186 research outputs found
Electrical conductivity and luminescence properties of two silver(I) coordination polymers with heterocyclic nitrogen ligands
No full textThe synthesis and X-raystructural characterization of two novel silver(I) coordination polymers, [Ag
(NO3)(quin)]n (1) and[Ag8(HL)2(H2O)4(mpyz)] . 3H2O (2) arereported, wherequin= 5,6,7,8-tetrahydro-
quinoxaline, H6L = cyclohexane-1,2,3,4,5,6-hexacarboxylic acid andmpyz = 2-methylpyrazine.The single
crystal diffractionan alyses showed that complex 1 is a 2D layered structure, while 2 presents a 3D
polymeric architecture .In complex 2 the network is stabilized by argentophilic interactions and
hydrogen bonding. Electrical conductivity of order 3x10-4 S cm-1 (1) and1.6x10-4 S cm-1 (2) is
measured on thin film specimen at room temperature.The photoluminescence and thermal properties
of the complexes have also been studied
1D coordination polymers formed by tetranuclear lead(II) building blocks with carboxylate ligands: In situ isomerization of itaconic acid
No full textThe synthesis of two new lead(II) coordination polymers, [Pb2(mpic)4(H2O)]·0.5H2O (1) and [Pb2(phen)2(cit)(mes)]·2H2O (2) has been reported, where mpic=3-methyl picolinate, phen=o-phenanthroline, H2cit=citraconic acid, H2mes mesaconic acid. X-ray single crystal diffraction analyses showed that the complexes comprise topologically different 1D polymeric chains stabilized by weak interactions and both containing tetranuclear Pb4 units connected by carboxylate groups. In compound 1 3-methylpicolinic acid is formed in situ from 3-methyl piconitrile, and mesaconate and citraconate anions were surprisingly formed from itaconic acid during the synthesis of 2. The photoluminescence and thermal properties of the complexes have been studied
Synthesis, Crystal Structure, Thermal and Luminescent Characterization of Two New 3D Cadmium–Carboxylate Frameworks
No full textTwo new cadmium coordination polymers have been synthesized with composition {[Cd2(tma)(atz) (H2O)].(H2O)}n (1) (tmaH3 = benzene-1,3,5-tricarboxylicacid, atzH = 5-aminotetrazole) and [Cd(isoor)2(H2O)2] (2) (isoorH = isoorotic acid). X-ray single crystal structure
analysis reveals that complex 1 is 3D coordination polymer. However 2 is mononuclear and turned 3D via hydrogen bonding. Thermogravimetric and luminescence characterization of the complexes were done
Two new metal-organic coordination polymers of lead with O-, N-donor ligands: Synthesis, characterization, luminescence and thermal behavior
No full textThe synthesis of two new lead(II) coordination polymers, [Pb2(picOH)4] .H2O (1) and [Pb3(Sip)2-
(H2O)2] .H2O (2) has been reported, where HpicOH = 3-hydroxypicolinic acid and NaH2Sip = 5-sulfoi-
sophthalic acid monosodium salt .Both the complexes were structurally characterized by X-ray single
crystal diffraction analysis.Complex 1, where the 3-hydroxypicolinate ligand is used for the first time
in conjunction withPb(II), revealed to bea1D polymericarray. Complex 2 showed a 3D structure with
5-sulfoisophthalate ligand adopting two novel binding modes of high denticity (eta-6mu-6 and eta-7mu-7). The
photoluminescence and thermal properties of the two complexes have been studied
3D Coordination Network of Ag(I) Ions with μ 3 -Bridging Melamine Ligands
No full textA new 3D silver complex [Ag(mela)(H2O)(NO3)]n (1) (mela = melamine or 2,4,6-triaminotriazine) is synthesized and characterized by single crystal X-ray diffraction, IR, and elemental analysis. The structural characterization shows that the compound crystallizes in space
group C c, a = 8.181(2), b = 10.269(3) c = 11.347(3) A ° , b = 105.88(2) A, Z = 4. Out of several structurally characterized transition metal compounds comprising melamine, the titled complex represents a rare example of l3-melamine coordination mode realized through the heterocycle nitrogen donors. The fluorescent property of complex 1 was investigated and the mechanism was validated
by means of a density functional theory (DFT) calculation
Two New Coordination Polymers of Manganese(II) with O/O- and N/O-Donor Ligands: Synthesis, Structure, Luminescence Study and Thermal Behavior
No full textTwo new coordination polymers of Mn(II), of formula C12H18MnN8O6 (1) and C21H16MnO9 (2), have been synthesized by using two different kind of ligands, namely 5-methyl-7-oxo-(1,2,4)triazolo(1,5-a)pyrimidine (HmtpO) and 3-(2-furyl)prop-2-enoic acid (fproH). The
X-ray single crystal structure analysis shows that complex 1 is a discrete molecular complex that turns into a 3D network through hydrogen bonding and p–p stacking interactions. Complex 2 is 1D polymeric chain comprising hexacoordinated Mn(II) centers. Luminescence study
revealed the presence of intraligand p*–p transitions. The thermal stability of the complexes has been also investigated
by thermogravimetric analysis
2D and 1D Coordination Polymers of Ag(I) Ions with 2,6-Naphthalenedicarboxylate and N–Donor Coligands
No full textTwo new Ag(I) coordination polymers [Ag2(mepyz)](2,6-ndc)]n (1) and [Ag4(4,40-bipy)]4(2,6-ndc)2.8(H2O) (2) (where 2,6-ndcH2 = 2,6-napthalene dicarboxylic acid, mepyz = 2-methyl pyrazine and 4,40-bipy = 4,4'-bipyridine) have been synthesized and characterized
by single crystal X-ray diffraction analysis. Complex 1 displays a 2D rectangular grid architecture comprising
short Ag-Ag interactions, while 2 is a 1D coordination polymer: both enlarge their dimensionality to 3D via weak interactions. Luminescence study performed on complexes
as well on ligands shows metal perturbed intraligand CT
transition
On the solution of bivariate population balance equations for aggregation: X-discretization of space for expansion and contraction of computational domain
No full textA new structured discretization of 2D space, named X-discretization, is proposed to solve bivariate population balance equations using the framework of minimal internal consistency of discretization of Chakraborty and Kumar [2007, A new framework for solution of multidimensional population balance equations. Chem. Eng. Sci. 62, 4112-4125] for breakup and aggregation of particles. The 2D space of particle constituents (internal attributes) is discretized into bins by using arbitrarily spaced constant composition radial lines and constant mass lines of slope -1. The quadrilaterals are triangulated by using straight lines pointing towards the mean composition line. The monotonicity of the new discretization makes is quite easy to implement, like a rectangular grid but with significantly reduced numerical dispersion. We use the new discretization of space to automate the expansion and contraction of the computational domain for the aggregation process, corresponding to the formation of larger particles and the disappearance of smaller particles by adding and removing the constant mass lines at the boundaries. The results show that the predictions of particle size distribution on fixed X-grid are in better agreement with the analytical solution than those obtained with the earlier techniques. The simulations carried out with expansion and/or contraction of the computational domain as population evolves show that the proposed strategy of evolving the computational domain with the aggregation process brings down the computational effort quite substantially; larger the extent of evolution, greater is the reduction in computational effort. (C) 2011 Elsevier Ltd. All rights reserved
ACTIVITY AND MECHANISM OF ASCOPHYLLUM NODOSUM EXTRACT INDUCED SALINITY TOLERANCE IN TOMATO
No full textSalinity affects crop production worldwide. Ascophyllum nodosum, a brown marine alga, has been used for decades as a bio-stimulant to promote plant growth and impart tolerance to biotic and abiotic stresses. However, the mechanism(s) of the bio-stimulatory activity of A. nodosum extract (ANE) is not well understood.
In vitro experiments were conducted to study the effect of the ethyl acetate fraction of ANE on two week old tomato plants (cv Scotia) grown under salinity stress (100 mM NaCl). The ethyl acetate fraction significantly improved seedling growth and development under salinity stress, i.e. the leaf area and root length of the treated plants improved while the in-planta sodium ion concentration decreased. Stimulated seedlings had higher catalase enzyme activity and recorded higher chlorophyll (chla, chlb and carotenoids) content than non-supplemented stressed plants. Moreover, when tested on four week old tomato plants in a greenhouse, ANE treated plants showed higher concentrations of potassium ions compared to controls. The results shed light on the complex nature of ANE
A Fast and Improved Tunable Aggregation Model for Stochastic Simulation of Spray Fluidized Bed Agglomeration
No full textAgglomeration in spray fluidized bed (SFB) is a particle growth process that improves powder properties in the chemical, pharmaceutical, and food industries. In order to analyze the underlying mechanisms behind the generation of SFB agglomerates, modeling of the growth process is essential. Morphology plays an imperative role in understanding product behavior. In the present work, the sequential tunable algorithm developed in previous studies to generate monodisperse SFB agglomerates is improved and extended to polydisperse primary particles. The improved algorithm can completely retain the given input fractal properties (fractal dimension and prefactor) for polydisperse agglomerates (with normally distributed radii of primary particles having a standard deviation of 10% from the mean value). Other morphological properties strongly agreed with the experimental SFB agglomerates. Furthermore, this tunable aggregation model is integrated into the Monte Carlo (MC) simulation. The kinetics of the overall agglomeration at various operating conditions, like binder concentration and inlet fluidized gas temperature, are investigated. The present model accurately predicts the morphological descriptors of SFB agglomerates and the overall kinetics under various operating parameters
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