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121.
Keane JM Chordia MD Mocella CJ Sabat M Trindle CO Harman WD 《Journal of the American Chemical Society》2004,126(21):6806-6815
A series of metal complexes was synthesized in which arenes were dihapto-coordinated to pi-basic metal fragments having the general form [TpM(pi-acid)(L)], where Tp = hydridotris(pyrazolyl)borate, M = rhenium, molybdenum, or tungsten, pi-acid = CO or NO(+), and L = 1-methylimidazole, 1-butylimidazole, pyridine, or trimethylphosphine. The arene complexes were shown to be significantly more basic than the analogous pentaammineosmium(II) arene complexes and were protonated by moderate acids to give remarkably stable eta(2) and eta(3) arenium cation complexes. A crystal structure of [TpRe(CO)(MeIm)(5,6-eta(2)-2H-anisolium)](OTf) confirmed the eta(2) coordination of the anisolium ligand, but suggests a weak long-range interaction between the metal and C1 of the anisolium. 相似文献
122.
123.
Wiecko M Girnt D Rastätter M Panda TK Roesky PW 《Dalton transactions (Cambridge, England : 2003)》2005,(12):2147-2150
The chiral phosphanylamido ligand, (N(CHMePh)(PPh2))-, has been introduced into co-ordination chemistry. As starting material the oily amines HN(R-*CHMePh)(PPh2)(1a) and HN(S-*CHMePh)(PPh2)(1b) were used. To reconfirm their absolute structure, 1b was oxidized with H2O2 in air to obtain HN(S-*CHMePh)(P(O)Ph2)(2) as a solid compound. The solid-state structure of 2 was established by single-crystal X-ray diffraction. The lithium salts of both enantiomers Li(N(R-*CHMePh)(PPh2))(3a) and Li(N(S-*CHMePh)(PPh2))(3b) were prepared by deprotonation reaction of 1a,b. Compounds 3a,b were further reacted with zirconocen dichloride to give the chiral metallocenes [(eta5-C5H5)2Zr(Cl)(eta2-N(R-*CHMePh)(PPh2))](4a) and [(eta5-C5H5)2Zr(Cl)(eta2-N(S-*CHMePh)(PPh2))](4b). In an alternative approach to give chiral zirconium compounds, the neutral amine 1b was reacted with [(PhCH2)4Zr] to give the enantiomeric pure complex [(PhCH2)3Zr(eta2-N(S-*CHMePh)(PPh2))](5). The solid-state structures of all zirconium complexes were determined by single-crystal X-ray diffraction. 相似文献
124.
The dispersion interaction between two pointlike particles confined in a dielectric slab between two plates of another dielectric medium is studied within a continuum (Lifshitz) theory. The retarded (Casimir-Polder) interaction at large interparticle distances is found to be strongly enhanced as the mismatch between the dielectric permittivities of the two media is increased. The large-distance interaction is multiplied due to confinement by a factor of (33gamma(5/2) + 13gamma(-3/2))/46 at zero temperature, and by (5gamma2 + gamma(-2))/6 at finite temperature, gamma = epsilon(in)(0)/epsilon(out)(0) being the ratio between the static dielectric permittivities of the inner and outer media. This confinement-induced amplification of the dispersion interaction can reach several orders of magnitude. 相似文献
125.
We experimentally demonstrate ultrafast all-optical modulation using a micrometer-sized silicon photonic integrated device. The device transmission is strongly modulated by photoexcited carriers generated by low-energy pump pulses. A p-i-n junction is integrated on the structure to permit control of the generated carrier lifetimes. When the junction is reverse biased, carriers are extracted from the device in a time as short as 50 ps, permitting greater than 5 Gbit/s modulation of optical signals on a silicon chip. 相似文献
126.
Karásek P Planeta J Varad'ová Ostrá E Mikesová M Goliás J Roth M Vejrosta J 《Journal of chromatography. A》2003,1002(1-2):13-23
Direct supercritical fluid extraction (SFE) of wines with carbon dioxide was compared to SFE of the sorbent used for solid-phase extraction of the same wine samples (SPE-SFE). Compared to SPE-SFE, the direct SFE results in amore specific and representative gas chromatographic fingerprint of the wine sample. The multivariate statistical processing of the direct SFE-GC data provides a clear-cut and sharp discrimination among the individual wine varieties while the discrimination based on the SPE-SFE-GC data is relatively poor. This finding reflects the adverse effects of additional analyte-sorbent interactions and sorption/desorption steps involved in SPE-SFE. 相似文献
127.
Yuval Peres Michal Rams Ká roly Simon Boris Solomyak 《Proceedings of the American Mathematical Society》2001,129(9):2689-2699
A compact set is self-conformal if it is a finite union of its images by conformal contractions. It is well known that if the conformal contractions satisfy the ``open set condition' (OSC), then has positive -dimensional Hausdorff measure, where is the solution of Bowen's pressure equation. We prove that the OSC, the strong OSC, and positivity of the -dimensional Hausdorff measure are equivalent for conformal contractions; this answers a question of R. D. Mauldin. In the self-similar case, when the contractions are linear, this equivalence was proved by Schief (1994), who used a result of Bandt and Graf (1992), but the proofs in these papers do not extend to the nonlinear setting.
128.
Thin narrow Au stripes suitable for propagating long-range surface plasmon-polaritons were deposited by evaporation and lift-off on a thermal oxide layer on a silicon substrate, and modified by direct adsorption of bovine serum albumin (BSA). Atomic force microscopy (AFM) measurements reveal that BSA adsorbs onto the Au stripes from phosphate buffer solutions forming an adlayer having an average thickness of about 2 nm (surface mass density of about 2 ng/mm2). Comparisons with a simple adsorption model suggest the side-on adsorption of a single monolayer of BSA followed by denaturation and flattening. The BSA-coated stripes have an increased surface roughness compared to a virgin stripe. 相似文献
129.
130.
Tomasz Goslinski Zbigniew Dutkiewicz Michal Kryjewski Ewa Tykarska Lukasz Sobotta Wojciech Szczolko Maria Gdaniec Jadwiga Mielcarek 《Monatshefte für Chemie / Chemical Monthly》2011,13(1):599-608