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1.
Density functional quantum chemical calculations of the mechanisms of metallotropic η2,η2-intra- and η2,η2-inter-ring haptotropic rearrangements (HRs) in 16e zero-valent η2-(naphthalene and anthracene)nickel complexes involving migration of the organometallic group within the same ring or from
one aromatic ring to the other were carried out. The structures of the initial complexes, transition states, and intermediates
were determined. The intra-ring HRs in these systems proceed via low-energy η4-cis-butadiene transition states. The inter-ring HRs proceed along the periphery of the naphthalene and anthracene ligands via high-energy η3-allylic transition states. In contrast to well-investigated η6,η6-inter-ring HRs in (naphthalene and anthracene)tricarbonylchromium complexes, the activation barriers to the η2,η2-inter-ring HRs in the corresponding nickel complexes are much lower. Transition states of these processes are characterized
by higher hapticity compared to the initial complexes. This also distinguishes the nickel complexes from the corresponding
Cr(CO)3 complexes for which the hapticities of transition states of the η6,η6-inter-ring HRs are lower than those of the initial complexes. The calculated activation barriers to the η2,η2-intra-ring HRs in the (naphthalene and anthracene)nickel complexes as well as the barrier to rotation of the organonickel
group in the naphthalene complex are in good agreement with the experimental data. The calculated barriers to the η2,η2-inter-ring HRs in the naphthalene and anthracene complexes are 3–5 kcal mol−1 lower than the experimental values. This is probably due to the competition between two mechanisms of this process, a low-energy
intramolecular mechanism and a high-energy intermolecular dissociative mechanism. 相似文献
2.
The ability of cyclopentadienyl type derivatives of corannulene C20H10 and fullereneI
h
-C60 to form η5-π-complexes and the problem of their existence is discussed. MNDO/PM3 calculations of half-sandwich complexes η5-π-MC20H15, η5-π-MC20H
15
+
, η5-π-MC60H5, η5-π-MC60H5 and sandwich complexes 2η5-π-M(C20H15)2, 2η5-π-M(C20H15)2, 2η5-π-M(C60H5)2 (M=Si, Ge, Sn, Pb) were performed. For all systems studied, local minima were found on corresponding potential energy surfaces
and the heats of formation, geometric parameters, and distributions of effective atomic charges were calculated. Sandwich
complexes are most likely to exist with M=Si and Ge. The energy and geometric characteristics of η5-π-complexes of corannulene were compared with those of η5-π-complexes of fullereneI
h
-C60. It was concluded that the results of quantum-chemical calculations of sandwich type corannulene derivatives can be used
for simulation of the geometry and electronic structure of analogous complexes of fullereneI
h
-C60.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1649–1656, September, 1999. 相似文献
3.
Yu. F. Oprunenko I. P. Gloriozov 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2012,86(6):979-986
The density functional theory method was used to perform quantum-chemical modeling of the mechanisms of η2,η2-intraring (Intra-HR) and η2,η2-interring (Inter-HR) haptotropic rearrangements for μ2 complexes of naphthalene with rhodium, ruthenium, and osmium. The structure of transition states and intermediates was studied,
and the energy parameters of haptotropic rearrangements in these complexes were determined. We used the PBE functional, the
TZV2p three-exponential basis set for valence electrons, and the SBK-JC relativistic pseudopotential for core electrons. η2,η2 Intra-HR was found to occur inside the aromatic ring of η2 naphthalene complexes without going outside it through intermediates and transition states with η
n
structures (n = 1, 2). Inter-HR occurred as metal replacements on the periphery of the naphthalene ligand through intermediates and transition
states with η
n
structures (n = 1, 2, 3) from one ring into another. The calculated activation barriers for η2,μ2 Intra-HR and η2,η2 Inter-HR in the complexes studied closely agree with their experimental values. 相似文献
4.
The molecular and electronic structure of hypothetical complexes of unsubstituted fullerene C60 withI
h
symmetry and its cyclopentadienyl type derivatives were simulated by the MNDO/PM3 method taking the C60(XC[)
n
molecules (n=1, 2, 10, 12; X=Si, Ge, Sn) and η5-C60H5XCp (X=Ge, Sn), respectively, as example. The complexes 12η5-πC60(XCp)12 and η5-πC60XCp withI
h
andC
5v symmetry, respectively, were found to be the most stable compounds. The energies of the X−C60 bonds in these complexes are close to those of X−Cp bonds in bis(cyclopentadienyl) complexes XCp2 and are substantially higher than the energies of similar bonds in complexes of unsubstituted fullerene η1-πC60(XCp)− and η5-πC60(XCp)+. Geometric parameters and spin densities in radicals C60XCp and biradicals C60(XCp)2 and C60H10 were calculated.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2155–2165, November, 1998. 相似文献
5.
E. V. Sergeeva V. I. Rozenberg E. V. Vorontsov V. V. Mikul'shina N. V. Vorontsova A. V. Smirnov F. M. Dolgushin A. I. Yanovsky 《Russian Chemical Bulletin》1998,47(1):144-152
The complexation reactions of monoaryl- and diaryl-substituted [2.2]paracyclophanes with (NH3)3Cr(CO)3 have been studied. The aromatic rings of [2.2]paracyclophane are more favorable for coordination than aryl substituents.
This leads to the regioselective formation of the corresponding mono- or binuclear tricarbonylchromium complexes. In some
cases, the tricarbonylchromium group is coordinated to the aryl ring of the substituent to form (in low yields) the corresponding
mononuclear complex or binuclear complexes with both the aromatic ring of paracyclophane and the aryl ring of the substituent
involved in coordination. The structure of such complex, namely, [4-(η6-2,4,6-trimethylpheny)-11-16-η6-[2,2]paracyclophane]bis[tricarbonylchromium(0)] was confirmed by X-ray diffraction study.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 142–150, January, 1998. 相似文献
6.
S. A. Belov D. P. Krut’ko R. S. Kirsanov D. A. Lemenovskii A. V. Churakov 《Russian Chemical Bulletin》2008,57(8):1657-1660
New zirconium sandwich complexes (η5-C9H5Ph2)2ZrCl2 (1) and (η5-C9H5Ph2)-(η5-C5(CH3)5)ZrCl2 (2) were synthesized and characterized. The molecular structures of complexes 1 and 2 were established by X-ray diffraction. The reduction of 1 and 2 does not stop at the formation of the ZrII derivatives with the η9-coordinated indenyl ligand; instead the reaction results in the destruction of the metallocene structure.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1626–1629, August, 2008. 相似文献
7.
V. A. Mamedov S. V. Vdovina E. I. Vorkunova L. V. Mustakimova A. F. Saifina A. T. Gubaidullin I. Kh. Rizvanov Ya. A. Levin I. A. Litvinov 《Russian Chemical Bulletin》2008,57(6):1257-1263
Condensation of diethyl isophthaloyldiacetate, aromatic aldehyde, and urea in the presence of Me3SiCl proceeds efficiently and faster than in the absence of the latter to form 1,3-bis(2-oxo-1,2,3,4-tetrahydropyrimidin-6-yl)benzene
derivatives capable to give inclusion complexes with DMF.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1233–1239, June, 2008. 相似文献
8.
The synthesis of linear and star-shaped oligomers containing cationic and neutral organoiron groups in their structures was achieved by reaction of cationic arene complexes of cyclopentadienyliron containing terminal hydroxyl groups with 1,1′-ferrocenedicarbonyl chloride or ferrocene carboxylic acid. The use of chloroarene complexes allowed for the formation of triiron complexes that were subsequently polymerized via nucleophilic aromatic substitution with various oxygen- and sulfur-based dinucleophiles. The corresponding polyethers and thioethers were isolated in good yields and these materials exhibited excellent solubilities in polar organic solvents. Cyclic voltammetric investigations revealed that the cationic iron centers pendent to the polymer backbones underwent reversible reduction steps, while the neutral iron centers within the polymer backbones underwent reversible oxidation steps. Photolysis of these polymers resulted in the removal of the cationic cyclopentadienyliron moieties pendent to the polymer backbones. Thermogravimetric analysis (TGA) revealed that the cationic iron complexes were cleaved from the polymers at approximately 210 °C. Differentials scanning calorimetry (DSC) revealed that the glass transition temperatures of the cationic polymers occurred at higher temperatures than their neutral analogs. 相似文献
9.
Beyhan Yiğit Murat Yiğit İsmail Özdemir Engin Çetinkaya 《Transition Metal Chemistry》2012,37(3):297-302
Three RuCl2(η6-arene, η1-carbene) and two RuCl2(NHC)(arene) complexes have been prepared by the reaction of bis(1,3-dialkylperhydrobenzimidazol-2-ylidene) (1) and bis(1,3-dialkyl-4-methylzimidazolin-2-ylidene) (3) with [RuCl2(arene)]2 in toluene and characterized by elemental analysis, 1H NMR, 13C NMR and IR spectroscopy. The catalytic activities of these complexes were examined in the transfer hydrogenation of aromatic
ketones using 2-propanol as hydrogen source. 相似文献
10.
In this paper, we used bond-length equalization, aromatic stabilization energies (ASE) and nucleus-independent chemical shifts
(NICS), calculated with (density functional theory) B3LYP levels at the 6-311+G** basis set, to evaluate the aromaticity of a set of 38 five-member planar π-electron aromatic systems: sila-, aza- and phospha-
derivatives and their parent systems. The result revealed statistically significant correlations among the above three criteria,
and the order of aromaticity of the whole set was: Aza- derivatives rings > Phospha- derivatives rings > Sila- derivatives
rings > Carbon-containing rings; NICS(0.6) and NICS(0.8) had the same results in evaluating the order of aromaticity in our
case. 相似文献
11.
Summary For improved determination of aromatic amines by gas chromatography and detection with an electron capture detector (GC-ECD)
a derivatization method based on the bromination of the aromatic ring in an acetic acid medium was developed. In general,
all free ortho and para-positions relative to the amino group undergo electrophilic substitution. Separation of at least 30
compounds in a single chromatographic run in 30 min is possible. With this method, 56 aromatic amines were studied and only
in 6 cases were no derivatives obtained. Quantitation limits determined from calibration data are 1.2–40 μg L−1 for a 100 mL sample and an injection volume of 1 μL. Previous experiments suggest that both sample and injection volume may
be increased to lower the quantitation limit. 相似文献
12.
Reactions of various η6-arene-η5-cyclopentadienyliron or substituted cyclopentadienyliron cations with trimethyl, triethyl or triphenyl phosphite under either thermal or photochemical conditions all resulted in the replacement of the arene ligand with three phosphite ligands to give η5-tris(trimethyl, triethyl or triphenyl phosphite)-η5-cyclopentadienyliron or substituted cyclopentadienyliron cations. The yields of the phosphite complexes were higher from photolysis than from the analogous thermolysis. Photolysis of the η6-chlorobenzene-η5-cyclopentadienyliron cation (IX) carried out in the presence of a more basic or more electron-rich aromatic ligand resulted in the exchange of the chlorobenzene of IX with the more basic arene, thus providing synthetic routes to cyclopentadienyliron complexes that may be difficult to prepare by other means. New complexes synthesized in this way are the η6-2-phenylethyl tosylate-η5-cyclopentadienyliron cation and the CpFe+ complexes of thiophene, 2-methylthiophene, 3-methylthiophene and 2,5-dimethylthiophene. 相似文献
13.
A. S. Abd‐El‐Aziz E. K. Todd G. Z. Ma 《Journal of polymer science. Part A, Polymer chemistry》2001,39(8):1216-1231
Soluble organoiron polyethers, thioethers, and amines were synthesized via nucleophilic aromatic substitution reactions. The synthesis of these classes of organometallic polymers involved either the reaction of cyclopentadienyliron complexes of dichloroarenes with various oxygen and sulfur dinucleophiles or the reaction of ether‐ or amine‐containing diiron complexes with dithiols. Polymerization reactions with the diiron complexes gave rise to organoiron polymers with alternating ether/thioether or amine/thioether bridges. Removal of the iron moieties from the backbone of these polymers allowed for the production of the corresponding organic materials. Furthermore, the organometallic polymers had much higher solubilities than their organic analogues. Thermogravimetric analysis of the organoiron polymers indicated that the polymers lost their metallic moieties at approximately 200 °C, whereas degradation of the polymer backbones occurred around 500 °C. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1216–1231, 2001 相似文献
14.
Zheng-Hua Zhang Guang-Xiang Liu Taka-aki Okamura Wei-Yin Sun Norikazu Ueyama 《Structural chemistry》2006,17(1):3-11
Three new coordination polymers with formula [Gd(bta)(H2O)·1.39H2O]
n
(1), [Dy(bta)(H2O)·1.35H2O]
n
(2) and [Y(bta)(H2O)2·0.5H2O]
n
(3) were synthesized by using corresponding rare earth nitrates and 1,3,5-benzenetriacetic acid (H3bta) under hydrothermal/solvothermal reaction conditions, and characterized by single-crystal X-ray diffraction. In these complexes, the carboxylate groups of bta3− adopt different coordination modes, namely one carboxylate group adopts μ2-η1:η1-bridging and each of the other two carboxylate groups adopts μ2-η2:η1-bridging coordination modes in 1 and 2, and one carboxylate group adopts a μ2-η2:η1-bridging coordination mode and each of the other two carboxylate groups adopts a μ2-η1:η1-bridging mode for the major component and one carboxylate group adopts a μ2-η2:η1-bridging coordination mode, one has a μ2-η1:η1-bridging mode and the third has a monodentate mode for the minor component in 3. The magnetic properties of the complexes 1 and 2 were investigated in the temperature range of 1.8–300 K. 相似文献
15.
A. V. Zakharova S. G. Semenov M. E. Bedrina A. V. Titov 《Russian Journal of General Chemistry》2020,90(2):287-291
Using the DFT PBE0/SDD method, the structural parameters of the Yb@η2-C60, Yb@η6-C60, Yb@η6-B2C58, and Gd@η6-B3C57 molecules, of corresponding anions (1,4-B2C58)2–, (1,3,5-B3C57)3–, and free radicals BkC60–k were calculated. Ytterbium is coordinated by the degraded C=C bond in the Yb@η2-C60 molecule and by the 1,4-diboratacyclohexa-1,3,5-triene fragment, in Yb@η6-B2C58. Symmetric substitution of three atoms of the cyclohexa-1,3,5-triene fragment leads to the formation of cyclopropane fragment, three 1,4-diboratacycloocta-1,3,5,7-tetraene fragments, and three boratacyclobutane fragments. The dipole moment μ(Yb@C60) is directed from the cavity center to Yb; the dipole moment μ(Gd@η6-B3C57) is greater and has the opposite direction (from B3 to Gd). The populations of the 4f-shells of the Yb and Gd atoms are conserved. The binding energy of the endoatom in Ln@BkC60–k is significantly higher than that in Yb@C60. 相似文献
16.
The prototropic properties of two nitro derivatives of aromatic α-hydroxy hydrazones [2,4-dinitro-N-phenyl-N′(2-hydroxy-1-phenylmethylene hydrazine) and 2,4-dinitro-N-phenyl-N′(2-hydroxy-1-naphthylmethylene hydrazine] have been analysed through electronic absorption, 1H and 13C NMR and semiempirical molecular orbital methods. The metal binding properties of both compounds and of the unsubstituted hydrazones were evaluated from potentiometric and spectrophotometric data in dioxane-water mixtures. On the basis of the spectral analysis and PM3 semiempirical calculations, the structures of the formed complexes were proposed. 相似文献
17.
Three dimeric cis-dioxomolybdenum(VI) complexes of bis-bidentate Schiff base derivatives containing aromatic nitrogen–nitrogen linkers (4,4′-diaminodiphenylmethane;
4,4′-diaminodiphenylether; 4,4′-diaminodiphenylsulfone) with 2-hydroxy-1-naphthaldehyde have been synthesised and characterized
by physico-chemical and spectroscopic methods. The catalytic activities of the complexes with respect to alkene epoxidation
using tert-butylhydroperoxide (TBHP) as oxidant have been studied. The addition of single wall nanotubes can enhance the catalytic activities
of the Mo complexes and the selectivity of epoxide formation. 相似文献
18.
V. A. Aver’yanov D. V. Vlasov A. A. Svechnikova A. I. Ermakov 《Kinetics and Catalysis》2000,41(2):152-158
The effect of several solvents on the selectivity of the free radical chlorination of 1,1-dichloroethane and 1-chloropropane
is studied. The selective action of aromatic solvents on free radical chlorination is explained. This explanation implies
that the process involves solvated chlorine atoms and their donor-acceptor complexes with aromatic molecules (ArH→Cl•) as intermediates. Using the findings of this work and previous studies, the ratios of the rate constants for hydrogen-atom
abstraction from different positions in chloroethane, 1,1-dichloroethane, 1-chloropropane, and 2-chloropropane by solvated
chlorine atoms and ArH→-Cl• complexes are determined. The differences in the activation energies of the competitive hydrogenatom abstractions from different
positions in substrates by the ArH→Cl• complexes and solvated chlorine radicals correlate with two HOMO energies of solvent and substrate molecules. The isokinetic
relationship is found for all the systems under study (the isokinetic temperature, 523 K). 相似文献
19.
S. Yu. Ketkov G. A. Domrachev C. P. Mehnert J. C. Green 《Russian Chemical Bulletin》1998,47(5):868-874
The effect of methylation of ligands in bis(η6-benzene)chromium (1) on the structure of Rydberg transitions in absorption spectra has been studied. A detailed analysis
and interpretation of all Rydberg elements of the vapor-phase spectra of bis(η6-benzene)chromium (2), bis(η6-o-xylene)chromium (3), bis(η6-m-xylene)chromium (4), and bis(η6-mesitylene)chromium (5) was carried out. The vapor-phase electronic absorption spectrum of bis(η6-p-xylene)chromium (6) was measured, and the assignment of the Rydberg bands was made for the first time. The first ionization
potentials of complexes 2–5 were refined. The energy of detachment of the 3dz
2 electron and the parameters of the Rydberg excitations for molecule 6 were determined. The vibronic components of the 3dz
2→R4p
x,y
transition in the spectra of complexes 2 and 6 were assigned. The differences in the Rydberg structure of the spectra of
compounds 2–6 were analyzed in terms of the selection rules for optical transitions in the corresponding symmetry groups.
The vapor-phase spectra correspond to conformers with the symmetry groupsC
2v
andC
2 for complexes 2–4, with the symmetry groupsD
3h
andD
3 for compound 5, and with the symmetry groupD
2d
for complex 6.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 897–903, May, 1998. 相似文献
20.
Alaa S. Abd-El-Aziz Nelson M. Pereira Waleed Boraie Shaune L. McFarlane Erin K. Todd 《Macromolecular Symposia》2004,209(1):207-216
The synthesis of sulfone-containing monomers with pendent cationic cyclopentadienyliron (CpFe+) moieties has been accomplished via nucleophilic aromatic substitution of dichloroarene complexes with a number aliphatic dithiols. These complexes were further oxidized using m-CPBA to give the sulfone-based monomers. Polymerization of the sulfone-based monomers with O-containing nucleophiles produced the sulfone-based polymers. Direct nucleophilic aromatic substitution of dichloroarene complexes with dinucleophiles allowed for the formation of organoiron sulfide-based polymers. Oxidation of these polymers led to the formation of sulfone polymers with the pendent iron moieties. The organometallic monomers and polymers were found to be more soluble in polar solvents in comparison to their organic analogues. 相似文献