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991.
应用加温加压气固多相催化原位红外光谱反应器,在H2/CO=2:1(mol)、0.5 ̄5.0MPa和20 ̄300℃的接近CO+H2工业反应条件下,考察了还原态和氧化态Rh/Al2O3催化剂表面CO吸附态,关联了吸附态与催化剂活性的关系。实验结果表明,还原态的Rh/Al2O3催化剂一氧化碳加氢生成烃类,其催化剂表面存在三种CO吸附态:线式Rh(CO),孪生式Rh(CO)2和桥式Rh2CO。在常温常压下 相似文献
992.
S. V. Awate P. N. Joshi V. P. Shiralkar A. N. Kotasthane 《Journal of inclusion phenomena and macrocyclic chemistry》1992,13(3):207-218
Crystalline gallosilicates with a pentasil (MFI) framework containing Ga3+ in lattice positions were synthesised. The kinetic features of the hydrothermal system containing triethyl-n-butylammonium cations (TEBA)+ as template in the gel system have been investigated. The gallosilicate products were characterized by XRD, framework-IR, TG/DTA,29Si and71Ga MASNMR and sorption measurements using standard techniques.
相似文献
993.
Davut Avcı Sümeyye Altürk Fatih Sönmez Ömer Tamer Adil Başoğlu Yusuf Atalay Belma Zengin Kurt Necmi Dege 《Tetrahedron》2018,74(50):7198-7208
Novel complexes of 6?methylpyridine?2?carboxylic acid and thiocyanate {[Cu(NCS)(6-mpa)2], (1); [Cd(NCS)(6-mpa)]n, (2); [Cr(NCS)(6-mpa)2·H2O], (3)} were synthesized, and their structures were characterized by XRD analysis, FT–IR and UV–Vis spectroscopic techniques. The inhibitory activities of the synthesized complexes (1–3) on α-glucosidase were determined by using genistein reference compound. Furthermore, the optimized geometry and vibrational harmonic frequencies for the complexes 1–3 were obtained by DFT/HSEh1PBE/6–311G(d,p)/LanL2DZ level. Electronic spectral properties were examined by using TD-DFT/HSEh1PBE/6–311G(d,p)/LanL2DZ level with CPCM model. Additionally, major contributions to the electronic transitions were determined via Swizard program. The refractive index, linear optical and non?nonlinear optical parameters of the complexes 1–3 were investigated at HSEh1PBE/6–311G(d,p) level. The docking studies of the complexes 1–3 to the binding site of the target protein (the template structure S. cerevisiae isomaltase are fulfilled. Lastly, natural bond orbital analysis was used to investigate inter- and intra-molecular bonding and interaction among bonds. 相似文献
994.
The FTIR and FT Raman spectra of p-alkylcalix[8]arenes (alkyl = tert-butyl, isononyl) were recorded. Analysis of IR spectra showed that the cyclic cooperative intramolecular hydrogen bond is realized in calix[8]arene. It was found that the strength of the cyclic cooperative intramolecular hydrogen bond in the series of alkyl derivatives of calix[8]arenes depends very little on the replacement of the p-tert-butyl groups by the more bulky isononyl group. From our data follows that the orientation of aromatic fragments in calixarene molecules depends on the type of alkyl substituent.An analysis of the changes in the IR spectra with heating and dissolution shows that the conformation of the “pleated-loop” is retained in p-tert-butylcalix[8]arene. It turned out that the intramolecular hydrogen bond is a “probe” of the conformation of calixarene molecules and IR spectroscopy is a unique method that allows one to follow the slightest nuances of changes in the H-bound system of these supermolecules. 相似文献
995.
IR Spectrum and Structure of Protonated Monosilanol: Dative Bonding between Water and the Silylium Ion
![]() M. Sc. Martin Andreas Robert George Dr. Nguyen Xuan Truong Dipl.‐Phys. Marco Savoca Prof. Dr. Otto Dopfer 《Angewandte Chemie (International ed. in English)》2018,57(11):2919-2923
We report the spectroscopic characterization of protonated monosilanol (SiH3OH2+) isolated in the gas phase, thus providing the first experimental determination of the structure and bonding of a member of the elusive silanol family. The SiH3OH2+ ion is generated in a silane/water plasma expansion, and its structure is derived from the IR photodissociation (IRPD) spectrum of its Ar cluster measured in a tandem mass spectrometer. The chemical bonding in SiH3OH2+ is analyzed by density functional theory (DFT) calculations, providing detailed insight into the nature of the dative H3Si+‐OH2 bond. Comparison with protonated methanol illustrates the differences in bonding between carbon and silicon, which are mainly related to their different electronegativity and the different energy of the vacant valence pz orbital of SiH3+ and CH3+. 相似文献
996.
PAN Wen-YuDepartment of Chemistry Fujian Medical College Fuzhou ChinaYU Xiu-FenDepartment of Chemistry Fuzhou University Fuzhou Fujian China 《中国化学》1994,(6)
The preparation and characterization of [CrnFe4-nO2(O2CMe)7(bipy)2]Cl (1, n=0; 2, n=2; 3, n=4, bipy=2,2'-bipyridine) are described. The three complexes (1, 2 and 3) are obtained by tipyridine-mediated conversion of trinuclear [CrnFe3-nO(O2CMe)6(H2O)3]+(1, n=0; 2, n=1;3, n=3), and crystallized as three of approximate isomorphs. Crystal 2 is monoclinic with space group C2/c, a=27.454(5)A, b=11.789(1)A, c=16.570(3)A, B=118.78(1), V=4700.8A, z=4, u(MoKa)=11.64cm-1, F(000)=2056, final R=0.058 and Rw=0.066 for 3479 reflections with I > 3o(I). The Fe and Cr atoms in the cation are all +3 oxide state and disordered in the lattice, which is also supported by its Mossbauer studies. The [Cr2Fe2O2]8+ core can be thought of as being derived from two edge-sharing M3O units (M=Fe or Cr), and as a butterfly-like structure. The cations' structure of all three crystals are similar to each other and have C2 symmetry. The species are characterized by IR spectra and magnetic techniques, with particular emphasis on different 相似文献
997.
Palladium-catalyzed carbonylation of methanol in presence of iodide promoters was investigated. Iodide bridged palladium dimeric complex, [PPh3CH3]2[Pd2I6] was isolated from the carbonylation reaction mixture and characterized using X-ray crystallography. Reaction mechanism was proposed based on IR and UV spectroscopic characterizations of catalytic species involved in the catalytic cycle. The isolated dimeric palladium species, [Pd2I6]2− underwent carbonylation to give monomeric species [PdI3CO]− at atmospheric pressure of carbon monoxide. It was also observed that PPh3 plays an important role to avoid catalyst deactivation at higher temperatures. Turnover frequency (TOF) of 1052 h−1 was achieved using Pd(OAc)2-HI-PPh3 catalyst system at 175 °C. 相似文献
998.
The electronic state of platinum supported on SO4/ZrO2, SO4/TiO2, SO4/Al2O3, and SO4/SiO2 systems and on systems unpromoted by sulfur was investigated by diffuse-reflectance IR spectroscopy using CO as the probe
molecule. The introduction of SO4
2− anions increases the electron deficit on platinum particles. This suppresses the formation of bridging CO complexes with
the metal, leads to the high-frequency shift of absorption maxima of CO adsorbed in the linear form, and stabilizes positively
charged metal species (Ptδ+ and Pt+) during the reduction process. The formation of the positively charged species includes the interaction between the acidic
protons and the metal particles yielding [Pt−H]δ+ adducts. The extent of the influence of the support on the electronic state of the metal increases in the series SO4/SiO2<SO4/Al2O3<SO4/TiO2<SO4/ZrO2 in parallel with an increase in the strength of the acid sites in the system.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1094–1099, June, 1998. 相似文献
999.
M. P. Pasechnik D. V. Tolkachev S. V. Matveev N. N. Bubnov E. I. Matrosov M. I. Kabachnik 《Russian Chemical Bulletin》1993,42(7):1140-1144
The complexation ofcis,cis-1,3,5-tri[2-(diphenylphosphinyl)ethylamino]cyclohexane (L1) with Cu2+ and Co2+ cations has been studied in different solvents by means of UV-Vis, ESR, and IR spectroscopy. It has been shown that in the CuL1 complex the metal ion is pentacoordinated by three nitrogen atoms and two phosphinyl groups of the ligand and has a tetragonal-pyramidal environment. The conformation of the coordination polyhedron for the CuL1 complex depends on the solvent. In the CoL1 complex, as well as in the CoL2 complex, where L2 is 1,4,7-tris(2-diphenylphosphinylethyl)-1,4,7-triazacyclononane, the Co2+ ion has an octahedral environment and is bound to all donor atoms of the ligands.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1199–1202, July, 1993.The authors are grateful to A. G. Matveeva and Yu. M. Polikarpov for the fruitful discussions. 相似文献
1000.
Márta?Palkó Elvira?Sándor Pál?Sohár Ferenc?Fül?pEmail author 《Monatshefte für Chemie / Chemical Monthly》2005,136(12):2051-2058
Summary. All-endo-3-amino-5-hydroxybicyclo[2.2.1]heptane-2-carboxylic acid and two epimers of 3-amino-6-hydroxybicyclo[2.2.1]heptane-2-carboxylic
acid were prepared via 1,3-oxazine or γ-lactone intermediates by the stereoselective functionalization of endo-3-aminobicyclo[2.2.1]hept-5-ene-2-carboxylic acid derivatives. Their structures were proved by IR and NMR spectroscopy, with
the use of HMQC, HMBC, DEPT, and DIFFNOE techniques. 相似文献
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