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191.
The preparation of an 1,3-alternate calix[4]arene phosphorus ligand, 25,27-bis(2-(diphenylphosphino)ethoxy)-26,28-bis(1-propyloxy)calix[4]arene (3), is presented. Ligand 3 is obtained in three steps in 64% overall yield. Reaction of 3 with [Rh(cot)2]BF4 produced the encapsulated rhodium complex [Rh[(P,P)-diphen-calix[4]arene]]BF4 (4). As revealed by a single-crystal X-ray diffraction study, the rhodium center has a bent coordination environment with a P-Rh-P angle of 135.66(3) degrees. Palladation of 3 employing [Pd(MeCN)4](BF4)2 yielded the chelate palladium complex 7 in which the palladium center has a slightly bent configuration. Treatment of the ligand with Pd(cod)Cl2 and [Pd(eta3-C4H7)(THF)2]BF4 leads to the isolation of the monometallic complex. Full characterization includes X-ray structural studies of compounds 3, 4, and 6. 相似文献
192.
A new isocoumarin, 3-acetyl-3,4-dihydro-5,6-dimethoxy-1H-2-benzopyran-1-one, was isolated from the cortex of Phellodendron chinense schneid. The structure was determined on the basis of spectroscopic evidences. 相似文献
193.
A kind of inorganic‐organic hybrid 18‐molybdodiphosphate nanoparticles ([(C4H9)4N]6P2Mo18Q62·4H2O) was firstly used as a bulk‐modifier to fabricate a three‐dimensional chemically modified carbon paste electrode (CPE) by direct mixing. The electrochemical behavior of the solid nanoparticles dispersed in the CPE in acidic aqueous solution was characterized by cyclic and square‐wave voltammetry. The hybrid 18‐molybdodiphosphate nanoparticles bulk‐modified CPE (MNP‐CPE) displayed a high electrocatalytic activity towards the reduction of nitrite, bromate and hydrogen peroxide. The remarkable advantages of the MNP‐CPE over the traditional polyoxometalates‐modified electrodes are their excellent reproducibility of surface‐renewal and high stability owing to the insolubility of the hybrid 18‐molybdodiphosphate nanoparticles. 相似文献
194.
As a new type of foldamers, oligoindoles containing 4, 6, and 8 indole rings were synthesized, and their folding properties were characterized by a combination of 1H NMR techniques and UV/visible titration experiments. When chloride was added, the NH signals of the oligoindoles were downfield shifted as a result of hydrogen-bond formation, and the aromatic signals were upfield shifted by stacking between two indoles. Moreover, the ROESY experiment provided definitive NOE evidence for the helical stacking in the presence of chloride. Finally, the UV/visible titration experiments demonstrated that the oligoindoles formed 1:1 complexes with chloride, and the association constants greatly increased with increasing the number of the indole NHs. These observations are all consistent with the fact that oligoindoles adopt a helical conformation when complexed with chloride by hydrogen-bonding interactions. 相似文献
195.
Kang HS 《The journal of physical chemistry. A》2005,109(3):478-483
Using density functional theory, we have theoretically studied the formation of neutral lithium-aromatic complexes R-nLi and R-nLi-R, where R is benzene, naphthalene, or pyrene. We first find that the maximum number of lithium atoms n in the complexes increases with the size of R. In addition, pyrene favors the sandwich compound R-4Li-R over R-4Li more than three times that of the corresponding tendency for benzene, strongly suggesting the possible existence of oligomer (R-4Li)x. We have also investigated energetics and band structures of infinite one-dimensional crystals of R-nLi, finding them metallic. Detailed analysis of the electronic structure shows that all these observations are related to the strong electrostatic interaction among the species, which is originated from the charge transfer from Li atoms to the aromatic rings. In addition, it is shown that the pyrene crystal is mechanically stable with respect to deformation. This also suggests the possibility of its existence, which, in turn, holds potential application in lithium storage in respect to its large Li/C ratio. 相似文献
196.
Xu-Chun Wang Jian-Feng Li He-Ping Chen Jie-Ying Wu Hong-Ping Zhou Jia-Xiang Yang Bao-Kang Jin Yu-Peng Tian 《Transition Metal Chemistry》2007,32(5):551-557
The novel compound, 3-(E)-ferrocenyl-vinyl-N-hexylcarbazole (FVHC) was first synthesized and fully characterized by elemental analysis, IR, 1H-NMR, single-crystal X-ray diffraction, ultraviolet (UV) absorption, cyclic voltammograms (CV) and optical limiting (OL)
measurements. The result of single crystal X-ray diffraction for the compound reveals that the ferrocenyl and carbazole groups
are approximately coplanar, and bridged by double-bond with E configuration, showing that there is a well-delocalized π-electron
system in the molecule. The electrochemical investigation indicated that the electron in the FVHC may partially be delocalized
over the π-conjugated system and CT process in functionalized carbazole systems. Besides, the compound exhibited strong UV
absorption and large optical limiting effect, indicating promising potential applications as useful OL materials. 相似文献
197.
Low-temperature synthesis of allyl dimethylamine by selective heating under microwave irradiation used for water treatment 总被引:1,自引:0,他引:1
Low-temperature synthesis of allyl dimethylamine (ADA) by selective heating under microwave irradiation (MI) used for water treatment is investigated. The effect of MI, ultrasound irradiation (UI) and conventional heating on yield of ADA, reaction time and the flocculation efficiency of polydiallyl dimethylammunion chloride (PDADMAC) prepared form ADA were studied. The results show that by selective heating at low temperature, MI not only increases yield of ADA and reduces reaction time, but also greatly enhances the flocculation efficiency of PDADMAC. 相似文献
198.
Photoreaction of 2,3-benzo-1,1-diphenyl(or dimethyl)-1-sila-2-cyclobutene with an aldehyde or ketone results in 1:1 cycloadduct of [4+2] type, the formation of which is accountd for in terms of SH2 process, i.e., attack of a triplet carbonyl compound on the silicon of the benzosilacyclobutene. 相似文献
199.
The hydrothermal reaction of VOSO4, As2O5, piperazine and H2O produces [H2N(CH2)4NH2]4[β‐As8V14O42(SO4)]·2HSO4 ( 1 ), which is the first arsenic‐vanadium cluster containing a spherical β‐As8V14O42 shell. The structure of this compound was characterized by single crystal X‐ray diffraction, elemental analysis, TG, and IR spectrum. Crystal data for 1 : Orthorhombic, Cmcm, a = 15.369(1) Å, b = 16.404(1) Å, c = 25.772(1) Å, V = 6497.4(9) Å3, Z = 4. 相似文献
200.
Xiu‐Li Dong Zheng‐Yu Zhou Lai‐Jin Tian Gang Zhao 《International journal of quantum chemistry》2005,102(4):461-469
The hydrogen bonding complexes HO(H2O)n (n = 1–3) were completely investigated in the present study using DFT and MP2 methods at varied basis set levels from 6‐31++G(d,p) to 6‐311++G(2d,2p). For n = 1 two, for n = 2 two, and for n = 3 five reasonable geometries are considered. The optimized geometric parameters and interaction energies for various complexes at different levels are estimated. The infrared spectrum frequencies and IR intensities of the most stable structures are reported. Finally, thermochemistry studies are also carried out. The results indicate that the formation and the number of hydrogen bonding have played an important role in the structures and relative stabilities of different complexes. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2005 相似文献