The synthesis of mixtures of cyclohexyltoluenes from cyclohexene and toluene, catalyzed by solid-acid catalysts, such as zeolites (H-USY, H-BEA, H-Mor) or activated clays (e.g. Filtrol-24), was studied. The ortho/meta/para ratio of these mixtures strongly depends on the structure of the catalysts involved. With zeolite H-USY and Filtrol-24 as the catalysts the meta/para ratio is found to be about 2:1, in agreement with the thermodynamic equilibrium, and the ortho-isomer is absent. As H-USY appeared to be a good isomerization catalyst for the cyclohexyltoluenes, the mechanism might involve ortho/meta/para-alkylation followed by isomerization. In this way a new route has been developed to the expensive intermediate 3-methylbiphenyl. The reaction of cyclohexene with xylenes or mesitylene, catalyzed by the zeolite H-USY or the clay Filtrol-24, gives mixtures of cyclohexylxylenes or cyclohexylmesitylene, respectively. 相似文献
Structural deoxyribonucleic acid (DNA) nanotechnology offers a robust platform for diverse nanoscale shapes that can be used in various applications. Among a wide variety of DNA assembly strategies, DNA origami is the most robust one in constructing custom nanoshapes and exquisite patterns. In this account, the static structural and functional patterns assembled on DNA origami are reviewed, as well as the reconfigurable assembled architectures regulated through dynamic DNA nanotechnology. The fast progress of dynamic DNA origami nanotechnology facilitates the construction of reconfigurable patterns, which can further be used in many applications such as optical/plasmonic sensors, nanophotonic devices, and nanorobotics for numerous different tasks. 相似文献
The development of high-resolution nanosized photoacoustic contrast agents is an exciting yet challenging technological advance. Herein, antibody (breast cancer-associated antigen 1 (Brcaa1) monoclonal antibody)- and peptide (RGD)-functionalized gold nanoprisms (AuNprs) were used as a combinatorial methodology for in situ photoacoustic imaging, angiography, and localized hyperthermia using orthotopic and subcutaneous murine gastric carcinoma models. RGD-conjugated PEGylated AuNprs are available for tumor angiography, and Brcaa1 monoclonal antibody-conjugated PEGylated AuNprs are used for targeting and for in situ imaging of gastric carcinoma in orthotopic tumor models. In situ photoacoustic imaging allowed for anatomical and functional imaging at the tumor site. In vivo tumor angiography imaging showed enhancement of the photoacoustic signal in a time-dependent manner. Furthermore, photoacoustic imaging demonstrated that tumor vessels were clearly damaged after localized hyperthermia. This is the first proof-of-concept using two AuNprs probes as highly sensitive contrasts and therapeutic agents for in situ tumor detection and inhibition. These smart antibody/peptide AuNprs can be used as an efficient nanotheranostic platform for in vivo tumor detection with high sensitivity, as well as for tumor targeting therapy, which, with a single-dose injection, results in tumor size reduction and increases mice survival after localized hyperthermia treatment.
