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991.
Formation of ternary complexes between a macrotricyclic host and hetero-guest pairs: an acid-base controlled selective complexation process 总被引:1,自引:0,他引:1
A triptycene-based cylindrical macrotricyclic host can include diquat and electron-rich aromatics simultaneously to form stable ternary complexes, which is stabilized not only by a charge-transfer (CT) interaction between electron-rich and electron-deficient guests but also by the face to face pi-stacking interactions between the host and the guests. Moreover, a selective complexation process between a ternary complex containing benzidine and a binary complex can be effectively controlled by the use of acid and base. 相似文献
992.
Ying Liu Ying‐Hui Yu Yi‐Fu Liu Guang‐Feng Hou Xiao‐Dan Wang Bo Wen Jin‐Sheng Gao 《无机化学与普通化学杂志》2013,639(1):193-196
The cage‐like complex, Ag4L4(NO3)4 ( 1 ) [L = 1, 4‐bis(pyridine‐2‐ylmethoxy)benzene] was synthesized by the reaction of the flexible bidentate ligand and silver nitrate. It was characterized by elemental analysis, IR spectroscopy, TG, and single‐crystal X‐ray analysis. Complex 1 is reported as the first cage‐like cluster constructed by four nitrate anions bridging two [2+2] macrocycles. A blue luminescent emission and luminescent enhancement effect are observed in complex 1 . 相似文献
993.
The results of dielectric studies performed in a broad frequency range for two compounds, 4-cyanophenyl 4-n-heptylbenzoate (7BBCN) and 4-(4-cyanobutyloxy)phenyl 4- n-heptylbenzoate (7BB4CN), are compared. They have the same molecular core whereas the strongly polar CN group is attached to the benzene ring in 7BBCN or is separated from it by the butyloxy chain in 7BB4CN. 7BBCN has a nematic phase, whereas 7BB4CN exhibits a monotropic nematic and smectic A2 polymorphism. Large differences in the dielectric properties of the two substances were found. The analysis of the results led to the conclusion that the antiparallel dipole-dipole associations are considerably stronger in the substance with a decoupled CN group. 相似文献
994.
995.
996.
Zengxia Zhao Yuning Han Chenghong Lin Dong Hu Fang Wang Prof. Xiaolan Chen Prof. Zhong Chen Prof. Nanfeng Zheng 《化学:亚洲杂志》2012,7(4):830-837
Lanthanide‐doped upconversion nanoparticles (UCNPs) have attracted considerable attention for their application in biomedicine. Here, silica‐coated NaGdF4:Yb,Er/NaGdF4 nanoparticles with a tetrasubstituted carboxy aluminum phthalocyanine (AlC4Pc) photosensitizer covalently incorporated inside the silica shells were prepared and applied in the photodynamic therapy (PDT) and magnetic resonance imaging (MRI) of cancer cells. These UCNP@SiO2(AlC4Pc) nanoparticles were uniform in size, stable against photosensitizer leaching, and highly efficient in photogenerating cytotoxic singlet oxygen under near‐infrared (NIR) light. In vitro studies indicated that these nanoparticles could effectively kill cancer cells upon NIR irradiation. Moreover, the nanoparticles also demonstrated good MR contrast, both in aqueous solution and inside cells. This is the first time that NaGdF4:Yb,Er/NaGdF4 upconversion‐nanocrystal‐based multifunctional nanomaterials have been synthesized and applied in PDT. Our results show that these multifunctional nanoparticles are very promising for applications in versatile imaging diagnosis and as a therapy tool in biomedical engineering. 相似文献
997.
Hongfang Yang Dr. Li Han Jing Zhao Prof. Dr. Xinyu Song Prof. Dr. Qisheng Song Prof. Dr. Yuxiang Bu 《Chemphyschem》2012,13(18):4148-4154
Graphene oxide has attracted intense research interest recently because the graphene oxide synthesis route, as a promising alternative for cost‐effective mass production of graphene, has been explored. To further study the oxidation process and possible mechanism and to explore applicability of the oxidized products, we have performed a computational study on three series of oligoacene dioxides, focusing on their structures and electronic properties. Taking 1,5‐dioxidized naphthalene as a starting point, three series of oligoacene dioxides are considered as follows: 1) middle insertion by 1–2 benzene rings; 2) single‐side expansion using 1–2 benzene rings; 3) double‐side expansion using two benzene rings. On the basis of density functional theory and complete active space self‐consistent field (CASSCF) calculations, we reveal that oligoacene dioxides in the middle insertion series have a triplet ground state, whereas those in the single‐side expansion series and the double‐side expansion series have open‐shell broken‐symmetry singlet diradical ground states except for their common origin naphthalene‐1,5‐dioxide whose ground state is triplet and which is also viewed as the origin of the middle insertion series. Magnetic coupling interactions of these oligoacene dioxides are also determined. This work should help people toward an atomistic understanding of the electronic structures and properties of possible intermediates or products and even the oxidation mechanism of graphene sheets, and provides a reasonable strategy of designing novel graphene‐oxide‐based magnetic materials. 相似文献
998.
Prof. Dr. Han Myoung Lee Prof. Dr. Kwang S. Kim 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(41):13203-13207
Since gold clusters have mostly been studied theoretically by using DFT calculations, more accurate studies are of importance. Thus, small neutral and anionic gold clusters (Aun and Aun?, n=4–7) were investigated by means of coupled cluster with singles, doubles, and perturbative triple excitations [CCSD(T)] calculations with large basis sets, and some differences between DFT and CCSD(T) results are discussed. Interesting isomeric structures that have dangling atoms were obtained. Structures having dangling atoms appear to be stable up to n=4 for neutral gold clusters and up to n=7 for anionic clusters. The relative stabilities and electronic properties of some isomers and major structures are discussed on the basis of the CCSD(T) calculations. This accurate structure prediction of small gold clusters corresponding to experimental photoelectron spectral peaks is valuable in the field of atom‐scale materials science including nanocatalysts. 相似文献
999.
Weizhun Yang Jiansong Sun Zhongyi Yang Wei Han Wei-Dong Zhang Biao Yu 《Tetrahedron letters》2012,53(22):2773-2776
Selective glycosylation of the 3-OH of 5,4′-di-O-acetyl-kaempferol was achieved with glycosyl ortho-alkynylbenzoates as donors under the catalysis of Ph3PAuNTf2, and subsequent glycosylation of the remaining 7-OH with glycosyl trifluoroacetimidates under the catalysis of BF3·OEt2, after global deprotection, afforded the kaempferol 3,7-O-bisglycosides conveniently. 相似文献
1000.
Huiqing Yin Ming Jin Wei Chen Chen Chen Likang Zheng Ping Wei Shiqing Han 《Tetrahedron letters》2012,53(10):1265-1270
A simple and mild method for the coupling of aryl halides with amino alcohols and diamines is described. The reactions can be performed under ligand-free and solvent-free conditions, and generate the products in good yield. 相似文献