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1.
The emission spectra of a series of molybdenum(II) chloride clusters containing thiolate ligands, [Mo6(μ3-Cl)8(SR)6]2− (R = Et, Bu, Ph, Bn), have been recorded. These complexes all show a broad emission at ~700 nm after excitation at 337, 400
and 410 nm. Determination of the excited state lifetimes and quantum yields of these complexes in acetonitrile reveals that
(Bu4N)2[Mo6(μ3-Cl)8(SPh)6] displays the longest excited state lifetime of this series (26 μs at 296 K).
相似文献
Lisa F. SzczepuraEmail: |
2.
Malcolm H. Chisholm Jason S. D’Acchioli Christopher M. Hadad 《Journal of Cluster Science》2007,18(1):27-49
The electronic structures and the physical properties (vertical excitation energies, vibrational stretching frequencies, and
bond lengths) of a variety of M–M quadruply bonded (M = Mo, W) complexes are investigated using density functional theory
(DFT). By utilizing a variety of pure and hybrid exchange-correlation (XC) functionals and a number basis sets, we are able
to recommend a theoretical methodology for most efficiently probing the electronic structures of homoleptic M2(O2CR)4 and bridged M2(O2C-X-CO2)M2 (R = organic group, typically H; X = conjugated organic group) complexes.
相似文献
Jason S. D’AcchioliEmail: |
3.
A u.v.–vis spectrophotometric study of the adduct formation of the nickel(II) Schiff base complexes,([NiL]) where L = [3-methoxysalophen,
N,N′-bis(3-methoxysalicylidene)-1,2-phenylenediimine] (1), [4-methoxysalophen, N,N′-bis(4-methoxysalicylidene)-1,2-phenylenediimine] (2), [5-methoxysalophen, N,N′-bis(5-methoxysalicylidene)-1,2-phenylenediimine] (3) and [Salophen, [N,N′-bis(salicylaldehydo)-1,2-phenylenediimine] (4) as donors with R2SnCl2 (R = methyl, phenyl and n-butyl) as acceptors have been investigated in chloroform, as solvent. Adducts have been characterized by 1H, 13C and 119Sn NMR, IR and electronic spectroscopy and CHN elemental microanalysis. The formation constants and the thermodynamic free
energies were measured using u.v.–vis spectrophotometry titration for 1:1 adduct formation at various temperatures (T = 278
to 308 K). The trend of the adduct formation of the nickel Schiff base complexes with a given tin acceptor decreases as follows:
and
The trend of the reaction of R2SnCl2 acceptors toward a given nickel Schiff base complex is as follows:
相似文献
4.
Hitoshi Shirase Yurie Miura Yutaka Fukuda 《Monatshefte für Chemie / Chemical Monthly》2009,140(7):807-814
Abstract Mixed-ligand NiII complexes have been synthesized with 1,3-diketonate and bulky tri- or tetra-amine ligands. Their structures were determined
by X-ray crystallography, and solvatochromic behavior was examined by UV–vis–NIR spectroscopy. Steric effects of the bulky
ligands on the coordination distances and spectral properties are discussed.
Graphical Abstract
相似文献
Yutaka FukudaEmail: |
5.
Renat R. Nazmutdinov Michael D. Bronshtein Dmitrii V. Glukhov Tamara T. Zinkicheva 《Journal of Solid State Electrochemistry》2008,12(4):445-451
Solvent dynamics effects on the electroreduction of [PtCl3(H2O)]− at a mercury electrode are explored in the framework of Sumi–Marcus model using an efficient computational scheme. According
to results of density functional calculations, the second electron transfer step may be regarded as rate controlling. The
nonmonotonous influence of solvent viscosity on the reaction rate is predicted and explained in terms of the saddle point
avoidance. The results of model calculations are employed to interpret experimental data reported earlier in the literature.
相似文献
Renat R. NazmutdinovEmail: |
6.
Michael Noyong Buelent Ceyhan Christof M. Niemeyer Ulrich Simon 《Colloid and polymer science》2006,284(11):1265-1273
The formation and the optical features of two-dimensional aggregates formed by DNA-directed immobilization and cross-linking of bifunctional DNA–gold nanoparticles at flat gold substrates are analyzed. The samples are structurally characterized by atomic force microscopy to evaluate the particle size, the particle densities, and the degree of aggregation. The optical characteristics determined by UV/visible measurements are correlated with the structural features observed.
相似文献
Ulrich SimonEmail: |
7.
Saad Alshehri John Burgess Colin D. Hubbard Christopher J. Jones Amit K. Das 《Transition Metal Chemistry》2008,33(4):417-420
The kinetics of substitution by alcohols and by aniline at [tris(3,5-dimethylpyrazolyl)hydroborato]molybdenum nitrosyl dihalides in toluene solution at 298.2 K and at atmospheric pressure
are reported and interpreted in terms of an associative mechanism.
相似文献
Colin D. HubbardEmail: |
8.
Manuel A. V. Ribeiro da Silva Luís M. N. B. F. Santos Ana C. P. Faria Filipa S. A. Sistelo 《Journal of Thermal Analysis and Calorimetry》2010,100(2):475-482
The molar heat capacity and the standard (p 0 = 0.1 MPa) molar enthalpies of formation of the crystalline of bis(glycinate)lead(II), Pb(gly)2; bis(dl-alaninate)lead(II), Pb(dl-ala)2; bis(dl-valinate)lead(II), Pb(dl-val)2; bis(dl-valinate)cadmium(II), Cd(dl-val)2 and bis(dl-valinate)zinc(II), Zn(dl-val)2, were determined, at T = 298.15 K, by differential scanning calorimetry, and high precision solution-reaction calorimetry, respectively. The standard molar enthalpies of formation of the complexes in the gaseous state, the mean molar metal–ligand dissociation enthalpies, M(II)–amino acid, \( \langle D_{\text{m}} \rangle \)(M–L), were derived and compared with analogous copper(II)–ligand and nickel(II)–ligand.θθ
相似文献
M(II)–amino acid | \( \Updelta_{\text{f}} H_{\text{m}}^{\text{o}} \)(cr)/kJ mol?1 |
---|---|
Bis(glycinate)lead(II), Pb(gly)2 | ?998.9 ± 1.9 |
Bis(dl-alaninate)lead(II), Pb(ala)2 | ?1048.7 ± 1.8 |
Bis(dl-valinate)lead(II), Pb(val)2 | ?1166.3 ± 2.5 |
Bis(dl-valinate)cadmium(II), Cd(val)2 | ?1243.7 ± 2.7 |
Bis(dl-valinate)zinc(II), Zn(val)2 | ?1306.1 ± 2.3 |
9.
Daniela Aiello Luca Malfatti Tongjit Kidchob Rosario Aiello Flaviano Testa Iolinda Aiello Mauro Ghedini Massimo La Deda Tonino Martino Maria Casula Plinio Innocenzi 《Journal of Sol-Gel Science and Technology》2008,47(3):283-289
Highly fluorescent materials have been prepared by incorporation of a zinc complex in mesoporous silica thin films with ordered
pore structure. The zinc complex has been introduced into the mesoporous materials via impregnation in an ethanol solution.
The incorporation into the films has been monitored by UV–Vis, Fourier transform infrared spectroscopy and spectroscopic ellipsometry.
After 18 h of immersion in the doping solution the films showed strong blue emission, increase in the refractive index. Leaching
experiments performed by immersing the samples in ethanol or tetrahydrofuran have shown that the chromophore is retained in
the porous matrix.
相似文献
Plinio InnocenziEmail: |
10.
H. P. Zhang L. C. Yang L. J. Fu Q. Cao D. L. Sun Y. P. Wu R. Holze 《Journal of Solid State Electrochemistry》2009,13(10):1521-1527
Recent progress in studies of several types of core-shell structured electrode materials, including TiO2/C, Si/C, Si/SiO
x
, LiCoO2/C, and LiFePO4/C nanocomposites, including details of their preparation and their electrochemical performance is briefly reviewed. Results
clearly show that the coating shell can effectively prevent the aggregation of the nanosized cores, which are the electrochemically
active materials. In addition, the diffusion coefficients of lithium ions can be increased, and the reversibility of lithium
intercalation and deintercalation is improved. As a result, the cycling behavior is greatly improved. The reviewed results
suggest that core-shell nanocomposites are a good starting point for further development of new promising electrode materials.
相似文献
Y. P. WuEmail: |
R. Holze (Corresponding author)Email: |
11.
The thermodynamic phase behavior and the morphology in thin films of poly(3-hexylthiophene) (P3HT) has been studied using calorimetry, X-ray scattering, and scanning force microscopy (AFM). Around 225 °C a phase transition from the crystalline state to a layered, liquid crystalline structure occurs in regioregular P3HT, while the regiorandom counterpart material is disordered at all temperatures and displays a glass transition temperature Tg–3 °C. Regioregular P3HT is semicrystalline and forms needle or plate like crystallites which in solution cast thin films are oriented with respect to the substrate. Films produced by spin coating display a non-equilibrium structure with reduced order and orientation. Annealing of these films in the liquid crystalline state leads to the formation of a morphology similar to the one observed in solution cast films.
相似文献
T. Thurn-AlbrechtEmail: |
12.
Electrochemical studies of bi- and polymetallic complexes featuring acetylide based bridging ligands
Paul J. Low Rachel L. Roberts Richard L. Cordiner František Hartl 《Journal of Solid State Electrochemistry》2005,9(11):717-731
Acetylide-based bridging ligands have been widely used in the preparation of complexes that display a degree of electronic
interaction between metal-based redox groups located at the ligand termini. The electrochemical response of these systems
has been selectively reviewed, with a focus on the variation in properties that accompany changes in the structure of the
bridging ligand and the nature of the metal groups.
相似文献
Paul J. LowEmail: |
13.
T. N. Drebushchak M. A. Mikhailenko V. A. Drebushchak E. V. Boldyreva 《Structural chemistry》2007,18(4):449-456
The paper summarizes recent results on crystallization and characterization of two polymorphs of the sulfathiazole:pyridine
(1:1) adducts with substantially different space groups (P41 and P21/c) and packing. Intermolecular interactions in the adducts are compared. These two forms were obtained from solutions containing
different ratios of n-propanol, not participating directly in crystallization but obviously controlling the polymorphism, and pyridine. The adducts
are also formed by the contact of pure solid sulfathiazole (different polymorphs) with pyridine vapor. In air, the adducts
decompose giving initially the metastable polymorph I of sulfathiazole, and then the stable sulfathiazole-III.
相似文献
E. V. BoldyrevaEmail: |
14.
The molecular geometries, relative stabilities, binding energies, and dissociation energies of NaDyBr4 and its molecular ion are discussed. Both the bidentate and tridentate isomers are stable for the neutral species, while
only the bidentate form is stable for NaDyBr4
+.
相似文献
Magdolna Hargittai (Corresponding author)Email: |
15.
Katherine A. Willets 《Analytical and bioanalytical chemistry》2009,394(1):85-94
Surface-enhanced Raman scattering (SERS) provides vibrational information about molecules that are located within several
nanometers of the surface of a metallic nanoparticle. This review describes the various challenges and successes of applying
SERS inside living cells in order to gain information about the internal structure and dynamic processes occurring in the
intracellular matrix. In particular, the challenges associated with the introduction of metal nanoparticles into cells are
described, as well as the complexity of interpreting SERS spectra from within complex biological environments. Strategies
for understanding and improving the specificity of SERS in vivo are also presented.
相似文献
Katherine A. WilletsEmail: |
16.
M. V. Evstiferov N. G. Vanifatova O. M. Petrukhin A. I. Kokorin V. A. Reznikov L. B. Volodarskii 《Russian Chemical Bulletin》1989,38(5):921-926
1. | The low-spin Ni(II) ion in the square planar spin-labeled -dioximate NiL2 effectively exchanges spin density between the groups of the ligands. |
2. | Stepwise adduct formation NiL2 NiL2B NiL2B2 in the Ni-HL-toluene-neutral electron-donor compound system is observed and studied. Adduct formation is found to lead to a decrease of the value of the spin exchange integral ¦j¦ as a result of a decrease of the degree of covalency of the Ni bond with the ligand donor atoms in the equatorial plane. |
17.
Attila Sipos Miklós Tóth Franziska K. U. Mueller Jochen Lehmann Sándor Berényi 《Monatshefte für Chemie / Chemical Monthly》2009,140(4):473-478
Abstract The synthesis of 4H-thiochromene derivatives of apomorphines, a novel class of isoquinoline alkaloid-related compounds, has been achieved by
different O-dealkylation methods applied on previously published heteroring-fused aporphinoids. Detailed DFT study has been presented
regarding the mechanism of the L-selectride-mediated multiple O-dealkylation of a seven-ring aporphine analogue. Dopamine-binding tests confirmed the essential function of 11-hydroxy moiety
of the aporphine skeleton and revealed a remarkable D1 over D2 specificity for the derivative having the 4H-thiochromene ring system attached to positions 2 and 3 of the aporphine backbone.
Graphical Abstract
相似文献
Attila SiposEmail: |
18.
Reaction of 3-methoxycarbonyl-2-methyl- or 3-dimethoxyphosphoryl-2-methyl-substituted 4-oxo-4H-chromones 1 with N-methylhydrazine resulted in the formation of isomeric, highly substituted pyrazoles 4 (major products) and 5 (minor products). Intramolecular transesterification of 4 and 5 under basic conditions led, respectively, to tricyclic derivatives 7 and 8. The structures of pyrazoles 4a (dimethyl 2-methyl-4-oxo-4H-chromen-3-yl-phosphonate) and 4b (methyl 4-oxo-2-methyl-4H-chromene-3-carboxylate) were confirmed by X-ray crystallography. Pyrazoles 4a and 4b were used as ligands (L) in the formation of ML2Cl2 complexes with platinum(II) or palladium(II) metal ions (M). Potassium tetrachloroplatinate(II), used as the metal ion reagent, gave both trans-[Pt(4a)2Cl2] and cis-[Pt(4a)2Cl2], complexes with ligand 4a, and only cis-[Pt(4b)2Cl2] isomer with ligand 4b. Palladium complexes were obtained by the reaction of bis(benzonitrile)dichloropalladium(II) with the test ligands. trans-[Pd(4a)2Cl2] and trans-[Pd(4b)2Cl2] were the exclusive products of these reactions. The structures of all the complexes were confirmed by IR, 1H NMR and FAB MS spectral analysis, elemental analysis and Kurnakov tests. 相似文献
19.
The kinetic of the sol–gel hydrolysis and polycondensation reactions of a chiral ORMOSIL precursor was investigated by LCMS
technique as a function of water excess and pH. While the amount of water does not significantly change the kinetics, the
reactions strongly depend on the [H]+ concentration. At pH ≤ 3, the hydrolysis is very fast and the conversion of the precursor is completed within less than 1
h whereas at 80% of the precursor is still present after 50 h at pH = 3.5. This kinetic study allows to define a set of initial
conditions and time ranges required to provide good optical quality dip coated films .
相似文献
L. GuyEmail: |
20.
The molecular structure and vibrational characteristics of monomeric and dimeric tin diiodide, SnI2 and Sn2I4, were determined by high-level computational methods. For the dimer molecule two low-energy geometries were found, one with
C
s and the other with C
2v symmetry, the former with somewhat lower energy; their relative energy is strongly dependent on the computational method.
Thermodynamic functions for both species and their dimerization reaction were calculated based on the computed structures.
相似文献
Magdolna HargittaiEmail: |