共查询到20条相似文献,搜索用时 15 毫秒
1.
WEI Haiyan WANG Fan & CHEN Zhida State Key Laboratory of Rare Earth Materials Chemistry Applications College of Chemistry Molecular Engineering Peking University Beijing China 《中国科学B辑(英文版)》2005,48(5)
In the recent few years, transition metal complexeswith radical ligands have received much attentionaiming at a so-called metal-radical approach for novelmolecular magnet design[1]. One of the more popularfamilies is concerned in nitronyl nitroxide radica… 相似文献
2.
Mixed complexes of the type: Zn(Hsal)2(2-MeHim)2, Zn(Han)2(2-MeHim)2, Cd(Hsal)2(2-MeHim)2, Cd(Han)2(2-MeHim)2, where Hsal=OHC6H4COO−, Han=NH2C6H4COO−, 2-MeHim=2-methylimidazol) have been synthesized and characterized by IR spectroscopic and X-ray diffraction studies. Single-crystal
X-ray structure of Cd(Hsal)2(2-MeHim)2 has been obtained. Thermal behaviour of the compounds was investigated by thermal analysis (TG, DTG, DTA). A coupled TG-MS
system was used to analyse the principal volatile products of complexes. Thermal decomposition pathways have been postulated. 相似文献
3.
H. N. Al’tshuler E. V. Ostapova L. A. Sapozhnikova O. H. Al’tshuler 《Journal of Thermal Analysis and Calorimetry》2008,92(3):665-669
The thermodynamic characteristics of proton exchange in SO3H groups of a sulfonated network polymer based on cis-tetraphenylmetacyclophanoctol for Na+, Cu2+ cations from aqueous solutions were considered for the first time. Microcalorimetric measurements of the heat effects of
Na+-H+ and Cu2+-H+ exchanges were performed, equilibrium compositions of polymer and solution were determined. The changes of Gibbs energy,
enthalpy and entropy of ion exchange were calculated. 相似文献
4.
Summary. Condensation of (2-iodophenyl)ethylamines with cyclohexanoylacetaldehyde provided the corresponding aldimines which were reduced yielding secondary phenethylcyclohexanoylethylamines. These in turn were appropriate intermediates to prepare several erythrinanes by a sequential intramolecular Strecker and intramolecular Bruylants reaction. In contrast, the C-ring homologue schelhammeranes were not available on this route.Part of PhD thesis, LMU München, D 相似文献
5.
Nahid Shahabadi Soheila Kashanian Kani Shalmashi Hamideh Roshanfekr 《Applied biochemistry and biotechnology》2009,159(1):1-10
The [PtCl2(LL)] complex, as a cisplatin derivative, which LL is diamine chelate ligand (N,N-dimethyltrimethylendiamine), was synthesized and characterized by elemental analysis (CHN) mass, 1H, and 13C nuclear magnetic resonance techniques. Then the binding of this complex to calf thymus DNA was investigated by various physicochemical
methods such as spectrophotometric, circular dichroism, spectrofluorometric, melting temperature, and viscosimetric techniques.
Upon addition of the complex, important changes were observed in the characteristic UV–Vis bands (hypochromism) of calf thymus
DNA, increase in melting temperature and some changes in specific viscosity. Also, the fluorescence spectral characteristics
showed an increase in the fluorescence intensity of methylene blue–DNA solutions in the presence of increasing amounts of
metal complex, indicating PtCl2(LL) is able to displace the methylene blue bound to DNA but not as complete as intercalative molecules. The experimental
results showed that the platinum complex is bound to DNA non-intercalatively, and an outside binding is the preferred mode
of interaction. 相似文献
6.
G. I. Zharkova S. V. Sysoev I. A. Baidina P. A. Stabnikov I. K. Igumenov 《Journal of Structural Chemistry》2005,46(3):494-500
The temperature dependence of the saturated vapor pressure of the trans-Pt(ktf)2 complex obtained from fluorinated β-ketoimine (CF3-CO-CH2-C(NH)-CH3) was studied by the flow method. The standard thermodynamic parameters ΔH 0 T and ΔS 0 T of sublimation have been determined. Full crystal-chemical study has been performed for the complex. Crystal data for C10H10F6N2O2Pt: a = 5.9790(8) Å, b = 7.373(2) Å, c = 8.5767(2) Å,α = 84.05(2)°, β = 72.43(1)°, γ = 67.14(1)°, V = 332.1(1) Å3, Z = 1, dcalc = 2.496 g/cm3, triclinic, space group \(P\bar 1\). The structure is molecular and consists of isolated trans-Pt(ktf)2 complexes. The Pt atom lies at the symmetry center and has a square planar environment of two oxygen and two nitrogen atoms; the distances Pt-O (1.984 Å) and Pt-N (1.969 Å) are similar within the limits of 2σ; the OPtN bond angle is 93.9°. Molecular packing in crystal is considered based on structural data; van der Waals energy of the crystal lattice of trans-Pt(ktf)2 was calculated by the atom-atom potential method. 相似文献
7.
A. B. Burdukov N. V. Pervukhina M. A. Vershinin Ya. Z. Voloshin 《Journal of Structural Chemistry》2007,48(2):358-361
The structure of 1,8-bis(fluoroboro)-2,7,9,14,15,20-hexaoxa-3,6,10,13,16,19-hexaaza-4,5,11,12-tetraphenyl-17,18-bisc(tert-butylamino)-bicyclo[6.6.6]eicosa-3,5,10,12,16,18-hexaene(2−)iron(2+) tris-dioximate clathrochelate was determined by X-ray diffraction (XRD) analysis. The compound has a molecular structure and crystallizes
as triclinic crystals: a = 10.7673(2) Å, b = 11.9520(4) Å, c = 22.5473(7) Å, α = 75.729(1)°, β = 89.161(1)°, γ = 65.334(1)°, V = 2542.64(13) Å3, Z = 2, space group 1. P1ˉ.
Original Russian Text Copyright ? 2007 by A. B. Burdukov, N. V. Pervukhina, M. A. Vershinin, and Ya. Z. Voloshin
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Translated from Zhurnal Strukturnoi Khimii, Vol. 48, No. 2, pp. 366–369, March–April, 2007. 相似文献
8.
Chiral nonracemic 3-substituted cis- and trans-4-aminopiperidines, which are precursors of anilidopiperidine analgesics, were obtained by diastereoselective synthesis from 1-methyl- and 1-benzyl-4-[(S)-1-phenylethyl]iminopiperidines, using the following reaction sequence: metalation with lithium diethylamide, alkylation with alkyl halides, and hydride reduction or hydrogenation over Raney nickel. The steric direction of the reaction, three-dimensional structure, preferred conformation, and absolute configuration of the resultant aminopiperidines were determined. 相似文献
9.
M. A. Kuznetsov A. V. Ushkov S. I. Selivanov A. S. Pan’kova A. Linden 《Russian Journal of Organic Chemistry》2009,45(8):1200-1207
Thermolysis of dimethyl esters of stereoisomeric phthalimidoaziridine-2,3-dicarboxylic acids in the presence of dimethyl fumarate,
dimethyl maleate, and N-phenylmaleimide occurred stereo-specifically and stereoselectively led to the formation of derivatives of 1-phthalimidopyrrolidine,
products of 1,3-dipolar additrion of intermediately arising azomethine ylides. In keeping with the rules of the conservation
of orbital symmetry the thermal opening of the 2,3-disubstituted 1-phthalimidoaziridines into azomethine ylides occurred conrotatory.
The relative positions of the substituents in the dipolarophiles is retained in the reaction products indicating the concerted
addition mechanism. 相似文献
10.
V. E. Bryndin A. I. Smolentsev P. A. Stabnikov I. K. Igumenov 《Journal of Structural Chemistry》2008,49(3):556-559
trans-Bis-(4-phenyliminopentan-2-onato)Cu(II) (5), which is a phenyl-substituted ketoimine, was synthesized, and an X-ray study was performed for this compound. Crystal data for CuN2O2C22H24: a = 11.4557(3) Å, b = 26.6845(9) Å, c = 14.2976(5) Å, β = 113.2270(10)°; space group P21/n, Z = 8, d calc = 1.363 g/cm3, R = 0.033. The structure is molecular and built of isolated trans complexes. The central copper atom is surrounded by four atoms (2O+2N) with the average distances Cu-O 1.904(3) Å and Cu-N 1.962(3) Å. The polyhedron around the copper atom is a distorted tetrahedron; the average values of the O-Cu-O and N-Cu-N trans bond angles are 147(2)° and 150(2)°, respectively. The average value of the O-Cu-N angles is 94(1)°. 相似文献
11.
U. S. Makhmudov Sh. B. Rakhimov B. Tashkhodzhaev M. G. Levkovich V. I. Vinogradova 《Chemistry of Natural Compounds》2008,44(2):208-212
The molecular structures of N-(o-and p-hydroxybenzyl)cytisine were investigated by NMR spectroscopy, x-ray structure analysis, and molecular modeling. It was found
that NMR resonances of the OH and aromatic protons in N-(o-hydroxybenzyl)cytisine were doubled because of the presence of two conformers in solution.
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Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 165–168, March–April, 2008. 相似文献
12.
Summary. Complexes of Co(II), Ni(II), Cu(II), and Mn(II) containing Schiff base NOS donor ligands have been synthesised via chemical and electrochemical techniques. The structure of the complexes has been elucidated by elemental analysis, conductance, magnetic susceptibility measurements, IR, ESR, electronic spectral studies and thermal techniques (TGA and DTA). The electrochemical behaviour of the metal complexes was studied using DC polarography and cyclic voltammetry. Antimicrobial activity of the title Schiff base and its complexes has been tested against different microorganisms. 相似文献
13.
Aytaç Gürhan Gökçe Hayati Türkmen Muhittin Aygün Bekir Çetinkaya Orhan Büyükgüngör 《Structural chemistry》2008,19(1):57-62
Trans-Bis[1,3-bis(2,4-dimethylphenylimidazolidin-2-ylidene)]dichloropalladium(II), 4, was prepared from 1,3-bis(2,4-dimetilphenyl)imidazoliniumchloride. The crystal and molecular structure of 4 have been determined by single crystal X-ray diffraction. The title compound, C38H44N4PdCl2, crystalizes in the monoclinic space group P 21/n with a = 13.8713(9) Å, b = 12.1365(6) Å, c = 21.5499(15) Å. The Pd atom has a slightly distorted square planar coordination geometry. The molecules of the title compound are linked by C–H···Cl weak hydrogen bonds into two-dimensional sheets parallel to the (001) plane. In addition, the title compound was characterized by elemental analyses and NMR spectroscopy. 相似文献
14.
The trans(O)-cis(C)-bis(pyridine-2-carboxylato)dicyanocobaltate(III) ions, [Co(Pic)2(CN)2]?, crystallize from acid medium with three water molecules per two crystallographically nonequivalent complexes whose charge is compensated by protons. One of the water molecules forms an oxonium ion (H3O+) with a proton. The other two water molecules bound to each other through a short hydrogen bond O-H…O (2.403(2) Å) and thus forming (H5O2)+ cations is another proton site. The (H3O)(H5O2)[Co(Pic)2(CN)2]2 crystals are monoclinic: a = 10.7027(7) Å, b = 25.786(1) Å, c = 11.4865(8) Å, β = 91.411(9)°, Z = 4, space group P21/n. 相似文献
15.
Parnajyoti Karmakar Subhasis Mallick Biplab K. Bera Arup Mandal Subala Mondal Sudip K. Mukhopadhyay Alak K. Ghosh 《Transition Metal Chemistry》2010,35(8):911-916
The kinetics of the interaction of glycine-l-leucine (Glyleu) with cis-[Pt(cis-dach)(OH2)2]2+ (dach = 1,2-diaminocyclohexane) has been studied spectrophotometrically as a function of [cis-[Pt(cis-dach)(OH2)2]2+], [Glyleu] and temperature at pH 4.0, where the complex exists predominantly as the diaqua species and Glyleu as a zwitterion.
The substitution reaction shows two consecutive steps: the first is the ligand-assisted anation and the second is the chelation
step. The activation parameters for both the steps were evaluated using Eyring’s equation. The low ∆H1≠ (51.9 ± 2.8 kJmol−1) and large negative value of ∆S1≠ (−152 ± 8 JK−1mol−1) as well as ∆H2≠ (54.4 ± 1.7 kJmol−1) and ∆S2≠ (−162 ± 5 JK−1mol−1) indicate an associative mode of activation for both the aqua ligand substitution processes. 相似文献
16.
M. E. Matthews I. Atkinson Lubaina Presswala O. Najjar Nadine Gerhardstein R. Wei Elizabeth Rye A. T. Riga 《Journal of Thermal Analysis and Calorimetry》2008,93(1):281-287
Dielectric analysis (DEA), supported by thermogravimetric analysis (TG), differential scanning calorimetry (DSC), powder X-ray
diffraction analysis (PXRD) and photomicrography, reveal the chiral difference in the amino acids. The acids are classified
as dielectric materials based on their structure, relating chirality to the vector sum of the average dipole moment, composed
of the constant optical (electronic) and infra-red (atomic) polarizabilities, as well as dipole orientation. This study encompasses
14 L-and D-amino acid isomers. Physical properties recorded include AC electrical conductivity, charge transfer complexes, melting,
recrystallization, amorphous and crystalline phases, and relaxation spectra, activation energies and polarization times for
the electrical charging process. 相似文献
17.
I. I. Zakharov V. F. Anufrienko O. I. Zakharova S. A. Yashnik Z. R. Ismaguilov 《Journal of Structural Chemistry》2005,46(2):213-219
A comparative quantum chemical analysis has been made for the most stable dimer of nitrogen oxide with the structure cis-ONNO in a singlet state 1A1 by ab initio method of SCF MO LCAO, allowing for electron correlation according to Meller-Plesset perturbation theory of the second order (MP2), and density functional technique (DFT). The computations by MP2 method show anion-radical (ONNO)? to have a strong bond between nitrogen atoms (N-N 1.44 Å) in contrast to molecular weakly bound cis-dimer with equilibrium distance N-N 2.23 Å. Molecular orbital structure of the dimer and its anions was examined that made it possible to suggest a reason of preferable stabilization of nitrogen oxide dimer in the cis-form. Calculated high affinity to electron (Ea = ?1.55-?1.69 eV) for the molecular dimer ONNO (1A1) explains an intense strengthening of N-N bond in anion-radical and confirms the experimental data on a possibility of surface anion-π-radical formation on electron donor centers. The DFT computations indicate that this technique poorly reproduces the experimental geometry and electron structure of the cis-dimer ONNO having predicted a triplet ground state with the equilibrium distance N-N ≈2 Å instead of a singlet one with N-N 2.26 Å. The comparison between MP2 and DFT calculations for complex dimer ONNO with copper cation reveals the energy state of the complex (Cu-O2N2)+ corresponding to stabilization of anion-π-radical (N2O2)? {term-3A2, Cu(d)9-(ONNO)?1} to be highly overestimated by DFT. 相似文献
18.
K. É. Miminoshvili A. N. Sobolev É. B. Miminoshvili L. A. Beridze É. R. Kutelia 《Journal of Structural Chemistry》2005,46(3):560-565
X-ray structural analysis has been performed for two complex compounds: Cu(en)2(o-HB)2H2O (I) (a = 16.873(4) Å, b = 8.713(2) Å, c = 14.803(3) Å, β = 91.15(2)°, V = 2175.8(8) Å3, C2/c, Z = 4, R(F) = 0.0263, 1516 reflections with I > 3σ (I)) and [Cu(en)2(OH2)2]2+(o-AB?)2 (II) (a = 7.488(5) Å, b = 22.122(8) Å, c = 7.856(5) Å, β = 118.77(2)°, V = 1140.7(11) Å3, P21/n, Z = 2, R(F) = 0.0432, 1684 reflections with I > 3σ(I)) synthesized under identical conditions (en is ethylenediamine, o-HB is o-hydroxybenzoate, and o-AB is o-aminobenzoate). Although the compounds were assumed to have similar structures and the Cu-Lig bond lengths and the cis and trans angles are acceptable for an octahedral structure, the geometric parameters of o-HB suggest that the copper atom has a plane square environment. 相似文献
19.
D. A. Köse G. Gökçe S. Gökçe İ. Uzun 《Journal of Thermal Analysis and Calorimetry》2009,95(1):247-251
Three novel mixed ligand complexes of Ni(II), Zn(II) and Cd(II) with p-chlorobenzote and N,N-diethylnicotinamide were synthesised and characterized on the basis of elemental analysis, FTIR spectroscopic
analysis, solid state UV-Vis spectrometric and magnetic susceptibility data. The thermal behavior of the complexes was studied
by simultaneous TG-DTA methods in static air atmosphere and the mass spectra data were recorded.
According to microanalytical results, formulas of complexes are C34H40N4O8ClNi, C34H40N4O8ClZn and C34H44N4O10ClCd. The complexes contain two moles of coordination waters, two moles p-chlorobenzoate and two mole N,N-diethylnicotinamide (dena) ligands per formula unit. In these complexes, the p-chlorobenzoate and N,N-diethylnicotinamide behave as monodentate ligand through acidic oxygen and nitrogen of pyridine ring.
The decomposition pathways and the stability of the complexes are interpreted in the terms of the structural data. The final
decomposition products were found to be as metal oxides. 相似文献
20.
A. N. Kalenchuk S. E. Bogorodskii V. I. Bogdan 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2016,90(10):1921-1924
Comparative studies on the temperature dependence of the dehydrogenation of cis- and trans-isomers of perhydro-m-terphenyl are performed in a flow catalytic reactor. Rate constants and equilibrium constants of all elementary acts of this reaction are calculated on basis of experimental data using the KINET 0.8 program for the mathematical modeling of the kinetics of complex reactions. The resulting data indicate that perhydro-m-terphenyl cis- and trans-isomers structural differences have no appreciable effect on dehydrogenation. 相似文献