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1.
Harris RK Kinnear KA Morris GA Stchedroff MJ Samadi-Maybodi A Azizi N 《Chemical communications (Cambridge, England)》2001,(23):2422-2423
The first use of silicon-29 diffusion-ordered NMR spectroscopy (DOSY) is reported, in a study of the speciation of aqueous silicates. 相似文献
2.
Robin K. Harris Judith A. K. Howard Abdolraouf Samadi-Maybodi Jing Wen Yao Warren Smith 《Journal of solid state chemistry》1995,120(2)
The first crystal structure is reported for a silicate clathrate hydrate involving a triply charged cation [C18H30N3]3+ and an octameric cubic silicate cage. The structure is essentially a host/guest system, with the silicate cages linked into a framework by hydrogen bonding to water molecules. The space group is P
with Z = 2, and the asymmetric unit includes a complete cation and half the anion, plus 21 water molecules (4 of which are in disordered positions). Solid-state (CPMAS) 29Si and 13CNMR spectra are consistent with the diffraction-determined structure and indicate substantial distortion of the anion from cubic symmetry. Solution-state spectra of precursor solutions and of melted material are also presented and discussed. 相似文献
3.
Samadi-Maybodi A Goudarzi N 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2006,65(3-4):753-758
The effect of (2-hydroxyethyl)trimethylammonium (2-HETMA) cation on the equilibrium of silicate oligomers in aqueous alkaline silicate solutions was investigated using (29)Si NMR spectra. The results indicate role of structural directing of 2-HETMA in which it particularly directs the silicate species to the Q(4)(1)Q(4)(3)Q(4)(4) silicate anion. Results reveal that composition of the alcohols in solution affect the distribution of anionic species. The effect of methanol concentration is also discussed. 相似文献
4.
Abdolraouf Samadi-Maybodi Reza Akhoondi Mohammad Javad Chaichi 《Journal of fluorescence》2010,20(3):671-679
Quinoxaline derivatives are a great interest as fluorescent emitters for peroxyoxalate chemiluminescence. Reaction of peroxyoxalates
such as bis-(2,4,6-trichlorophenyl) oxalate with H2O2 can transfer energy to fluorophore via formation of dioxetanedione intermediate. Two quinoxaline derivatives used as a fluorophore
in this study which produce a green light in the chemiluminescence systems. The relationship between the chemiluminescence
intensity and concentrations of fluorophore, peroxyoxalate, sodium salicylate and hydrogen peroxide was investigated. Kinetic
parameters for the peroxyoxalate-chemiluminescence were also calculated from the computer fitting of the corresponding chemiluminescence
intensity/time profiles. It was found that the biphenylquinoxaline can be used as an efficient green fluorescent emitter. 相似文献
5.
Samadi-Maybodi A 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2006,64(4):1025-1031
(27)Al NMR spectroscopy can be used for study of coordination and solvation in both aqueous and non-aqueous solutions. Various octahedral and tetrahedral aluminium complexes have been proved to exist in solution by (1)H and (27)Al NMR spectroscopy. (27)Al nuclear magnetic resonance (NMR) spectroscopy also can be used to determine thermodynamic properties of complexes in the solution. The formation of [Al(OH)(4-n)(CH(3)OH)(n)]((n-1)+) (n=1, 2, 3 and 4) species through the reaction of aluminate anion with methanol has been investigated by (27)Al NMR spectroscopy. (27)Al NMR spectra reveal evidence for Al bound to one, two, three and four CH(3)OH, the production of aluminate species is affected by the MeOH/H(2)O. Results obtained from 2D EXSY experiments clearly confirm there are exchanges among the species. 相似文献
6.
Oscillating chemical reactions are complex systems, involving a large number of chemical species. In oscillating chemical reaction, some species, usually a reaction intermediate, exhibit fluctuation in its concentration. In this report, visible oscillating chemiluminescence produced by the addition of luminol (3-aminophthalhydrazide) to the oscillating system of H2O2=KSCN=CuSO4=TMAOH was investigated using spectrofluorimetry method. The effects of ingredient concentration of the oscillating system and complexing agents like citric acid and cysteine on the behavior of the oscillating system were investigated. Moreover, the influence of nonaqueous solvents such as ethanol and ethylene glycol has been studied. 相似文献
7.
It has been shown that Chlorpheniramine maleate (CPM) increases chemiluminescence intensity of bis-(2,4,6-trichlorophenyl)oxalate (TCPO) with hydrogen peroxide in the presence of biphenylquinoxaline as a fluorophore. In this work, the effect of CPM on the intensity of chemiluminescence (CL) in the system of (TCPO-sodium salicylate-fluorophore-hydrogen peroxide) was investigated. The fall and rise rates constants were also studied. A pooled-intermediate model was used for determining the kinetics parameters of CL with and without CPM. Results indicated that addition of CMP to this system increases the fall rate constant and decreases the rise rate constant. Results also specified that there is a linear relationship between CPA concentration and chemiluminescence intensity in the range 0.66-21.5 μg/ml. Detection limit 0.18 μg/ml and the relative standard deviation (RSD) <7% was obtained. This work is introduced as a new method for the determination of CMP. 相似文献
8.
Samadi-Maybodi A Darzi SK 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2008,70(5):1167-1172
Resolution of binary mixtures of vitamin B12, methylcobalamin and B12 coenzyme with minimum sample pre-treatment and without analyte separation has been successfully achieved by methods of partial least squares algorithm with one dependent variable (PLS1), orthogonal signal correction/partial least squares (OSC/PLS), principal component regression (PCR) and hybrid linear analysis (HLA). Data of analysis were obtained from UV-vis spectra. The UV-vis spectra of the vitamin B12, methylcobalamin and B12 coenzyme were recorded in the same spectral conditions. The method of central composite design was used in the ranges of 10-80mgL(-1) for vitamin B12 and methylcobalamin and 20-130mgL(-1) for B12 coenzyme. The models refinement procedure and validation were performed by cross-validation. The minimum root mean square error of prediction (RMSEP) was 2.26mgL(-1) for vitamin B12 with PLS1, 1.33mgL(-1) for methylcobalamin with OSC/PLS and 3.24mgL(-1) for B12 coenzyme with HLA techniques. Figures of merit such as selectivity, sensitivity, analytical sensitivity and LOD were determined for three compounds. The procedure was successfully applied to simultaneous determination of three compounds in synthetic mixtures and in a pharmaceutical formulation. 相似文献
9.
Abdolraouf Samadi-Maybodi Seyed Karim Hassani Nejad-Darzi Mohsen Tafazzoli 《Journal of solution chemistry》2012,41(5):888-897
In this work, phosphorus-31 and aluminum-27 nuclear magnetic resonance techniques were used to characterize the distribution of soluble aluminophosphate species in methanol + water and ethanol + water mixtures. The assignment of the peaks to aluminate species was attempted, clarifying earlier work and producing information on the different aluminophosphate complexes. Nine peaks were observed at ?0.41, ?6.4, ?7.5, ?7.9, ?13.1, ?13.9, ?16.6, ?18.1 and ?20.6 ppm. Four new peaks appeared in the 31P NMR spectra of the alcoholic aluminophosphate solutions and their intensities changed with changes of the alcohol:water volume ratio. These new peaks were observed in the presence of methanol or ethanol but not in aqueous solutions. 相似文献
10.