共查询到20条相似文献,搜索用时 31 毫秒
1.
Oliver Mechnich Gerhard Messier Horst Kessler Michael Bernd Bernhard Kutscher 《Helvetica chimica acta》1997,80(5):1338-1354
The conformational analysis of naturally occurring cytostatic cyclic heptapeptides axinastatin 2, 3, and 4 was carried out by two-dimensional NMR spectroscopy in combination with distance-geometry (DG) and molecular-dynamics (MD) calculations in explicit solvents. The synthesized secondary metabolites were examined in (D6)DMSO. Axinastatin 2 was also investigated in CD3OH. In all structures, Pro2 is in the i + 1 position of a βI turn and Pro6 occupies the i + 2 position of a βVIa turn about the cis amide bond between residue 5 and Pro6. In all peptides, a bifurcated H-bond occurs between residue 4 CO and the amide protons of residue 1 and 7. For axinastatin 2 and 3, an Asn Ig turn was found about Asn1 and Pro2. We compared these structures with conformations of cyclic heptapeptides obtained by X-ray and NMR studies. A β-bulge motif with two β turns and one bifurcated H-bond is found as the dominating backbone conformation of cyclic all-L-heptapeptides. Axinastatin 2, 3, and 4 can be characterized by six trans and one cis amide bond resulting in a β/βVI(a)-turn motif, a conformation found for many cyclic heptapeptides. Detailed biological tests of the synthetic compounds in different human cancer cell lines indicates these axinastatins to be inactive or of low activity. 相似文献
2.
V. N. Khrustalev N. N. Zemlyanskii I. V. Borisova Yu. A. Ustynyuk E. A. Chernyshev 《Russian Chemical Bulletin》2000,49(5):929-932
The structures of three silicon-containing organophosphorus betaines containing the+P−C−Si−S− fragment were established by X-ray diffraction study. Due to the attractive electrostatic interaction between the anionic and cationic centers, the main chain adopts agauche conformation, whereas this chain in theS-ethyl derivative of the phosphonic salt [Ph3P+−CMe2−SiMe2SEt]Br− adopts atrans conformation. The changes in the geometric parameters of betaines depending on the substituents at the phosphorus, carbon, and silicon atoms were analyzed. The P−S bond can in principle be formed, resulting in the closure of the four-membered ring provided that additional steric hindrances at the silicon atom occur. 相似文献
3.
V. G. Avakyan L. E. Gusel’nikov S. L. Gusel’nikov V. F. Sidorkin 《Russian Chemical Bulletin》2005,54(9):2013-2022
The effect of the nature of substituents at sp2-hybridized silicon atom in the R2Si=CH2 (R = SiH3, H, Me, OH, Cl, F) molecules on the structure and energy characteristics of complexes of these molecules with ammonia, trimethylamine,
and tetrahydrofuran was studied by the ab initio (MP4/6-311G(d)//MP2/6-31G(d)+ZPE) method. As the electronegativity, χ, of the substituent R increases, the coordination bond
energies, D(Si← N(O)), increase from 4.7 to 25.9 kcal mol−1 for the complexes of R2Si=CH2 with NH3, from 10.6 to 37.1 kcal mol−1 for the complexes with Me3N, and from 5.0 to 22.2 kcal mol−1 for the complexes with THF. The n-donor ability changes as follows: THF ≤ NH3 < Me3N. The calculated barrier to hindered internal rotation about the silicon—carbon double bond was used as a measure of the
Si=C π-bond energy. As χ increases, the rotational barriers decrease from 18.9 to 5.2 kcal mol−1 for the complexes with NH3 and from 16.9 to 5.7 kcal mol−1 for the complexes with Me3N. The lowering of rotational barriers occurs in parallel to the decrease in D
π(Si=C) we have established earlier for free silenes. On the average, the D
π(Si=C) energy decreases by ∼25 kcal mol−1 for NH3· R2Si=CH2 and Me3N·R2Si=CH2. The D(Si←N) values for the R2Si=CH2· 2Me3N complexes are 11.4 (R = H) and 24.3 kcal mol−1 (R = F). sp2-Hybridized silicon atom can form transannular coordination bonds in 1,1-bis[N-(dimethylamino)acetimidato]silene (6). The open form (I) of molecule 6 is 35.1 and 43.5 kcal mol−1 less stable than the cyclic (II, one transannular Si←N bond) and bicyclic (III, two transannular Si←N bonds) forms of this molecule, respectively. The D(Si←N) energy for structure III was estimated at 21.8 kcal mol−1.
Dedicated to Academician N. S. Zefirov on the occasion of his 70th birthday.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1952–1961, September, 2005. 相似文献
4.
Metallosurfactant complexes of the type trans- [Co(DH)2(HA)X], where DH = Dimethyl glyoxime, HA = Hexadecyl amine and X = Cl−, Br−, I−, N3
−, NO2
− or SCN−, were synthesized and characterized by physico-chemical and spectroscopic methods. In addition, the single crystal X-ray
structure of the ionic complex trans-[Co(DH)2(HA)2][Co(DH)2(I)2)] is presented. The critical micelle concentration values of the complexes in ethanol were obtained by measuring the absorption
at 290 nm. Specific conductivity data (at 303–313 K) served for the evaluation of the thermodynamics of micellization
) \left( {\Updelta G^{0}_{{{\text{m}}}}, \Updelta H^{0}_{{{\text{m}}}}, \Updelta S^{0}_{\text{m}} } \right) . Steady-state photolysis, cyclic voltammetry and biological activities of the complexes were studied. The compounds were
tested for antimicrobial activity. 相似文献
5.
Sheng Liu Miao Chen JinDu Li HaoBo Zhang JinQing Wang ShengRong Yang 《中国科学B辑(英文版)》2009,52(7):1009-1013
Hybridization of peptide nucleic acids probe containing azobenzene (NH2-TNT4, N-PNAs) with DNA was performed by covalently immobilizing of NH2-TNT4 in sequence on the 3-mercaptopropionic acid self-assembled monolayer modified gold electrode with the helps of N-(3-dimethylaminopropy1)-N′-ethylcarbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS), and the hybrid was coded as N-PNAs/DNA. Using [Fe(CN)6]4−/3− (1:1) as the electrochemical indicator, the electrochemical properties of the N-PNAs self-assembled monolayer (N-PNAs-SAMs) and N-PNAs/DNA hybridization system under the conditions of before and after UV light irradiation were characterized with cyclic
voltammetry (CV), differential pulse voltammetry (DPV), and electrochemical impedance spectra (EIS). Results showed that the
redox currents decreased with the increase of irradiation time, suggesting that the ability of the charge transfer on the
electrode surface was weakened and the conformation of hybrid system had been changed, and the control of PNAs/DNA hybridization
could be realized by UV light irradiation.
Supported by the National Natural Science Foundation of China (Grant No. 50572107) and “Top Hundred Talents Program” of Chinese
Academy of Science 相似文献
6.
Tae-Young Kim Stephen J. Valentine David E. Clemmer James P. Reilly 《Journal of the American Society for Mass Spectrometry》2010,21(8):1455-1465
Singly-protonated proline-containing peptides with N-terminal arginine are photodissociated with vacuum ultraviolet (VUV)
light in an ESI linear ion trap/orthogonal-TOF (LIT/o-TOF). When proline is the nth residue from the N-terminus, unusual b
n
+ 2 and a
n
+ 2 ions are observed. Their formation is explained by homolytic cleavage of the Cα− C bond in conjunction with a rearrangement of electrons and an amide hydrogen. The latter is facilitated by a proline-stabilized
gas-phase peptide conformation. 相似文献
7.
Felipe Gómez-de la Torre Yolanda Gutiérrez Félix A. Jalón Blanca R. Manzano Ana Rodríguez 《Monatshefte für Chemie / Chemical Monthly》2000,131(12):1267-1280
Summary. Partial removal of chloride anions from the dimer [Pd(η3-2-CH3*C3H4)(μ-Cl)]2 with AgTf(Tf = CF3SO3) followed by addition of dppm affords [Pd2(η3-Me*C3H4)2(μ-Cl)(μ-dppm)]Tf (1). The substitution of Cl− by X− (X = pz, SC6F5, S
py
) using the appropriate salts yields the new derivatives [Pd2(η3-Me*C3H4)2(μ-X)(μ-dppm)]Tf (2–4). All complexes exhibit a dinuclear half-A-frame structure with two isomers present in solution. The isomers differ in the
relative orientation of the two allyl groups (cis or trans). The isomer interconversion was studied by variable temperature 1H NMR spectroscopy. The molecular structures of 2 and 4 were solved by X-ray diffraction studies. A distorted boat conformation of the seven- or six-membered metallacycle was found
in both cases.
Received June 7, 2000. Accepted June 20, 2000 相似文献
8.
Felipe Gómez-de la Torre Yolanda Gutiérrez Félix A. Jalón Blanca R. Manzano Ana Rodríguez 《Monatshefte für Chemie / Chemical Monthly》2000,35(5):1267-1280
Partial removal of chloride anions from the dimer [Pd(η3-2-CH3*C3H4)(μ-Cl)]2 with AgTf(Tf = CF3SO3) followed by addition of dppm affords [Pd2(η3-Me*C3H4)2(μ-Cl)(μ-dppm)]Tf (1). The substitution of Cl− by X− (X = pz, SC6F5, S py ) using the appropriate salts yields the new derivatives [Pd2(η3-Me*C3H4)2(μ-X)(μ-dppm)]Tf (2–4). All complexes exhibit a dinuclear half-A-frame structure with two isomers present in solution. The isomers differ in the relative orientation of the two allyl groups (cis or trans). The isomer interconversion was studied by variable temperature 1H NMR spectroscopy. The molecular structures of 2 and 4 were solved by X-ray diffraction studies. A distorted boat conformation of the seven- or six-membered metallacycle was found in both cases. 相似文献
9.
Kiran Kumar Morishetti Betty De Suan Huang Jessica Marney Yates Jianhua Ren 《Journal of the American Society for Mass Spectrometry》2010,21(4):603-614
The sequence and conformational effects on the gas-phase acidities of peptides have been studied by using two pairs of isomeric
cysteine-polyglycine peptides, CysGly3,4NH2 and Gly3,4CysNH2. The extended Cooks kinetic method was employed to determine the gas-phase acidities using a triple quadrupole mass spectrometer
with an electrospray ionization source. The ion activation was achieved via collision-induced dissociation experiments. The
deprotonation enthalpies (Δacid
H) were determined to be 323.9 ± 2.5 kcal/mol (CysGly3NH2), 319.2 ± 2.3 kcal/mol (CysGly4NH2), 333.8 ± 2.1 kcal/mol (Gly3CysNH2), and 321.9 ± 2.8 kcal/mol (Gly4CysNH2), respectively. The corresponding deprotonation entropies (Δacid
S) of the peptides were estimated. The gas-phase acidities (Δacid
G) were derived to be 318.4 ± 2.5 kcal/mol (CysGly3NH2), 314.9 ± 2.3 kcal/mol (CysGly4NH2), 327.5 ± 2.1 kcal/mol (Gly3CysNH2), and 317.4 ± 2.8 kcal/mol (Gly4CysNH2), respectively. Conformations and energetic information of the neutral and anionic peptides were calculated through simulated
annealing (Tripos), geometry optimization (AM1), and single point energy calculations (B3LYP/6-31+G(d)), respectively. Both
neutral and deprotonated peptides adopt many possible conformations of similar energies. All neutral peptides are mainly random
coils. The two C-cysteine anionic peptides, Gly3,4(Cys-H)−NH2, are also random coils. The two N-cysteine anionic peptides, (Cys-H)−Gly3,4NH2, may exist in both random coils and stretched helices. The two N-cysteine peptides, CysGly3NH2 and CysGly4NH2, are significantly more acidic than the corresponding C-terminal cysteine ones, Gly3CysNH2 and Gly4CysNH2. The stronger acidities of the former may come from the greater stability of the thiolate anion resulting from the interaction
with the helix-macrodipole, in addition to the hydrogen bonding interactions. 相似文献
10.
Issa Yavari Hassan Kabiri-Fard Shahram Moradi 《Monatshefte für Chemie / Chemical Monthly》2002,133(11):1459-1468
Summary. Ab initio calculations at the HF/6-31G* level of theory for geometry optimization and the MP2/6-31G*//HF/6-31G* level for a single point total energy calculation are reported for (Z,Z)-, (E,Z)-, and (E,E)-cycloocta-1,4-dienes. The C
2-symmetric twist-boat conformation of (Z,Z)-cycloocta-1,4-diene was calculated to be by 3.6 kJ·mol−1 more stable than the C
S-symmetric boat-chair form; the calculated energy barrier for ring inversion of the twist-boat conformation via the C
S-symmetric boat-boat geometry is 19.1 kJ·mol−1. Interconversion between twist-boat and boat-chair conformations takes place via a half-chair (C
1) transition state which is 43.5 kJ·mol−1 above the twist-boat form. The unsymmetrical twist-boat-chair conformation of (E,Z)-cycloocta-1,4-diene was calculated to be by 18.7 kJ·mol−1 more stable than the unsymmetrical boat-chair form. The calculated energy barrier for the interconversion of twist-boat-chair
and boat-chair is 69.5 kJ·mol−1, whereas the barrier for swiveling of the trans-double bond through the bridge is 172.6 kJ·mol−1. The C
S symmetric crown conformation of the parallel family of (E,E)-cycloocta-1,4-diene was calculated to be by 16.5 kJ·mol−1 more stable than the C
S-symmetric boat-chair form. Interconversion of crown and boat-chair takes place via a chair (C
S) transition state which is 37.2 kJ·mol−1 above the crown conformation. The axial- symmetrical twist geometry of the crossed family of (E,E)-cycloocta-1,4-diene is 5.9 kJ·mol−1 less stable than the crown conformation.
Corresponding author. E-mail: isayavar@yahoo.com
Received March 25, 2002; accepted April 3, 2002 相似文献
11.
The rate of substitution of the chloride and aqua moieties from the platinum(II)-amine complexes, viz. [Pt(dien)Cl]Cl(Pt1-Chloro) and [Pt(en)(NH3)Cl]Cl (Pt2-Chloro) and their corresponding aqua analogues, viz. [Pt(dien)(OH2)] (ClO4)2 (Pt1-Aqua) and [Pt(en)(NH3)(OH2)](ClO4)2 (Pt2-Aqua), by a series of neutral and anionic nucleophiles,viz. thiourea (TU), 1,3-dimethyl-2-thiourea (DMTU), 1,1,3,3-tetramethyl-2-thiourea (TMTU), iodide (I−) and thiocyanate (SCN−), was determined under pseudo first-order conditions as a function of concentration and temperature using UV/Visible spectrophotometry
and standard stopped-flow techniques. The observed pseudo first-order rate constants for the substitution reactions obeyed
the simple rate law k
obs = k
2[Nucleophile]. Second-order kinetics and negative activation entropies, ca. −93 J K−1 mol−1 and −71 J K−1 mol−1, for the chloro and aqua complexes respectively, support an associative mode of activation. The rate of substitution of both
the chloro and aqua moieties are observed to decrease with an increase in the steric bulk of the neutral nucleophiles, whilst
rate of substitution by SCN− was observed to be faster than that of I−, in correlation with the observed nucleophilicities of the two nucleophiles. A comparison of the second-order rate constants,
k
2, at 298 K, obtained for the substitution reactions of Pt1and Pt2 shows that an increase in chelation in moving from Pt2 to
Pt1 results in a corresponding increase in the reactivity, by a factor of ca. 3, (28.31 ± 0.15 and 8.02 ± 0.13 m
−1 s−1 for Pt1 and Pt2 respectively, in the case of substitution of the aqua species by TU). Computational analysis of the chloro
complexes, viz. Pt1-Chloro, Pt2-Chloro and [Pt(NH3)3Cl]Cl (Pt3) support this conclusion by demonstrating that the Pt–N bond trans to the leaving group is shortened and that the Pt–Cl bond is lengthened when chelation is increased from Pt3 to Pt1. Consequently,
these results suggest that the increase in reactivity of Pt1 over Pt2, promoted by increased chelation, is as a result of
ground state destabilization. 相似文献
12.
Electronic structure, charge distributions and vibrational characteristics of CH3 O(CH2 CH2 O)
n
CH3 (n=3-7) have been derived using the ab initio Hartree Fock and density functional calculations. For tri- to hexaglymes the lowest
energy conformers have trans- conformation around the C-C and C-O bonds of the backbone. For heptaglyme (n=7 in the series), however, gauche-conformation around the C-C bonds renders more stability to the conformer and turns out to be 10.1 kJ
mol
−1 lower in energy relative to the conformer having trans-orientation around the C-C and C-O bonds. The molecular electrostatic potential topographical investigations reveal deeper
minima for the ether oxygen in conformers having the gauche conformation around the C-C bonds over those for the trans- conformers. A change from trans- to gauche-conformation around the C-C bonds of the lowest energy conformer of heptaglyme engenders a triplet of intense bands ∼1,150 cm
−1 in the vibrational spectra. Theoretical calculations predict that Li
+ binds strongly to the heptaglyme conformer in the above series. The frequency shifts in the vibrational spectra of CH3O(CH2CH2O)
n
CH3- Li+ (n=3-7) conformers have been discussed 相似文献
13.
Isolated radicals.NH2 and radical-molecule complexes.NH2−HF, which are products of the reactions of mobile fluorine atoms with NH3 molecules in solid argon, were identified by EPR spectroscopy. The isotropic HFC constants of the complex (a N=1.20,a H=2.40, anda F=0.70 mT) were determined experimentally. The constant of isotropic HFC with the nucleus of hydrogen atom of the HF molecule is less than 0.1 mT. This assignment was confirmed in the experiments on isotope substitution of atoms (H→D),14N→15N) in the NH3 molecule. According to quantum-chemical calculations, the free complex.NH2−HF has a planar structure withC 2, summetry and a binding energy of 12 kcal mol−1. Optimization of the arrangement of the complex in the crystal showed that its structure is only slightly distorted in the Ar lattice so that the equilibrium configuration is close to that obtained from gas-phase calculations. Different ratios of relative intensities of the proton triplet lines in the EPR spectra of isolated.NH2 radicals and.NH2−HF complexes were qualitatively explained by different heights of the barriers to rotation of the NH2 fragment in the Ar lattice. 相似文献
14.
E. A. Shusharina A. A. Rybinskaya P. E. Plyusnin Yu. V. Shubin S. V. Korenev S. A. Gromilov 《Journal of Structural Chemistry》2011,52(3):621-624
An XRD analysis is used to study the single crystal of [Pd(NH3)4][Rh(NH3)(NO2)5] double complex salt at T = 150(2) K. Crystallographic characteristics are as follows: a = 7.6458(5) ?, b = 9.8813(6) ?, c = 9.5788(7) ?, β = 109.469(2)°, V = 682.30(8) ?3, P21/m space group, Z = 2, d
x = 2.553 g/cm3. The geometry of the complex [Rh(NH3)(NO2)5]2− anion is described for the first time: Rh-N(NO2) distances are 2.020(4)–2.060(3) ?, Rh-N(NH3) 2.074(4) ?, N(NO2)-Rh-N(NH3) trans-angle is 178.8(2)°. 相似文献
15.
Tsung-Hsuan Tsai Tse-Wei Chen Shen-Ming Chen Ramiah Sarawathi 《Russian Journal of Electrochemistry》2012,48(3):291-301
The NiHCF-PEDOT, CuHCF-PEDOT and MnHCF-PEDOT films were prepared on glassy carbon electrode (GCE) by multiple scan cyclic
voltammetry and characterized using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and scanning electron
microscope (SEM) techniques. The advantages of these films are demonstrated for selectivity detection of ascorbic acid using
cyclic voltammetry and amperometric method. Interestingly, the NiHCF-PEDOT and CuHCF-PEDOT modified electrodes exhibited a
wide linear response range (5 × 10−6−3 × 10−4 M, R
2 = 0.9973 and 1.8 × 10−3−1.8 × 10−2 M, R
2 = 0.9924). The electrochemical sensors facilitated the oxidation of AA but not responded to other electroactive biomolecules
such as dopamine, uric acid, H2O2, glucose. The difference is MnHCF-PEDOT/GCE that no response to AA. In addition, the NiHCF-PEDOT and CuHCF-PEDOT modified
electrodes exhibited a distinct advantage of simple preparation, specificity, stability and reproducibility. 相似文献
16.
The kinetics of nucleophilic substitution of pyridine in bis-cationic [Pt(L)(py)]2+ complexes (L=SNS, NNN, NSN) [SNS=bis(methylthiomethyl)pyridine, NNN=bis(2-pyridylmethyl)amine, NSN=bis(2-pyridylmethyl)sulphide]
by a series of nucleophiles (Cl−, Br−, I−, N3−, (C2H5)2S, NH3, thiourea (tu), NO2−, C5H10NH, SeCN−, SCN−, CN− when L=SNS; Cl−, Br−, I−, N3−, (C2H5)2S, SCN−, NH3, NO2− when L=NNN; Br−, N3−, NO2−, NH3, C5H10NH when L=NSN) have been measured in MeOH at 25 °C, μ =0.1 mol dm−3 (LiClO4 or LiCF3SO3). The logarithms of the second-order rate constants calculated at μ=0, log k° 2, do not follow the dependence upon the n° Pt scale. In particular, the reactivity of the biphilic reagents tu, SeCN−, SCN− and, to a lesser extent, NO− 2, towards these doubly charged substrates is largely lower than expected on the basis of the n° Ptscale. There are good linear relationships between logk° 2 for the bis-cationic substrate [Pt(SNS)(py)]2+, chosen as the standard, and log k° 2 for the same reactions with [Pt(NNN)(py)]2+, [Pt(NSN)(py)]2+ and other double charged complexes previously studied. A new wide nucleophilicity scale based on [Pt(SNS)(py)]2+, that is appropriate to all the bis-cationic substrates, is here proposed 相似文献
17.
We report the modification of various electrode surfaces with electropolymerized Magnus' green salts, [Pt(NH3)4 · PtCl4]
n
and [Pt(NH3)4 · PtCl6]
n
. The modified electrodes were prepared by cyclic scanning of the electrode potential in an aqueous solution containing Pt(NH3)4
2+ and PtCl4
2− or PtCl6
2− and the supporting electrolyte. The conditions for the film deposition were studied in detail. Several surface analytical
techniques, including micro-Raman scattering and X-ray diffraction, were employed to characterize the modifier film. The electrochemical
behavior of the modified electrode was studied in detail and the modified electrodes display very good electrocatalytic activity
in the oxidation of ascorbic acid, hydrogen peroxide, thiosulfate, and especially nitric oxide.
Received: 22 April 1999 / Accepted: 30 June 1999 相似文献
18.
Absorption of ammonia on tantalum hydroxide synthesized by a hydrofluoric acid method 总被引:1,自引:0,他引:1
Ammonia is strongly absorbed on tantalum hydroxide prepared by ammonia neutralization of TaF7
2− or TaF6
− complexes. FTIR analysis of tantalum hydroxide shows a characteristic peak around 1,400 cm−1, attributed to NH4
+. TG and FTIR analyses show that the NH4
+ decomposes at about 500 °C. The correct chemical formula of tantalum hydroxide prepared by ammonia neutralization of TaF7
2− or TaF6
− is thus TaO
x
(OH)5-x
(NH4)
x
. This conclusion is also confirmed by TG and FTIR analysis of tantalum hydroxide treated with various concentrations of inorganic
acid at room temperature. The NH4
+ in tantalum hydroxide can be exchanged completely in aqueous HNO3 solution, and the weight loss of the resulting sample is ended at about 415 °C by TG analysis. The NH4
+ can also be exchanged completely with aqueous H2SO4 solution; however, SO4
2− is weakly absorbed on the tantalum hydroxide. Finally, the NH4
+ can be exchanged partially with aqueous H3PO4 solution; however, PO4
3− is strongly absorbed on the tantalum hydroxide. 相似文献
19.
Teresa Avilés António Dinis Michael G. B. Drew Vitor Félix 《Monatshefte für Chemie / Chemical Monthly》2000,131(12):1305-1310
Summary. The self-assembly of Ag[BF4] with trans-azobenzene in dichloromethane yields a new coordination polymer ([Ag(μ-trans-azobenzene)H2O][BF4])n which was characterized by X-ray single crystal diffraction. The crystal consists of 1-D zigzag cationic chains made up from
[Ag(H2O)]+ units linked by trans-azobenzene bridges and BF−
4 anions. Hydrogen bonding interactions between the chains and BF−
4 anions occur via intermolecular C*H⋯F and O*H⋯F contacts, and the crystal displays a 2-D supramolecular structure.
Received May 31, 2000. Accepted June 30, 2000 相似文献
20.
Teresa Avilés António Dinis Michael G. B. Drew Vitor Félix 《Monatshefte für Chemie / Chemical Monthly》2000,6(1):1305-1310
The self-assembly of Ag[BF4] with trans-azobenzene in dichloromethane yields a new coordination polymer ([Ag(μ-trans-azobenzene)H2O][BF4])n which was characterized by X-ray single crystal diffraction. The crystal consists of 1-D zigzag cationic chains made up from [Ag(H2O)]+ units linked by trans-azobenzene bridges and BF− 4 anions. Hydrogen bonding interactions between the chains and BF− 4 anions occur via intermolecular C*H⋯F and O*H⋯F contacts, and the crystal displays a 2-D supramolecular structure. 相似文献