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Eu3+ photoluminescence is studied in La5Si2BO13 with apatite related structure. La5−xEuxSi2BO13 [x=0.05, 0.1, 0.3, 0.5, 0.7, 1.0, 2.0] compositions are synthesized. The emission results shows that Eu3+ ions occupy two different cationic sites viz., La(1) and La(2). The increase in the intensity of 5D0-7F0 line with increasing Eu3+ content shows the preferential occupancy of Eu3+ in La(2) site due to the existence of short La(2)-O(4) (free oxide ion) bond. The observation of antiferromagnetic interactions in Gd and Dy analogues supports the structural features elucidates from photoluminescence studies. 相似文献
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Danish Muhammad Akhtar Arusa Ashfaq Muhammad Arshad Muhammad Nadeem Asiri Abdullah M. 《Journal of chemical crystallography》2021,51(4):543-552
Journal of Chemical Crystallography - In this paper, we report new sulfonamide derivatives, 4-((2,4-dichlorophenylsulfonamido)methyl)cyclohexanecarboxylic acid (1), ethyl... 相似文献
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Sajjad Dadashi‐Silab Abdullah Mohamed Asiri Sher Bahadar Khan Khalid A. Alamry Yusuf Yagci 《Journal of polymer science. Part A, Polymer chemistry》2014,52(10):1500-1507
Photoinduced free radical polymerization of vinyl monomers by using semiconductor inorganic nanoparticles (NPs) is investigated. Zinc oxide and iron‐doped zinc oxide were used as photosensitive compounds to initiate the polymerization of acrylamide as a water‐soluble monomer in aqueous environment and methyl methacrylate as an oil‐soluble monomer in organic media under UV‐light irradiation. The method uses photochemically generated electrons and holes from the NPs to form initiating hydroxyl radicals in aqueous media, while tertiary amines and iodonium salt served as coinitiator in organic media. The initiation mechanism in organic media involves hydrogen abstraction or reduction processes via charge carriers, respectively. The kinetic of the polymerization in both environments was studied by means of a photo‐differential scanning calorimetry. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 1500–1507 相似文献
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Asiri Nanayakkara 《Pramana》2003,61(4):739-747
In this paper, we present a semiclassical eigenenergy expansion for the potential |x|α when α is a positive rational number of the form2n/m (n is a positive integer and m is an odd positive integer). Remarkably, this expansion is found to be identical to the WKB expansion
obtained for the potentialx
N(N-even), if2n/m is replaced byN. Taking the limitm → 2 of the above expansion, we obtain an explicit asymptotic energy expansion of symmetric odd power potentials |x|2j+1 (j- positive integer). We then show how to develop approximate semiclassical expansions for potentials |x|α when α is any positive real number. 相似文献
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Solution properties of phenothiazine drug promazine hydrochloride with cationic hydrotropes in aqueous/electrolyte solution at different temperature 下载免费PDF全文
Malik Abdul Rub Naved Azum Abdullah M. Asiri Mohie E. M. Zayed Abdulrahman O. Al‐Youbi 《Journal of Physical Organic Chemistry》2016,29(9):476-489
The current work deals with the mixed micellization phenomena of surface active promazine hydrochloride (PMZ) drug with cationic hydrotropes (para‐toluidine hydrochloride and ortho‐toluidine hydrochloride) in absence and occurrence of 50 mmol kg?1 NaCl at five different temperature (293.15–313.15 K). PMZ is an amphiphilic phenothiazine drug and employed for the cure of mania and schizophrenia. Conductometry measurement was employed to gain a detailed picture of the interactions between drug and hydrotrope molecules. The experimental data were analyzed according to different mixing models within the outline of the pseudophase separation model. The evaluated values of critical micelle concentration (cmc) were found to be inferior than cmcid values signifying attractive interactions involving the both components in the solutions. NaCl further reduces the cmc of pure amphiphiles and their mixed systems as a result of screening of the electrostatic repulsion between the polar head groups. The micellar mole fractions (X1) of hydrotropes evaluated by various proposed models were constantly more than ideal values ( ) signifying high involvements of hydrotrope in mixed micelles. Activity coefficients ( and ) were always below one in all cases signifying synergism in mixed micelles. Thermodynamic parameters favor the process of micellization which is found to be entropy driven. The negative values of free energies of mixing demonstrated the stability of the mixed systems of drug and hydrotrope. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
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Presence versus Proximity: The Role of Pendant Amines in the Catalytic Hydrolysis of a Nerve Agent Simulant 下载免费PDF全文
Dr. Timur Islamoglu Dr. Manuel A. Ortuño Emmanuel Proussaloglou Dr. Ashlee J. Howarth Dr. Nicolaas A. Vermeulen Ahmet Atilgan Prof. Abdullah M. Asiri Prof. Christopher J. Cramer Prof. Omar K. Farha 《Angewandte Chemie (International ed. in English)》2018,57(7):1949-1953
Amino‐functionalized zirconium‐based metal‐organic frameworks (MOFs) have shown unprecedented catalytic activity compared to non‐functionalized analogues for hydrolysis of organophosphonate‐based toxic chemicals. Importantly, the effect of the amino group on the catalytic activity is significantly higher in the case of UiO‐66‐NH2, where the amino groups reside near the node, compared to UiO‐67‐m‐NH2, where they are directed away from the node. Herein, we show that the proximity of the amino group is crucial for fast catalytic activity towards hydrolysis of organophosphonate‐based nerve agents. The generality of the observed amine‐proximity‐dictated catalytic activity has been tested on two different MOF systems which have different topology. DFT calculations reveal that amino groups on all the MOFs studied are not acting as Brønsted bases; instead they control the microsolvation environment at the Zr6‐node active site and therefore increase the overall catalytic rates. 相似文献