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71.
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In this text, we use inexpensive and natural amino acid, successfully obtained the asymmetric crystallization of three PTCs, [Tis(O~iPr)_(14)(μ_2-O)(μ_3-O)_2(D/L-pGlu)_2](D-PTC-53; L-PTC-53; H2 pGlu=pyroglutamic acid) and [Ti_6(O~iPr)_(14)(μ_2-O)(μ_3-O)_2(D-pGlu)_2][Ti_6(O~iPr)_(14)((μ_2-O)(μ_3-O)_2(L-pGlu)_2](D,L-PTC-53). Interestingly, in situ lactamide reaction starting from glutamic acid to pyroglutamic acid was observed. In addition,the chirality features of these PTCs have been thoroughly discussed.The two enantiomers crys tallize in chiral P21 space group.The optically pure pGlu ligands transform its chirality to the inorganic titanium oxo clusters. As a result, the stack of these inorganic clusters generates homochiral helical chains along the characteristic axial direction.Apart from the microscopic structural analysis, the macroscopic solid-state samples exhibit unusual strong circular dichroism(CD) signals,further verified the homochiral feature of the enantiomers. 相似文献
74.
75.
X. Zhou Y. Guo X. Sun X. Lei X. Chen Z. Liu Y. Zhang H. Jin Y. Luo S. X. Wen G. J. Yuan G. S. Li C. X. Yang 《Zeitschrift für Physik A Hadrons and Nuclei》1995,351(1):3-4
The high spin states of119Te, populated in110Pd(13C,4n) and110Pd(12C,3n) reactions, have been studied through -ray spectroscopy. The level scheme has been established upto a spin of 55/2. Three-quasiparticle states, based on g2
7/2h11/2 and g7/2d5/2h11/2 configurations, have been identified. The 35/2 and 39/2 states are suggested to be the fully aligned states constituted by five valence h11/2
3, g7/2, d5/2 quasiparticles. 相似文献
76.
77.
Gong WT Li XC Ning GL Zhu L Wang L Lin Y 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2005,62(4-5):835-839
Two novel phenylated pyrylium compounds, silver (I)-bridged 2,3,4,5-tetraphenylpyrylium perchlorate (P1) and its silver (I)-free pyrylium ligand (P2) were prepared from 1,2,3,4-tetraphenylcyclopentadiene to examine their spectroscopic behaviors. The UV/vis absorption and fluorescent emission spectra of P1 and P2, measured in three solvents (acetonitrile, dichloromethane and toluene), reveal that the photophysical behaviors are closely related to silver (I) fragment, and strongly dependent on solvent polarity. In polar acetonitrile, P1 displays longer absorption wavelength and much lower fluorescent emission intensity than P2, although they exhibit much similarity in shape. In contrast, in nonpolar toluene, while P2 shows an apparent absorption band at 338 nm, P1 displays a tail-like line without absorption band observed. All the spectra obtained indicate a better coplanarity and a stronger intra-molecular charge transfer in P1 due to the effect of silver (I) fragment. Additionally, the 1H NMR spectra of P1 and P2, which were recorded under the same conditions, indicate that the silver (I) fragment reinforces pyrylium ring's capacity to localize the formal positive charge within the heterocyclic ring. 相似文献
78.
An amphiphilic tetrathiafulvalene molecule can gelate a variety of organic solvents in view of multiple intermolecular interactions, especially in polar solvent with the formation of highly-ordered columnar structures. The formation of mixed-valence states shows the semiconductive behaviors with the conductivity of 10-4 S/cm, as promising candidates for organic electronics. 相似文献
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An all-atom dimethyl sulfoxide (DMSO) model and a TIP5P water model have been adopted for molecular dynamics simulation. Two new qualities ηrelE and ηrel are introduced to describe the anomalous nonideal behaviors of DMSO–water mixtures. The simulation is compared with chemical shift and excess enthalpy of mixing, which shows good concentration dependences. In addition, our all-atom simulation also indicates that the C–H groups of DMSO may interact with the oxygen atoms of water and DMSO. The weak C–HO contacts and the strong O–HO hydrogen bonds represent the consistent concentration dependences, which exhibits the cooperation effect. 相似文献