Applications of microwave-assisted processes (MAP™) to environmental analysis

The use of microwave-assisted extraction has gained wide acceptance as a powerful tool for the recovery of environmental contaminants and their subsequent analysis. This paper reviews the historical and fundamental basis of the technology. It also provides a cursory review of the current state-of-the-art and literature (2000–2006) in the area of environmental analysis in addition to providing a critical review of the level of efforts being devoted to its further development. MAP is a Trademark of Her Majesty the Queen in Right of Canada as represented by the Minister of the Environment.     

Multiplexed identification of different fish species by detection of parvalbumin, a common fish allergen gene: a DNA application of multi-analyte profiling (xMAP™) technology

Fish are a common cause of allergic reactions associated with food consumption, with parvalbumin being the major allergenic protein. Some fish-hypersensitive patients tolerate some fish species while being allergic to others. Reliable detection methods for allergenic fish species in foods are necessary to ensure compliance with food allergen labeling guidelines to protect fish-allergic consumers. The objective of this project was to develop a multi-analyte detection method for the presence of fish in food. Therefore, conserved parvalbumin exon sequences were utilized for the design of universal PCR primers amplifying intron DNA and small regions of exons flanking the enclosed intron from even very distantly related fish species. An assay for the identification of eight fish species was developed using xMAP™ technology with probes targeting species-specific parvalbumin intron regions. Additionally, a universal fish probe was designed targeting a highly conserved exon region located between the intron and the reverse primer region. The universal fish assay showed no cross-reactivity with other species, such as beef, pork, lamb, chicken, turkey, and shrimp. Importantly, with the exception of one notable case with fish in the same subfamily, species-specific detection showed no cross-reactivity with other fish species. Limits of detection for these eight species were experimentally estimated to range from 0.01% to 0.04%, with potential to increase the detection sensitivity. This report introduces a newly developed method for the multiplex identification of at least eight allergenic fish species in food, which could conceivably be extended to detect up to 100 species simultaneously in one sample.     

Synthesis and characterization of a monomeric and a dihydroxo-bridged dimeric complexes of iron(III) with α-benzoinoxime

The reaction of α-benzoinoxime, H₂BNO with FeCl₃ in the presence of Et₃N as a base gives the mononuclear Fe(III) complex, Fe(HBNO)₃ (1). Treatment of 1 with a methanolic solution of KOH at room temperature leads to a dinuclear Fe(III)–Fe(III) complex, [Fe(HBNO)₂OH]₂ (2). The complexes were initially characterized on the basis of their elemental, mass and thermal analyses. The IR studies were useful in assigning the coordination mode of the benzoinoxime ligand to the iron metal. In addition, the presence of a hydroxo-bridge in the dimeric complex 2 is inferred from the IR spectral studies. Room-temperature Mössbauer studies indicated octahedral, high-spin iron(III). Variable-temperature magnetic susceptibility measurements supported the existence of the μ-dihydroxo-bridging structure core, Fe^III(μ-OH)₂Fe^III in the dinuclear complex 2. Theoretical modelling of the magnetic data indicated a weak antiferromagnetic spin exchange between the iron(III) centers (J = −8.35 cm⁻¹, g = 2.01, ρ = 0.02 and TIP = 1.7 × 10⁻⁴ cm³ mol⁻¹ for H = −2JS₁ · S₂). The electronic spectra of the complexes revealed two bands due to d–d transitions and one band assignable to an oxygen (p_π) → Fe(d_π∗) LMCT transition observed in each complex. An additional charge-transfer transition, assignable to μ-hydroxo(p_π) → Fe(d_π∗), was observed for the dimeric complex 2. The structural and vibrational behaviors of these complexes have been elucidated with quantum mechanical methods.     

Synthesis and Conductivity of a One-dimensional Polymer of a Copper(Ⅱ)-porphyrazine with Sulfur Bridges

Phthalocyanines(Pcs)andtheirpolyinershavebeenasubjectofgreatinterestduetotheirhighthermalstabilityanduniquephotoelectricpropertiesl4.Ithasbeenfoundthatsomeelectronicfunctionsofthemetalthioporphyrazinesandtheirconjugatedpolymers,suchasgas-sensitivityphotosensitivity,photoconductivityandelectrocatalyticactivity,aremorepeculiarthancorrespondingPcs5'6.Oneofourinterestsistodesignanovelpolymerofmetalporphyrazines(PMPzs)withswitchingpointsunderthecontrolofachangingexternalfieIdorenvironment.Inthepr…     

Synthesis and Crystal Structure of a New Dinuclear Manganese(Ⅱ) Manganese(Ⅲ) Complex of a Macrocyclic Ligand

A mixed-valence dinuclear manganese complex, [MnⅡMnⅢL](ClO4)·1/2MeOH, where L is a macrocyclic ligand derived from the cyclocondensation of sodium 2,6-diformyl-4-methylphenolate with N,N-bis(2-aminoethyl)-2-hydroxybenzyl amine, was obtained and its structure was determined by X-ray diffraction. The orange crystal is a monoclinic system with space group P21/c and lattice parameters a=1.1617(4), b=1.4005(3), c=1.4641(3) nm, β=113.03(2)°, and Z=2. The crystal structure shows that each pendant-arm is bonded in a bidentate fashion to the adjacent metal atom and that both the arms are on the same side of the macrocycle. The two Mn atoms are bridged by two μ2-phenoxy oxygen atoms of the tetra-imine macrocycle, and each Mn atom, locating in a trigonal prismatic coordination environment(N3O3), is six-coordinated by the two imine nitrogen atoms, one tertiary nitrogen atom and a pendant phenol moiety apart from the two oxygen atoms.     

Synthesis and Electrochemical Properties of a New Tetraazamacrocyclic Complex of Silver (Ⅰ)

Themetalmacrocycliccomplexeswiththeirunusualoxidationstateshaveattractedmuchinterest.Silver(Il)andsi1ver(IlI)compoundsareusuallyunstab1eduetotheirstrongoxidation.Butsometetraazamacrocyclicligandscandirectlygivestablecom-plexesofsiIver(Il)throughdisproportionatedreactionofsilver(I).12fIere,wereportthesynthesisandeIectrochemicalbehaviorofanewsilver(Il)com-plexAgL(CIO')2(L=5,7,l2,l4-tetraethyl-5,l2-dimethyl-l,4,8,ll-tetraazacyclotetradec-4,l1-diene).Therelativeinformationaboutothersilver(1I…     

Synthesis and characterization of 4,4′-methylenebis (2,6-di-tert-butylphenol) derivatives of a series of metal alkoxides and alkyls

Investigation of the coordination behavior of 4,4′-methylenebis(2,6-di-tert-butylphenol) (or H₂-4DBP) with a series of metal alkoxides led to isolation of [(OR)₃M]₂(µ-4DBP), where M/OR?=?Ti/OBu^t (2), Ti/ONep (3), Zr/OBu^t (4), Hf/OBu^t (5), and [(py)(OR)₃M]₂(µ-4DBP)?·?py (5a), where py?=?pyridine and ONep?=?OCH₂C(CH₃)₃. Metal alkyl derivatives of 4DBP were also studied and found to form similar di-substituted species: [(py)₂(Et)Zn]₂(µ-4DBP)?·?py (6), [(THF)₃(Br)Mg]₂(µ-4DBP) (7), [(THF)₂(Br)Mg](µ-4DBP)[Mg(Br)(THF)₃]?·?(THF, tol) (7a), and [(py)(R)₂Al]₂(µ-4DBP), where R?=?CH₃ (8), Et (9), CH₂CH(CH₃)₂ (10); tol?=?toluene and THF?=?tetrahydrofuran. All structures demonstrate the bridging nature of 4DBP and the ability to bind a variety of metal centers. Solution state NMR indicates that the structures of 2–10 are retained in solution. Thermal analyses indicate that 4DBP is preferentially lost during heating.     

Synthesis of a new conjugated 2,2′-(1,4-phenylenedivinylene)bis-quinoxaline and a series of styryl derivatives of quinoxaline and quinoline as promising electro- and photoluminescent materials

A new poly(p-phenylenedivinylene) oligomer 2,2'-(1,4-phenylenedivinylene)bisquinoxaline, a promising candidate in organic electroluminescent devices, was synthesised via a Knoevenagel condensation reaction of 2-methylquinoxaline with 1,4-benzenedicarbaldehyde. The same synthetic strategy was applied to obtain substituted styryl dyes, derivatives of quinoxaline, whereas styryl derivatives of quinoline were prepared by "Anil Synthesis". The considered dyes are of interest as fluorescence emitting materials. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 95–100, January, 2009.     

The formation of a neutral manganese(III) complex containing a tetradentate Schiff base and a ketone – synthesis and characterization

2-Benzoylphenolato-(2,2′-((2,2-dimethylpropane-1,3-diyl)bis((nitrilo)(phenylmethylidyne)))-diphenolato-manganese(III) methanol solvate, [Mn(C₃₁H₂₈N₂O₂)(C₁₃H₉O₂)]·CH₃OH (1), was synthesized and characterized by FTIR, UV–vis, TG-FTIR, TG/DSC, molar conductivity, magnetic moment measurement, and quantum chemical calculations. During the synthesis, partial hydrolysis of ligand is observed. The compound was obtained as amorphous, dark-brown powder. The effects of organic solvents of various polarities on the UV–vis spectra of ligands and complex were investigated. In addition, the IR and UV–vis spectra were also calculated and compared with the experimental data. A single crystal for analysis was obtained by dissolving the amorphous complex in methanol, and slow evaporation of solvent at 4 °C. Single-crystal X-ray analysis indicated that the methanol molecules are not incorporated into the crystal lattice after the recrystallization process ([Mn(C₃₁H₂₈N₂O₂)(C₁₃H₉O₂)] (2)). In the structure Mn(III) is surrounded by two nitrogens and four oxygens of deprotonated Schiff base and α-hydroxy ketone ligands, and adopts a distorted octahedral geometry.     

Thermochromic and Magnetic Properties of a Copper(Ⅱ) Coordination Compound

Copper complexes that can experience reversible heat-induced dehydration and rehydration in the solid state were rarely reported although thermochromic copper complexes have been widely reported, and their heat-induced magnetic properties have not been studied. We firstly observed the reversible thermochromic phenomena of the known copper(II) complex [Cu(bpy)(OOCCH_3)_2]n·xn H_2O(x = 2.5 or 3; bpy = 4,4?-bipyridine) in the solid state, which is associated with the dehydration and rehydration processes, and found that heat-induced coloration clearly enhanced the magnetic susceptibility.     

Syntheses and Bioactivity of 4″-Sulfonate-5-triphenylsilyl Avermectin B_(1a) and Ivermectin B_(1a) Derivatives

IntroductionAvermectins occuring in nature are macro-cyclic lactones with important anthelmintic,insec-ticidal and miticidal activities.Avermectins andtheir many analogues,such as ivermectins( 2 2 ,2 3-dihydroavermectin B1) and4″- epi- ( methylamino) -4″- deoxyavermectin B1benzoate[1] ,bind to verte-brates′ and invertebrates′ γ- gaminobutyric acid( GABA ) - gated and invertebrate glutamate- gatedchloride channels to increase ion conductance,thereby disrupting inhibitory or excitatory ac…     

Synthesis and characterization of a one-dimensional polymeric copper(Ⅱ)-tetrathioporphyrazine

The title polymer PCuS4Pz was synthesized by reaction of 2,3-dicyano-5,6-dihydro-1,4-dithiin,pyromellitic dianhydride and urea with cuprous salt in optimized gentle method.The structure and properties of the PCuS4Pz were characterized by elemental analysis,X-ray powder diffraction,IR,UV-Vis,fluorescence and EPR spectra and variable-temperature magnetic susceptibility.The polymer is black sublimable crystallite and the degree of polymerization has been found to be n>4.The PCuS4Pz in H2SO4 exhibits intensive absorption bands at 236,342,656 and 767 nm and intensive fluorescence band at 410 nm or 464 nm under the excitation of the ultraviolet light of a determined wavelength at room temperature.It has been found that the polymer exhibits a weaker antiferromag-netic interaction (J=-2.cm-1,εff=1.68 B.M.) with an apparent spin S<1/2 in the ground state and its conductivity 298K is 1.01×10-5 S-cm-1 at 13.73 MPa.     

Synthesis and Structural Characterization of a New Cadmium(II) Complex with a Double Betaine

1 INTRODUCTION The construction of supramolecular aggregates has received much attention due to their intriguing network topologies and potential functions as new classes of materials[1, 2]. Multiple noncovalent interac- tions, such as hydrogen bonds, π-π stacking and host- guest ionic interactions, play important roles in the supramolecular assembly of metal ions and organic ligands[3, 4]. In this context the multidentate ligands with conjugated groups are employed as building blocks in…     

Synthesis and in Vitro Cytotoxicity of a Novel Conjugate of Polyamide and Phospholipid

Small molecules with the ability to target predetermined sequences of DNA would be valuable tools in molecular biology and potentially in human medicine1-3. Synthetic polyamides consisting of N-methylpyrrole (Py), N-methylimidazole (Im) have received spec…     

Fabrication of Micro‐ and Nanoscale Crystals and Thin Films of a Phthalocyanine

Micro‐ and nanosized crystals of 1, 4, 8, 11, 15, 18, 22, 25–octabutoxy–29H, 31H–phthalocyanine (Pc) were successfully fabricated through the reprecipitation approach followed by ultrasonication treatment from acetone solution. Phthalocyanine thin films were prepared by vacuum sublimation, spin‐coating and drop‐cast methods, respectively. Field emission scanning electron microscopy (FESEM), UV/VIS/NIR spectroscopy, polarizing optical microscopy and luminescence spectrometry were applied to study phthalocyanine crystal's surface morphology, electronic absorption, birefringence and light emission properties accordingly. The electronic absorption maximum of Pc nanocrystals shifts to longer wavelength compared to that in acetone solution. Birefringence phenomena exist for Pc crystals with different sizes. Fluorescence is observed for both the Pc in acetone solution and thin film.     

A short total synthesis of (±)-epimeloscine and (±)-meloscine enabled by a cascade radical annulation of a divinylcyclopropane

The first stereoselective synthesis of epimeloscine has been accomplished in 13 total steps with a longest linear sequence of 10 steps. The core of the synthesis takes only five steps, the key ones being acylation, stereoselective tandem radical cyclization of a divinylcyclopropane to make two rings, and group-selective ring-closing metathesis of the resulting divinylcyclopentane to make the last ring.     

Synthesis and characterization of a novel series of unsymmetrical porphyrins

A novel series of unsymmetrical porphyrins with aldehyde group at the terminal of the linkage which connected to meso-phenyl through acylamide bond have been synthesized and structurally characterized by IR,~1H NMR,MS,UV-vis,fluorescence.     

Synthesis and Crystal Structure of a Dicopper(Ⅰ) Complex with Bis(diphenylphosphino)methane and Diethyldithiocarbamate

1 INTRODUCTION Dithiocarbamate derivatives and their metal complexes are extremely versatile compounds which have been used, for example, in the treatment of alcoholism, sarcoma cell and as possible pro- tection against the lethal effect of X-rays etc[1]. Owing to the striking structure features and diversified applications of the metal complexes with dithiocarbamate[2～6], it is of theoretical and practical significance to study the coordination chemistry much more adequately. The meta…     

Synthesis and Properties of a Heteronuclear Ag(Ⅰ)/Ni(Ⅱ) Complex

A complex, Ni (en)2 Ag3 (CN) 5 (en = ethylenediamine), was obtained through the reaction of [Ag (CN) 2] -units with Ni Ⅱ -diamine cation [Ni (en)2] 2 , and the structure was determined by single crystal X-ray diffraction. It is indicated that the complex has a 3D architecture through the silver-silver interactions and the bridging cyano groups. This complex displays interesting luminescent properties caused by argentophilicity at room temperature in solid state.