共查询到20条相似文献,搜索用时 437 毫秒
1.
G. V. Loukova O. N. Babkina T. A. Bazhenova N. M. Bravaya V. V. Strelets 《Russian Chemical Bulletin》1990,49(1):60-63
The reduction in THF and oxidation in CH2Cl2 of the bent-sandwich complex (η5-lnd)2ZrMe2 (1) (Ind=C9H7, indenyl) were studied by cyclic voltammetry. Complex1 in THF undergoes one-electron reduction to radical anion1
−, which partially decomposes with the liberation of the Ind− anion. Even at −45°C the one-electron oxidation leads to the formation of an unstable 15-electron radical cation undergoing
fast heterolytic decomposition to the Me• radical and (η5-lnd)2ZrMe2 cation, which is the key reaction center in the catalytic polymerization of olefins. Comparative analysis of electron-transfer-induced
transformations of bent-sandwich dimethyl and dichloride zirconocenes of the general formula L2ZrX2 (L=η5-lnd, η5-Cp: X=Xl, Me) was performed.
The material of the paper was first reported at the 195th Meeting of the Electrochemical Society (see Ref. 1).
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 59–62, January, 2000. 相似文献
2.
G. V. Loukova O. N. Babkina T. A. Bazhenova N. M. Bravaya V. V. Strelets 《Russian Chemical Bulletin》2000,49(1):60-63
The reduction in THF and oxidation in CH2Cl2 of the bent-sandwich complex (η5-lnd)2ZrMe2 (1) (Ind=C9H7, indenyl) were studied by cyclic voltammetry. Complex1 in THF undergoes one-electron reduction to radical anion1
−, which partially decomposes with the liberation of the Ind− anion. Even at −45°C the one-electron oxidation leads to the formation of an unstable 15-electron radical cation undergoing
fast heterolytic decomposition to the Me• radical and (η5-lnd)2ZrMe2 cation, which is the key reaction center in the catalytic polymerization of olefins. Comparative analysis of electron-transfer-induced
transformations of bent-sandwich dimethyl and dichloride zirconocenes of the general formula L2ZrX2 (L=η5-lnd, η5-Cp: X=Xl, Me) was performed.
The material of the paper was first reported at the 195th Meeting of the Electrochemical Society (see Ref. 1).
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 59–62, January, 2000. 相似文献
3.
O. N. Babkina T. A. Bazhenova N. M. Bravaya V. V. Strelets M. Yu. Antipin A. Lysenko 《Russian Chemical Bulletin》1996,45(6):1458-1465
Redox reactions of the sandwich jn5-(Ph)Ind]2Ni complex (1) (where (Ph)Ind is the 2-plrenylindenyl anion) in CH2CI2 and of the bent-sandwich (5-(Plr)Ind]2ZrCl2 complex (2) in THF have been studied by low-temperature cyclic voltammetry. Complex ( undergoes quasi-reversible two-step oxidation to cation i+ and dication 12+, which are stable at room temperature within the cyclic voltammetry time scale. Two-electron reduction of complex 1 is irreversible up to -50 °C, and this process is accompanied by destruction of the sandwich structure of the complex. Redaction of complex 2 is described by the conventional scheme for bent-sandwich complexes. According to this scheme, further one-electron reduction of radical anion 2- generates dianion 22–, which eliminates two CI– ions to afford bisindcnyl sandwich complex (5-(Ph)lnd]2Zr (3). This complex is stable at T < -45 °C within the cyclic voltammetry time scale and is capable of undergoing one-electron reduction to the corresponding radical anion 3-. Synthesis and crystal structures of complexes 1 and 2 are reported.Translated fromIzvestiya Akademii Nauk. Seriya Kidmicheskaya, No. 6, pp. 1529–1536, June, 1996. 相似文献
4.
T. V. Petrovskaya I. L. Fedyushkin M. N. Bochkarev G. Shumann R. Veimann 《Russian Chemical Bulletin》1997,46(10):1766-1768
Reaction of Sm(bpy)4 (bpy is 2,2′-bipyridyl) with di-tert-butyldiazabutadiene (dad) in tetrahydrofuran (THF) affords the mixed-ligand complex Sm(dad)2(bpy) (1). Complex1 was isolated as black paramagnetic crystals readily soluble in THF, 1,2-dimethoxyethane (DME), toluene, and ether. Compound1 was characterized by IR and ESR spectroscopy, X-ray diffraction analysis, and by the results of magnetic measurements. Based
on the difference between the Sm−N bond lengths and on the data of IR spectroscopy, the following formal charge distribution
in the molecule of complex1 was proposed: Sm3+(dad)2−(dad)1−(bpy)0.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1860–1862, October. 1997. 相似文献
5.
A. A. Trifonov E. N. Kirillov E. A. Fedorova N. P. Makarenko M. N. Bochkarev H. Schumann S. Muehle 《Russian Chemical Bulletin》1998,47(11):2274-2279
The stilbene complex of ytterbium (PhCH=CHPh)Yb(THF)2 (1) was prepared by the reaction of YbI2(THF)2 with a twofold excess of (PhCH=CHPh)− Li+. Based on the data of IR and ESR spectroscopy and on the results of magnetic measurements, compound1 was characterized as a complex of divalent ytterbium with the stilbene dianion. The reactivity of complex1 toward different types of reagents was studied. The structure of the product of the reaction of1 with 2,4,6-tri(tert-butyl)phenol (2,4,6-But
3C6H2O)2Yb(THF)3 was established by X-ray diffraction analysis.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2345–2350, November, 1998. 相似文献
6.
D. M. Roitershtein K. A. Lyssenko P. A. Belyakov M. Yu. Antipin E. S. Petrov 《Russian Chemical Bulletin》1997,46(9):1590-1594
The reaction of the cyclopentadienyllutetium anthracenide, C5H5Lu(C14H10)2−(THF)2 (1), with azobenzene yielded the [C5H5(THF)Lu(μ−η2:η2−PhN—NPh)]2(THF)2 (2) binuclear complex. The structure of the reaction product was established by X-ray structural analysis. The dynamic behavior
of complex2 in a THF-d8 solution was studied by1H NMR spectroscopy in the temperature range of 265–330 K.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1667–1671, September, 1997. 相似文献
7.
Ismail Yilmaz 《Transition Metal Chemistry》2008,33(2):259-265
The new asymmetric, fluorescent Schiff-base ligand, N-(pyrene)-salicylaldimine (L), and its copper complex having an ONNO donor set, [Cu(L)
2
], were synthesized and characterized using elemental analysis, IR, UV-vis, 1H and 13C-NMR spectroscopies. Their electrochemical and spectroelectrochemical behaviors were investigated in a detail by using cyclic
voltammetry (CV), square wave voltammetry (SWV), in-situ UV-vis, and fluorescence spectroelectrochemistry. The formation of
the complex was monitored by the in-situ fluorescence technique based on the quenching of the fluorescence-probe ligand. Electrochemical
studies showed that L exhibits a single irreversible reduction process. However, the SWV indicated that this process was not totally irreversible
in the time scale of the measurement. The cathodic peak potential of the reduction process occurred at E
pc = −1.35 V vs Ag/AgCl (scan rate: 0.025 Vs−1). On the other hand, [Cu(L)
2
] showed one quasi-reversible one-electron reduction process in the scan rates of 0.025–0.50 Vs−1, which was assigned to metal-based one-electron process; [Cu(2+)(L)2] + e− → [Cu(+)(L)2]−. The value of half-wave potential (E
1/2) of the reduction process was −0.54 V vs Ag/AgCl (scan rate: 0.025 Vs−1). The time-resolved spectra showed, when the potential (E
app = −1.60 V) was applied in a thin-layer cell, that the main and shoulder bands of (L) at 385, 336, and 407 nm almost disappeared and a new band at 443 nm with a shoulder formed during the reduction process. No
change was observed on the final spectrum of the totally reduced ligand for long period under nitrogen atmosphere, which indicated
that the singly reduced species remained stable and was not accompanied by a chemical reaction in the time scale of the spectroelectrochemical
measurement. The spectral changes during the reduction process of [Cu(L)
2
] confirmed the metal-centered reduction process. The fluorescence intensity of L decreased during the reduction process in the thin-layer cell, as result of the perturbation of the conjugated system of
the reduced species. 相似文献
8.
A. A. Trifonov E. A. Fedorova E. N. Kirillov M. N. Bochkarev F. Girgsdies H. Schumann 《Russian Chemical Bulletin》2000,49(8):1436-1439
Reaction of Sml2(THF)2 with metallic lithium andtrans-stilbene in 1:2:2 ratio in DME gives the stilbene complex of divalent samarium (PhCHCHPh)Sm(DME)2. This complex reacts with hydrogen in THF to give SmH2(THF)2 and 1,2-diphenylethane. The reaction with (Me3Si)2NH gives the amide [(Me3Si)2N]2Sm(DME)2 and the reaction with triphenylgermane yields Ph3GeGePh3. Reaction of CpLuCl2(THF)2 with 2 equivalents of [PhCHCHPh]·−Na+ in DME results in the dimerization of stilbene fragments to give anate-complex {Cp2Lu[μ-CH (Ph)CH(Ph)CH(Ph)CH(Ph)]}Na(DME)3. In the reaction of Cp2GdCl with [PhCHCHPh]·−Na+, the known complex Cp3Gd(THF) was isolated as the only lanthanidecontaining product.
Published inIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1442–1446, August, 2000. 相似文献
9.
Electrochemistry of hydrofullerene C60H36 was studied by cyclic voltammetry in THF and CH2Cl2 in the −47–14 °C temperature range. Hydrofullerene undergoes reversible one-electron reduction to form a radical anion in
THF (E
0=−3.18 V (Fc0/Fc+), Fc=ferrocene) and irreversible one-electron oxidation in CH2Cl2 (E
p
a
=1.22 V (Fc0/Fc+)). The reduction potential was used to estimate electron affinity of hydrofullerene as EA=−0.33 eV. It was suggested that
C60H36 is an isomer withT-symmetry in which 12 double bonds form four isolated benzenoid rings located in vertices of an imaginary inscribed tetrahedron
on the molecular surface. For hydrofullerene, the “electrochemical gap” is an analog of the energy gap (HOMO−LUMO), equal
to (E
Ox−E
Red)=4.4 V, and indicates that C60H36 is a sufficiently “hard” molecule with a low reactivity in redox reactions.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2083–2087, November, 1999. 相似文献
10.
Nikos G. Tsierkezos 《Journal of solution chemistry》2007,36(10):1301-1310
The reduction of benzophenone (Bzph) in 3-pentanone (PEN), acetone (ACE), N,N-dimethylacetamide (DMA), N,N-dimethylformamide (DMF), tetrahydrofuran (THF), acetonitrile (ACN) and dimethyl sulfoxide (DMSO) with n-tetrabutylammonium hexafluorophosphate (TBAPF6) as background electrolyte was studied using the technique of cyclic voltammetry at the temperature of 263.15 K. The half-wave
potentials (E
1/2) were extracted. The reduction of Bzph occurs in two successive one-electron steps to produce first the free radical anion
Bzph− and then the dianion Bzph2−. The results indicated that the radical anion Bzph− is reoxidized to Bzph in all investigated solvent media whereas the dianion Bzph2− is reoxidized to Bzph− only in THF. The heterogeneous electron-transfer rate constants (k
s
) were evaluated by employing the electrochemical rate equation proposed by Nicholson. The rate of electron transfer for the
Bzph/Bzph− couple was found to be relatively slow in all investigated solvent media. Consequently, the electron-transfer processes can
be recognized as quasi-reversible. The diffusion coefficients (D) of Bzph in the investigated solvent media have been calculated using the modified Randles-Sevcik equation. The effect of
the physical and chemical properties of the solvent medium on the electrochemical behavior of Bzph has been examined. 相似文献
11.
Goldberg A. E. Kiskin M. A. Kozyukhin S. A. Sidorov A. A. Eremenko I. L. 《Russian Chemical Bulletin》2011,60(5):1012-1015
The new binuclear complex [(1,10-phen)2Zn2(μ2-OOCR)2(η2-OOCR)2]·4THF (2·4THF, RCOO− is the β-naphthoate anion) was synthesized. According to the single-crystal X-ray diffraction study, a one-dimensional supramolecular
structure is formed through intra- and intermolecular π-π interactions between the phenanthroline moieties of complex 2. Compound 2 exhibits photoluminescence properties at room temperature. 相似文献
12.
The reaction of [M(L)]Cl2 · 2H2O (M = Ni2+ and Cu2+, L = 3,14-dimethyl-2,6,13,17-tetraazatricyclo[14,4,01.18,07.12]docosane) with 1,1-cyclobutanedicarboxylic acid (H2-cbdc) generates 1D and 2D hydrogen-bonded infinite chains [Ni(L)(H-cbdc−)2] (1) and [Cu(L)(H-cbdc−)2] (2). (H-cbdc− = cyclobutane-1-carboxylic acid-1-carboxylate). These complexes have been characterized by X-ray crystallography, spectroscopy,
and cyclic voltammetry. The crystal structure of 1 shows a distorted octahedral coordination geometry around the nickel(II) ion, with four secondary amines and two oxygen atoms
of the H-cbdc− ligand at the trans position. In 2, the coordination environment around the central copper(II) ion shows a Jahn–Teller distorted octahedron with four Cu–N bonds
and two long Cu–O distances. The cyclic voltammogram of the complexes undergoes two one-electron waves corresponding to MII/MIII and MII/MI processes. The electronic spectra and electrochemical behavior of the complexes are significantly affected by the nature
of the axial H-cbdc− ligand. 相似文献
13.
A. A. Trifonov E. N. Kirillov M. N. Bochkarev H. Schumann S. Muehle 《Russian Chemical Bulletin》1999,48(2):382-384
The diazadiene complex of trivalent ytterbium, Cp2Yb(DAD) (1) (DAD=But−N=CH−CH=N−But) was prepared according to three different procedures, namely, by oxidation of Cp2Yb(THF)2 with diazadiene in THF, by the reaction of Cp2YbCl with DAD2−Na+
2 taken in a ratio of 2∶1, and by the reaction of Cp2YbCl(THF) with DAD2−Na+
2 taken in a ratio of 1∶1. Complex1 was characterized by microanalysis, IR spectroscopy, magnetochemistry, and X-ray diffraction analysis.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 384–386, February, 1999. 相似文献
14.
S. V. Kukharenko L. N. Novikova V. V. Strelets N. A. Ustynyuk A. I. Yarmolenko 《Russian Chemical Bulletin》1994,43(10):1710-1714
The electrochemical reduction of (6-C13H9)Mn(CO)3 (1, where C13H9—fluorenyl) has been studied in THF by cyclic voltammetry and preparative controlled potential electrolysis. One-electron reduction of1 to the corresponding 19-electron radical anion1
.– is accompanied by the haptotropic isomerization of the latter to the radical anion (5-C13H9)Mn(CO)3
.– (2
.–), which is oxidized at the electrode to neutral complex2. Electron-transfer induced isomerization1 2 is an electrocatalytic process with current efficiency of 600%, which can be also promoted by catalytic amounts (20%) of the chemical reducing agents (benzophenone radical anion or sodium amalgam). If the reaction is chemically induced, the radical anion2
.– is oxidized by initial complex1; as a result the electron-transfer induced isomerization1 2 proceeds by a chain mechanism. The influence of the electronic state (18e–/19e–) of 6- and 5-fluorenyl complexes on the position of the equilibrium of the intra-ring haptotropic isomerization reaction is discussed.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1805–1809, October, 1994.This work was supported in part by the Russian Foundation for Basic Research (Project No. 93-03-05209) and the International Science Foundation (Grant No. REV 000). 相似文献
15.
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
16.
L. A. Shundrin N. V. Vasilieva I. G. Irtegova V. A. Reznikov 《Russian Chemical Bulletin》2007,56(6):1273-1275
It has been shown by cyclic voltammetry for the first time for nitrons that the first step of electrochemical reduction of
3,3′-bi(2-R-5,5-dimethyl-4-oxopyrrolinylidene)-1,1′-dioxides in water and its binary mixtures with acetonitrile is a reversible
one-electron process. The potentials of the first one-electron reduction peaks shift toward less negative values with an increase
in the water content in the binary mixture, being in water equal to −0.14, −0.09, −0.08, and +0.19 V vs. saturated calomel electrode for dinitrons with R = Me, Ph, But, and CF3, respectively. Such very low reduction potentials allow one to use derivatives of these dinitrons as redox-active labels
in applied bioorganic electrochemistry.
Dedicated to the memory of Academician N. N. Vorozhtsov on the 100th anniversary of his birth.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1227–1229, June, 2007. 相似文献
17.
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
18.
A sensitive complex absorptive wave of Ca-ARS was obtained by using differential pulse voltammetry when a mercury film glass
carbon electrode was immersed in 0.1 mol L−1 KOH and 4.5×10−4 mol L−1 ARS solution. The peak potential obtained was −1.17 V (vs Ag-AgCl). The peak current was proportional to the concentration
of calcium in the range of 5.0×10−8−4.2×10−5 mol L−1. The detection limit was 2.0×10−8 mol L−1. This method was applied successfully to determining traces of calcium in blood serum. The electrochemical behavior of the
system was also studied by cyclic voltammetry, and the experiment results showed that the electrode process was an irreversible
absorptive with two electrons participating.
Translated from Journal of Beijing Normal University (Natural Science Edition), 2005, 41(2) (in Chinese) 相似文献
19.
I. D. Gudilenkov G. K. Fukin A. V. Cherkasov A. S. Shavyrin Yu. E. Larionova A. A. Trifonov 《Russian Chemical Bulletin》2008,57(10):2081-2089
The interaction of the ytterbium bis(indenyl) complex (C9H7)2YbII(THF)2 (1) with the 1,4-diazabutadiene 2-MeC6H4N=C(Me)-C(Me)=NC6H4Me-2 (MeDAD) is accompanied by the oxidation of the metal atom to the trivalent state and results in a paramagnetic compound of the
metallocene type (C9H7)2YbIII(MeDAD−·) (3) containing the radical anion of 1,4-diazabutadiene. The structure of the complex 3 was determined by X-ray diffraction analysis. The reactions of the bis(indenyl) (1) and bis(fluorenyl) (C13H9)2YbII(THF)2 (2) derivatives of divalent ytterbium with the 1,4-diazabutadiene PhN=C(Ph)-C(Ph)=NPh (PhDAD) (with the molar ratio of the reactants 1:2) proceed with a complete cleavage of the bonds Yb-C and the oxidation of the
ytterbium atom to the trivalent state and result in a homoligand complex (PhDAD−·)3Yb (6) containing three radical anion 1,4-diazadiene ligands. Complex 6 was also obtained by an exchange reaction of YbCl3 with PhDAD−·K+ (1: 3) in THF. Complex 6 was characterized by X-ray diffraction analysis. 相似文献
20.
Pagonda Haribabu Yogesh Prakash Patil Katreddi Hussain Reddy Munirathinam Nethaji 《Transition Metal Chemistry》2011,36(8):867-874
The mononuclear Cu(II) complex [Cu(phen)(H2O)(NO3)2] (1), obtained by the reaction of 1,10-phenanthroline with Cu(NO3)2·3H2O in methanol solution, reacts with anionic ligands SCN−, AcO−, N3
− and PhCO2
− in MeOH solution to form the stable binuclear complexes [Cu2(H2O)2(phen)2(μ-X)2]2 (NO3)2, where X = SCN− (2), AcO− (3), N3
− (4) or PhCO2
−(5). The molecular structure of complex 3 was determined by single-crystal X-ray diffraction studies. These complexes were characterized by electronic, IR, ESR, magnetic
moments and conductivity measurements. The electrochemical behaviour of the complexes was investigated by cyclic voltammetry.
The interactions of these complexes with calf thymus DNA have been investigated using absorption spectrophotometry. Their
DNA cleavage activity was studied on double-stranded pBR322 plasmid DNA using gel electrophoresis experiments in the absence
and presence of H2O2 as oxidant. 相似文献