both complexes could bind DNA in a intercalation mode and the DNA-binding affinity of [Ru(MeIm)₄(tip)]²⁺ (K _b?=?(7.2?±?0.3)?×?10⁵?(mol?L^?1)^?1) is greater than that of [Ru(MeIm)₄(iip)]²⁺ (K _b?=?(6.1?±?0.2)?×?10⁵?(mol?L^?1)^?1).     

Synthesis and Crystal Structure of (L)_2W(CO)_4·CH_3COCH_3 (L=1-Phenacylimidazole)

1 INTRODUCTION Due to their variability in binding modes, five- membered heterocyclic ligands such as pyrazole[1] and 1,2,4-triazole[2] have been drawn much attention. Consequently, there are numerous reports on their derivatives. Imidazoles resemble pyrazoles, and they are isomeric five-membered heterocyclic molecules containing two nitrogen atoms. Furthermore, imida- zole is also a ring component of adenine and purine, one of the most versatile binding sites in biological systems, so th…     

Thermal evolution of carbonate pillared layered hydroxides with (Ni,L) (L = Fe,Co) based slabs: grafting or nongrafting of carbonate anions?

The thermal evolution, from room temperature up to 300 degrees C, of layered double hydroxides (LDHs) with (Ni, Co) or (Ni, Fe) based slabs and containing intercalated carbonate anions, was studied. A new lamellar phase, exhibiting a 6.5-6.6 A interslab distance, was observed in the 200-260 degrees C temperature range. The infrared study and the chemical analysis results allowed us to give prominence to a monografting of carbonate anions to the slabs. The thermogravimetric studies seem to indicate that intercalated water is first lost, followed by a monografting of carbonate anions. A stay in water of the 200 degrees C thermally treated phase leads to a reintercalation of water molecules. The interslab distance indeed reincreases up to the value of the pristine material, reinforcing the hypothesis of the monografing.     

Synthesis of L‐6‐Chloropyrroloindoline of Chloptosin Cyclohexapeptide

Abstract

Chloptosin is an apoptosis‐inducing dimeric cyclohexapeptide. Enantioselective synthesis of L‐6‐chloropyrroloindoline, as the key chiral synthon of the cyclohexapeptide of chloptosin, was successfully achieved starting from 3‐chloroaniline by utilizing Fischer indole/Schöllkopf protocol and oxidative cyclization of resulting L‐6‐chlorotryptophan.     

Crystal Structure of L—arginine Fluoroborate

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Studies on Chemical Ingredients of Fruit of Alpinia Galanga, (L.) Swarts(Ⅱ) -Four Esters and Their Hydrolysis

Four esters have been isolated from a Chinese medicinal herb, fruit of Alpinia galanga(L.) Swarts, and identified as 1'-acetoxychavicol acetate(1) , trans-p-acetoxycinnamyl acetate(2), 1'-acetoxyeugenol acetate(3), and trans-3'-acetoxytsoeugenol acetate(4). Among them compound 2 has not been reported in literature and compound 4 has nor been found in natural product before. Compound 1 and 3 were hydrclysed rapidly in boiling wacerinto 1'-hydroxychavicol acetate(5), tians-p-acetoxycinudmic alcnhol (6), 1 '-hydroxyeugenol acetate (7) and trans-3' - hydroxyisoeueugenol acetate(8) respectively. The mechanism of these hydrolyses is discussed. The mass spectrometric fragmentations of these compounds are proposed.     

Uronic (hexenuronic) acid profile of ethanol–alkali delignification of giant reed Arundo donax L.

The effect of process variables on uronic acids (UAs) and hexenuronic acids (HexAs) in the annual crop Arundo donax L. during ethanol–alkali pulping has been examined. A substantial loss of UA moieties (up to 90%) was observed by the end of pulping (target kappa number 18) performed with 25% NaOH and 40% EtOH (by volume) within the temperature range of 130–150 °C. At the same time, the progressive formation of HexA in pulp was detected from the early phases of delignification. The proportion of HexA in the residual UA of the final pulp was found to be 84%, indicating almost complete conversion of 4-O-methylglucuronic acid side groups (MeGlcA) of heteroxylan into HexA. The kinetics of UA degradation and HexA formation has been described in terms of three consecutive first-order reaction stages. The overall rate of UA degradation was one order higher than the rate of UA conversion into HexA. The values of apparent activation energy were estimated as 68.6 and 94.7 kJ mol^–1, respectively. The reaction medium alkalinity was shown to be the controlling factor for UA and HexA stability during ethanol–alkali pulping. An increase in alkali charge from 5% to 35% (as NaOH) led to UA loss of 40%, but promoted HexA formation from 11.8 to 20.1 mol g^–1. The addition of organic solvent to the alkaline pulping solution had a similar effect, and about 10% of UA was lost and the content of HexA increased from 6.9 to 10.9 mol g^–1 with an increase in ethanol proportion in the liquor from 20% to 60%.     

The preparation and characterisation of a series of cationic bimetallic linear triphos-bridged complexes of the type [Mo (CO) (L,L′ or L″–P) (η2-RC2R′)Cp] [BF4] {L,L′ or L″= [WI2 (CO){PhP(CH2CH2PPh2)2–P,P′} (η2-RC2R′)] (L,R=R′=Me; L′,R=R′=Ph; L″,R=Me,R′=Ph}

Equimolar quantities of [Mo (CO) (η²-RC₂R′)₂Cp] [BF₄] (R=R′=Me Ph R=Me R′=Ph) and L L′ or L″ {L L′ or L″= [WI₂ (CO){PhP(CH₂CH₂PPh₂)₂-PP′} (η²-RC₂R′)]} (L R=R′=Me L′ R=R′=Ph L″ R=Me R′=Ph) react in CH₂Cl₂ at room temperature to give the new bimetallic complexes[Mo (CO) (L L′ or L″–P) (η²-RC₂R′)Cp] [BF₄] (1–9) via displacement of the alkyne ligand on the molybdenum centre The complexes have been characterised by elemental analysis IR and ¹ H NMR spectroscopy and in selected cases by ³¹ P NMR spectroscopy.     

Studies on Chemical Constituents of Belamcanda Chinensis(L.)DC.(Ⅱ)

IntreductionTherhizomesofBelamcandachinensiS(L.)DC,aChineseherbalmedicine,hasbeenusedinChinaf0rthetreatInentofantiinfective,antitUssiveandexpectorantagentS,TwelveknowncompoundshaveaireadybeenisolatedfromthechloroformsolublefractionofethanolicextractofBelamcandechinensis(L.)DC.Mostofthembelongtoisoflavoneandtheirglucoside"'.Inc0ntinuation0fourstUdies,ninecompoundswereis0latedfromtheacetonesolublefractionofetLhanolicextractoftherootSoftheplant.Thispaperreportstheisolationandidentificatio…     

Behavior of Lβ2 visible satellites in gold around L1 threshold

The Au $L{\beta }_2$ visible satellites, $L{\beta }_2^{\prime }$ and $L{\beta }_2^{″}$ were measured around the $L_1$ absorption edge using a high-resolution Johann-type spectrometer at BL15XU, SPring-8. The relative intensities of the $L{\beta }_2^{\prime }$ and $L{\beta }_2^{″}$ satellites to that of the $L{\beta }_2$ line exhibit an abrupt jump at the $L_1$ threshold. The results suggest that the origin of the $L{\beta }_2$ satellites is mainly the $L_1$–$L_3{M}_{4,5}$ Coster–Kronig transitions.     

GC–MS Analysis of the Essential Oils of Piper nigrum L. and Piper longum L.

A simple, rapid and solvent-free method based on gas chromatography–mass spectrometry (GC–MS) following microwave distillation and headspace solid-phase microextraction (MD–HS-SPME) was developed for the analysis of the essential oils in two traditional Chinese medicines, Piper nigrum L. and Piper longum L. Thirty compounds were separated and identified from P. nigrum L. The main components were β-caryophyllene (23.49%), 3-carene (22.20%), d-limonene (18.68%), β-pinene (8.92%) and α-pinene (4.03 %). Forty-five compounds were separated from P. longum L. and identified. The main components were β-caryophyllene (33.44%), 3-carene (7.58%), eugenol (7.39%), d-limonene (6.70%), zingiberene (6.68%) and cubenol (3.64%). To demonstrate its advantages, MD–HS-SPME was compared to conventional HS-SPME. With conventional HS-SPME, only 28 and 33 compounds were detected in P. nigrum L. and P. longum L, respectively. Relative standard deviation (RSD) values of MD–HS-SPME for the essential oils in P. nigrum L. under optimal conditions were less than 10%. The results show that microwave distillation has a high extract efficiency and good precision and can be used to compare similarities and differences of essential oils.     

Inhibiting the growth of tumor cells by ruthenium(II) complexes [Ru(phen)2L] (L = o-TFMPIP and p-CPIP) through DNA-binding

[Ru(phen)₂o-TFPIP]²⁺ (1) and [Ru(phen)₂p-CPIP]²⁺ (2) have been synthesized and demonstrated to inhibit the growth of tumor cells. The inhibitory activities (IC₅₀) of 1 against the growth of C6, MDA-MB-231 and HepG2 cells were about 24.5, 36.7, and 36.1 μM, respectively. Studies show that both complexes bind to CT-DNA, explained by using density functional theory calculations. The LogP calculated for 1 and 2 are ?0.4859 and ?1.279, respectively. These complexes, especially 1, can be used as promising inhibitors in chemotherapy, and their DNA-binding behaviors play a key role.     

Synthesis and characterization of poly [N-acryloyl-(D/L), (+/−)-phenylalanine-co-(D/L), (−/+)N-methacryloyloxyethyl-N′-2-hydroxybutyl(urea)] copolymers

Two monomers of (D/L), (+/?)-N-methacryloyloxyethyl-N′-2-hydroxybutyl(urea) methacrylate (D/L-MABU) type were prepared and further polymerized through free radical polymerization with optically active monomers containing phenylalanine sequences such as N-acryloyl-(D/L), (?/+)-phenylalanine (A-D/L-Phe). The resulting copolymers, i.e., poly[N-acryloyl-(D/L), (?/+)-phenylalanine-co-(D/L), (+/?)-N-methacryloyloxyethyl-N′-2-hydroxybutyl(urea)], A-D/L-Phe-co-D/L-MABU, were characterized by FT-IR, 1D/2D NMR (¹H and ¹³C), UV-vis, and circular dichroism (CD) spectroscopies, differential scanning calorimetry (DSC), and gel permeation chromatography (GPC). The copolymers obtained with a molar fraction of 0.76: 0.24 / 0.64: 0.36 monomer units had optical rotation values of ?25° and +15°, respectively. Upon chemical modification of the phenylalanine-based copolymers with fluorescein-isothiocyanate, new fluorescent copolyacrylates (A-D/L-Phe-co-D/L-MABU-F) were synthesized and further studied for pH measurements in DMF solutions using HCl and NaOH 10^?1M. It was found that sterioselectivity of the A-L-Phe-co-L-MABU-F copolymer is higher than of its dextro-form, especially at basic pH.      

Effect of L‐Aspartate Concentration on the Response of the Amperometric L‐Glutamate Sensor for the Measurement of L‐Glutamate and Aspartate Aminotransferase Activity in Serum

Abstract

L‐glutamate oxidase was immobilized in a photo‐cross‐linkable polymer membrane on a palladium strip electrode for the amperometric measurement of aspartate aminotransferas eactivity. The sample, serum for example, was injected into a buffered L‐aspartate and α‐ketoglutarate solution. L‐aspartate is the essential substrate and can transfer to L‐glutamate via the aspartate aminotransferase catalyzing reaction. Aspartate aminotransferase activity can be measured by determining the increasing rate of L‐glutamate. Under the optimal condition, the current increasing rate was proportional to the aspartate aminotransferase activity of the sample in the range of 8–200 U/L. The data are in good correlation (R²= 0.998) with data from a commercial aspartate aminotransferase assay kit. Good reproducibility (relative standard deviation=3.03%, n=8) was obtained from a sample with 50 U/L aspartate aminotransferase activity. The sensor is expectable to be applied in a clinical point‐of‐care diagnosis.