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191.
Treatment of tetrakis(trimethylsilyl)butatriene (2) with lithium in tetrahydrofuran (THF) led to quantitative formation of the corresponding dianion species. Yellow crystals of the dilithium salts of 2 were isolated as an unexpected dimeric structure (4) as well as a monomeric structure (3). Both of the crystal structures, which havebeen confirmed by X-ray diffraction, reveal a doubly bridged lithium bisallylic structure. The unique dynamic behaviour of the lithium ions of the dimer 4 in toluene-d8 is demonstrated. 相似文献
192.
Takei I Nishibayashi Y Ishii Y Mizobe Y Uemura S Hidai M 《Chemical communications (Cambridge, England)》2001,(22):2360-2361
Chiral ruthenium(II) complexes, RuCl2(PPh3)(oxazolinylferrocenylphosphine), have been found to be effective catalysts for asymmetric hydrosilylation of ketoximes to give the corresponding primary amines in good yields with high enantioselectivities (up to 89% ee) after acid hydrolysis. 相似文献
193.
Takayuki Shiohama Masanobu Taniguchi 《Annals of the Institute of Statistical Mathematics》2001,53(1):142-158
Integral functional of the spectral density of stationary process is an important index in time series analysis. In this paper we consider the problem of sequential point and fixed-width confidence interval estimation of an integral functional of the spectral density for Gaussian stationary process. The proposed sequential point estimator is based on the integral functional replaced by the periodogram in place of the spectral density. Then it is shown to be asymptotically risk efficient as the cost per observation tends to zero. Next we provide a sequential interval estimator, which is asymptotically efficient as the width of the interval tends to zero. Finally some numerical studies will be given. 相似文献
194.
Gakuse Hoshina Masanobu Tsuchimoto Shigeru Ohba 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(5):e190-e190
The title mononuclear oxovanadium(IV) complex, [VO(C36H38N2O2)], has a distorted square‐pyramidal coordination. The complex was shown to be the exo isomer. 相似文献
195.
Gakuse Hoshina Masanobu Tsuchimoto Shigeru Ohba 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(4):e122-e122
In crystals of the title compound, [Ni(C28H22N2O2)], the coordination geometry around the Ni atom is square planar with a slight tetrahedral distortion. The five‐membered N,N′‐chelate ring adopts a distorted gauche conformation with the two phenyl groups in axial and equatorial orientations. 相似文献
196.
Masanobu Mizusaki 《Liquid crystals》2013,40(8):1167-1174
Two series of asymmetric banana-shaped compounds have been synthesized and studied. In the 1,3-phenylene bis[4-(4′-alkoxybenzoyloxy)]benzoate series the lack of symmetry was derived solely from the difference in length of the two terminal alkoxy chains. In the 3,4′-biphenylene bis[4-(4′-alkoxybenzoyloxy)]benzoate series the asymmetric nature originates from the 3,4′-substitution of the central biphenyl group and from the difference in length of the two terminal chains. All the melting points of the asymmetrical compounds in the series with the central phenyl unit are lower than those of the symmetrical compounds. The liquid crystalline B1 or B2 phase was retained in all cases. In the series with the central biphenyl unit the compounds with the shortest chain attached to the para-position of the central biphenyl unit have the lowest melting points. A significant lowering of the melting points in comparison with the symmetrically substituted compounds, however, could not be achieved. All the compounds of both series show a layer spacing which is comparable to those of the symmetrically substituted parent compounds. The observed switching behaviour of both the symmetric and asymmetric compounds with a B2 phase was antiferroelectric. 相似文献
197.
As new and chiral macrocyclophanes with unique structures, variously sized Pn and Mn (n=2–7=number of ‘rod’ segments) with D2–D7 symmetry were constructed by alternating connection of axially chiral binaphthyls and linear biphenyls via –CH2O– moieties, so that the macrocycle consists of multiple rod-like naphthalene–biphenyl–naphthalene units linked together at the binaphthyl bonds. The dihedral angle of the two naphthalene rings of binaphthyl is restricted to around 90°, and the calculated values of strain energy difference per naphthalene–biphenyl unit in P2–P7 are almost independent of the macrocycle size, presumably owing to the flexibility of the –CH2O– connectors. 相似文献
198.
199.
We used an asymmetric layered system functioning as a plasmon waveguide coupler to couple surface plasmon modes with gap plasmon
modes. The planar system was analyzed by the transfer matrix method to design the optical dimensions of the system. We simulated
the effective mode indexes and H-field distribution of the coupled modes, for different gap widths and refractive indexes. For the calculated modes the propagation
lengths were calculated. Furthermore, a sample structure was fabricated and odd gap plasmon modes were excited with a coupling
prism in an attenuated-total-reflection (ATR) configuration. The mode index measurement showed good agreement with the simulation
data. 相似文献
200.
Yue Wang Koki Ogasahara Daisuke Tomihama Radomir Mysliborski Masatoshi Ishida Yongseok Hong Yusuke Notsuka Yoshihisa Yamaoka Tomotaka Murayama Atsuya Muranaka Masanobu Uchiyama Shigeki Mori Yuhsuke Yasutake Susumu Fukatsu Dongho Kim Hiroyuki Furuta 《Angewandte Chemie (International ed. in English)》2020,59(37):16161-16166
The synthesis of organometallic complexes of modified 26π‐conjugated hexaphyrins with absorption and emission capabilities in the third near‐infrared region (NIR‐III) is described. Symmetry alteration of the frontier molecular orbitals (MOs) of bis‐PdII and bis‐PtII complexes of hexaphyrin via N‐confusion modification led to substantial metal dπ–pπ interactions. This MO mixing, in turn, resulted in a significantly narrower HOMO–LUMO energy gap. A remarkable long‐wavelength shift of the lowest S0→S1 absorption beyond 1700 nm was achieved with the bis‐PtII complex, t ‐Pt2‐3 . The emergence of photoacoustic (PA) signals maximized at 1700 nm makes t ‐Pt2‐3 potentially useful as a NIR‐III PA contrast agent. The rigid bis‐PdII complexes, t ‐Pd2‐3 and c ‐Pd2‐3 , are rare examples of NIR emitters beyond 1500 nm. The current study provides new insight into the design of stable, expanded porphyrinic dyes possessing NIR‐III‐emissive and photoacoustic‐response capabilities. 相似文献