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981.
982.
Maryam Anafcheh Fereshteh Naderi Fatemeh Ektefa Reza Ghafouri Mansour Zahedi 《Journal of Cluster Science》2018,29(5):889-896
We have applied density functional theory calculations to study polarizability of the Si60H60 derivatives with epoxide moieties (Si60H60?2nOn with n up to 30). The results show that mean polarizability, α, of oxygen-containing silicon fullerene derivatives is higher than that of Si60H60. The mean polarizabilities of the isomers slightly depend on the positional relationship of the epoxide moieties, and are determined mainly by the number of epoxide moieties. Mean polarizabilities of Si60H60?2nOn linearly increase with n, and are characterized by the depression of polarizability. The formula describing the mean polarizability as a function of the number of epoxide groups has been obtained, which may be important for the design of silicon-containing nanostructures with regulated polar parameters. 相似文献
983.
Maryam Sadat Majdolashrafi 《Phosphorus, sulfur, and silicon and the related elements》2018,193(7):415-422
The complex [Pt2(μ-mtrzt)4(mtrzt)2] (1) was synthesized from the reaction of a mixture of 4-methyl-4H-1,2,4-triazole-3-thiol (Hmtrzt) and ethylenediamine (en) with K2PtCl4 in CH3OH/H2O (2:1) as solvent. The complex [Pt2(μ-mtrzt)4] (2) was synthesized by the same procedure as described for preparation of complex 1 but in the absence of ethylenediamine. Both complexes were characterized by elemental analysis, IR,1H NMR,13C{1H}NMR, UV-Vis, as well as luminescence spectroscopy and their structures were analyzed by single-crystal X-ray diffraction method. The X-ray structure determinations show that complexes of 1 and 2 have binuclear structures in a paddle-wheel fashion with Pt-Pt distances of 2.6628(7) and 2.7977(16)Å, respectively. In complex 1, each platinum(III) atom has a distorted octahedral coordination geometry with the sulfur atom and the second platinum subunit in axial positions and two nitrogen and two sulfur atoms in equatorial positions. Also, in complex 2, each platinum(II) atom has a distorted square-pyramidal coordination geometry with the second platinum subunit in axial position and two nitrogen and two sulfur atoms in equatorial positions. In addition, intermolecular C?H···N and C?H···S hydrogen bonds in 1 and 2 as well as intermolecular anagostic C?H···Pt and C?H···π interactions in 2 are effective in the stabilization of the crystal packing of these complexes. 相似文献
984.
Hossein Aghabozorg Abolghasem Moghimi Faranak Manteghi Maryam Ranjbar 《无机化学与普通化学杂志》2005,631(5):909-913
Starting with a zirconium salt and LH2 , (pydaH2)2+(pydc)2?, (pyda=2, 6‐pyridinediamine; pydcH2=2,6‐pyridinedicarboxylic acid), as a 1:1 proton transfer self‐associated compound, two different compounds were resulted. One of them is a new complex of ZrIV with a flat pyridine containing ligand and structure of (pydaH)2[Zr(pydc)3] · 5H2O (1) and the other, (pydaH)+(NO3)? (2) is an ion pair with no zirconium ion. The zirconium(IV) complex (1) is crystallized in triclinic system with space group and Z = 2, the crystallographic parameters are: a = 10.612(5) Å, b = 10.617(5) Å, c = 16.815(8) Å, α = 103.654(9)°, β = 95.821(9)°, γ = 98.891(9)° and R‐value for 16767 collected reflections is 0.0592. The ion pair (2) has crystals of monoclinic system with P21 space group and Z = 2. Its crystallographic parameters are: a = 3.6227(11) Å, b = 10.034(4) Å, c = 10.296(4) Å, β = 93.422(9)° and R‐value for 4031 collected reflections is 0.0521. The two compounds were characterized with elemental analysis, ESI/MS, NMR and IR spectroscopy. 相似文献
985.
Ganjali MR Norouzi P Gol-Mohammadi M Mizani F Poursaberi T Salavati-Niasari M Shamsipur M Hosseini M Javanbakht M 《Annali di chimica》2003,93(7-8):679-690
A strontium Schiff's base complex (SS) can be used as a suitable ionophore to prepare a sulfate-selective PVC-based membrane electrode. The use of oleic acid (OA) and hexadecyltrimethylammonium bromide (HTAB), as additives, and nitrobenzen (NB), dibutyl phthalate (DBP) and benzyl acetate (BA) as solvent mediators, were investigated. The best performance was observed with a membrane composition PVC: NB: SS: HTAB of 30%: 62%: 5%: 3% ratio. The resulting sensor works well over a wide concentration range (1.0 x 10(-2)-1.0 x 10(-6) M) with a Nernstian slope of -29.2 mV per decade of sulfate activity over a pH range 4.0-7.0. The limit of detection of the electrode is 5 x 10(-7) M. The proposed sensor shows excellent discriminating ability toward SO4(2-) ions with regard to many anions. It has a fast response time of about 15 s. The membrane electrode was used to the determination of zinc in zinc sulfate tablets. The sensor was also used as an indicator electrode in the potentiometric titration of SO4(2-) against barium ion. 相似文献
986.
Akbar Heydari Samad Khaksar Maryam Esfandyari Mahmoud Tajbakhsh 《Tetrahedron letters》2007,48(7):1135-1138
A simple and convenient procedure for direct reductive amination of aldehydes and ketones with sodium borohydride is described. The reaction has been carried out in methanol in the presence of a catalytic amount of H3PW12O40 (0.5 mol %). α,β-Unsaturated aldehydes and ketones can be easily converted into the corresponding allyl alcohols by reaction with H3PW12O40 (0.5 mol %)/NaBH4. 相似文献
987.
Mojtaba Shamsipur Farhang Mizani Ali Akbar Saboury Hashem Sharghi Reza Khalifeh 《Electroanalysis》2007,19(5):587-596
Novel PVC membrane (PME) and coated graphite (CGE) Cu2+‐selective electrodes based on 5,6,7,8,9,10‐hexahydro‐2H‐1,13,4,7,10‐benzodioxatriazacyclopentadecine‐3,11(4H,12H)‐dione are prepared. The electrodes reveal a Nernstian behavior over wide Cu2+ ion concentration ranges (1.0×10?7–1.0×10?1 M for PME and 1.0×10?8–1.0×10?1 M for CGE) with very low limits of detection (7.8×10?8 M for PME and 9.1×10?9 M for CGE). The potentiometric responses are independent of the pH of the test solutions in the pH range 2.7–6.2. The proposed electrodes possess very good selectivities for Cu2+ over a wide variety of the cations including alkali, alkaline earth, transitions and heavy metal ions. The practical utility of the proposed electrodes have been demonstrated by their use in the study of interactions between copper ions and human growth hormone (hGH) in biological systems, potentiometric titration of copper with EDTA and determination of copper content of a sheep blood serum sample and some other real samples. 相似文献
988.
Akbar Heydari Roohollah Kazem Shiroodi Hossein Hamadi Maryam Esfandyari Mehrdad Pourayoubi 《Tetrahedron letters》2007,48(33):5865-5868
The commercially available heteropoly acid H3PW12O40 (0.5 mol %) is a very efficient and environmentally benign catalyst for N-tert-butoxycarbonylation of amines (primary, secondary) with di-tert-butyl dicarbonate at room temperature in short reaction times (<10 min). No competitive side products such as isocyanates, ureas, N,N-di-tert-butoxycarbonyls, O-Boc and oxazolidinones were observed. Chiral α-amino alcohols and esters afforded the corresponding N-Boc derivatives chemoselectively in excellent yields. 相似文献
989.
Issa Yavari Zinatossadat Hossaini Maryam Sabbaghan Majid Ghazanfarpour-Darjani 《Tetrahedron》2007,63(38):9423-9428
The reaction of ethyl propiolate with triphenylphosphine (Ph3P) in the presence of N-alkylisatins led to ethyl 2,2,2-triphenyl-2,5-dihydro-1,2-λ5-oxaphosphole-4-carboxylate-spiro-1-alkyl-1,3-dihydro-2H-indol-2-ones in good yield. The reaction of dialkyl acetylenedicarboxylates with Ph3P in the presence of N-alkylisatins led to dialkyl 2,2,2-triphenyl-2,5-dihydro-1,2-λ5-oxaphosphole-3,4-dicarboxylate-spiro-1-alkyl-1,3-dihydro-2H-indol-2-ones and alkyl 4-(alkoxy)-5-oxo-2,5-dihydro-3-furancarboxylate-spiro-1-alkyl-1,3-dihydro-2H-indol-2-ones. 相似文献
990.
Two new ZnII(μ‐4,4′‐bipy) coordination polymers with acetate anions, [Zn(4,4′‐bipy)(AcO)2] ( 1 ) and [Zn2(4,4′‐bipy)(AcO)4] ( 2 ), have been synthesized. The compounds were characterized with elemental analysis, IR‐, 1H NMR‐, 13C NMR spectroscopy and studied by thermal analysis, fluorescence measurements and x‐ray crystallography. The structural studies of compound 1 suggest the structure is a coordination polymer of zinc(II) consisting of linear double chains formed by bridging 4,4′‐bipy ligand and connection of the acetate‐bridged centrosymmetric [Zn2(OAc)2]2+ nodes. 相似文献