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1.
Following the newly-discovered UV absorption spectrum of Br2Si, its reactions with oxygen and nitric oxide in the gas phase have been quantitatively investigated using the flash photolysis-kinetic
absorption spectroscopy technique. The room temperature bimolecular rate constants are:
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2.
The geometries and bonding characteristics of the complexes of the first-row transition-metal ions with CH, CH2 and CH3 were investigated byab initio molecular orbital theory. MCH+ and MCH2
+ are linear and coplanar, respectively. Both of them are with obvious treble or double bond characteristics, but these multiple
bonds are mostly “imperfect”. The calculated bond dissociation energies of
, and
are mostly close to the experimental values, and appear in similar periodic trends from Sc to Zn.
Project supported by the National Natural Science Foundation of China (Grant No. 29170070). 相似文献
3.
S. V. Osintseva E. A. Petrovskaya L. V. Rybin A. Z. Kreindlin F. M. Dolgushin A. I. Yanovsky P. V. Petrovskii M. I. Rybinskaya 《Russian Chemical Bulletin》2000,49(9):1605-1612
The reaction of Ru3(CO)12 with 1,3-diferrocenylprop-2-en-1-one,trans-FcCH=CHCOFc (where Fc is ferrocenyl), in boiling hexane afforded the complex
(2c), which was converted into
(3c) upon further heating. These complexes gave the complex
(4) containing two Cl-bridged oxaruthenacycles upon dissolution in CHCl3 or CH2Cl2. The structures of complexes 3 and 4 were established by X-ray diffraction analysis. According to the data of1H NMR spectroscopy, the Cl-bridged complex exists in solutions as a mixture of isomers along with the monomeric form resulting
from the cleavage of the halide bridges. All interconversions of the isomers occur with the participation of the monomeric
form.
Published inIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1616–1623, September, 2000. 相似文献
4.
Zhengbin Zhang Liansheng Liu Hongbin Zhao Youjun Fu Fengyun Cheng Weihong Zhao 《中国科学B辑(英文版)》1997,40(4):353-364
A new method for the study of ternary surface complexes at liquid-solid interface, theE(%) -pH curve method, was proposed. Four types ofE(%)-pH curves, namely, phenomenon of left-right shifts of S-shaped curve, V-shaped curve, monodirection shift curve and X-shaped
curve, were discovered. Correspondingly, apart from type (I) ternary surface complex
and type (II) ternary surface complex
, a new type of ternary surface complex
was discovered.
Project supported by the National Natural Science Foundation of China and the Fund of Doctoral Degree’s Spot. 相似文献
5.
Quantum yields of the stable products, CO, CO2 and H2, formed in the excimer laser photolysis of formcc acid vapor at 222 nm and 296 K, have been determined. The results, taken together with the primary quantum yield of OH and the mechanssm of the subsequent reaction of OH with formic acid, studied earlier in our laboratory, are consistent with the photolytic channels, . Although calculated and measured yields from the photolysis of a range of pressures of formcc acid are in good agreemen,, the mechanism is not unique, and molecular photodecomposition paths may occur for the monomer to some extent. 相似文献
6.
I. V. Borisova N. N. Zemlyanskii A. K. Shestakova V. N. Khrustalev Yu. A. Ustynyuk E. A. Chernyshev 《Russian Chemical Bulletin》2000,49(5):933-941
The [Ph3P+−CMe2−SiMe2−SEt]Br− salt was prepared by the reaction of betaine Ph3P+−CMe2SiMeR−S− (1a: R=Me) with EtBr. Acetylation of betaine1a or Et3P+−CHMeSiMe2−S− (2a) afforded 2,2,6-trimethyl-1,3-dioxa-2-silacyclohex-5-ene-4-thione 相似文献
7.
The weak (φf < 103) fluorescence at around 430 nm of the S2 upper excited singlet state of metal-free phthalocyanine and metallophthalocyanines is presented. Polarization measurements indicate that the emission is short-lived (< 800 ps) contrary to the intense (φf > 0.3) normal emission at around 700 nm originating from S1 and having a lifetime in the 4.1 to 10.6 ns range, depending on the solvent. The short wavelength emitting S2 excited state has been populated by a two photon absorption process using the excitation light at 695 nm of a pulsed ruby laser. This process is shown not to involve the triplet state but the following stepwise two photon absorption process: . 相似文献
8.
T. K. Gar O. A. Dombrova D. A. Ivashchenko V. F. Mironov 《Russian Chemical Bulletin》1993,42(10):1717-1723
The formation of trichlorogermyl-substituted amides, lactams, and imides occurs when 2Et2O·HGeCl3 is condensed with compounds possessing the -NCH2Cl fragment and equally well when HGeCl3 interacts with compounds containing -NCH2OH and-NCH2OSiMe3 groups. In some cases, the use of the latter is more advantageous from the preparative point of view. In compounds thus obtained,
the germanium is five-coordinate due to the coordination
.
Deceased August 13, 1993.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1793–1799, October, 1993. 相似文献
9.
Infrared spectra and normal vibrations of ions of the type
and
, with X and Y as S, O and N have been compared and discussed. 相似文献
10.
A synthetic method for a new unsymmetrical Schiff base and its Ln (III) complexes including multi
groups is reported. The complexes are characterized by elemental analysis, IR spectra, 1H and13C NMR, especially 2D-COSY 1H, 1H NMR spectra. The general formula of the obtained complexes is [Ln3(TBLY)(NO3)3]\sdnH2O (Ln = La, n = 3; Ln = Nd, n=5; Ln = Gd, Dy, Yb, Y, n = 7), where TBLY = tetraglycol aldehyde-2,4-dihydroxy benzaldehyde bis-lysine Schiff base. In addition, the evidence for existence
of
group is supported by the AM1 method. The complexes obtained may be used as a catalyst. Conversion rate of 80% with the viscosity-average
molecular weight 220000 for the polymerization of methyl methacrylate (MMA) without addition of any cocatalyst has been obtained. 相似文献
11.
Solutions of benzidine and diphenylamine in benzene produce cation radicals on the surface of zeolite, -alumina and V2O5 doped alumina and zeolite. The sequence of the electron acceptor site strength on the surface is as follows: 相似文献
12.
Résumé Les auteurs ont étudié le comportement chromatographique sur plusieurs phases stationnaires polaires et non polaires de composés cyclopropaniques stéréoisomêres: où R=H ou CH3 et X=CH, COOCH3 ou CH2OH. Les résultats sont interprétés en fonction de la configuration de X par rapport à , de la nature électronique de X et de l'orientation du phényle par rapport au plan du cyclopropane.
Relationship between chemical structure and retention. VII. Cyclopropane compounds
Summary The chromatographic behaviour, on several polar and non polar phases, of stereoisomeric cyclopropanes has been studied R=H or CH3 and X=CN, COOCH3, CH2OH. The results are interpreted in terms of the X versus configuration, the electronic nature of X and the orientation of the phenyl ring in relation to plane of the cyclopropane ring.相似文献
13.
The triplet excited state properties and photosensitization mechanisms of indigo were investigated based on density functional
theory calculations. The solvent effects on the photosensitization mechanisms of indigo have also been considered. The thermodynamic
feasibility of the possible 1O2 and O2·−-photogeneration pathways by triplet excited state indigo in different solvents was explored, in order to gain some deeper
insights into the photosensitization characters of the dye.
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14.
New hybrid organic-inorganic alumina gels have been prepared by reacting aluminum sec-butoxide and propane-1,2-diol, in CCl4 as solvent. This reaction occurred without water addition and without the use of any catalyst, leading to the formation of
transparent and monolithic gels. IR,27Al and13CNMR show that an interchange reaction between OBu
s
alkoxide groups and
diol groups occurred, leading to the hybrid gels.
Samples heat treated at different temperatures under argon are weakly porous and have a small specific surface area. XRD indicates
the presence of pure α-alumina at 1450°C. 相似文献
15.
Isabel Castro Juan Faus Miguel Julve Michèle Philoche-Levisalles 《Transition Metal Chemistry》1992,17(3):263-269
Two complexes of formula [Cu(terpy)(H2O)](CF3SO3)2 (1) and [Cu(terpy)(OH)]BPh4 (2) (terpy=2,2′∶6′,2″-terpyridine and BPh4=tetraphenylborate anion) have been synthesized and characterized by spectroscopic techniques. The x-ray crystal structure
of (1) has been determined by x-ray diffraction. The structure is made up of [Cu(terpy)(H2O)]2+ mononuclear cations plus semi-coordinated CF3SO3
− anions. The coordination geometry around the copper atom is approximately elongated tetragonal octahedral. The oxygen atom
of water and the three nitrogen atoms of terpy occupy the equatorial sites whereas the apical ones are filled by trifluoromethanesulphonate
oxygen atoms. The formation of hydroxo complexes of [Cu(terpy)(H2O)]2+ has been investigated by potentiometry in aqueous solutions and the constants of the Equilibria (1) and (2)
相似文献
16.
A. A. Kamyshova A. Z. Kreindlin M. I. Rybinskaya P. V. Petrovskii 《Russian Chemical Bulletin》1999,48(3):581-585
Decamethylmetallocenes Cp*
2M (M=Ru, Os) in the presence, of acids (CF3CO2H, CF3SO3H) give thepprotonation products [Cp*
2MH]+An−. Broad-band UV photolysis of their solutions results in the formation of the salts of onium cations
. A preparative procedure for the synthesis of these salts has been developed. Hydrolysis of the salts gives the carbinol
Cp*MC5Me4CH2OH.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 587–591. March, 1999. 相似文献
17.
Ghasem Rezanejade Bardajee Farnaz Jafarpour Hamid Samareh Afsari 《Central European Journal of Chemistry》2010,8(2):370-374
In this report, a rapid, efficient and environmental friendly synthesis of 3-carboxycoumarins under ultrasound irradiation
in water media is described. The Knoevenagel condensation of Meldrum’s acid with substituted benzaldehydes in the presence
of zirconium oxide chloride (ZrOCl2·8H2O) and ultrasonic irradiation in water gave the corresponding 3-carboxycoumarins in good to excellent yields.
相似文献
18.
S. V. Burov O. A. Kaurov V. F. Martynov M. P. Smirnova 《Chemistry of Natural Compounds》1980,16(5):518-524
In order to study the influence of substituents of the aromatic ring of D-phenyl-alanine on the inhibiting capacity of luliberian
analogs, we have synthesized two new analogs:
and
luliberin. The synthesis was performed by the fragmentary condensation method using 2+(3+5) and 2+(5+3) schemes. A new and
convenient method of obtaining the amide of the C-terminal tetrapeptide of the luliberin sequence has been developed. In the
condensation of the fragments, both the azide and the carbodimide method of synthesis with the addition of l-hydroxybenzotriazole
were used. The guanidino group of arginine was protected by nitration, while the hydroxy groups of serine and of tyrosine
were not protected. The complete elimination of the protective groups from the decapeptides was performed by catalytic hydrogenation
over Pd on carbon and by anhydrous HF with the addition of anisole at 0°C. The protected octa- and decapeptides were purified
by gel filtration on Sephadex LH-20 in ethanol or by preparative thin-layer chromatography on silica gel plates. The final
peptides were purified by ion-ex-exchange chromatography on Sephadex CM-25.
A. A. Zhdanov Leningrad State University. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 706–714, September–October,
1980. 相似文献
19.
Lachezar Radev Vladimir Hristov Irena Michailova Bisserka Samuneva 《Central European Journal of Chemistry》2009,7(3):317-321
In this work we present experimental results about synthesis, structure evolution and in vitro bioactivity of new calcium phosphate silicate/wollastonite (CPS/W) glass-ceramics. The samples obtained were synthesized
via polystep sol-gel process with different Ca/P+Si molar ratio (R). The structure of the materials obtained was studied by
XRD, FTIR spectroscopy and SEM. XRD showed the presence of Ca15(PO4)2(SiO4)6, β-CaSiO3 and α-CaSiO3 for the sample with R=1.89 after thermal treatment at 1200°C/2h. The XRD results are in good agreement with FTIR analysis.
SEM denotes that apatite formation can be observed after soaking in simulated body fluid (SBF).
相似文献
20.
Meysam Soleymani Ahmad Moheb Ezatolah Joudaki 《Central European Journal of Chemistry》2009,7(4):809-817
Single phase nanocrystalline La0.6Ca0.4MnO3 powder was synthesized by both the usual and a modified citrate gel precursor method, and the effects on the formation of
homogeneous nano-sized powder with a perovskite structure were investigated. In the modified method, single phase La0.6Ca0.4MnO3 powder with an average particle size of 17.2 nm was obtained when the powder was pyrolyzed at 520°C for 2 h. Its specific
surface area was 40.7 m2 g−1, about 4-fold larger than that of powder made by the usual citrate gel method.
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