O-phenylene Bis Research Articles

Physiological and photochemical profiling of soybean plant using biological and chemical methods of treatment against biotic stress management

Phyto-pathogenic fungal species is a leading biotic stress factor to agri-food production and ecosystem of globe. Chemical (Systemic fungicides) and biological treatment (micro-organism) are globally accepted methods that are being used against biotic stress (disease) management. Plant Growth-Promoting Microbes are being used as an alternative to ease chemical dependency as their overdoses have generated injurious effects on plants and environment. Therefore, present study performs to evaluate the photochemical and physiological profiling of plants exposed to chemical and biological treatment in biotic stress (disease) environment. Two concentrations of each chemical treatment i.e. Topsin-M 70 (Dimethyl 4,4′-o-phenylene bis 3-thioallaphanate, MF1 = 3 g kg−1 and MF2 = 6 g kg−1 seeds) and biological treatment i.e. Trichoderma harzianum strain Th-6 (MT1 = 106 spores mL−1and MT2 = 107 spores mL−1) were used in this experiment. Macrophomina phaseolina (MP) were used as biotic stress factor causing root rot disease in soybean plants. Morpho-physiological assessments and light harvesting efficiency of photosystem II were conducted after 52 days of treatment. Maximum quantum yield (Fv/Fm), number and size of active reaction center (Fv/Fo), photochemical quenching (qP), efficiency of photosystem II (ΦPSII), electron transport rate (ETR), chlorophyll content index (CCI), relative water content (RWC) and stomatal conductance (SC) were increased in MT2 and MF1 treatments as compared to stress plants (MP). Biological (MT2) and chemical (MF1) treatment lessen the production of stress markers showing −48.0 to −54.3% decline in malondialdehyde (MDA) and −42.0 to −53.7% in hydrogen peroxide (H2O2) as compared to stress plant (MP). Biological treatment in both concentration (MF1 & MF2) while chemical treatment at low dose effectively mitigates biotic stress and eases the magnitude of disease. Increasing doses of chemical treatment persuaded deleterious effects on the physiology and light harvesting efficiency of stressed plant suggesting the role of biological treatment (T. harzianum) against biotic stress management in future of crop protection.

Synthesis, Structural Characterization, Reactivity and Bioactivity Studies of Some Binuclear Salen Type Schiff Base Complexes of Manganese(III)

Four new phenoxy bridged binuclear Salen type Schiff base complexes of manganese(III), [MnLX]2 with tetradentate Schiff base, H2L [H2L = N,N′-O-phenylene bis(salicylaldimine)] containing anionic co-ligands, X (X = benzoate, p-hydroxy benzoate, p-aminobenzoate, 3,5-dinitrobenzoate) have been synthesized from manganese(II) acetate, Schiff base (H2L) and the corresponding co-ligands in methanol medium. Schiff base ligand (H2L) was obtained in situ by condensation of salicylaldehyde and o-phenylenediamine in aqueous methanol. Elemental analyses, FT-IR, molar conductance, UV-visible spectroscopic studies and magnetic moment measurements at room temperature were used to characterize the binuclear Schiff base complexes. The IR spectra of [MnLX]2 (X = benzoate, p-hydroxy benzoate, p-aminobenzoate, 3,5-dinitrobenzoate) complexes showed the characteristic absorptions due to coordinated azomethine nitrogen and phenolic oxygen atoms of the Schiff base. In addition, IR spectra of the compounds also suggest coordination of the co-ligands namely benzoate, p-hydroxy benzoate, p-aminobenzoate, 3,5-dinitrobenzoate in the respective complexes. A consistent presence of a band at ca. 755 cm-1 in all the binuclear complexes arises due to (Mn-O-Mn) moiety originated from interactions of phenoxy oxygen and manganese atoms, resulted in dimeric structure of the compounds. The magnetic moment values ranging from 4.74-4.91 B.M. per manganese centre for the complexes suggest presence of Mn(III) ion in the complexes. The overall coordination geometry around the manganese centres is distorted octahedral. Redox behaviour of the synthesized complexes was ascertained from cyclic voltametric studies. The Schiff base complexes, [Mn(L)X]2 (X = p-aminobenzoate, 3,5-dinitrobenzoate) have demonstrated their catalytic potentials in oxidizing selective organic substrates namely cyclohexene and styrene by hydrogen peroxide as oxidant. The oxidized products were characterized as trans-cyclohexane 1,2-diol and styrene epoxide, respectively. Complex 4 demonstrated a considerable level of effectiveness against a wide variety of pathogenic microorganisms.

Modular Synthesis of Tetraurea and Octaurea Macrocycles Encoded with Specific Monomer Sequences

Modular Synthesis of Tetraurea and Octaurea Macrocycles Encoded with Specific Monomer Sequences

Synthesis and application of ion-imprinted polymer nanoparticles for the extraction and preconcentration of zinc ions

A new Zinc (II) ion-imprinted polymer (IIPs) nanoparticles was synthesised for the separation and recovery of trace Zn (II) ion from food and water sample. Zn (II) IIP was prepared by copolymerisation of methyl methacrylate (monomer) and ethylene glycol dimethacrylate (cross-linker) in the presence of Zn (II)-N,N′-o-phenylene bis (salicylideneimine) ternary complex wherein Zn (II) ion is the imprint ion and is used to form the imprinted polymer. Moreover, control polymer (NIP) particles were similarly prepared without the zinc (II) ions. The unleached and leached IIP particles were characterised by X-ray diffraction, Fourier transform infra-red spectroscopy and scanning electron microscopy. The preconcentration of Zn2+ from aqueous solution was studied during rebinding with the leached IIP particles as a function of pH, the weight of the polymer material, the uptake and desorption times, the aqueous phase and the desorption volumes. Flame atomic absorption spectrometry was employed for determination of zinc in aqueous solution.

The Synthesis of Dimeric Re I –Phenylenediimine Conjugates: Spectroscopic and Electrochemical Studies

A series of dimeric ReI(CO)3 compounds have been prepared by means of a one-pot reaction of [Re(CO)5X] (X = Cl, Br), pyridine-2-carboxyaldehyde, and o-, m-, or p-phenylenediamine. For the m- and p-substituted phenylenediamine reactions, phenyl-bridged bis(pyridine-2-carbaldimine) compounds of the formula [Re(CO)3X]2(μ-PPC) [3–7; X = Cl, Br; μ-PPC = m- or p-phenylene bis(pyridine-2-carbaldimine)] were produced, with m-phenylenediamine forming a mixture of isomers. For reactions with o-phenylenediamine, multiple products formed (compounds 8–11), which ranged from the desired o-phenylene bis(pyridine-2-carbaldimine) adduct to 2-pyridylbenzimidazole and bridging dipyridinylquinoxaline complexes. An example of each complex was structurally elucidated by single-crystal X-ray methods. The dimeric m- and p-phenylene-bridged Re(CO)3X compounds, including a sulfonate derivative designed to improve solubility, were investigated for possible photophysical applications through the use of UV/Vis spectroscopy and cyclic voltammetry; the study revealed coupling between the rhenium centers.

Photodynamic action of bis(tertiary arsine (diars)) metal(III) complexes trans-[M(diars) 2X 2] + (X = Cl, Br, I); M = Co 3+, Cr 3+, Rh 3+: Optical and EPR spin-trapping studies

Photodynamic properties of series of metal complexes having the general formula [M(diars) 2X 2]ClO 4 or BF 4 where M = Co 3+, Cr 3+, Rh 3+; X = Cl, Br, I, diars = o-phenylene bis(dimethylarsine) are studied. Photogeneration of singlet oxygen is monitored by both optical and EPR methods. In comparison with rose bengal ( ϕ( 1O 2) for RB = 0.76), singlet oxygen generating efficiencies of these complexes are determined. Rate of N, N-dimethyl-4-nitrosoaniline (RNO) bleaching is found to be retarded by specific 1O 2 quencher NaN 3, confirming the involvement of 1O 2 as an active intermediate. Photolysis of these complexes in the presence of spin trap 5,5-dimethyl-1-pyrroline- N-oxide (DMPO) generates 12-line EPR spectra, characteristic of O 2 − adduct. Photogeneration of O 2 − is also monitored by optical spectroscopy using superoxide dismutase (SOD) inhibitable cytochrome c reduction assay. The results indicate that the [Co(diars) 2Br 2]ClO 4 complex possesses high ability to generate reactive oxygen species (ROS). Both Type I and II paths are involved in the photosensitisation of the metal complexes. The antimicrobial activity of the complexes against selected bacteria is estimated. The relationship between the enzymatic production of ROS and antimicrobial activity of the complexes is examined and a good correlation between two factors is found. The [CoBr 2(diars) 2]ClO 4 complex investigated in this study effect photo cleavage of the plasmid DNA (pUC18).

Preparation and Characterization of Tin(II) Complexes with Isomeric Series of Schiff Bases as Ligands

[X=ortho (L1), meta(L2) 및 para(L3)]리간드를 갖는 주석(II) 화합물들을 합성하고, 그 특성을 원소분석, 적외선 분광광도법, 자외선/가시광선 분광광도법 및 열분석법을 이용하여 확인하였다. 자외선 분광광도법을 통하여, 주어진 ONNO 주게 리간드들의 이민(imine) 및 카보닐기의 배위 모드가 C2v 대칭성을 갖는 것으로 나타났다. 또한 열분석 결과, Sn(L3) 화합물이 가장 높은 활성화 에너지를 가지는 반면, Sn(L2) 화합물이 가장 낮은 활성화 에너지를 가짐을 알 수 있었다. Complexes of Sn(II) with L1 = acac-o-phdnH2 [N,N'-o-phenylene bis(acetylacetoneimine)], L2 = acac-m-phdnH2 [N,N'-m-phenylene bis(acetylacetoneimine)] and L3 = acac-p-phdnH2 [N,N'-p-phenylene bis(acetylacetoneimine)] have been prepared and characterized by elemental analyses, vibrational, electronic spectra and thermal studies (TGA and DTA). Vibrational spectra indicated the coordination mode of imine and carbonyl oxygen for ligands giving (ONNO) that belong to C2V point group symmetry. The [Sn(L3)] complex has a maximum activation energy and [Sn(L2)] complex has a minimum activation energy.

<b>Spectroscopic studies and thermal analysis of lead(II) and tin(II) solid complexes with bi- , tri- and tetradentate Schiff bases</b>

The Schiff base complexes of Pb(II) and Sn(II) with bidentate (NO), [M(sal-An)2] (sal-An = aniline salicylideneiminato); tridentate (ONO), [M(sal-OAP)H2O)] (sal-OAP = ortho- aminophenol salicylideneiminato); and tetradentate (N2O2), [M(sal-o-phdn)] (sal-o-phdn = N,N'-o-phenylene bis(salicylideneiminato) have been synthesized. The infrared spectra were recorded and full assignments of all observed bands have been made. Differential thermal analysis (DTA) and thermogravimetric (TG) for all complexes were also carried out. The data obtained indicate that the complexes of both bi- and tetradentate ligands are decomposed in one stage, but the complexes of tridentate are decomposed in two steps. KEY WORDS: Lead, Tin, Schiff base, Infrared spectra, Thermal analysis Bull. Chem. Soc. Ethiop. 2004, 18(2), 149-156.

Ethylene Oligomerization Catalyzed by Nickel(II) Diimine Complexes

AbstractEthylene oligomerization has been investigated by using catalyst systems composed of nickel(II) diimine complexes (diimine = N, N′‐o‐phenylene bis (salicylideneaminato), N, N′‐o‐phenylenebisbenzal, N, N′‐ethylenebisbenzal) and ethylaluminoxane (EAO). The main products in toluene and at 110–200 °C were olefins with low carbon numbers (C4—C10). Effects of reaction temperature, Al/Ni molar ratio and reaction period on both the catalytic activity and product distribution were explored. The activity of 1.84 × 105 g of oligomer/(molNI · h), with 87.4% of selectivity to C4—C10 olefins, was attained at 200 °C in the reaction when a catalyst composed of NiCl2 (PhCH = o‐NC6H4N = CHPh) and EAO was used.

Polythiophene Hybrids of Transition-Metal Bis(salicylidenimine)s: Correlation between Structure and Electronic Properties

The synthesis, electrochemistry, and spectroscopic behavior of tetradentate bis(salicylidenimine) transition metal complexes 5−9 are reported. Appending these complexes with 3,4-ethylenedioxythiophene (EDOT) moieties allows for electrochemical polymerization at much lower potentials than the parent salen complexes. The resulting polymers display well-defined organic-based electrochemistry at potentials <0.5 V vs Fc/Fc+. The EDOT-modified N,N‘-ethylene bis(salicylidene), N,N‘-o-phenylene bis(salicylidene), and N,N‘-trans-cyclohexylene bis(salicylidene) complexes 5a−b, 6a−b, and 8a−b display cyclic voltammograms with four organic-based redox waves. Increasing the interchain separation through the use of nonplanar bis(salicylidene) ligands results in only two redox waves. The conductivity of the copper-based polymers decreases with increasing interchain spacing, with the maximum conductivity being 92 S cm-1 for poly(5a) and 16 S cm-1 for poly(7a). The nickel complexes were less sensitive to increased interchain separation and showed conductivities greater than 48 S cm-1 regardless of the interchain spacing and near 100 S cm-1 in the case of poly(6b). In situ spectroelectrochemistry was consistent with the segmented electronic nature of these polymers. Cyclic voltammetry of an analogous uranyl complex, 5c, revealed that two electrons per repeat unit were removed during oxidation. Consideration of our collective investigations, which also included in situ EPR spectroscopic studies, led to a postulation that π-aggregation processes are occurring in those polymers which are allowed to have close interchain spacing.

Comparison of Rhizoctonia zeae Isolates from Florida and Ohio Turfgrasses

The growth responses of 10 Rhizoctonia zeae isolates, obtained from turfgrasses in Florida and Ohio, to four temperatures (20, 25, 30, and 35 °C) and seven fungicides at four concentrations (0, 1, 10 and 100 μg·mL-1 a.i.) were compared. Greenhouse pathogenicity tests were conducted using hybrid bermudagrass [Cynodon dactylon (L.) Pers. × C. transvaalensis Burtt-Davy]. Optimal temperature for growth for all isolates was 30 °C. Growth of R. zeae isolates from both geographic locations was severely limited (&gt;75%) at 20 °C. All R. zeae isolates were insensitive to the benzimidazole fungicides, benomyl and thiophanate methyl. Their sensitivities to iprodione, mancozeb, and quinotzene fungicides were similar. The Florida isolates were more sensitive to chlorothalonil, and the Ohio isolates to thiram. All isolates were pathogenic to hybrid bermudagrass. Chemical names used: methyl 1-(butylcarbamoly)-2-benzimidazolecarbamate (benomyl); dimethyl 4,4′-O-phenylene bis(3-thioallophanate) (thiophanate methyl); pentachloronitrobenzene (quintozene); 3-(3,5-dichlorophenyl)-N-(1-methylethyl)-2,4-dioxo-1-imidazolidinecarboxamide (iprodione); tetrachloroisophtalonitrile (chlorothalonil); tetramethylthiuram disulfide (thiram); manganese ethylenebisdithiocarbamate (mancozeb).

Ion-Pairing Liquid Chromatographic Determination of Benzimidazole Fungicides in Foods

A method is described for determining residues in foods of thiabendazole, thiophanate methyl, the di-oxygen analogue metabolite [dimethyl 4,4'-O-phenylene bis (allophanate)] that is the metabolite name of the latter, and methyl-2-benzimidazole carbamate, which is the major metabolite and fungitoxic principle common to both thiophanate methyl and benomyl. The residues are extracted from the product using methanol and are partitioned into dichloromethane after initial acidification and again after subsequent alkalinization of the extract. Residues are separated and quantified by reverse-phase liquid chromatography using an ion-pairing mobile phase with UV and fluorescence detectors in tandem. Recoveries from 7 different food crops fortified at 0.2-35 ppm levels ranged from 64 to 105%.

The Anthelmintic Activity of Thiophanate in Sheep and Cattle

Thiophanate [diethyl 4,4’-o-phenylene bis (3-thioallophanate)] administered to sheep and cattle at 50 mg/kg bodyweight removed 97–100 per cent of Haemonchus contortus, Ostertagia circumcincta, O. ostertagi, Trichostrongylus axei and T. colubriformis; 100 mg/kg was highly efficient against Nematodirus spp. and Cooperia oncophora but variable against Dictyocaulus filaria in sheep. It was equally efficient whether dosed by mouth, via the rumen, or via the abomasum. Le thiophanate [diéthyl 4,4’-o-phénylène bis (3-thiall-phanate)] administré à des moutons et au bétail à la dose de 50 mg/kg de poids corporel supprima 97–100 pour cent des Haemonchus contortus, Ostertagia circumcincta, O. ostertagi, Trichostrongylusa xei et T. colubriformis : la dose se 100 mg/kg fut largement efficace contre Nematodirus spp. et Cooperia onocophora mais d’efficacité variable contre Dictyocaulis fileria chez les moutons. Il fut également efficace par voie orale, via le rumen, ou via la caillette. Thiophanat [Diäthyl 4,4’-o-Phenyl-bis(3-thioallophanat)] wurde Schafen und Rindern in Dosen von 50 mg pro kg Körpergewicht gegeben und bewirkte eine Ausscheidung von Haemonchus contortus, Ostertagia circumcincta, O. ostertagi, Trichostrongylus axei und T. colubriformis bis zu 97–100 Prozent 100 mg pro kg Körpergewicht waren höchst wirksam gegen Nematodirus spp. und Cooperia onocophora aber von wechselnder Wirkun ggegen Dictyocaulus fileria bei Schafen. Die Wirkung war die gleiche, wenn es oral gegeben wurde oder via den Pansen oder den Labmagen. El tiofanto [dietil 4,4’-o-fenileno bis (3-tioallofanato)], administrado a ganado lanar y bovino a dosis de 50 mg/kg de epso corporal, eliminó de un 97 a 100 por ciento de Haemonchus contortus, Ostertagia circumcincta, O. ostertagi, Trichostrongylus axei y T. colubriformis : a 100 mg/kg, fue muy eficaz contra Nematodirus spp. y Cooperia onocophora pero de eficacia variable contra Dictyocaulus filaria en las ovejas. Fue igualmente eficaz cuando se administró por vía oral, por vía de la panza o del abomaso.

Complexes of Protactinium with o-phenylene bis(dimethyl arsine)

Complexes of Protactinium with o-phenylene bis(dimethyl arsine)

Complexes of mercury(II) pseudo-halides

Coordination complexes of triphenylarsine (TPA) triphenylstibine(TPS), bis(1,2-diphenyl-phosphino) ethane(DIPHOS), bis(1,2-diphenylarsino) ethane(BDPAE) and o-phenylene bis(dimethylarsine)(DIARS) with mercuric pseudo-halides, Hg X 2 (where X = SCN or CN) have been prepared and characterised. The i.r. spectra in the region 4000-200 cm −1 have been studied. On the basis of the ν(CN) (stretching) bands compounds having bridged and terminal thiocyanato groups have been identified. It seems that in all the compounds the cyano and the thiocyanato groups remain covalently bonded to the mercury atoms. Tentative assignments have been made of the Hg− X and Hg-ligand stretching vibrations.

Acute toxicity on dimethyl 4,4′- o-phenylene bis(3-thioallophanate), thiophanate-methyl fungicide

A new thiophanate-methyl fungicide, dimethyl 4,4′- o-phenylene bis(3-thioallophanate), was studied in a variety of species of animals. The toxicologic examination of the compound showed the acute toxicity of thiophanate-methyl to be low, and the species or sex variation in sensitivity also to be low. Thiophanate-methyl did not exhibit significant activity in any of the toxicologic tests utilized, including inhalation, subchronic dermal, cutaneous sensitization, contact phototoxicity and photosensitivity and acute toxicity to fish.