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排序方式: 共有397条查询结果,搜索用时 15 毫秒
91.
Gu H Ng Z Deivaraj TC Su X Loh KP 《Langmuir : the ACS journal of surfaces and colloids》2006,22(8):3929-3935
Electrochemistry and electrochemical surface plasmon resonance (SPR) spectroscopy have been applied to study the electrochemical deposition and the redox transition of poly(4-nitro-1,2-phenylenediamine) (P4NoPD) on gold disk. It was shown that SPR can be the signal transducer for the different redox states of P4NoPD. Using a model biomolecular system, involving streptavidin, biotinylated DNA, and its complementary target DNA, it was found that the presence of nitro groups in P4NoPD allows the biorecognition events to be modulated by voltages. There is minimal nonspecific binding of biomolecules on oxidized (+0.2 V) or as-prepared P4NoPD, and binding occurs more significantly on the reduced P4NoPD (-0.2 to -0.6 V) with the presence of amine groups. The electrochemical deposition of P4NoPD film was also conducted on boron-doped diamond (BDD) electrode. The stability of the reduced P4NoPD film on gold and BDD was comparatively evaluated by electrochemical impedance spectroscopy (EIS). The result showed that BDD allows the electrochemical reduction of the P4NoPD film at wider cathodic limits than gold. 相似文献
92.
Chen W Wang L Huang C Lin TT Gao XY Loh KP Chen ZK Wee AT 《Journal of the American Chemical Society》2006,128(3):935-939
Electron transfer at the molecule-metal interface of self-assembled monolayers of 1,1';4',1'-terphenyl-4'-thiol (BBB) and its partially fluorinated counterpart (BFF: p-thiophenyl-nonafluorobiphenyl) on Au(111) is investigated by core-hole clock spectroscopy. Ultrafast electron transfer at the BBB/Au(111) interface in the low-femtosecond regime (on the same time scale as the C 1s core-hole lifetime, approximately 6 fs) was observed. In contrast, for BFF/Au(111), the interface electron transfer was forbidden during the core-hole decay. This strongly suggests that fluorination of phenyl rings significantly enhances the localization of the excited electrons in the LUMO. 相似文献
93.
94.
Loh E 《Physical review letters》1985,55(22):2371-2374
95.
96.
The asymmetric synthesis of tetrahydropyridin-2-ols from enals and enaminones is described. The organocatalytic domino reaction involves a Michael addition-hemiaminalization sequence using the J?rgensen-Hayashi catalyst. Dehydration or oxidation leads to the corresponding 1,4-dihydro-pyridines or 3,4-dihydropyridin-2-ones in a one-pot fashion. 相似文献
97.
Dr. Hai-Sen Xu Dr. Yi Luo Pei Zhen See Dr. Xing Li Dr. Zhongxin Chen Yi Zhou Dr. Xiaoxu Zhao Dr. Kai Leng Dr. In-Hyeok Park Dr. Runlai Li Dr. Cuibo Liu Fangzheng Chen Dr. Shibo Xi Prof. Junliang Sun Prof. Kian Ping Loh 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(28):11624-11629
The marriage of dynamic covalent chemistry (DCC) and coordination chemistry is a powerful tool for assembling complex architectures from simple building units. Recently, the synthesis of woven covalent organic frameworks (COFs) with topologically fascinating structures has been achieved using this approach. However, the scope is highly limited and there is a need to discover new pathways that can assemble covalently linked organic threads into crystalline frameworks. Herein, we have identified branching pathways leading to the assembly of three-dimensional (3D) woven COFs or one-dimensional (1D) metallo-COFs (mCOFs), where the mechanism is underpinned by the absence or presence of ligand exchange. 相似文献
98.
A chiral indium complex has been discovered to effect high enantioselectivities in the addition of allyltributyl stannanes to aldehydes. The allylation of a variety of aromatic, alpha,beta-unsaturated and aliphatic aldehydes resulted in good yields and high enantioselectivities (90-96% ee). 相似文献
99.
[reaction: see text] A chiral indium complex has been developed to effect high enantioselectivities in catalyzing enantioselective Diels-Alder reaction. The cycloaddition of a variety of cyclic and open-chained dienes to 2-methacrolein and 2-bromoacrolein resulted in good yields and excellent enantioselectivities (up to 98% ee). 相似文献
100.
The formal synthesis of (+)-SCH 351448 has been accomplished with the catalytic Prins cyclization strategy, yielding the monomeric unit as a single isomer. 相似文献