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891.
合成了两个酰腙类荧光探针1和2,在DMSO-H_2O(7∶3,体积比)体系中,两者分别在478 nm和460 nm处对Al~(3+)具有较好的荧光选择识别作用。Job's法、核磁滴定、质谱分析表明,探针1和2与Al~(3+)的配位比均为1∶2,且对Al~(3+)的检出限分别为9.58×10~(-8) mol/L和6.52×10~(-8) mol/L。同时提出了探针1和2对Al~(3+)的荧光传感机理。实际应用研究表明,探针1和2可用于河水和自来水中一定浓度范围内Al~(3+)的检测。 相似文献
892.
以Al2O3为基质,添加ZrO2和La2O3,制成La2O3-ZrO2-Al2O3复合载体,然后采用SO42-进行改性,再负载上Cu2+,制备了铜基SO42-改性的复合载体催化剂(Cu/SO42-/La2O3-ZrO2-Al2O3)。考察了它在富氧条件下对丙烯选择还原NO的催化性能,并借助XRD、SEM、TG、Py-IR、NH3-TPD、FTIR和TPR等方法研究了Cu/SO42-/La2O3-ZrO2-Al2O3的结构和性能的关系。结果表明,ZrO2的加入主要有利于提高催化剂的低温活性;La2O3的加入则主要有利于提高催化剂的热稳定性和还原性能;SO42-能够与Zr形成螯合双配位结构,大幅度促使催化剂表面酸量增加并且酸性增强;因此,有效地提高了Cu/SO42-/La2O3-ZrO2-Al2O3在富氧条件下对丙烯选择还原NO的催化活性和水热稳定性。在无水条件下,Cu/SO42-/La2O3-ZrO2-Al2O3能使NO的最大转化率高达84.3%,即使在275 ℃ 10%水蒸气存在的情况下,仍能使NO的转化率高达81.2%。 相似文献
893.
水热条件下,合成了三个新的配合物[Ni(en)3] (ndt) ·H2O 1,
[Co(en)3] (ndt) ·H2O 2 和[Mn(en)3] (ndt) ·H2O
3。晶体结构通过X-射线单晶衍射进行了表征。三个配合物均属于单斜晶系,Cc空间群。[M(en)3]2+阳离子、ndt阴离子和结晶水分子通过氢键自组装出相同结构的三维网。通过紫外-可见-近红外漫反射光谱对这三个配合物的光吸收性能和能带进行了测定。 相似文献
894.
Binary zirconium orthophosphates R1/3Zr2(PO4)3 and M1/4Zr2(PO4)3, where R = Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb, Lu; M = Th, U, have been synthesized and studied by IR spectroscopy [structural family of NaZr2(PO4)3 (NZP)]. Vibrational analysis for the PO4 tetrahedron and investigation of symmetry relations among trigonal NZP phases showed that ordering of lanthanide atoms in structures of NaZr2(PO4)3 type with space group R
c leads to symmetry reduced to P
c. The lanthanide atoms occupy the 2b sites. The phosphorus atoms occupy two independent sites: 6f with C
2 symmetry and 12g with C
1 symmetry. Factor group analysis admits that the IR spectrum can contain eight v3 bands and two v1 bands of the stretching vibrations of the PO4 ions. The M atoms of actinides occupy statistical positions in the structure, and space group R
c is retained.Original Russian Text Copyright © 2004 by V. S. Kurazhkovskaya, D. M. Bykov, and A. I. Orlova__________Translated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 6, pp. 1013–1019, November–December, 2004. 相似文献
895.
《Tetrahedron letters》2003,44(46):8445-8448
Fused β-carboline systems, as indolo[2,3-a]indolizidinones, indolo[2,3-a]quinolizidinones, their 2-oxa analogues, and benzo[a]indolo[2,3-a]indolizidinones are prepared efficiently via an RLi addition-N-acyliminium ion cyclisation sequence on readily available imides. In an enantioselective variant of these α-amidoalkylation reactions, the addition of MeLi to a chiral non-racemic imide derived from tryptophan yielded an oxo amide, which was cyclised diastereoselectively upon treatment with BF3·OEt2, to afford 5,11b-trans-indoloindolizidinone in moderate yield and high ee (99%). 相似文献
896.
A new layered aluminophosphate, denoted AlPO-CJ12, has been synthesized in the system Al(OPri)3-H3PO4-tetramethylethylenediamine-triethyleneglycol and its structure solved by single-crystal X-ray diffraction analysis. It is further characterized by X-ray powder diffraction, ICP, TG, DTA, and elemental analyses. The compound has an empirical formula of [Al3P4O16][(CH3)2NHCH2CH2NH(CH3)2][H3O], and crystallizes in the triclinic space group P-1 (No. 2) with a=8.9907(6) Å b=9.8359(6) Å, c=14.5566(8) Å, α=75.872(3)°, β=88.616(3)°, γ=63.404(3)°, Z=2, R1=0.0451, and wR2=0.1094. The alternation of tetrahedral AlO4 and PO3 (=O) units forms a sheet structure with a 4×6×8 network. The inorganic layers stacked in an AAAA sequence are held together by the protonated organic amine and water molecules. The co-templating role of the water molecules is studied by the calculation of the nonbonding host-guest interaction energies through a computational simulation. 相似文献
897.
(RCp)_2MCl_2,(RCp)TiCl_3分别与N-(4-苯基-2-噻唑基)二硫代氨基甲酸钾和3-苯基-5-(2-呋哺基)-吡唑啉-1-二硫代甲酸钠进行反应,合成了三十二个未见报道的(RCp)M(S_2CNHR′)_nCl_(3-n),(RCp)_2M-(S_2CNHR′)_nCl_(2-n),[R=H,Me;M=Ti,Zr;R′=4-苯基噻唑基(PTDTC),n=1,2,3]以及(RCp)M(S_2CR~2)_nCl_(3-n),(RCp)_2M(S_2CR~2)_nCl_(2-n)[R=H,Me;M=Ti,Zr,R~2=3-苯基-15-(呋喃-2)吡唑啉基(PFPDTC),n=1,2,3]型配合物。所有配合物经元素分析、UV、IR和'H NMR谱证实,二硫代氨基甲酸是以双齿配体键合的。 相似文献
898.
Tadatomi Nishikubo Atsushi Kameyama Jun Yamashita Takahiro Fukumitsu Chika Maejima Masao Tomoi 《Journal of polymer science. Part A, Polymer chemistry》1995,33(7):1011-1017
The addition reaction of oxiranes ( 15a-d ) with carbon dioxide (CO2) was carried out using 1 mol % of soluble polymer-supported quaternary onium salts as catalysts under atmospheric pressure. The reaction of 15a-d with CO2 proceeded very smoothly to give the corresponding five-membered cyclic carbonates ( 16a-d ) in high yields at 90-100°C. The catalytic activity of the soluble polymer-supported quaternary onium salts was strongly affected by the following factors: kind of reaction solvent, degree of introduction of the pendant onium salt residues in the polymer chain, and type of alkyl group on the onium salts due to the balance between lipophilicity and steric hindrance of the onium salt residue. Furthermore, these soluble polymer-supported quaternary onium salts were found ordinarily to have higher catalytic activity than low molecular weight quaternary onium salts under the same reaction conditions. It was also found that the rate of reaction was proportional both to catalyst concentration and to oxirane concentration. © 1995 John Wiley & Sons, Inc. 相似文献
899.
Shaobin Miao Zhan Yu Qian-Feng Zhang Yinglin Song Alexander Rothenberger Wa-Hung Leung 《Journal of Cluster Science》2006,17(3):495-507
Two isostructural crown-like heteroselenometallic cluster compounds, [Et4N]4[(μ5-WSe4)(CuX)5(μ-X)2] (X = Cl 1, Br 2), were prepared from the reactions of [Et4N]2[WSe4] with CuX and [Et4N]X· xH2O in the presence of 2-picoline and characterized by single-crystal diffraction analysis. The [(μ5-WSe4)(Cu-X)5(μ-X)2]4− anions in the cluster compounds consists of five CuX fragments coordinated to the five edges of the tetrahedral [WSe4]2− moiety along with two bridging halides connected to each of the two pairs of the symmetric copper atoms, exhibiting a novel
crown-like core structure. The nonlinear optical absorption and refraction of cluster compound 2 were determined to be α2 = 6.15 × 10−10 m/W and n
2 = 4.18 × 10−11 esu, respectively. 相似文献
900.
Asymmetric multicomponent reactions involve the preparation of chiral compounds by the reaction of three or more reagents added simultaneously. This kind of addition and reaction has some advantages over classic divergent reaction strategies, such as lower costs, time, and energy, as well as environmentally friendlier aspects. All these advantages, together with the high level of stereoselectivity attained in some of these reactions, will force chemists in industry as in academia to adopt this new strategy of synthesis, or at least to consider it as a viable option. The positive aspects as well as the drawbacks of this strategy are discussed in this Review. 相似文献